What’s Up? – February, 2024

Constellations, Planets, and Astronomical Events Visible in February 2024

Written and Compiled by Alyssa Whalen

 

While winter brings cold winds and slippery sidewalks, it also brings long nights to go out and observe! However, the long nights are growing shorter with each passing day. The sun rises around 7:25 am, and sets around 6:05 pm every evening, providing 10 hours and 40 minutes of sunlight, though it varies slightly every day. On average, approximately 2 minutes and 27 seconds of daylight is added every day this month.

February’s full moon occurs the night of February 24th. This full moon has two names given by Native American Tribes. The first, and most common name is the Snow moon, named for the heavy snowfall experienced during this time of year. However, the winter months also made hunting difficult, which is how it also got the nickname the Hunger moon from some tribes. February’s new moon occurs earlier in the month on February 9th. In the lucky event that the sky is clear this winter, the best time to observe is always during a new moon, since the moon’s bright shine can make fainter objects impossible to view.

February is not a great month to observe planets this year. Mercury, Venus, Mars, and Saturn are all too close to the sun to observe this month. Mercury and Mars will show themselves again in our sky next month, but Saturn won’t be visible until early May. Saturn has begun its long journey behind the sun; however it will be visible in the day during the solar eclipse on April 8th if you are able to find yourself within the path of totality with clear skies.

Jupiter is the crown jewel of the sky this month. It is nearly overheard after the sun sets, and it will set near midnight this month. Uranus is closely behind Jupiter, setting at 1am, but the ice giants Uranus and Neptune are not visible without the aid of powerful binoculars or a telescope.

Auriga is a lesser known constellation that is directly overhead between sundown and midnight. Auriga is Latin for Charioteer, and it is located on top of Taurus. In fact, the two constellations share the star Elnath, which is known as both Beta Tauri and Gamma Aurigae. While looking for Taurus is the easiest way to find Auriga, it can also be identified by the bright star Capella that is located to the west of the constellation Gemini.

Northwest of Auriga is the constellation Perseus, named for the mythological Greek hero. Perseus is most well known to be the home of the Alpha Persei Star Cluster. This cluster is found through the star Mirfak, the brightest star in Perseus; however, the star cluster contains many stars within the constellation. Another bright star cluster is visible this month: the Pleiades! This famous cluster is located in the constellation Taurus. Also called “the Seven Sisters” the Pleiades cluster contains hundreds of stars, but there are seven bright blue stars that are easily visible with the naked eye. This cluster is a beautiful sight for any astronomer on a clear winter night.

 

Happy Observing!

 

Sources:

https://www.timeanddate.com/sun/@5165418?month=2&year=2024

http://www.seasky.org/astronomy/astronomy-calendar-2024.html

https://www.timeanddate.com/astronomy/night/@5165418

https://stellarium-web.org/

 

Image Credits:

Sunset: https://unsplash.com/s/photos/winter-sunset

Jupiter: https://www.space.com/jupiter-opposition-closest-approach-skywatching

Credit: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley)

Winter Constellations: https://stellarium-web.org/

Pleiades: https://www.space.com/pleiades.html

Credit: Manfred_Konrad

When Did Our Planetary Neighbors Move Out?

Written by Alex Torres

Something that has captured my curiosity, and indeed the curiosity of many astronomers, is why the Earth is the only terrestrial planet we know to currently harbor life. Looking at the other potential candidates in the habitable zone around our Sun, Venus and Mars, the answer seems rather obvious. Venus is often described as a hellscape with surface temperatures hot enough to melt lead, a surface pressure equivalent to being one mile underwater on Earth, as well as a host of other characteristics that make it about as inhospitable to life as we can think of. On the other hand, Mars has an average surface temperature of -85°F (-65°C) with a surface atmospheric pressure equivalent to less than one hundredth that of the Earth’s at sea level. Weirdly enough, despite these two planets being almost complete opposites in just about every way, they are the same with respect to one crucial characteristic: neither are capable of supporting liquid water at their surfaces. Both Mars and Venus are bone dry, the water having evaporated due to lack of pressure on the former and extraordinarily high temperatures on the latter. Mars, however, is capable of supporting long term frozen water on its surface, giving it a slight advantage over Venus on its water content, but regardless, neither has surface conditions capable of supporting life as we know it on Earth whose chemistry relies on liquid water. Though, interestingly enough, it is possible and even likely that both planets had liquid water on their surfaces at some point in the past. While this may be surprising given their current state of affairs, it is important to consider that both planets were not always as they currently are, and they both owe their transformations over time to the Sun.

Let’s begin with Venus shortly after its formation. Soon after Venus’s surface solidified, it would have had surface temperatures very similar to modern-day Earth. Without its incredibly thick carbon dioxide atmosphere, Venus with its closer proximity to the Sun coupled with the Sun’s lower luminosity in the past would have put the planet smack dab in the middle of the habitable zone, allowing liquid water to sustainably exist on the surface. Estimates for how long this liquid water remained on Venus range from about one billion years after its formation to just a billion years ago that Venus lost its water. Regardless of how long it could have sustained liquid water on its surface, given that Venus formed in a similar manner as the Earth in the same environment, we are relatively confident that Venus had surface oceans at one point. What makes this a truly interesting fact to consider is that we know life on Earth developed pretty much right after our planet’s surface solidified and the oceans formed. This means that before Venus became the hot, greenhouse world it is today with sulfuric acid rain and surface pressures capable of smashing a person like a pancake, it could have supported life. Of course, as the Sun became more luminous over time, any oceans on Venus would have evaporated, allowing for all the carbon locked up in that water and the underlying surface rock to escape into the atmosphere and form the extremely thick CO2 blanket that envelopes Venus today. What’s more, as the planet underwent this runaway greenhouse transformation, its atmospheric temperature increased which, in conjunction with Venus’s lack of intrinsic magnetic field to deflect solar wind, caused the gaseous H2O on Venus to reach escape velocity in the upper atmosphere and leak from the planet until pretty much no water remained. Therefore, even though it was the evaporation of its oceans that kick started its runaway greenhouse transformation, very little water remains in the Venusian atmosphere at all.

