If you happen to be around the Four Corners area on October 14, make sure to have your solar-eclipse glasses with you, and you’ll be able to tell your friends that you saw an eclipse from four different states!
An annular solar eclipse will grace our skies that morning, with the full eclipse beginning around 9:30 MST and lasting for just under five minutes. People will be enjoying this path of totality along a swath of the US stretching from the Oregon coast to South Texas.
An annular eclipse is a type of solar eclipse, where the moon is directly between the Earth and Sun. With a total solar eclipse the moon completely covers the sun’s disk, but with an annular eclipse it covers the center, leaving a slim ring of sunlight visible around it. This halo is the annulus, from the Latin anulus (‘finger ring’), which in mathematics is defined as the area between two concentric circles.
We have both total and annular eclipses because of the non-circular nature of the moon’s orbit. While we may think of them as neat circles, the orbital paths that objects in space usually follow are ellipses. At one point in its elliptical orbit, called the perigee, the moon is closest to us and we experience “supermoons,” as we saw in August (twice!). At the opposite point, the apogee, it’s as far away as it gets. So when the moon is at apogee during a solar eclipse, its apparent diameter is not enough to fully cover the sun, giving us a “ring-of-fire” eclipse that’s quite the sight to behold.
Whether total or annular, solar eclipses happen about twice each year, though with more than 70% of the planet’s surface covered by water they’re not always conveniently visible. In addition, the earth’s rotation can put a viewable eclipse path on any continent, making the few we can see locally unique events.
The path of this month’s annular eclipse will be only around 120 miles wide as it tracks across the western US, down Central America and across Colombia and Brazil, but viewers hundreds of miles away from the path of totality will still experience a partial eclipse. Here in central Yavapai County we’ll see approximately 82% coverage of the sun’s face that morning.
Enjoy, and again, be safe, don’t forget your solar glasses!
From double full supermoons to ringed giants at opposition, August was full of local events within our solar system, where September takes us back to some amazing deep-sky objects.
Many of the best clusters and nebulae lie along the galactic plane, easily identifiable in the sky as the Milky Way. While we can technically define the Milky Way as everything around us, the vast swath painted across the night sky represents the edge-on view of much of our galaxy, given Earth’s position somewhat centrally located on what we call the Orion Arm of our barred spiral galaxy. Being in the middle of all the action, looking toward this denser region of stars offers the casual viewer opportunities to pick out many more “faint fuzzies.”
The constellation Sagittarius borders the western edge of the Milky Way, pointing his bow and arrow into this hotbed of stellar activity. Hundreds of stars inhabit this constellation, with 17 making up the primary outline of the centaur archer. More easily identifiable are the eight primary stars that make up the “Teapot” asterism, which defines the torso and bow of the Archer. Within or abutting the Teapot are five globular clusters, catalogued by Charles Messier as M22, M28, M54, M69 and M70. Each of these clusters of stars is only a few light years across, yet all are packed with thousands or even millions of stars orbiting the galactic center together. To the naked eye these may seem like a single star, then binoculars will show the observer a fuzzy cottonball-like image, and larger telescopes begin to resolve many of the individual members of these heavenly neighborhoods. Use your binoculars or a wide-angle eyepiece on your telescope to scan the Teapot and see how many star clusters you can find.
The stellar life cycle may begin or end with a large cloud of gas and dust, either coalescing over millions of years into stars and planets, or inversely created when a star runs out of fuel and collapses in on itself, exploding in one of the universe’s greatest displays of light and energy. These clouds are known as nebulae, Latin for ‘mists’ or ‘fogs.’ As you study the Teapot and Milky Way, areas of light and dark gas will highlight against the dark backdrop of space. The Lagoon Nebula is visible to the naked eye in the darkest skies, a perfect starting point for the amateur astronomer. As an emission nebula it has a pinkish hue, created by the ionized particles coming off nearby stars. Separately, the Trifid Nebula is a combination emission and reflection nebula, appearing both pink and blue as you scan the region. Also containing an open star cluster, the Trifid Nebula is a late-summer favorite among many astronomers.
So remember to look to the south for the teapot pouring out the milk, and you will be locked on to some of the greatest views in the northern-hemisphere summer.
August hosts a plethora of lunar and planetary events, perfect for the backyard astronomer. Even the most basic binoculars or telescope will allow you to enjoy our celestial neighbors as they put on quite the display this month.
August 1 starts off the month with a full supermoon, the second one this year. This event occurs when the moon appears slightly larger in the sky due to its proximity to us in its elliptical orbit. While there is no strict definition of a supermoon, it is commonly accepted that the moon be within 90% of perigee, its closest approach to us. By contrast, the farthest part of an elliptical orbit is called the apogee, and the moon’s distance can vary from about 405,500km to as close as 363,400km (about 252,000-225,000 miles). This full moon was also known in the Great-Lakes region as the Sturgeon Moon for its correlation with the preferred fishing season.
On August 10 Mercury will be at greatest Eastern elongation from the sun, meaning it is as high in the evening sky as we can see it, before it begins to move back around the sun. “Eastern elongation” may seem like a misnomer, referencing where the planets are in relation to each other, because to see it you will look to the western horizon just after sunset. This is the best day of the year to catch a glimpse of the elusive owl whom the Maya regarded as a messenger to the underworld.
In the early hours between August 12 and 13 the Earth will pass through the tail of comet Swift-Tuttle. Having last visited the inner solar system in 1992, and not returning till 2126, the debris cloud of dust and ice particles gives us the annual Perseid meteor shower, with excellent viewing this year because the moon will only be a crescent. Enjoy this show after midnight, when you may catch upward of 60 meteors per hour.
On August 24 the moon will eclipse the bright red head of Scorpius. This rare event will see the occultation of Antares, disappearing behind the moon at 6:55pm and reappearing an hour later, at 7:55.
Saturn puts on a show on August 27, at what we call opposition. Saturn will be closest to Earth on this night, and fully illuminated by the sun directly opposite. Moving through the constellation Aquarius in the southern sky, a medium-sized telescope will allow you to see the rings and maybe even its moon Titan.
Wrapping up the month, the evening of August 31 brings the month’s second supermoon. When two full moons occur in the same calendar month, we call the second one a blue moon. This moon won’t really appear blue, but it is relatively rare to have both full moons in a single month be supermoons.
One of my personal favorite constellations is Scorpius. It’s very easy to identify in the summer months when it rises in the southeast and sways above the Bradshaw Mountains like the traditional scorpion promenade à deux pairing dance.
The red supergiant Antares defines the head of the scorpion and is often confused with Mars for its brightness and somewhat ochre coloration. Just one degree westward of Antares is the globular cluster Messier 4 (M4), the first cluster to have individual stars resolved by astronomers in the mid-1700s. Today backyard astronomers can easily locate this cluster with a decent pair of binoculars or a small telescope.
While the head of the scorpion is dominated by Antares and the five stars making up its head and claws, its tail rises above the mountaintops a little later in the evening, defined by the large hook at its tip. The Hawaiian culture saw these stars as the fishhook of the demigod Maui, calling it Ka Makau Nui o Māui, ‘The Big Fishhook of Maui.’
Here in northern Arizona we certainly have scorpions and will use a fishhook for landing a trout, but the Dineh culture sees something different in these stars. The last four stars in the tail are strikingly similar to tracks left by a running rabbit, so it’s known as Gah Haat’e’ii (‘rabbit tracks’). Each year the return of the rabbit tracks signify to Navajo hunters that hunting season is over.
The time this constellation is visible in the night sky is when deer, elk, and other large game have given birth, and their newborns are still reliant on their mothers for sustenance. When Rabbit Tracks moves to the east and is no longer upright in the sky, the young are then old enough to care for themselves, and hunting season resumes.
Due to its placement along the main swath of the Milky Way, Scorpius contains many other deep-sky objects, including double stars, nebulae and both open and globular clusters. Enjoy the beautiful summer nights of northern Arizona and get your telescope out to look at this amazing patch of sky!
Spring brings with it the pollinators that make our world possible, and the Beehive Cluster shines prominent in the sky this month. You may be able to spot these industrious little lights ‘buzzing’ around Mars on the night of June 2, when the Red Planet will be centrally located in this open cluster.
As one of the most clearly crimson objects in the night sky, Mars is easy to spot and should help you locate the Beehive Cluster above the southwestern horizon just after dusk. On many nights, and from dark skies, it’s easy to locate with the naked eye, as astronomers and observers have done for millennia.
A handful of these stars have always been visible to the eye, but when Galileo turned his telescope on the cluster in 1609 as one of his first observations, he was able to discern 40 individual stars. Modern observations have catalogued over 1,000 stars that are gravitationally linked in this area of space, within a radius of about twelve light-years, around 30% of them like our sun.
Just as bees are busily spreading life around our planet, the stars of the Beehive Cluster are busy forming new planets of their own. In 2012 researchers using the Kepler Space Telescope announced the discoveries of two planets orbiting separate stars in the cluster. Known as ‘hot Jupiters,’ these planets are among the largest gas giants, orbiting much closer to their host stars, making them — you guessed it — much hotter. While this is not in itself a unique discovery in this age of planets, what’s unique is that the stars they orbit are similar to our own in size and brightness. From our limited observations since the first exoplanet discovery in 1992 we’ve found 9,432 exoplanets, fewer than 5% of them being rocky, earthlike bodies, and K-type orange dwarf stars as the most common type to host planets. By comparison, our sun is a G-type yellow dwarf, slightly larger and hotter.