On the other hand, even though Mars would have received even less energy from the Sun in the past than it does presently, it too would have had more favorable conditions for liquid water right after formation due to more significant internal heat and a more substantial atmosphere. When Mars was still molten inside, it likely had a magnetic field much like the Earth does currently which would have protected it from high energy solar radiation. Therefore, it could have hosted a much thicker atmosphere than it does now without the solar wind stripping it away, and with the presence of that atmosphere and its associated greenhouse effect, Mars would have had a higher surface temperature than it would otherwise. This higher surface temperature above the freezing point of water in addition to an atmospheric pressure at the surface capable of keeping water from boiling could have allowed Mars to host liquid water on its surface in the past. There is even well-studied evidence for surface water having existed Mars in the form of visible river deltas, valleys potentially carved out by liquid water, and basins where water could have resided in the form of lakes and oceans. However, due to Mars having a significantly smaller volume than Earth, and therefore a larger surface area to volume ratio, Mars radiated away its internal heat much faster than the Earth. As the mantle and core of Mars cooled off, the dynamo powering its magnetic field shut down exposing the Martian atmosphere to high energy solar wind capable of stripping away gas from the planet with its relatively low gravity. Over time, this means that the surface of Mars would have cooled off without its insulating atmosphere, forcing much of the surface water to freeze with any remaining liquid water doomed to boil away due to the low atmospheric pressure.

In the end, this means that our two next door planetary neighbors, Venus and Mars, both likely had everything they needed to host life just like the Earth. However, by the time the Earth would go on to develop multicellular life with the Cambrian Explosion a few hundred million years ago, Venus and Mars would already have been dry, desolate wastelands with little hope of harboring any form of life at all on their surfaces. It is a little disappointing to think of all we could have missed out on with two planets right next door hosting life just as cool, crazy, and complex as that on Earth, but at the same time, perhaps Venus and Mars never had life at all. Maybe Earth really is unique in its development of life, and even in the billions of years that Venus and Mars had oceans, all of their water never hosted anything more interesting than lifeless molecules. The point is that we can speculate all we want about the enigmatic histories of our planetary neighbors, but what is truly interesting is our ability to actually visit these alien worlds for ourselves and figure out if they truly ever did host aliens of their own.

 

References

Atmosphere of Mars. (n.d.). Wikipedia. Retrieved November 6, 2023, from https://en.wikipedia.org/wiki/Atmosphere_of_Mars

Brooks, F. (n.d.). Mars. Wikipedia. Retrieved November 6, 2023, from https://en.wikipedia.org/wiki/Mars

Choi, C. Q. (2016, October 14). Water on Mars: The Story So Far | News | Astrobiology. NASA Astrobiology. Retrieved November 6, 2023, from https://astrobiology.nasa.gov/news/water-on-mars-the-story-so-far/

Climate of Mars. (n.d.). Wikipedia. Retrieved November 6, 2023, from https://en.wikipedia.org/wiki/Climate_of_Mars

Dynamo theory. (n.d.). Wikipedia. Retrieved November 6, 2023, from https://en.wikipedia.org/wiki/Dynamo_theory

Magnetic field of Mars. (n.d.). Wikipedia. Retrieved November 6, 2023, from https://en.wikipedia.org/wiki/Magnetic_field_of_Mars

McCall, R., Hammer, J., & Robison, M. (2019, September 23). Venus May Have Been Habitable for 3 Billion Years. Newsweek. Retrieved November 6, 2023, from https://www.newsweek.com/venus-habitable-three-billion-years-before-runaway-greenhouse-effect-1460686

New Models Show That Venus Was Likely Habitable Four Billion Years Ago. (2019, March 9). Forbes. Retrieved November 6, 2023, from https://www.forbes.com/sites/brucedorminey/2021/09/24/new-models-show-that-venus-was-likely-habitable-four-billion-years-ago/?sh=523478f41caf

Scudder, J. (2015, February 12). The sun won’t die for 5 billion years, so why do humans have only 1 billion years left on Earth? The Conversation. Retrieved November 6, 2023, from https://theconversation.com/the-sun-wont-die-for-5-billion-years-so-why-do-humans-have-only-1-billion-years-left-on-earth-37379

Solar System Temperatures. (n.d.). NASA Science. Retrieved November 6, 2023, from https://science.nasa.gov/resource/solar-system-temperatures/

Sutter, P. (2019, August 7). How Venus Turned Into Hell, and How the Earth Is Next. Space.com. Retrieved November 6, 2023, from https://www.space.com/venus-runaway-greenhouse-effect-earth-next.html

Tomaswick, A. (2020, August 23). Did Jupiter Push Venus Into a Runaway Greenhouse? Universe Today. Retrieved November 6, 2023, from https://www.universetoday.com/147535/did-jupiter-push-venus-into-a-runaway-greenhouse/

 

What’s Up? – November, 2023

Constellations, Planets, and Astronomical Events Visible in November 2023

Written and Compiled by Alyssa Whalen

 

The weather continues to grow colder as Autumn reaches its peak, but the nights are growing longer, so it’s time to bundle up and go out to observe! This month we have to remember the end of daylight savings time. On the morning of November 5th, don’t forget to set your clocks 1 hour earlier. After the clock adjustment, the sun will be rising around 7:15 am and setting around 5:15 pm. This means we will have an average of 10 hours of daylight every day this month. Each day, we will lose nearly 2 minutes of daylight. This rate will decrease until the winter solstice next month, where we will then start gaining daylight back.

 

 

This month’s full moon occurs on November 27th. It is commonly referred to as the Beaver Moon, since this is when the Native Americans would set their traps to hunt the beaver. The new moon occurs on November 13th, nearly perfect time to observe the meteor showers that occur this month.

There are two meteor showers this month: the Taurids and the Leonids. The Taurids are a minor meteor shower that produces 5-10 meteors at its peak. It is a long running shower that runs from September 7th to December 10th; this year it peaks on the night of November 4th. Meteors will radiate from the constellation Taurus, which rises around 10pm. The third-quarter moon might make viewing difficult, so the best way to observe this shower would be from a dark sky sight. The combination of light pollution, the third quarter moon, and the low rate of meteors make this shower difficult to observe, but with some patience there should be a few visible meteors

The Leonids run annually from November 6-30, and peaks on the evening of November 17th. This year, the shower is expected to produce around 15 meteors per hour at its peak, but it is unique in that it actually varies in intensity. It has a 33 year cyclical period where the rate of meteors varies greatly, and at the peak of this 33 year period there can be hundreds of meteors every hour! The peak was last observed in 2001, so we can look forward to quite a show in November 2034. Until then, we can enjoy a moderate shower this year thanks to the waxing crescent moon keeping the sky dark. The meteors will radiate from the constellation Leo, which does not rise until the early morning, so the best time to observe the shower will be after 3 am on the morning of November 18th.