If you missed the conjunction of Mars and the Beehive Cluster on June 2, you can witness an earthlike planet join the cluster on the nights of June 12 and 13. Earth’s celestial twin, Venus, will be making a close approach to the cluster as it traverses the ecliptic. Though separated by millions of miles of empty space, both these wanderers appear to move along the same cosmic road, as determined by our solar system’s formation out of a disk of gas and dust, and few planets have strayed more than a few degrees from this original stellar plane.
Spring has sprung in northern Arizona, and with it comes the return of budding flora and emerging fauna. The sky also graces us with clusters in bloom, and the slithering serpents that herald their homecoming.
The constellation Serpens is often depicted as two halves of a snake, as held by Asclepius, the Greek god of medicine, aka Ophiuchus. The snake was observed to shed its skin, an act seen by the ancients as a sort of rebirth and resurrection, and the return of the constellation Serpens brings the rebirth of the plant and animal life that lay dormant through the winter. The serpent begins to rise in the eastern sky during May, bringing with it a host of deep-sky objects for your viewing pleasure.
Messier 5 (M5) is a globular cluster near the head of the Serpent, where more than 100,000 stars densely pack into a ball of space about 165 light-years in diameter. Despite having so many individual stars, its distance from Earth at around 25,000 light-years makes it appear to the naked eye as a single, faint star. Through your binoculars you’ll be able to see that it’s not a single object, and a larger telescope can resolve many of the brighter individuals, which include 105 variable stars, two millisecond pulsars and a dwarf nova. The entirety of M5 is speeding away from our solar system at more than 50km/s, so by the time you finish reading this article it will have moved a full Earth diameter farther from your backyard telescope.
The most daring backyard astronomers can also hunt galaxies off the head of the Serpent. Hoag’s Object is an extremely rare ring galaxy, and Seyfert’s Sextet is a group of six galaxies that are gravitationally bound like a globular cluster, albeit over a grander scale.
For early-bird astronomers Jupiter and the moon will be dancing together on the morning of May 17. Jupiter will be hidden behind the moon as it rises from the eastern horizon, in what is known as a lunar occultation. Jupiter will reemerge at 5:17am, with sunrise just a few minutes later at 5:26, potentially obscuring the view for all but the most astute observers.
When I was growing up we remembered the names of the planets in order with the mnemonic My Very Excellent Mother Just Sent Us Nine Pizzas. However, on August 24, 2006, the International Astronomical Union voted on a stricter definition of what it means to be a planet. Pluto had become a problem.
It was discovered by Clyde Tombaugh at Flagstaff’s Lowell Observatory in 1930, and nearly a dozen more distant worlds were discovered within our solar system in the early 2000s. Our planetary family was expanding to include at least nine more, or we needed a better way to classify different types of worlds.
It was decided that a planet must be in orbit around the sun, large enough that its own gravity creates an essentially spherical shape, and that as the gravitationally dominant body in its orbit it has successfully cleared its neighborhood of other large bodies, excepting natural satellites or moons. Pluto did not meet this definition, nor did the recently discovered Eris, Haumea, Makemake, Gonggong, Sedna, or Orcus. As such, planetary scientist Alan Stern is credited as coining the term ‘dwarf planet’ to classify these worlds that border on the definition. Pluto-lovers worldwide were disheartened as we amended the mnemonic to to My Very Excellent Mother Just Sent Us Nachos.
This wasn’t the first time that a planet had been demoted. On January 1, 1801, a Catholic priest at the Academy of Palermo in Sicily, searching for a dim star, found one that moved from night to night. First assuming it to be a comet, 24 consecutive observations led Giuseppe Piazzi to conclude, “since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet.”
Mathematical predictions placed this new object’s orbit as coming back into view on the other side of the sun, and astronomers worldwide looked skyward for its return. On December 31 of that year the orbit of Ceres was confirmed, and astronomers celebrated the addition of a new planet. Located between the orbits of Mars and Jupiter, Ceres is in what we now call the asteroid belt, so named because of its high concentration of solid bodies, some large and spherical and many small and irregular.
Just 15 months after the discovery of Ceres, Heinrich Olbers found Pallas, and by 1807, Vesta and Juno joined the planetary family. William Herschel, who discovered Uranus in 1781, suggested the term ‘asteroid’ for these new worlds, meaning ‘starlike.’ By 1868 over 100 asteroids had been discovered, and by 1921, primarily due to the introduction of astrophotography in 1891, the number of asteroids discovered tallied over 1,000. ‘Asteroid’ stuck, and we now count around a million within our solar system.
Ceres is not visible to the naked eye, but a good pair of binoculars or small telescope should allow you to find this dim world, which fluctuates in apparent magnitude from 6.7 to 9.3 through its orbit. At 2.97AU and just 595 miles in diameter, it represents about 25% of the asteroid belt’s total mass. Look for it this month as it approaches Denebola, the bright star marking the tail of Leo.
The Red Planet shines bright this month, transiting between the horns of Taurus the Bull and up toward Gemini the Twins, at just over one astronomical unit from Earth. One AU is the average distance from the Earth to the Sun, or about 150 million kilometers (93 million miles).
The peaks of the horns of Taurus are the bright stars Zeta Tauri and Elnath. At apparent magnitudes of 3.0 and 1.67, respectively, they are relatively easy to find by looking to the southwest after sunset. Zeta Tauri is a binary system, with the brighter Zeta Tauri A eleven times more massive than our sun and separated from its partner Zeta Tauri B by only 1.17 AU, nearly as close to each other as we are to the Sun or Mars right now, so we cannot see them as separate objects with backyard telescopes. Scientists have been able to measure their Doppler shift — the change in the frequency of their light spectra — to calculate an orbital period of just 133 days.
About one degree west of Zeta Tauri is the popular and magnificent Crab Nebula. You can approximate one degree in the sky using the width of your finger at arm’s length. The Crab Nebula bears the designation Messier 1 (M1) because it was the first object recorded by Charles Messier in 1758 during his research to locate the predicted return of a comet, as previously calculated by its namesake, Edmund Halley. This same nebula was independently discovered by multiple astronomers during the 18th century, and has since become one of the most studied and beloved objects in the night sky. Modern observations using the Hubble Space Telescope, the Chandra X-Ray Observatory and the Spitzer Infrared Telescope have continued to provide extraordinary detail of this magnitude-8.4 remnant of an ancient supernova, which was recorded by Chinese astronomers in 1054.
Defining the bull’s other horn is Elnath (from the Arabic for “butting one”). Relatively close at 130 light-years distant, this giant star is five times the mass of our sun and puts out about 700 times more light.
While the Pleiades is the most familiar open cluster in the constellation Taurus, it hosts many other star clusters and nebulae. The Hyades cluster is nearer the bright star Aldebaran in the face of the bull, with about 100 stars of similar age and chemical composition filling a spherical area of space.
Moving counterclockwise from the west around Elnath, you can find the Flaming Star Nebula (magnitude 6.0), M38 or the Starfish Cluster (magnitude 7.4), and M36, the Pinwheel Cluster (magnitude 6.3).
The Upper Paleolithic, an age of human prehistory ranging from 50,000 to 12,000 years ago, brought the first known organized settlements, advancements in tools and weapons, and artistic work. Early petroglyphs (carved or etched) and pictographs (painted) started with simple lines and dots, and soon evolved to include traced hands, animals, people and boats. While we cannot presume to know the full intents of the respective artists, some appear to have been purely artistic, while others seem to relay information on game animals, locations, even seasons and the passage of time. Lunar cycles, constellations and unique astronomical events have been documented on cave walls worldwide.
Ancient people certainly looked to the skies, because similar stories behind constellations carry across continents and millennia. Archaeo-astronomers study how these cultures understood the heavens and the effects it had on their civilizations. From Chaco Canyon in New Mexico to the dense jungles of Borneo, to caves across Europe, we find repeated patterns of stars, crescent moons, seasonal equinoxes and solstices, supernovae, eclipses and the sudden appearance and retreat of comets.
The appearance of comets became among the first celestial events to be predicted, because short-period comets return in cycles of less than 200 years. Well before the invention of the telescope in the early 17th century astronomers measured these long-tailed visitors against historical records and saw patterns in their return. But some of these comets never fit with historical records. With modern technology we can now identify these as long-period comets from the distant Oort cloud, a bubble of icy bodies well beyond the orbits of Neptune and Pluto. It’s extremely difficult to predict how much these comets will brighten as they approach the sun, with some visible during the day and others only through binoculars.
Comet C/2022 E3 (TZF) is one such long-period comet, currently making its way through the inner solar system. Discovered at the Palomar Observatory in California on March 2 last year, it reached perihelion — its closest approach to the sun — on January 12, became visible to the naked eye on January 17, and will be closest to us on February 1. Clear skies permitting, step outside and look toward Polaris, the North Star. Draw a line to the moon, and about a third of the way from Polaris, in the constellation Camelopardalis, you may be able to see this ancient interloper. Grab a pair of binoculars or a telescope and you will certainly be able to resolve the fuzzy green tail of this comet, which last graced our skies and was seen by our ancestors nearly 50,000 years ago.
The first and most basic element on the periodic table is hydrogen. A single atom of hydrogen consists of one positively charged proton in the center or nucleus, and one negatively charged electron orbiting it. This simple element was the first thing in the universe after the Big Bang, and there was a lot of it. Every one of these hydrogen atoms has a vanishingly small amount of gravity, and they immediately began to pull on and toward one another. As more atoms found gravitational friends, they coalesced into clouds of hydrogen. The more dense a cloud became, the greater its gravitational force, and subsequently it was able to attract more hydrogen in a never-ending cycle.
Now let’s compare this with a material we are all familiar with — water. If you dip your hand in a small bowl of water, you will feel its temperature and the unique, wet texture, but if you dive to the bottom of a deep pool or body of water, you will also feel the pressure of the water push in on your body. The larger the body of water, and the deeper one dives, the more pressure it exerts on the diver. The same phenomenon occurs with any element or compound, and the clouds of hydrogen were no exception. Clouds of hydrogen gas larger than our solar system pushed inward as they grew, the individual atoms packing tighter and tighter into the center and generating heat under the intense pressure. At around 25,000,000 degrees Fahrenheit the hydrogen atoms ran out of space and began to merge, fusing four hydrogen nuclei into the heavier helium atom and releasing electrons, gamma rays, neutrinos, and heat energy in the process. This process is known as nuclear fusion, and it’s how stars are born.
The James Webb Space Telescope has been hard at work this past year, looking deep into nebulous clouds of gas around our galaxy that act as stellar nurseries. Comparing against the Hubble Space Telescope’s famous images of the Carina Nebula, Tarantula Nebula, and the Eagle Nebula’s Pillars of Creation, we can see that the additional data available through observation in the near and mid-infrared allow astronomers to better understand this process of star formation and stellar nucleosynthesis.
Looking to our own star, we are constantly observing in many different wavelengths. With filters like Hydrogen Alpha that are readily available to backyard astronomers, we can begin to resolve the product of the fusion process taking place deep within the sun’s core, and using satellites and observatories we can trace the radiation, heat, and energy produced as it travels the 93 million miles to Earth and beyond.
Understanding this process has been a key focus of physicists since 1920. After calculating that the mass of four hydrogen atoms was slightly greater than that of one helium atom, British chemist Francis William Aston laid the groundwork of a science to understand how stars produce energy, and how we may be able to replicate it. On December 5, 2022, scientists at the Lawrence Livermore National Laboratory in California successfully produced a fusion reaction in which the energy output was, for the first time, greater than the input, using lasers targeted on a gold canister containing deuterium and tritium. As we continue to develop technology, systems and materials that can withstand such extreme temperatures and environments, we stand at the junction of a future right out of science fiction.
There were once seven boys who spent all of their time playing a game called gatayusi.
They would roll the stone gatayusi wheel along the ground, taking turns hitting it with sticks to push it along. These boys never worked in the fields, never helped their parents with the chores, and would only stop to eat and sleep.
Finally, their mothers were so fed up that they took some gatayusi stones and threw them in the pot with supper. When the boys came home to eat, they were offered the warmed gatayusi stones that they loved so much. Angry, as any young boy would be if denied dinner, they ran off, jointly deciding they would go to a place where they could play gatayusi and never bother anyone else ever again.
They danced, and sang, and prayed to the spirits to help them escape. After a time their mothers became worried, and found them in this ritual dance, the boys’ feet beginning to float away from the earth.
The mothers ran to their children, and one was even able to grab her son’s feet with the gatayusi stick and pull him back down. But the other six were too high, and they continued to float into the sky.
The six circled higher and higher, till they were just bright blue dots in the heavens, which the Cherokee still refer to as Ani’tsutsa (‘The Boys’).
The boy who fell back came down so hard that he sank into the ground and vanished. His mother wept over the spot every day, her tears watering a little shoot that began to sprout, and it grew into the first pine, showing that life on Earth is of the same nature as the stars.
You most likely know these six blue dots in the sky as the Pleiades, which the Greeks named in honor of the seven daughters of Atlas. Canada’s Cree Nation knows this open star cluster as Pakone Kisik, the hole in the sky where the original Star Woman came from, leading all other people to find their way after her.
Every culture has names and stories for the stars. Many have striking similarities, despite thousands of miles and thousands of years of separation.
The Big Dipper is an asterism for some of the stars that make up Ursa Major, ‘the Great Bear’ in Latin. The Iroquois have a story of hunters who chased a bear through the forest, where protective giants transported the bear to the heavens. The Zuni tribe tell of a great bear that protects from the ice gods of the north, and when the bear enters hibernation, the land is subjected to the gods’ icy breath till the bear returns in spring. In the Navajo story a maiden marries a bear, angering her father, who kills the bear. Her grief transforms her into a bear, bent on vengeance.
Manuel Lucero, Director of Prescott’s Museum of Indigenous People, is my ultimate “space nerd” brother. His upbringing as a member of the Cherokee Nation and background in American Indian Studies has brought him to Prescott to share these and many other stories from the people who inhabited this land for thousands of years, and continue to bring a rich and storied culture to our world. I urge you to take an afternoon and visit the Museum of Indigenous People at 147 N. Arizona Avenue. You’ll be amazed by the collection of artifacts and history, knowledge of art and culture, and even Native American astronomy.
The year 1989 was an eventful one historically. Tiananmen Square and the fall of the Berlin Wall contrasted demonstrations for human rights and freedom against corporate disasters like the Exxon Valdez oil spill in Alaska’s Prince William Sound. The same year we experienced advancements in entertainment, such as Nintendo introducing its Game Boy, signaling the era we now live in with an estimated 83% of the Earth’s population carrying a pocket communication device capable of surfing the web and playing games at any time. Indiana Jones and the Last Crusade and Back to the Future II topped the film box-office numbers, while The Simpsons premiered on television.
So what does this all have to do with space?
Since we first began distributing information and communicating via wireless media using radio waves and other electromagnetic frequencies, we have created a digital bubble of information that is expanding into the universe. Across the vacuum of space, many of these transmissions spread out in all directions at the speed of light, about 186,000 miles per second. Whether it’s the light of our sun traversing the 93 million miles to Earth in about eight minutes, or us communicating with the Voyager 1 probe 14.7 billion miles away with one-way communication time of around 21 hours, these various forms of light move extremely quickly to cover vast distances.
Our nearest neighboring star system is Proxima Centauri b, about 4.24 light-years distant, meaning any aliens on that world listening on the right wavelengths would be able to hear and observe transmissions sent from earth around July 2018. They could then respond with their enjoyment or distaste for Cardi B’s July 2018 chart topper “I Like It” with a message sent now, which we would receive in another 4.24 years, or about March 2027.
One distant exoplanet currently of high interest to astronomers and researchers is GJ 436 b. At 33 light-years from Earth, this “hot Neptune” is estimated at 21 times the mass of Earth and 4.5 times its radius in size. This makes it similar in size to Uranus or Neptune, albeit in an orbit much closer to its host star and therefore much hotter. Combining data from ground and space-based observatories, we believe this planet is composed of a high percentage of water, but under such extreme pressure that it is compressed into a rare form of hot ice. Though humans would have a difficult time (read “virtually impossible”) surviving in such a hostile environment, the planet could have moons or other planets in its system that may be hospitable for life as we know it. That and its massive, comet-like tail of water vapor trailing behind it in orbit make this a top contender among strange worlds for us to study.
On November 5 the Jim and Linda Lee Planetarium at Embry-Riddle Aeronautical University, in partnership with the Museum of Indigenous People, NAZ Astro and your own Backyard Astronomer, will present information about this and other exoworlds as part of the International Astronomical Union’s 2022 naming event for 20 exoplanets and their host stars. This process will soon replace the name GJ 436 b with one more suitable and this year’s naming theme is indigenous languages. Stay tuned for a series of events, interviews and presentations related to this project.
And for any aliens on GJ 436 b listening to our signals today, on behalf of all of humanity, I apologize for 1989s Milli Vanilli hit “Blame It on the Rain.”
October 4, 1957 was truly the beginning of a new age. While humans had spent the previous few decades dreaming of, dabbling in, and testing their mettle in the high reaches of Earth’s atmosphere, the launch of Sputnik I on that day was the true harbinger of what was to come on the new frontier beyond Earth.
The Soviet-made sphere was roughly 23 inches in diameter with a mass of 83.6 kg/184 lbs, its one watt of power provided by three silver/zinc batteries designed to last just two weeks. It was programmed to issue a series of beeps on various frequencies, encoded to provide information about temperature and pressure around the world’s first artificial satellite.
A team of engineers working on the project watched and waited with apprehension for more than 90 minutes after it launched to make sure Sputnik survived a full orbit, and only then called Soviet Premier Nikita Khrushchev to announce their success with the first human-made object to orbit the Earth.
By the following night amateur radio operators and astronomers joined professional scientists and engineers around the world to track the satellite’s path across the sky. The American Radio Relay League — the largest association of amateur radio operators in the US — quickly issued directions to its members around the country and the world on how to tune in to hear the signals from space. Whole communities gathered outdoors, with warm beverages and craned necks, hoping to witness the dawn of the Space Age.