 

 

Mercury is too close to the sun to easily observe at the start of November, but it will continue to move further to the east, so it will become more visible in the evenings later in the month. Venus is still easily visible in the morning sky before sunrise, but it is moving closer to the sun so there will be a time soon when it is invisible in our sky. Mars is still behind the sun, and it will be impossible to observe until next May.

Both Jupiter and Uranus are in opposition this month. Opposition means that a line can be drawn from the Sun, through Earth, to the planet. From our perspective, the surface of the planet will be fully illuminated by the sun, and it will rise at sunset, and set at sunrise. Jupiter’s opposition occurs on November 3rd, and Uranus’ opposition occurs on November 13th. Opposition is the best time to observe planets, since they will be at their brightest. However, Uranus will still not be visible without the aid of a telescope since it is extremely far away, and therefore very dim.

Saturn is starting the night closer to the western horizon. This means it is starting to set only a few hours after sunset. Soon, Saturn will make its journey behind the sun where it will be invisible to stargazers on Earth, just as Mars is right now. Neptune is slightly further east than Saturn. It will be up at sunset and it will set around 2:30 am; but it is too faint to observe without the aid of a telescope.

 

It is time to say goodbye to the summer triangle. It will still be visible in the western sky at sundown this month, but it will continue to begin the night closer to the horizon. By mid-November, it will no longer be observable until it rises again next summer. However, the end of the summer constellations means the beginning of the winter constellations! The famous hunter, Orion, is visible in the late night/early morning. He chases Taurus the Bull toward the western horizon. These famous winter constellations currently rise around 10 pm, but as we approach the winter season, they will continue to rise earlier in the night.

 

Sources:

https://www.timeanddate.com/sun/@5165418?month=11&year=2023

http://www.seasky.org/astronomy/astronomy-calendar-2023.html

https://www.timeanddate.com/astronomy/night/usa/columbus

https://stellarium-web.org/

 

Images:

Full Moon: https://inews.co.uk/news/long-reads/beaver-moon-full-november-2021-meaning-names-why-science-explained-448478

Meteor Showers: https://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide/

Jupiter/Galilean Moons: https://www.thoughtco.com/tour-of-jupiters-moons-3073639

Image Credit: Carolyn Collins Petersen

Taurus/Orion: https://stellarium-web.org/

 

What’s Up? – October, 2023

Constellations, Planets, and Astronomical Events Visible in October 2023

Written and Compiled by Alyssa Whalen

Happy autumn! With the September equinox behind us, we have passed into the astronomical start of the fall season! For those of us in the northern hemisphere, the sun is now below the horizon more than above it. The sun rises around 7:45 am and sets around 6:50 pm, providing 11 hours of sunlight throughout the day. However, the sunrise/sunset times vary greatly throughout the month. Every day, we lose an average of 2 minutes and 30 seconds of sunlight. Nights will continue to grow longer until the winter solstice in December, but longer nights means more time to go out and observe!

There is a solar eclipse occurring this month! A solar eclipse is when the moon passes directly between the Sun and Earth. When this happens, the moon’s shadow falls on a fraction of the Earth’s surface, and creates a path of darkness as it moves across the sun. This path is called the path of totality, and it is the best place to view the full spectacle that a solar eclipse creates. Solar eclipses are especially interesting on Earth because our moon happens to have the right combination of size and distance to appear nearly the same size as the Sun; however, the moon’s apparent size does have some variation since its orbit around Earth is not completely circular. This variable moon size is what differentiates a total solar eclipse from an annular solar eclipse. A total solar eclipse is when the moon completely blocks the sun’s light, allowing people in the path of totality to see the sun’s corona which is typically invisible to the unaided eye. An annular solar eclipse occurs when the moon appears smaller than during a total eclipse, so it does not completely block the sun. The moon still casts its shadow, but the edges of the sun’s surface can be seen behind it creating a ‘ring of fire.’

This month there is an annular solar eclipse on October 14th. Sadly, the ring of fire will not be visible in Ohio; here we will only see a partial solar eclipse. From our perspective, the moon will cover between 30-40% of the sun at its peak. For those in Columbus, the eclipse will begin at 11:46 am, and it will reach its peak at 1:07 pm. This partial eclipse will still dim the sun drastically, but Ohioans will have to wait until April 8th, 2024 to see a total eclipse. Mark your calendars and hope for clear skies, because that should be a sight to behold!

The new moon occurs at the same time as the solar eclipse on October 14th. The moon’s phases as viewed from Earth show us where the moon is in its orbit relative to the sun. Just as half of the Earth is always day and half is always night, the moon has a day side and night side too. When the moon is full, it is on the opposite side of the sun, so the side that is facing Earth is fully illuminated. When it is a new moon, the moon is between the sun and Earth, so we can only see its night side. Solar eclipses can only occur during new moons, because the moon is positioned between the Earth and the Sun. On the other hand, lunar eclipses can only occur during full moons because that is when the Earth is between the moon and Sun. October’s full moon occurs on the night of October 28th. This moon is nicknamed the Hunter Moon, because this is the time of year that game is hunted.

October is a busy month for astronomical events; on top of the eclipse, there are two minor meteor showers peaking this month. The first is the Draconids shower. This minor shower runs annually from October 6-10, and it is caused by the remnant dust from the comet 21P Giacobini-Zinner. This year, the Draconids peak the night of October 8th with a rate of approximately 10 meteors per hour. Due to its low rate, it will be difficult to observe from light polluted areas, but it should make for a pleasant evening shower if you find yourself in a dark sky area.

The second shower this month is the Orionids. This shower runs annually from October 2nd – November 7th annually, and this shower is caused by the remnants of the famous Halley Comet. It peaks the night of October 20th, but the first quarter moon will make evening viewing more difficult. At its peak, there is expected to be around 20 meteors per hour, and it will best be observed in the early mornings as the moon sets and the constellation Orion rises higher in the sky.

Mercury will be difficult, but possible to observe in the first week of October before it is too close to the sun. With each passing day, Mercury moves closer to the sun, but it is slightly visible in the early morning before sunrise. Venus will continue to be perfectly visible every morning throughout the month. In fact, Venus reaches its greatest western elongation on October 23rd, meaning it is located at its furthest west point from the sun in our sky. It will rise approximately 4 hours before sunrise. On a clear night, Venus is so bright it is possible to cast shadows. Besides the sun and moon, Venus is the brightest object in our sky, which gives it its nickname: the Morning Star. Mars remains too close to the sun to observe. Relative to Earth, Mars is beginning its journey behind the Sun. It won’t be visible again until late January where it will begin to rise in the mornings before sunrise.

Both Jupiter and Saturn are perfectly visible throughout almost the entire night. Jupiter rises about 2 hours after sunset, and will remain in the sky through sunrise. Saturn will already be above the eastern horizon once the sun sets, and it will set in the early morning near 3:30 am. The Ice Giants Uranus and Neptune will both be up during the night, but they are both nearly impossible to observe with the naked eye alone. Uranus rises 30 minutes behind Jupiter, and it is located in the constellation Taurus. Neptune rises an hour after Saturn, but it will still rise before sunset. It is located on the western edge of the constellation Pisces.

This month, I am going to step back and discuss the zodiac constellations. As Earth orbits the Sun, the position of the Sun in our sky changes. With respect to the stars, the sun moves slightly further east every day. Over the course of a year, the sun will make a full loop, and return to the same position in our sky. The path the sun takes as it moves throughout the year is called the ecliptic. The zodiac constellations are the constellations that the ecliptic passes through. The twelve zodiacs are made popular by horoscopes and astrology; however, there is a thirteenth zodiac constellation that is excluded from popular culture. A portion of the constellation Ophiuchus falls in the path of the ecliptic, and it is dismissed.

The zodiac constellations we know today were created by the Babylonians 3,000 years ago, and even then they knew about the 13th constellation in the sun’s path; they chose to omit it so that the zodiac would neatly match their 12 month calendar. In most cases, stars in a constellation have no relation to one another; they happen to appear in some formation in our sky, and ancient humans used the formations they saw to tell stories. Different cultures saw different pictures in the stars, and told different stories – such as Maui’s Hook as opposed to Scorpius in Polynesian culture. While the International Astronomical Union (IAU) has officially recognized constellations, they are mostly derived from Middle Eastern, Greek, and Roman culture. The constellations that fall upon the ecliptic could have been much different if IAU decided to use other cultures’ interpretations of the sky.

Sources:

https://www.timeanddate.com/sun/@5165418?month=10&year=2023

http://www.seasky.org/astronomy/astronomy-calendar-2023.html

https://solarsystem.nasa.gov/eclipses/about-eclipses/types/

https://education.ohio.gov/Topics/Learning-in-Ohio/Science/Resources-for-Science/2024-Solar-Eclipse#:~:text=On%20Saturday%2C%20October%2014%2C%202023,partial%2C%20annual%20and%20total%20eclipses.

https://www.timeanddate.com/eclipse/in/usa/ohio?iso=20231014

https://www.timeanddate.com/astronomy/night/usa/columbus

https://stellarium-web.org/

https://time.com/5867647/nasa-zodiac-star/

https://www.lpi.usra.edu/education/skytellers/constellations/#:~:text=Most%20of%20the%20constellation%20names,and%20objects%20of%20their%20stories.

 

Images:

Annular Eclipse: https://solarsystem.nasa.gov/eclipses/2023/oct-14-annular/overview/

Image Credit: NASA/Bill Dunford

Eclipse Path: https://www.greatamericaneclipse.com/october-14-2023

Image Credit: Michael Zeiler

Moon Phases: https://www.astronomy.ohio-state.edu/pogge.1/Ast161/Unit2/phases.html

Draconids: https://earthsky.org/astronomy-essentials/everything-you-need-to-know-draconid-meteor-shower/

Orionids: https://earthsky.org/clusters-nebulae-galaxies/everything-you-need-to-know-orionid-meteor-shower/

Venus (Morning Star): https://earthsky.org/sky-archive/venus-spectacular-in-morning-sky/

Image Credit: Larry Estes

Zodiac Diagram: https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_%28OpenStax%29/02%3A_Observing_the_Sky_-_The_Birth_of_Astronomy/2.01%3A_The_Sky_Above

An Extreme Solar System Wonder

written by Alex Torres

The Solar System is filled with a massive diversity of unique celestial bodies, the scope of which is hard to imagine. Not only do we see huge variety among the eight main planets, the Solar System contains all kinds of objects with wildly different properties, including asteroids, trans-Neptunian objects, comets, and moons. While our Solar System is far from the only kind of star system present in the universe, it is a great demonstration of the amazing sights, places, and objects that our universe has to offer.

However, one object in particular has the ability to stand out as especially unique even in the most incredible subsystem of our own Solar System. I am of course talking about IO in orbit around the King, Jupiter. It is no secret that I LOVE Jupiter and everything associated with the absolutely spectacular, grand planet. However, even with how much I love Jupiter by itself, IO still manages to capture a lot of my wonder of the Jovian system. Though, enough about me, let’s talk about why exactly IO is one of the craziest places in the known universe.

Although IO is commonly depicted with vivid yellows, reds, and greens (see image on the left), this is likely more exaggerated than IO would actually appear to the human eye (see image on the right)

Even just looking at the planet, it is immediately clear that it is different from most of the rocky bodies in our Solar System. For one thing, it has a noticeably not gray color, something very easy to spot in comparison with our Moon. IO’s assortment of yellows, greens, and reds is likely due to large amounts of sulfur on the moon’s surface, something you may have seen around hot springs and geysers here on Earth at places like Yellowstone. Just like on Earth, IO has volcanoes that produce this sulfur, with larger eruptions spewing material as much as 300 miles into the air, some of which later falls back down onto the moon and frosts over. Unlike Earth, however, the surface of IO is dominated by these sulfur deposits because eruptions on IO occur very, very frequently. In fact, IO is the most volcanically active body in the entire Solar System, and it is the only other known body in the Solar System besides Earth to have volcanic activity producing surface lava. Some of this lava can reach temperatures as high as 1300 °C, hotter than any found on Earth which caps out at about 1200 °C. If you were reading carefully, however, you might have noticed that the sulfur blanketing the surface of IO is frosted over, a feat that IO apparently manages with 1300 °C lava as well. In fact, most of IO’s surface remains at -130 °C with only select volcanically active locations getting up to the aforementioned 1300 °C. This gives IO one of the largest, if not the largest, temperature differentials on the surface of any object in the Solar System other than the Sun.