The 1999 film October Sky relates the story of one such community. Coalwood, West Virginia was a small mining town, not unlike hundreds of others dotting the central Appalachian region. Then-14-year-old Homer Hickam, Jr. was one such observer, and seeing Sputnik fly overhead in the West Virginia sky that week was a catharsis to a boy who was supposed to grow up and work the coal mines, like every other boy in Coalwood.
A ragtag group of friends developed a new passion for rockets and the self-education that would be required to make them fly. The self-proclaimed Big Creek Missile Agency spent the next two and a half years learning to weld, teaching themselves calculus and trigonometry, destroying countless bits of their mothers’ borrowed kitchenware, and eventually winning the National Science Fair gold and silver medals in the field of propulsion.
To celebrate the 65th anniversary of the launch of Sputnik I and the beginning the Space Age, tune in to our podcast for the audio version of this article series and a special Backyard Astronomer interview with retired NASA engineer and co-founder of the Big Creek Missile Agency, Homer Hickam.
For two months running we are fortunate to have the largest of our solar system’s gas giants put on stunning displays.
Where in August Saturn was at opposition, Jupiter will also be at its nearest and brightest to Earth on the night of September 26. Unlike the Saturnian opposition, however, when the moon lit up the sky on August 14 at 93% full, in the coming opposition backyard astronomers the world over will appreciate the darkness afforded by a new moon.
The ancient Romans gave Jupiter its name in honor of their chief god. This naming pattern parallels the Grecian title Zeus, the Babylonian designation Marduk, the Sanskrit honorific Brihaspati, and the Hebrew title Tsedek. Mùxīng, as it is known in Chinese, is so important in that culture’s mythology that the entire zodiac revolves around the approximately twelve-year cycle of Jupiter’s orbit around the Sun.
If one was able to take all the “stuff” in the solar system, excluding the Sun, and push it together into a giant ball, Jupiter would still be more than twice as large as everything else combined. Even the smallest of telescopes and binoculars can pick out the four Galilean moons orbiting the planet, though with larger scopes one can begin to resolve many more of its 79 known satellites. On clear nights you may also start to notice colored bands across the surface of the planet. These are clouds of gas, like jet streams on Earth, with currents moving in different directions in colors ranging from white to orange and brown.
The Juno spacecraft arrived in Jovian orbit in 2016 and has been studying the planet in detail ever since. While your backyard observations will be in the visible-light spectrum, Juno is able to study Jupiter’s gravitational and magnetic fields using the microwave, infrared and ultraviolet spectra. In addition, the new James Webb Space Telescope has already gazed at Jupiter in the infrared, allowing scientists to merge data across the spectrum to understand more about how this giant planet formed and continues to evolve as the defender of our inner solar system today.
The planet Saturn has intrigued astronomers, both professional and amateur, since Galileo first sketched what he thought were two odd-shaped moons on either side of the planet. His final telescope at 30x magnification was still not quite able to resolve the rings we love so much to gaze on. Dutch mathematician Christiaan Huygens explained the rings of Saturn by 1659 and identified its moon Titan with a slightly larger telescope at 43x magnification. Both were major accomplishments for their time, and now even the most basic telescopes and binoculars can show us the beautiful rings and Titan nearly any time of year.
With a volume 763 times that of Earth, Saturn is the second-largest of our system’s gas giants, behind Jupiter. Despite its huge size, its average density is less than that of water, so it’s only 95 times the mass of Earth.
In August the planets align to give the best view of the year, an exceptional viewing opportunity. Saturn reaches opposition on August 14, when it is the closest to us and at its brightest, its earthward side fully illuminated by the sun. It will be one of the brightest objects in the sky this month, moving westward along the ecliptic, the path that all planets take across our southern sky. On that night you’ll find it near the tail of the constellation Capricornus.
At that point it will be about 816 million miles away, a distance that takes light 73 minutes to traverse. So when you’re gazing at the Ringed Planet, you are actually seeing light that left the Sun, traveled for an hour and 21 minutes to Saturn, then back an hour and 13 minutes to your eyepiece in Northern Arizona. Those same photons may have taken upward of a million years to escape the 430,000 miles of the Sun’s dense plasma, but we’ll have to discuss that in more detail on another day.
If your telescope mirror is two inches or larger in diameter, you should also be able to see Titan off to the side, with the rings nearly making a line pointing to that moon, which is larger than Mercury. Titan’s dense methane atmosphere is often tinged with orange.
The new James Webb Space Telescope will be photographing the outward planets, starting with the orbit of Mars, over the next few months and years, and the results will be sure to amaze. In the meantime, if you are able to get a picture of Saturn through your telescope, share it with us on social media!
In the early summer months, the constellation moves to the western sky. Adjacent the Big Dipper, some Ancient Greek Mythology tells of how Boötes invented the plough and was rewarded with a place in the heavens for this history-altering advancement. Keeping in line with feeding the masses, the Yup’ik language – second most widely spoken Native American language after Navajo - of the Eskimo-Aleut people refers to this same grouping of stars as Taluyaq, literally translated as “fish-trap” for the funnel shape of the stars. Many different Chinese constellations have focused around Arcturus, the brightest star in Boötes and in the Northern hemisphere, which was so important in their mythology that it’s position in the sky marked the beginning of the lunar calendar.
Boötes is home to a plethora of deep sky objects, many of which represent the earliest discoveries after the invention of the telescope. The easiest star to locate first is the bright orange-giant Arcturus. Just under 37 light years distant, 25 times larger than our sun and 170 times as luminous, it should be a quick task. The next brightest star is Izar, which viewed with a scope of diameter 3” or larger reveals a beautiful multi-colored double star. Approximately the same distance but in the opposite direction of Izar is magnitude 11 galaxy Caldwell 45. Six degrees to the Southeast of Arcturus is Pi Bootis, another double star visible to the naked eye. Remember, you can easily approximate degrees in the sky with your hand at arm’s length – a fingertip is about 1 degree, three fingers about 5 degrees, and a clenched fist is about 10 degrees.
The early solar system was a violent place. We know this courtesy of modern telescopes and models generated by today’s supercomputers, allowing us to peer at clouds of gas around distant stars, observe their planets forming, and hypothesize how our own system could have formed under similar conditions.
A young star usually forms in a cloud of tenuous gas, slowly pushing inward and becoming more and more dense, with the star at the center hosting the majority of the mass — and therefore gravity — and the outer gas coalescing into rocks, planets, moons, asteroids and comets. Over time, these objects run into each other, as we observed with objects hitting Jupiter over the past few decades, as well as large craters on the surface of Earth and elsewhere around the system, preserved as monuments to these cataclysmic events.
It is generally believed that the sun absorbed enough material to initiate nuclear fusion around 4.6 billion years ago. Over the following 100 million years the disk of gas around it formed all the planets we now know, as well as many others long since forgotten.
One of those protoplanets, about the size of Mars, was Theia, which formed much farther out in the solar system with the comets, composed of much more water ice than the inner planets. Its orbit was erratic, or possibly disturbed by the passing of a wayward star, and after countless close encounters, Earth and Theia collided in what must have been an awesome event.
The violent impact knocked Earth sideways, merged the heavy planetary cores into a much larger core and mantle and ejected debris for hundreds of thousands of miles into orbit. The slow process of cooling formed our continents and oceans, even our moon.
Many other bodies experienced this same type of event, which we can see in the different tilts and rotations of every planet in our system. The largest, Jupiter, was able to better withstand impacts than the smaller, rocky planets, and has a tilt of only 3°, while Venus was somehow knocked completely upside down to a 177° tilt, rotating in the direction opposite that of the other planets. Uranus lies at a 98° tilt relative to the sun, essentially orbiting on its side, while Earth, Mars, Saturn and Neptune all have relatively stable seasons due to their axial tilts, Earth at 23.5°, Mars at 25°, Saturn at 27°, and Neptune at 30°.
Earth’s 23.5° tilt leans different parts of the planet toward or away from the sun at different times of year. As we orbit the sun, the northern hemisphere gets closer and more direct sunlight in spring, culminating on June 21 this year, which we celebrate as the summer solstice. The sun will appear to stand still in the sky for three days as it reaches its northernmost view of Earth, and then will begin to move southward again for six months. This change in the seasons affects all planetary weather patterns and the evolutionary habits of plants and animals alike.
And it’s all thanks to Theia.
As the morning sun rises earlier and the evening sun sets later each day through the end of June, our nights are inversely shorter and shorter. This makes for prime viewing of our closest star, the sun.
Galileo and his contemporaries focused on the sun starting around 1609, and we have been fascinated with the detail on the sun’s “surface” ever since. The dark areas they observed were recorded and compared over time, and by 1755 it was established that a roughly eleven-year cycle of activity is visible from earth as these darker spots. That first cycle, from 1755 to 1766, is documented as cycle 1, with high and low phases referred to as solar maximum and solar minimum. At maximum, as many as 285 sunspots have been recorded (1958), and the surface has gone more than a month (2019) with no sunspots.