The reason that IO is so cold on average is because it is really far away from the Sun, about five times further away than the Earth is. However, IO still manages incredibly active geological processes due to something called tidal heating. IO is the closest of the Galilean moons to Jupiter, and in fact, it orbits almost as close to Jupiter as the Moon orbits to Earth (262,000 mile average orbital radius as opposed to 239,000 mile average orbital radius for the Moon). Being so close to the most massive object in the Solar System, other than the Sun, subjects IO to incredible gravitational forces. However, the other Galilean moons, most notably Europa and Ganymede which share an orbital resonance with IO, tug on IO in its orbit around Jupiter. While this tugging is nowhere near enough to pull IO out of orbit from around Jupiter, it is enough to give IO an abnormally eccentric orbit. As a result, even though IO is tidally locked with Jupiter, the oblong orbit of IO causes the tidal bulge from Jupiter to change both in size and location relative to a fixed point on the surface of the moon as IO goes around its host planet. With tidal forces creating bulges as high as 100 meters from stretching solid rock, this creates a LOT of internal friction inside IO, enough to keep the moon at least partially molten underneath its crust. In fact, this tidal heating may keep IO geologically active enough to have its own induced magnetic field. Regardless, this tidal heating is why IO is the most volcanically active body in the Solar System, with regular eruptions producing plumes both higher and with a larger volume of ejecta than any known eruptions in Earth’s recent history (this is partially due to IO’s weaker gravity, but it is nonetheless impressive and awe-inspiring to think about).

 

These frequent large eruptions launch a lot of material away from IO and into orbit around Jupiter. In fact, there is a large collection of atomic material in orbit around Jupiter called the “neutral cloud” which IO is responsible for and shares an orbit with. Additionally, IO is the main contributor to a cloud of charged particles around Jupiter called the “plasma torus” which also shares an orbit with IO. However, the plasma torus travels faster than IO due to the Jovian magnetic field rotating with Jupiter itself and pushing the particles of the plasma torus along with it. The movement of charged particles in the plasma torus allows for Jupiter’s magnetosphere to be several times larger than it otherwise would be if Jupiter was the only contributor to its own magnetic field. Furthermore, because the plasma torus moves faster around Jupiter than either the neutral cloud or IO, particles from the plasma torus frequently collide with particles in the thin atmosphere of IO as well as in the neutral cloud. This interaction creates more charged particles that themselves join the plasma torus. Because of this constant replenishing of the plasma torus, it does not dissipate over time, and its magnifying effect on Jupiter’s magnetosphere remains consistent over time.

Another interesting interaction of Jupiter’s magnetic field with IO is a flux tube of magnetic field lines through IO that generates a potential difference of 400,000 volts across and a current of three million amps through the moon. This current generates electromagnetic waves that travel along the magnetic field lines of Jupiter before interacting with the planet at its poles, contributing heavily to the massive lightning storms and aurora on the Solar System’s most massive planet.

Image courtesy of the James Webb Space Telescope

This post is starting to get very long, but before I end it, I want to share a few other fun facts about IO that I feel are worth noting:

  • IO is the densest moon in the solar system with the highest surface gravity because of that density
  • In terms of atomic ratios, IO has the lowest amount of water out of any known body in the Solar System (including the Sun). This contributes heavily to its higher density when compared to other moons in the outer Solar System, so while IO is made mostly of metals and silicates, other moons derive much of their mass from water-ice. It is possible that IO’s tidal heating is responsible for its very low quantity of water-ice, however, Europa, which also has a much higher density than other outer Solar System moons, has a much lower proportion of water-ice than other outer Solar System bodies with no known volcanic activity. Indeed, the mass density of the Galilean moons decreases as you get further away from Jupiter, so there could be a different process entirely responsible for IO’s low composition of water-ice that I simply did not stumble upon in my research
  • IO has one of the youngest surfaces in the Solar System due to volcanic activity that constantly reshapes the moon’s appearance. As opposed to Callisto which has the oldest and most heavily cratered surface in the entire solar system with an appearance that has likely not changed for over four billion years, the surface of IO is likely only a few million years old
  • Tides on Earth due to the Moon can cause a difference in water level of at most about eighteen meters from low tide to high tide. The tidal bulge on IO, on the other hand, is an astounding 100 meters tall, and that is the result of solid rock being warped rather than simply liquid water here on Earth
  • While the Earth has 600 active volcanoes as compared to the 100 known volcanoes on the surface of IO, the volcanoes on the Jovian moon put out twice as much energy as the volcanoes on Earth. Additionally, just one volcano on IO, Loki, is more powerful than all of Earth’s volcanoes combined
  • While calderas, volcanic craters, and lava flows exist on both IO and Earth, they are all much larger on IO. Additionally, not only is the lava much hotter on IO, but IO also erupts 100 times more lava each year than Earth does (including underwater eruptions on Earth)

 

Citations:

https://www.youtube.com/watch?v=98iCzrNRWmQ

https://science.nasa.gov/jupiter/moons/io/facts/

https://en.wikipedia.org/wiki/Volcanism_on_Io

https://www.youtube.com/watch?v=8QSl_t65wnw&t=317s

https://www.britannica.com/science/lava-volcanic-ejecta

https://www.jpl.nasa.gov/news/lava-flows-freely-on-jupiters-moon-io

https://en.wikipedia.org/wiki/Orbit_of_the_Moon

https://www.discovermagazine.com/the-sciences/ios-footprint-on-jupiter-takes-the-lead

 

Citations for Images (in order of appearance):

https://planetary.s3.amazonaws.com/web/assets/pictures/20130308_14ISPOLAR_01_truecolor.jpg

https://www.astronomynotes.com/solarsys/tidal-heating.png

https://flickr.com/photos/nasawebbtelescope/52302207952/in/album-72177720301006030/

What’s Up? – September, 2023

Constellations, Planets, and Astronomical Events Visible in September 2023

Written and Compiled by Alyssa Whalen

The astronomical start of the fall season is fast approaching! The Autumnal Equinox occurs on September 23rd. Equinox gets its name from the fact that the sun spends equal time above and below the horizon on this day. The equinox and solstices, as well as the seasons themselves, are caused by the tilt of the Earth. Earth rotates around its axis, and orbits the sun, but there is an angular difference between the rotational and orbital axes, a ‘tilt’ of approximately 23.5 degrees. As highlighted in the diagram, the equinoxes occur when the entire day-side of the Earth is receiving sunlight at the same angle. The solstices (and the summer and winter seasons) occur when one hemisphere is tilted towards the sun, therefore one hemisphere receives more direct sunlight than the other. This is also why seasons are switched in the northern and southern hemispheres.

After the blue moon in August, the next new moon occurs September 15th. Especially due to the string of supermoons this season, observing during a new moon is much better to view fainter objects. The full moon occurs on September 29th, and this will be the last supermoon of the year. A supermoon occurs when there is a full moon at perigee, or the closest point to Earth in the moon’s orbit. Since the moon is closer to the Earth than average, it appears larger and brighter in the sky. The image below shows the difference in size of the moon at perigee (closest point) and apogee (furthest point).

Mercury has shifted to its point of greatest western elongation. While it is still extremely close to our sun, the best chance to observe the planet will be in the early morning before sunrise on September 22nd. Venus will also be visible in the early mornings before sunrise; it will rise on the eastern horizon around 4:15 am. Venus is much brighter than Mercury, and further from the sun in our sky, so it is much easier to view this month.

Photo of Mercury

Mars sets only an hour after sunset, so it is only visible for a short time during the night. Soon, Mars will be behind the sun, and it will be completely unobservable for a long stretch of time. Jupiter and Saturn are perfectly visible this month. Jupiter rises around 10 pm; Saturn will have already risen and be located high in the sky at sundown. The gas giants are extremely bright; they are popular observing targets with the aid of binoculars or telescopes.

Uranus rises shortly after Jupiter; however the ice giants cannot be easily observed with the naked eye. Neptune is in opposition this month on September 19th. Opposition is theoretically the best time to observe planets, as this is when they are fully illuminated by the sun. Neptune will still not be visible with the naked eye due to its distance from Earth (29 AU or 2.7 billion miles), but the use of a telescope will greatly improve the ability to take advantage of Neptune’s illumination.

Photo of Neptune

A popular constellation to observe in the fall is Cassiopeia. This constellation depicting the vain Greek queen is above the horizon year-round in Ohio, but this season it begins the night far above the north-eastern horizon for easy viewing. Cassiopeia is known for its zig-zag shape of bright stars that can be seen even in areas with considerable light pollution. Cassiopeia is another popular guide constellation; it points the way to the Andromeda Galaxy to the south and the constellation Perseus to the east.

The fall and winter seasons are the best time to view some popular star clusters in this area of the sky. The brightest star in Perseus, called Mirphak or Alpha Persei, is the home of a popular star cluster. In the fall, the Alpha Persei star cluster is above the horizon from sundown to sunup, and it will begin the night higher in the sky as the month progresses.

Another popular star cluster is beginning to make its appearance in the night sky: the Pleiades! This cluster is located in the constellation Taurus, and it rises above the horizon around midnight this month. The Pleiades is an extremely bright star cluster that is visible with the naked eye; though binoculars or a telescope will help in heavily light polluted areas. It is one of the oldest celestial objects to be discovered due to its brightness, and it is a popular target for astrophotographers. As the autumn season progresses and turns to winter, these star clusters will continue to brighten our sky and provide excellent opportunities to go out and observe!

Sources:

http://www.seasky.org/astronomy/astronomy-calendar-2023.html

https://www.timeanddate.com/astronomy/night/usa/columbus

https://in-the-sky.org/news.php?id=20230919_12_100

https://stellarium-web.org/

 

Images Credits:

Orbit Diagram: https://www.weather.gov/cle/Seasons

Moon Size: https://moon.nasa.gov/diy-moon-orbit/

Mercury: https://science.howstuffworks.com/46004-mercury-explained.htm

Neptune: https://solarsystem.nasa.gov/planets/neptune/overview/

Constellations: https://stellarium-web.org/

Pleiades: https://astrobackyard.com/m45-the-pleiades/#:~:text=The%20Pleiades%20star%20cluster%20can,and%20noticeable%20as%20the%20Pleiades.

A Planetary History

written by Alex Torres

Most people probably know that there are 8 official planets in our solar system, and those same people likely know that there were 9 planets up until not that long ago. Such is the story of Pluto, the “demoted” dwarf planet of the Kuiper Belt that many still maintain is a full-fledged planet despite its officially altered classification. However, what I don’t think most people fully understand, even those passionate about astronomy, is that the definition of a planet was fairly loose until very recently.

Going way back, the word planet is derived from the word ‘planetai’ which is Greek for ‘wanderer’. The reason that the ancient Greeks called Mercury, Venus, Mars, Jupiter, and Saturn (which did not have those names at the time if I may remind you) planets is because these sources of light in the night sky were notorious for not moving in the same way as the background stars. Indeed, from our point of view on Earth, the stars behave very much as though they were simply points of light painted on the inside of a giant rotating sphere. In other words, the distance between individual stars does not change very noticeably over the course of time, and they move in predictable arcs across the sky. Planets, however, DO move with reference to other points of light over the course of time, and they do so by quite a bit. They frequently relocate from constellation to constellation (though, they do stay near the ecliptic, the sun’s path across the sky), but what’s worse, the planets regularly engage in retrograde motion across the sky. Over the course of one night, planets move westward across the sky, just like the sun and stars. However, over many nights, the planets will move eastward with reference to the background stars due to their orbits around the sun. What’s worse, when the Earth approaches the outer planets (at that time: Mars, Jupiter, and Saturn) in its orbit (which it does because it completes its orbit faster than the outer planets), those planets appear to halt their eastward motion from night to night and begin to move westward from night to night. Eventually, once Earth has surpassed those outer planets by a sufficient margin in its orbit, the planets resume their eastward motion, though the whole process creates a highly unconventional pattern of movement across nights when compared to the movement of stars.