For most of recorded history we have been able to view the sun only from the terrestrial standpoint, and so could only document what was visibly facing earth. As we have ventured out into the solar system a great deal of time, energy, and resources have gone into furthering our understanding of the sun and how solar cycles affect our home planet and the system. What we know is still in its infancy, but NASA’s Solar Dynamics Observatory launched in 2010, allowing us to continuously observe the sun in a range of wavelengths. The Parker Solar Probe in 2021 used special shielding to get closer to the Sun than any previous human-made object, giving us insight into the inner and outer workings of our star.
So what’s a sunspot? Visually, they are darker than the surrounding photosphere, and often appear irregular in shape, with fuzzy, elongated filaments that look like hairs emanating from dark centers. The center averages 2,700–4,200°C, with outer penumbral filaments at about 5,500°C. This difference in temperature makes a sunspot center appear dark, though if it were isolated it would be much brighter than the full moon.
We currently understand that sunspots are slightly depressed areas of the solar surface focusing strong magnetic fields. In tracking sunspots and solar cycles over the last 400 or so years, we see related patterns of their effect on our weather and on radio communication, and eleven-year cycles have been correlated with the rings of trees and layers of deep sediment. Solar cycles may even have directly or partially caused the Little Ice Age between 1250 and 1600CE.
We are currently in solar cycle 25, with the expected maximum peaking around 2025. As of this writing there are a few sunspots on the sun’s northern hemisphere, which can be safely viewed in a few different ways. Always check your equipment for punctures or tears before observing the sun, and use your solar glasses, solar telescope filters or shadow/reflection viewers in the manner instructed.
Imagine holding a full, unopened can of soda. The thin aluminum barrier separating you from the liquid within can flex slightly if you push on it, but it is relatively strong, enough to hold in the pressure. We can demonstrate this pressure difference by giving the can a shake and then opening the can, at which point a spray of carbonated sugar water shoots from the new opening until the outside pressure and inside pressure have balanced.
The pressure of our regular atmosphere is usually referred to as 1 standard atmosphere, or about 14.7 pounds per square inch at sea level. The pressure in the can of soda, depending on temperature and other variables, can easily be two or three times that. This difference in pressure is what makes the soda shoot out of the can, or what makes your ears pop as you dive to the bottom of a pool, lake or the ocean, where the equivalent three atmospheres is about 30 meters or 100 feet deep, and the deeper you go, the stronger the pressure. At the deepest levels of the Mariana Trench in the Pacific Ocean, the pressure can be more than 16,000psi, or 1070atm.
But what if we go up instead of down? At 20 kilometers (about 12.5 miles) altitude, the air pressure is just 1/20th of an atmosphere. This is because the air and moisture held close to our planet’s surface by gravity prevents our atmosphere from drifting away into space, but weakens and thins over just a few miles. By the time we reach the orbit of the International Space Station at about 227mi (420km), there is essentially zero atmospheric pressure. And while this provides benefits in orbital mechanics due to negligible atmospheric drag, it presents a whole other slew of problems for keeping humans alive in space.
Spacecraft like the ISS are carefully regulated and monitored to maintain an air pressure like that of Earth at 14.7psi. As spacecraft deliver humans and supplies, they must have the same air pressure as the docking station, or opening the hatch between craft could create an event similar to the shaken soda can, but with disastrous consequences, the pressure straining docking mechanisms and potentially pushing the objects apart. The same care must be taken when an astronaut performs an extravehicular activity (EVA), also known as a spacewalk. Their suit acts as a self-contained spacecraft that must also balance pressure to maintain life support systems and not damage the suit, the station, or any other object they may be working on.
Docking and EVAs aren’t the only time that atmospheric pressure is of a concern, though.
Micrometeoroids the size of grains of sand can and do collide with spacecraft. NASA estimates that the force of a paint fleck hitting the ISS in orbit would be the comparable to that of a 550lb object traveling at 60mph on Earth, and something just a few inches across could be equivalent to a 7kg blast of TNT.
On August 30, 2018, this scenario unfolded on the International Space Station. A 2mm hole was discovered in a Soyuz capsule that had delivered astronauts to the ISS two months prior, and sensors reported a drop in pressure and an oxygen leak. Luckily the repair could be done from inside the station, and no additional damage was found. The suspected culprit was a micrometeoroid. The picture shows a similar impact on the robotic Canadarm that also chipped a window in the Russian Zvezda ISS module.
Despite the risk, brave scientists have inhabited this orbiting laboratory continuously since November 2000, moving about five miles per second and orbiting the Earth every 90 minutes, or 16 times per day. Covering a total area of nearly a football field, its highly reflective solar panels make it easy to find in the evenings as the sun sets. Amateur astronomers with binoculars can make out its elongated shape as it quickly soars overhead. To find out when it will be passing over you, visit SpotTheStation.NASA.gov to type in your zip code and receive text alerts giving times and bearings of local sighting opportunities.
The Earth has been estimated at a total mass of about 5.9722×1024kg, more commonly notated as 1 earth mass (ME). One solar mass — or the mass of the sun, notated as Mo — is approximately 333,000 Earth masses. The whole of the solar system is estimated at 1.0014 solar masses, meaning all the planets, moons, asteroids, and comets make up just 0.0014 the mass of the sun. This all adds up to a lot of stuff floating around in our celestial backyard.
We Earthlings, however, love to produce trash. We have spent vast amounts of time and energy converting earthly resources into products that ultimately lose value and become garbage, subsequently dumped on land and in water, since well before recorded history. Some of the greatest archaeological discoveries of our past come from ancient landfills and latrines. So it’s no surprise that our forays off our planet have also produced large quantities of waste.
Beginning on October 4 1957, Sputnik I launched aboard a modified Russian ICBM to become the first artificial satellite in space. Its orbit decayed over the subsequent weeks and it fell back to Earth on January 4 1958, burning up in the atmosphere on in its way in. March 17 of the same year saw the United States launch the 3.2kg Vanguard I satellite, which still orbits the Earth today, along with the 31kg upper stage of its launch vehicle.
Now 64 years later, the US Space Surveillance Network tracks around 20,000 artificial objects orbiting the Earth, with only 2,218 of those being operational satellites. Those are the most recent numbers, from 2019, and with the rise of private space-industry giants like SpaceX and Blue Origin, and more countries entering the space race every year, those numbers are growing faster than ever.
But these are just the objects large enough to be tracked from ground-based observatories, like the Navy Precision Optical Interferometer outside Flagstaff, which can track objects the size of a quarter. Accounting for even the smallest paint flecks, estimates place the total number upward of 130 million objects made by humans and flying around the Earth at ungodly speeds.
“Space junk” is the colloquial term for all this debris, and generally carries a negative connotation. The International Space Station was recently forced to adjust its orbit and shield the resident scientists in their respective escape capsules when Russia tested a space weapon that destroyed a defunct satellite and created hundreds of thousands of small pieces of debris. Even the smallest piece of metal shaving orbiting at around 15,700 miles per hour could easily pierce through the outer layers of something like the ISS, causing depressurization, major repairs or loss of life.
Despite these astounding numbers, we know that space is a big place. Collisions are not common, even with billions and trillions of micro-meteoroids scattered across the solar system. Impact craters on Earth, the moon, Mars and elsewhere around the solar system tell us that major impacts do happen with relative frequency in the space timeline, but our technology is just advancing to the capability of capturing such events.
Two such events have been documented, and both were with Jupiter. Astronomers everywhere watched as Comet Shoemaker-Levy 9 flew its Icarus-like path and was torn apart by the immense gravity of Jupiter, crashing into it and leaving a trail of temporary scars in the Jovian atmosphere in July 1994. By comparison, on September 13 2021 a handful of amateur astronomers just happened to be photographing Jupiter when a bright flash appeared, thought to have been caused by an asteroid around 300 feet in diameter.
As we develop new ways of tracking objects across space, such as by Greg Leonard and the team at the Catalina Sky Survey in Tucson, more advance notice of impacts will follow. Many professional observatories are dedicating their clear nights to hunting for unknown comets and asteroids, while amateur astronomers are leading the charge in following the larger objects we have placed in uncontrolled and forgotten orbits.
Recently amateur astronomers found that a junk rocket will impact the far side of the moon on March 4 at around 12:26 UTC, in the first known unintentional collision of a human-made object with the moon.
The vehicle has been tentatively identified as a 3.6-ton SpaceX Falcon 9 booster that launched a weather satellite in 2015 or a Chang’e 5 booster from China, though both those ideas are disputed by their organizations. Either way we’re in for a scientific treat.
Such calculations by amateur astronomers have allowed international space agencies to adjust the orbits of lunar satellites that may be in the way, or even witness impacts.
Sadly, since the impact will be on the far side, we will not be able to observe it with our backyard telescopes. But with record numbers of orbital flights increasing year by year, I’m sure we’ll have more opportunities to witness collisions in space.
And just maybe, in a few thousand years, space archaeologists will look to all these defunct satellites, rocket bodies, landers, rovers, and nuts and bolts to catalog the many long-forgotten adventures of our current era. Or maybe it will just be another pile of orbiting space junk to dodge on our way to colonize
In 1609 Galileo pointed his rudimentary telescope at the heavens, finding three and then four moons orbiting Jupiter. He combined two polished glass lenses, slightly convex at different angles, and was able to magnify the image. This wasn’t a new technology; the basic monocular had been generally used for terrestrial purposes, allowing humans to peer across valleys and mountaintops, or at their military foes, from great distances.