Demonstration of apparent retrograde motion

Hopefully it is now clear that among the many points of light in the night sky, the planets are obviously different due to their movement over the course of many nights, which they do in a highly not intuitive manner. As a result, for millennia, the planets consisted only of Mercury, Venus, Mars, Jupiter, and Saturn (at some point during this time actually adopting their modern names). Earth would also be added to our list of planets once heliocentrism was widely accepted, and Uranus would be the first planet discovered by a telescope in 1781, again classified as a planet due to its irregular motion across the sky. Though, the next object to be classified as a planet would be Ceres in 1801. This would probably come as a surprise to most people today not only because Ceres is not currently on the list of eight known planets (instead, we know Ceres today as the only dwarf planet located in the inner solar system), but because this means that Pluto is not the only celestial body that lost its designation as a planet. In fact, Ceres and Pluto are not even the only two bodies to have lost that designation as many objects similar to Ceres were discovered in the same part of the solar system soon after 1801, so they too (Pallas, Juno, Vesta, etc.) were classified as planets. However, by 1863, 62 bodies had been discovered between the orbits of Mars and Jupiter. This fact, along with the prediction and then discovery of Neptune in 1846 and the fundamental differences of these objects to other known planets (i.e. we now know most are not massive enough to be completely round), caused scientists to rethink their classification of those objects. So in 1863, they gained the classification ‘asteroid’ meaning ‘star-like’, and the space between the orbits of Mars and Jupiter where these asteroids were located was called the ‘asteroid belt’.

Photo of Ceres courtesy of the NASA space probe Dawn

However, after Neptune was discovered, there was speculation that there needed to be another planet past the orbit of Neptune in order to account for perturbations of the actual orbit of Uranus from its predicted orbit. In reality, these perturbations were the result of incomplete information on the mass of Neptune, and information gathered from Voyager 2 in the 1980’s confirmed that Uranus did in fact behave as expected without the need for another planet. Nonetheless, scientists searched for decades after the discovery of Neptune for a supposed ‘Planet X’, and observations in 1930 finally found such an object which immediately became a planet. Today, we know this object as Pluto. Though, it was not long until this designation became controversial when Pluto’s largest natural satellite, Charon, was discovered in 1978.

Combined Photos of Pluto and Charon courtesy of NASA space probe New Horizons

Charon allowed for the first accurate calculation of Pluto’s mass as only one twentieth the mass of Mercury and one fifth the mass of Earth’s own Moon. This came as quite a surprising result to many scientists who had suspected that Pluto would have been larger than Mercury, and it was only made worse by the realization that Charon is a very significant fraction of the mass of Pluto, such a significant fraction that the Pluto-Charon system has a center of mass that lies outside of either body, in effect meaning that they orbit each other. Additionally, Pluto and Charon are tidally locked with each other, which made Pluto the only planet to be tidally locked with one of its moons. On top of all this, Pluto has a very highly eccentric (elliptical) orbit that lies significantly outside the orbital plane of the 8 current planets, so it became clear rather quickly that Pluto was fundamentally different from the other known planets in 1978. Theories of a belt of objects lying beyond the orbit of Neptune, of which Pluto would have been the biggest, began to be taken more seriously, and we soon discovered many objects lying in this supposed ‘Kuiper belt’. With the discovery of objects like Eris in 2005, another Kuiper belt object found to be even more massive than Pluto, the planetary status of Pluto came under heavy questioning. Many debated adding Charon, Eris, and Ceres into the list of planets, but in the end, the International Astronomical Union decided in 2006 that such massive objects orbiting the sun, that were not themselves satellites of other massive objects, with enough gravity to be round but that have not cleared their orbits of other bodies would be designated as dwarf planets.

Photo of Eris and its moon Dysnomia courtesy of the Hubble Space Telescope

As a result, since 2006, the only official planets have been Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Ceres, Pluto, Eris, and a few other bodies are now considered dwarf planets, objects other than Ceres in the asteroid belt are asteroids, and objects beyond the orbit of Neptune but not considered dwarf planets are simply Kuiper belt objects (or stuff like comets in the Oort cloud). Everything considered, the definition of planet has shifted slowly over the course of time from objects other than the sun and moon that move uniquely against the background stars, to any object orbiting the sun and not orbiting a current planet, to a very specific designation defined by the IAU. All of this to say, while the definition of a planet seems very rigid and straightforward right now, it was not like this for the majority of human civilization. Even today, many astronomers, particularly planetary scientists, still consider Pluto and the other dwarf planets as fully fledged planets. So in reality, arguing over what is and is not a planet is rather pedantic. For scientists, such pedantic classification can be important in some cases (though as we mentioned earlier, the exact pedantic classification can still vary among different fields), but for the average person, it really does not matter if they still consider Pluto a planet or not. There is even speculation of an actual ninth planet to explain the unusual orbits of some Kuiper Belt objects, so again, what does and does not qualify as a planet is ever changing. So going forward, I will definitely have a much more open perspective when debating the planetary status of certain solar system bodies.

A Deep Dive into Star Remnants

Written by Alex Torres

I have always been fascinated by the cosmological objects created under one of the most extreme and traumatic events in our universe: the death of stars. In fact, I did a capstone project in 5th grade over what the “life” of a star looks like for different masses, though at the time I was unable to appreciate the truly marvelous results of a star’s demise.

This particular topic of discussion was inspired by the new Oppenheimer movie which introduced me to the fact that in addition to being the “father of the atomic bomb”, J. Robert Oppenheimer also pioneered research in what happens to a star after it exhausts fuel for fusion and can no longer support its own weight from gravitational collapse. We now know that once stars similar in mass to our sun run out of hydrogen to fuse into helium, pressure and temperature increase in the core allowing for helium to be fused into carbon and oxygen. However, once helium is exhausted in the core of sun-like stars, they are not massive enough to continue fusion with carbon/oxygen, so the still very hot outer layers of the star are shed in a spectacular planetary nebula while the core is left behind as an approximately Earth-sized white dwarf. Despite the still large amount of mass present in this star remnant, an amount on the same order of magnitude as the mass of our sun, it is stopped from being gravitationally compressed any more by electron degeneracy pressure, a force generated by the atoms inside the star remnant that won’t allow their electrons to occupy the same quantum state, a phenomenon explained by the Pauli exclusion principle.