This type of magnifying device is known as a refractor scope, for the way it bends (refracts) the light as it passes through a lens. The total light gathered across the surface is then bent to converge on a single point; the distance from the lens to the point of convergence is known as the focal length. By combining two lenses of different focal lengths at either end of a tube, it was discovered that the image could be greatly magnified.
The technology of polishing lenses exploded, with royalty hiring glass makers to design bigger and better lenses for government-sanctioned observatories and royal astronomers. But as lenses get bigger, the process of refraction gets more complicated. Like a child’s toy prism — or the cover of a Pink Floyd album — the light we see enter the glass divides into different colors as the various wavelengths slow to different speeds in passing through the dense medium of the glass. When this happens in a telescope the effect is called chromatic aberration, where the colors at the eyepiece don’t match up quite right and the image looks fuzzy.
Another problem is that as lenses get bigger, the glass gets very heavy, and it can only be supported from the thin edge of the lens, so as not to obstruct the light. And as lenses got bigger, so did the tubes.
To address this, a little-known polymath named Isaac Newton came up with a different type of magnification process in 1668, using a concave mirror to reflect the light back to the observer’s eye. A secondary mirror above the main mirror diverts the light to the side of the telescope. This solves all the main problems of the refractor, because the light does not divide into different wavelengths through the lens, the mirror can be fully supported at the end and therefore much more firmly, and reflecting the light back up through the tube and out essentially uses the tube twice, greatly reducing the length of the tube relative to refractors to achieve the same focal length.
Some of the largest refracting telescopes have been used for great discoveries, such as the 24-inch telescope at Lowell Observatory, used in discovering the red shift of galaxies and mapping the moon for the Apollo missions. Reflectors, on the other hand, have grown much, much larger, including many across Arizona, like the Discovery Telescope in Happy Jack, with its four-meter primary mirror. This is also the format commonly used for the great space telescopes, with the James Webb Space Telescope’s 18 gold hexagonal mirrors unfolding last month to a completed primary mirror diameter of 6.5 meters.
So which is best for you? Well, it depends on what you want to do. Many of the images we have featured in this column over the years have been from Joel Cohen, who has a seven-inch refractor he uses for astrophotography. My personal telescope is a type of reflector called a Dobsonian, great for viewing but less so for photos. Whichever route you choose, I wish you clear skies!
Images by Joel Cohen, Adam England and Lowell Observatory.
The new Netflix film Don’t Look Up features Leonardo DiCaprio and Jennifer Lawrence as astronomers who discover that a previously unknown comet will collide with Earth in about six months. Despite their repeated pleas, the media and government ignore their requests to act immediately to save the planet. While this film is meant as a satire of climate change and overall science skepticism, it puts to the forefront of American media an idea also floated back in 1998 with the releases of Armageddon and Deep Impact.
With similar plots, objects of tremendous size are found to be hurtling toward us with little time to avert a major catastrophe. The premise of “a last-ditch effort to save humanity by launching a spacecraft laden with nukes” guides each of these stories on slightly different trajectories, the overall premise being that we can save Earth from a newly discovered object before it slams into our planet by blowing it up with our biggest weapons of war — right?
In today’s reality astronomers really are looking to the sky in hopes of finding near-earth objects — NEOs— that could cross paths with our planet in the future. Much if this work is done in Southern Arizona’s Santa Catalina Mountains, in a partnership between the University of Arizona and NASA known as the Catalina Sky Survey.
Using a 1.5-meter telescope equipped with a 111-megapixel camera, the team takes a series of 30-second exposures to capture objects that would be impossible to locate with most land-based equipment. Using software to compare the resulting images, they can isolate objects moving across the background of distant stars, identifying them as either known or previously unknown objects of interest. Follow up observations with other telescopes dotting the mountains outside Tucson help calculate orbits and plot where those orbits might intersect with Earth in the future.
Gregory Leonard leads the team at the Catalina Sky Survey, and is often first to report newly discovered objects in our solar system. His resume includes discovery of more than 1,600 NEOs and 13 comets, including comet C/2021 A1 Leonard, which graced our morning skies in early December and evening skies later in the month.
On November 23 NASA and the ESA launched the DART spacecraft, for an October 2022 rendezvous with a binary asteroid that poses no threat to Earth, to study whether we can divert an asteroid given enough time. After it slams into its target, ground-based observations at Lowell Observatory in Flagstaff and other telescopes around the country and world will track the change in the asteroid’s orbit to determine how much mass is needed to move a body like this.
The dormant volcano Mauna Kea is the highest point of the Hawaiian Islands and the Central Pacific, peaking at 13,803 feet. At that height, the benefits of dry air above the clouds with little to no light pollution make it the preeminent site in the world for astronomical observation, so many large telescopes operate at its summit. One of these is the Subaru telescope of the National Astronomical Observatory of Japan.
Subaru, you say? They sold naming rights of a telescope to a car company? Well, no. The car company and the telescope were both named for the open star cluster Subaru, which graces the fall and winter skies of the Northern Hemisphere. The closest naked-eye star cluster to Earth, the six bright stars of Subaru glow hot blue and are surrounded by beautiful nebulosity that can be seen with even the smallest binoculars or telescopes. This cluster has been clearly recorded in dozens of ancient cultures and even referenced in the bible. The oldest known depiction of the night sky is a bronze disc found in Germany that dates to around 1600 BCE and is believed to include the sun, moon, and the stars of the Subaru cluster.
Fast-forward to 1953, when the Japanese businessman Kenji Kita combined six smaller companies across the manufacturing sector to create Fuji Heavy Industries, producing everything from scooters to cars to buses. Drawing on his love of the sky to characterize the six businesses he brought together as a group, he named his first car the Subaru 1500, its logo a clear representation of the star cluster.
Whoa, whoa, whoa. The brightest and best star cluster, most visible to the naked eye, with visible nebulosity, and you’ve never heard of it? That may be because Western culture traditionally uses ancient Greek and Roman names for the primary constellations, and we know Subaru as The Pleiades.
December3 brings a great opportunity to see the Subaru constellation in person! Findlay Subaru and Manzanita Insurance are sponsoring a Subaru viewing night, with amateur astronomers on hand to point out this and other objects in the night sky. Follow us at Facebook.com/BackyardAstronomerAZ for details.
In the same patch of sky as Andromeda is possibly the most distant object one can see with the naked eye. In good viewing conditions, with 20/20 vision and without magnification, you may be able to spot the Triangulum Galaxy, or Messier 33. It is sometimes referred to as the Pinwheel Galaxy, however another galaxy is recorded in separate astronomical databases as the Pinwheel, and so, to prevent confusion, we will stick with Triangulum, so named based on the simple triangle its three main stars form. While certainly one of the smallest and simplest of the 48 Ptolemaic constellations, it is a great place to look for deep-sky objects.
The Babylonians referred to this formation of stars as The Plough and recorded it on clay tablets dating back nearly 3,000 years, making it possibly the oldest documented constellation. (This is not to be confused with the UK nickname for Ursa Major, which we usually call the Big Dipper and they call The Plough.) In ancient times this constellation would have risen early in the predawn hours in early spring, signifying the time for the farmers of the Fertile Crescent to begin plowing their fields. The Greeks referred to it as Deltoton for its resemblance to the Greek letter delta, a shape also referenced where the Nile River empties into the Mediterranean, the Nile delta. The Romans had a few names for this triad, one of which was Sicilia, for the roughly triangular shape of the island of Sicily. Roman mythology stated that Ceres, the island’s patron goddess, begged the god Jupiter to place it in the heavens, and so the triangle in the sky came to be. Other names used by ancient Mediterranean cultures almost universally reference the tri- prefix we associate with the number three, including Tricuspis, Triquetrum, Trigonon, Trigonum and eventually Triangulum. The modern International Astronomical Union, which regulates the accepted names of astronomical bodies and objects, assigned the abbreviation “Tri” to this constellation in 1922.
While much smaller than its neighbor, with an apparent size of 70.8 x 41.7arcminutes, we view the Triangulum Galaxy nearly face-on, and as such we can see its features much more clearly defined. It has prominent arms of dust, gas, and stars spiraling out from its center, but it differs from the Milky Way and Andromeda on one major feature, in that it does not have a bulge at its center. Surveys of the galactic center of M33 show the stars there orbit normally, suggesting that it does not have a supermassive black hole like its two larger neighbor sin the Local Group. The future may yet provide it with such a blackhole, as a major collision with either Andromeda, the Milky Way or both is expected to combine all three galaxies into one mega-galaxy in about 2.5 billion years.
If you found Andromeda last month, you’re on the right path. You used the bright star Alpheratz to star hop across the stream of stars to its left. The second star in the stream is Mirach, and the Triangulum Galaxy is approximately the same distance below it as Andromeda is above it. Since it is face-on, the brightness of its stars seems spread over a much larger area, so it can be tough to find the first time with your binoculars or small scope. Look for a fuzzy spot, almost like a smudge on a window, then adjust your focus and play with different eyepieces to resolve more detail.
As you’re probably aware, we live on Earth, which orbits the sun every365.256 days as part of our solar system. Our system is one of hundreds of millions of stars and similar systems that orbit the center of our Milky Way galaxy about every 225 million years.
We are familiar with the cloudy or “milky” swath above our heads that is visible on moonless nights through much of the year. With advancements in radio astronomy in recent decades, we have been able to peer deeper into the sky and analyze the structure of our galaxy to learn we are on the outskirts of an arm in a giant spiral galaxy, held together by the gravitational pull of dark matter and a massive black hole in the center that we call Sagittarius A*, pronounced ‘Sagittarius A Star.’
For hundreds of years we had to guess what the structure of our galaxy was, as we are inside of it and cannot see it from an outside perspective. Our best approximation comes from looking at our neighboring galaxies, some of which are visible to the naked eye.
Our nearest partner in space is the Andromeda galaxy. Although it hangs out about 2.5 million light-years distant, it is large enough and bright enough to have been documented over a thousand years ago, long before the advent of the telescope. In the tenth century Persian astronomer Abd al-Rahman al-Sufi described Andromeda as a “nebulous smear;” later astronomers used rudimentary telescopes to define the blurry spot in the sky as an “island universe.”
With a diameter more than six times that of the full moon, Andromeda is one of the largest objects that astronomers can see with either the naked eye or simple ground-based equipment, and many astronomers have spent their lives dedicated to researching it. But it was not until Edwin Hubble studied Andromeda in 1925 that we truly understood it was a separate galaxy at such a distance from our own. This realization expanded our understanding of the universe from essentially believing in one galaxy to now knowing there are upward of two trillion separate galaxies in the observable universe.
October is arguably the best month to view Andromeda in the evening sky, reaching the zenith (directly above you) around midnight. On October6 is the new moon, and about an hour after sunset that evening Andromeda will be approximately 30° above the northeast horizon. You can find it by looking for the Great Square of Pegasus — an easily identifiable asterism — with the bright double star Alpheratz forming the northern corner. Two streams of stars seem to pour left from this point, and about 12° from Alpheratz (slightly more than the size of your fist held at arm’s length) and just above the topline of stars will have you looking at a cloudy patch of sky. Bust out the binoculars and you will see this is Andromeda, and then with the telescope you will begin to resolve the bright galactic center and swirls of stars around it. You will see Andromeda just slightly off from edge on, so it should look like a long oval getting brighter and denser toward the center.
In July we talked about using the Summer Triangle asterism to locate Messier 57,the Ring Nebula. If you were able to make it to our August Star Party at Pronghorn Park, you most likely were able to view it and the planets Saturn and Jupiter shining bright at opposition. But M57 is just one of the heavenly surprises hiding within the Summer Triangle.
One of the three points of the Summer Triangle is Deneb, the brightest star in the constellation Cygnus, the Swan. The main stars of the Swan make up the Northern Cross, making it easily identifiable to the naked eye just after sunset. Move down from Deneb to about midway between Vega and Altair, and the main body of the Northern Cross is formed with Deneb at the top and Albireo at the bottom. Inversely, the Swan is viewed as diving down, with Deneb at the tail and Albireo the head. Albireo appears as one bright star until a look through your binoculars or telescope reveal it to be a fun double star, with Albireo A being the brighter, yellow star and Albireo B smaller and blue. It is believed that these two stars are not actually a binary system and orbiting each other, as Albireo B is most likely 300 light years further past Albireo B, and just appears to be a neighbor as viewed from Earth.
Another fun object to view in the Summer Triangle is M27, the Dumbbell Nebula. The first planetary nebula to be discovered during Messier’s charting of non-comets, the Dumbbell is much larger and closer than the Ring Nebula and has higher reflectivity. This makes it much easier to find with binoculars, and higher magnification with a telescope reveals a beautiful shape and some color.
The Prescott Astronomy Club is doing a star party at Pronghorn Park in Prescott Valley on the evening of
Saturday, September 11.
We often hear “the dog days of summer” used to describe a seasonal period of stagnation or inactivity, usually brought on by long days and extreme heat. In the Arizona central highlands, much as our ancient predecessors experienced in Greece and Rome, this time correlates with the beginning of the monsoon season, connected with heat, drought and sudden thunderstorms.
While we may feel like spending this time lying in a backyard kiddie pool with our dogs, the term has absolutely nothing to do with terrestrial canines, and everything to do with astronomy.
The three stars of Orion’s belt point almost directly to the bright star Sirius, which in ancient times returned to view in the northern hemisphere during the hottest phase of summer, just prior to the annual flooding of the Nile River valley. As the brightest star in the sky and part of the constellation Canis Major (“the Greater Dog”), it is often called the Dog Star, and from this reference we still call this time of year the “dog days of summer.”
This year we can experience the opposition of both Saturn and Jupiter during this time, as we reach closest approach to these gas giants on August 2 and 19, respectively. Just a few days on either side of the August 8 new moon s the best opportunity of the year to view details of these planets and their natural satellites.
With the sun giving us the brightest illumination on these evenings, even smaller and medium-sized telescopes can pick out the weather bands of Jupiter, ring divisions around Saturn, and a handful of moons around each.
Specifically with Jupiter, watch over consecutive nights and sketch the locations of the four Galilean moons you see, documenting how they change position during their orbits from evening to evening.
Join us on the evening of August 7 at Pronghorn Park in Prescott Valley for an opportunity to view these and other objects in the night sky!
July offers longer days but also some great stargazing for the moderate-sized telescope. The constellations Aquila the Eagle, Cygnus the Swan and Lyra the Lyre converge directly overhead at solar midnight, with their three brightest stars forming the Summer Triangle. Easily identifiable asterisms such as the Big Dipper, Southern Cross and Summer Triangle have long been a way for the layperson to identify patterns of stars.
The Big Dipper is probably the first asterism kids in North America become familiar with. Popularized as the Drinking Gourd in an African-American folk song in the 1920s, the end stars of the bowl form a line to the bright star Polaris, the one closest to Earth’s celestial north pole, which helped lead escaped slaves north to freedom.
The Southern Cross is a series of four (sometimes five) bright stars visible in the southern hemisphere nearly any time of year. Used in a similar fashion to find the southern celestial pole, everyone from ancient Pacific navigators to Argentine gauchos have used this grouping of stars to navigate vast tracts of land and desolate expanses of ocean.
Used on no less than ten national, regional and organizational flags, Crosby, Stills, Nash and Young spoke of it in their aptly named 1982 hit “Southern Cross,” positing, “When you see the Southern Cross for the first time, you understand now why you came this way.”
The Summer Triangle is formed by the three bright stars Altair, Deneb and Vega, with Vega the brightest of the three. The second star (after the Sun) to be photographed and the first to have its spectrum recorded, Vega is relatively close at just 25 light-years distant, and is the second-brightest star visible in the Northern Hemisphere. Just below Vega, and directly on the leg of the Triangle formed with Altair, is the Ring Nebula, a small planetary nebula formed when a dying star ejects gas in all directions as it runs out of fuel to maintain nuclear fusion. Visible with three-to four-inch telescopes, you can begin to resolve the rings of gas and eventually the central remaining white dwarf star with eight-inch scopes and higher magnification.
Every 26 months our planets align in a way that shortens travel time from Earth to Mars to about nine months, and as more countries develop space programs, more robotic explorers are sent to the red planet during this window. In 2021 the UAE orbiter Hope arrived on February 9, China’s Tianwen-1 entered orbit on February 10, and the NASA Perseverance rover touched down on February 18.
Perseverance carried with it the Ingenuity helicopter, which has spent the last month proving the first powered flight on another world, and on May 14 Tianwen-1 released the Zhurong rover, making China only the second country to successfully land a rover on the Martian surface.
Mars is easily identifiable with the naked eye, its deep red hue due to high levels of oxidized iron in its crust. Basically the whole planet has rusted over the last couple billion years.
The arrivals of the orbiters and landers in February signaled a (relatively) close approach of our two planets. For most of 2021 they have been moving farther from one another, making Mars lower and dimmer in our night sky.
Sinking closer to the setting sun, Mars enters the constellation Cancer on June 8. As the month wanes, you may be able to catch one last conjunction with Mars passing just 0.5 arc-minutes from the Beehive Cluster M44 on June 23, just minutes after sunset, low in the western sky.
The Beehive Cluster – Messier 44 – is one of the nearest open clusters to Earth. Ptolemy referred to it as the “nebulous mass in the breast of Cancer,” proving how easily identifiable it is with the naked eye. Galileo resolved 40 stars within the cluster, though we now count at least 1,000 stars spread across 39 light-years, close enough to be gravitationally bound with one another. At least three exoplanets are known to orbit stars within the Beehive Cluster.
If you are lucky enough to catch the conjunction of this open cluster and our neighboring planet, both should easily fit within the field of view of your telescope or binoculars. With the right magnification, one can resolve some nebulosity from the Beehive Cluster and the Martian polar ice cap.
Zeus, observing all of this from on high, snatched up the two duelists and placed them in the sky as a lesson to mortals forever to curb their pride. It is also said that Orion now hunts across the heavens for the winter months but is chased away every spring by the return of the scorpion.
As we enter the spring months of 2021, the scorpion is again rising in the eastern sky. This constellation consists of 18 main stars, one clearly outshining the rest. Antares is the 15th-brightest star in the sky, often called the “rival of Mars” from its visibly red hue.
A wide-field view with binoculars reveals a unique ball of light just 1.3 degrees west of Antares, known as Messier 4. M4 is a globular cluster, which initially will appear as a fuzzy cotton ball covering a swath of sky about the size of the Moon.
M4 was the first globular cluster to have individual stars resolved by astronomers in the 18th century. Having spent more than 250 years analyzing this dense gravity well, we now estimate over 20,000 stars are packed into an area just 27 light-years across.
Once you locate M4 with your wide-field view, switch to a telescope or more magnifying eyepiece and you will begin to resolve some of the outlying stars and see how densely packed the center of this cluster truly is.
From M4, move slightly northwest to find another globular cluster. Messier 80 contains several hundred thousand stars spread across approximately 95 light-years. Despite having many more stars, M80 is less visible through binoculars due to its distance, at 3,200 light-years, as opposed to the much closer M4 at 7,200.
Charles Messier initially began sketching and cataloging anything that was not a comet using a four-inch refracting telescope, adopting the Latin word for “cloud,” which he used to classify his objects as either a star cluster or “nebula.” He documented Messier 51 in 1773 as one of these first 110 objects. William Parsons again observed M51 in 1845 with a 72-inch reflecting telescope, resolving what he dubbed the first spiral nebula. His 1845 drawing clearly defines what we now know to be a spiral galaxy, however it was not until the 1920s that Edwin Hubble, using the 100-inch Hooker telescope at Mount Wilson Observatory in Los Angeles, proved that our Milky Way was just one of an untold number of galaxies spinning through the cosmos.
Modern astronomers now use the relationship of M51 and neighboring NGC 5195 to study how galaxies interact. Due to its near-constant observation, three recent supernovae have been observed in M51, in 1994, 2011, and 2019. Just in September 2020 a potential exoplanet was detected in M51 using the eclipsing-transit method for observing distant stars. If confirmed, this would be the first planet discovered outside our galaxy. By way of comparison, all the current exoplanetary candidates in the Milky Way galaxy are within a radial distance of no more than 25,000 light-years. The candidate in the Whirlpool Galaxy is 31 million light-years distant.
Today many amateur astronomers enjoy M51 or the Whirlpool Galaxy as a good place to learn how to hop from star to star in search of other objects in the sky. The basic spiral structure of the galaxy can be seen with a good pair of binoculars or small telescope, and is relatively easy to find through much of the year. Start at the Big Dipper, locating the last two stars in the handle. Moving southwest 3.5 degrees at a near right angle, the Whirlpool Galaxy and its companion galaxy are unmistakable, first as an elongated fuzzy gray ball, then resolving in greater detail with larger scopes.
A prime example of this is the northern equinox, which we most commonly refer to as the spring or vernal equinox, although if one resides south of the equator, it’s more correctly the fall or autumnal equinox. On this day the center of the sun is directly perpendicular to the equator.
Derived from the Latin aequus (“equal”) and nox (“night”), March 20 and September 23 represent the two points in the year that most closely approximate equal times of day and night across the planet.
Ancient cultures did not recognize the exact angle of the sun relative to the center of the earth, but rather that the sun would rise and set directly east and west. The equinox also became a date for the beginning of many annual calendars and subsequent regional festivals.
The Persian and Indian calendars both begin on the day of or day immediately following the northern equinox, and are still used today in their respective countries. The Babylonians began their calendar on the first new moon following the March equinox, celebrating the return of the goddess Inanna from the underworld. The Jewish Passover and Christian Easter are both calculated based on the first full moon after the vernal equinox.
The equinox is a perfect time to do home science projects. You can wake up with the sun and measure for yourself the exact hours of daylight. Find a local sundial (Sharlot Hall Museum!) or make one yourself, align it using a compass to magnetic north, and find what the solar time is at your home.
Last but not least, maybe we can bring back broom-balancing and pretend it’s real science!
Monoceros – ‘mono’ meaning ’one’ and ‘ceros’ meaning ‘horn,’ or the Unicorn — is a simple seven-point constellation, though only two of the stars are usually discernible without the aid of binoculars or telescope. Dutch mapmaker Petrus Plancius first noted the Unicorn in 1612, with others following through the 17th century. With better telescopes William Herschel studied the area in 1781, becoming the first to discover that Beta Monocerotis, the brightest of the constellation’s stars, is actually three separate entities, observed as a curved line of pale blue-yellow stars. He later described this triple-star system as “one of the most beautiful sights in the heavens.”
Using a telescope to starhop around the dark areas among these constellations, you can find a slew of other heavenly surprises. The Rosette Nebula (NGC 2244) is known for its ring shape and dense nebulosity. The open cluster Messier 50 and NGC 2506 will appear as fuzzy cotton balls in the smallest apertures, and larger scopes can begin to define many close stars.The real highlight of Monoceros, though, is NGC 2264, the Cone Nebula. Appearing as though a celestial bowling ball was thrust down a foggy lane, parting the fog around it, a dark cone imparts densely defined edges to a large diffusion of nebulous clouds. At 2,600 light-years distant it is one of the closer nebulae to Earth, and covers a large swath of space with star-forming elements to create its stellar nursery. Along with the Fox Fur Nebula, this diffuse nebula is often referred to as the Christmas Tree Cluster due to its triangular shape with a star at the apex.
Take your binoculars or telescope out and start at the bright star Betelgeuse in Orion, exploring the area just below and down to the Hunter’s belt. As you scan the sky, moving downward toward the Beta Monocerotis triple-star system, you’ll be surprised at what you find.
the Moon is directly between the Earth and the Sun? — a solar eclipse.
the Earth is directly between the Moon and the Sun? — a lunar eclipse.
the Sun is directly between the Earth and the Moon? — an apocalypse!
The word ‘eclipse’ stems from the Greek ekleipsis, meaning, “failure to appear.” Between two and five times each year the Sun fails to appear, either partially or in full, due to the orbital mechanics of Earth, Sun and Moon. As the Earth swings around the Sun and the Moon spins around the Earth, their orbits periodically line up to where they are on a direct line, causing the Moon’s shadow to cover a small portion of the Earth’s surface.
“Small” is a relative term here, as we experienced on August 21, 2017, when the shadow of the Moon traversed from the Pacific northwest to the southeast United States. Where the shadow completely blocks out light from the sun, we call it ‘totality.’ While the path of totality in 2017 covered thousands of miles and amazed millions of onlookers, we know that the Earth’s surface is mostly uninhabited, covered by dense forest, vast desert, frozen tundra or open ocean. So many eclipses go unseen, able to cross thousands ofmiles of the Pacific Ocean with few if any human viewers.
Eclipse-chasers from around the world reserve hotels and campsites years in advance to get views of these rare events.
In central Yavapai County we were able to observe a partial eclipse in 2017, with the Moon covering at most 76% of the Sun. Sometimes we see partial eclipses where the Moon is slightly farther from Earth in its orbit, causing it to block out the center of the Sun, leaving a ring of light around the Moon. This is called an annular eclipse, such as that seen at the Grand Canyon on May 20, 2012. Also called a Ring of Fire eclipse, these events make for great images, but only with the proper equipment — even the small ring of light radiating from the Sun can damage your eyes. The next annular eclipse visible in our area will come on October 14, 2023.
Just a few months later, a total solar eclipse will once again grace the skies of North America on April 8, 2024. The path of totality will cross Mexico and Texas, continuing over much of the Midwest and almost directly over Indianapolis and Buffalo, then on to northern Maine.
Should you want to travel for a view of totality, book your reservations now! Eclipse-chasers from around the world reserve hotels and campsites years in advance to get views of these rare events. If you don’t intend to travel, mark your calendar to keep an eye out for local events to celebrate with amateur astronomers and skywatchers locally.
Homes, businesses, pets and even an iconic tree along the highway are all adorned with lights representing hues across the spectrum.
At home the celebratory scenes carry over from outside to inside, blanketing every room of our house. We love this time of year and the joy we receive from all the lights and colors around our community.
One can enjoy these splendid colors gracing the night any time of the year, just by looking to the heavens. The constellation Orion is full of colors, though you might need a pair of binoculars or a small telescope to define some of them. Deep red/oranges and bright blue/whites are all easily discernible against the inky backdrop.
The easiest grouping of stars to find is the belt of The Hunter. Three stars in a nearly straight line rise almost vertically above the eastern horizon each evening. Just to the lower right of the bottom star in the belt is The Hunter’s sword, a cluster of three more stars that contain the Orion Nebula. Even the smallest viewing instruments can begin the resolve the beautiful colors of this hydrogen-rich star nursery 1,300 light years from earth. Larger and more advanced scopes will often photograph this nebula with various filters to accentuate the variety of elements comprising this massive cloud of star dust.
Working around the perimeter of the constellation, the left shoulder of Orion is Betelgeuse, one of the largest stars visible to the naked eye, apparent by the bright red hues it emits. Continuing clockwise around the belt are Bellatrix, Rigel, and Saiph, each with a cool blue-white tone.
Varying in distance from about 250 to over 2,000 light years, the stars in the Orion constellation give the amateur astronomer the perfect opportunity to learn their new equipment and the sky. Take a few evenings this month and use different eyepieces to look at the stars and nebulae in Orion. There are three nebulae and multiple double-star systems, How many can you find?