However, at more extreme masses, something more interesting happens when a star dies. Instead of stopping at fusing helium, very massive stars continue to fuse material until they start producing iron and nickel in their cores. At this point, nuclear fusion is no longer an energetically favorable process (it actually consumes more energy to fuse iron and nickel into heavier nuclei than the energy that the fusion process releases), so the star rapidly starts to collapse under its own weight. Electron degeneracy pressure is no longer enough to stave off forced compression of atoms into each other, so protons begin merging with electrons, and the result is a core made almost entirely of neutrons in an object akin to one giant nucleus. The maximum mass of a stable white dwarf that can stave off gravitational compression with electron degeneracy pressure is approximately 1.4 stellar masses and is known as the Chandrasekhar limit. However, past this limit, the core begins a process of collapse that only stops once the pressure and temperature inside are high enough to start a runaway fusion reaction ending in a type 1a supernova.

However, if the stellar remnant having reached the Chandrasekhar limit were to continue its collapse, it would eventually stop its gravitational compression anyways. This time, the collapse is no longer halted by electron degeneracy pressure but rather by a combination of neutron degeneracy pressure (named similarly to electron degeneracy pressure because it is based on the same phenomenon of particles resisting occupation of the same quantum state) as well as repulsive interactions between neutrons resulting from the strong nuclear force. What is leftover is a neutron star, and this was the object that Oppenheimer first began theorizing about in response to Einstein’s theory of general relativity and the extreme conditions created by a star’s demise. He would go on to explore the maximum mass such an object could have before it too collapsed under its own gravity, and this value is known as the Tolman-Oppenheimer-Volkoff limit with a currently estimated value slightly above two stellar masses.

Neutron stars are made of an incredibly interesting material called nuclear matter which, as I stated earlier, is a substance akin to the nuclei of atoms. Nuclear matter is as dense and as strong as the nucleus of an atom, making it the densest and strongest material known to man. Unfortunately, it is only possible to create nuclear matter under insane conditions such as the gravity of a neutron star or incredibly high energies, so it is unlikely that we will be able to use this as a material anytime soon. However, what is even cooler in my opinion is something called quark matter. Quark matter is similar to nuclear matter, but rather than acting as a giant nucleus with quarks bound in well-defined nucleons (mostly neutrons), quark matter consists of free quarks not bound to specific nucleons. As a result, instead of being one giant nucleus, quark matter is like one giant nucleon made up of equal parts up, down, and strange quarks. The presence of strange quarks in this mixture is particularly interesting because the vast majority of ordinary matter is made up of protons and neutrons consisting only of up and down quarks. Quark matter has been created in extremely high energy collisions at particle accelerators like the Large Hadron Collider (LHC), but it is theorized to be present in the cores of massive neutron stars where extreme pressures are able to liberate quarks to move around almost like a liquid. Additionally, it is theorized that there are entire celestial objects made mostly of this quark matter called strange stars, named thus because they would have a very high proportion of strange quarks as compared to ordinary matter.

Anyways, I thought all of this was interesting, so I thought I would share my Oppenheimer inspired deep dive into the deaths of stars, a pleasant learning experience that came after an incredibly interesting and enjoyable movie. I hope you too enjoyed Oppenheimer if you have seen it, and if you haven’t, I would highly recommend that you do.

 

Citations:

What’s Up? – August, 2023

Constellations, Planets, and Astronomical Events Visible in August 2023

-Written and Compiled by Alyssa Whalen

Happy August! The days are long and hot, but the nights have perfect weather for stargazing. The days are steadily growing shorter since the solstice has passed. The sun rises around 6:40 am, and sets at 8:30. As each day passes, the amount of daylight changes by approximately 2 minutes and 15 seconds. This rate of change will continue to increase until the equinox next month, but the nights will continue to get longer until the winter solstice in December.

Once in a blue moon is here at last! When two full moons occur in the same calendar month, the second is called a blue moon. This phenomena is possible because the time it takes for one full cycle of the moon’s phases, or one orbit of the moon around the Earth, is 29.5 days. It also happens that both of the full moons this month are supermoons!. The full moon is continuing to occur when the moon is at its closest point to Earth, causing it to appear larger and brighter than usual. The first full supermoon occurred on August 1st, which is known as the Sturgeon moon, as this is when the Native Americans would catch the fish in the Great Lakes. The second full moon has many titles: The full super-blue moon. However, since it is also in August, it would not have another nickname like the other full moons have, since there are only 12 nicknames used to describe the full moons of the year.

Despite its nickname, the blue moon does not actually have a blue hue. The name comes from the 16th century saying “when the moon is blue” meaning something is impossible; although, it is true the moon can have a blue or green tint due to dust in the atmosphere. After a real blue-tinted moon was observed after a volcanic eruption in Indonesia in the late 1800’s, the phrase shifted to mean a rare event. The term “blue moon” was only used to describe the occurrence of two full moons starting in the mid 1900s. If you were ever wondering how often “once in a blue moon” is, it is about once every 33 months, or 2.75 years.

The new moon occurs on August 16th; this day and the surrounding days when the moon is in its crescent phases are the best time to stargaze if the weather permits. Especially since the full moons are supermoons, their brightness will make observing faint celestial objects very difficult.

There is a meteor shower occurring this month! The Perseids shower is a popular meteor shower known for a high frequency of bright meteors that should be visible even from light polluted areas. The shower runs annually from July 17th to August 24th, but its peak is on the night of August 12th this year. At its peak, it is expected to produce around 60 meteors per hour. The shower will radiate from the constellation Perseus, which can be found near the northeastern horizon at sundown. The constellation will rise further above the horizon as the night goes on, so the best viewing will be near midnight or later at a dark sky sight. However, the waning crescent moon provides very little light to interfere with the show, so viewing is still possible from light polluted areas.

The Perseid meteor shower comes from the debris of the comet 109P/Swift-Tuttle. This comet was discovered in 1862, and orbits the sun every 133 years. Sadly, we will never see the comet again in our lifetimes, but we will continue to enjoy the meteor shower caused by its remnants every year.

Mercury is visible once again. As the innermost planet in our solar system, Mercury orbits the sun in only 88 days, but it is also too close to the sun most nights. Only during its greatest elongation will it be visible. This is when the planet is at its furthest point from the sun in our sky, and even at this time it is still difficult to observe. Mercury will be in greatest eastern elongation on August 10th. This means the planet will be visible in the western sky for a few moments after sundown.

Venus is currently difficult to view. It is directly in front of the sun for most of the month, but it will be visible in the early morning before sunrise at the end of the month. Mars is also too close to the sun to observe. It won’t be easily visible again until next year.

Unlike the terrestrial planets, Jupiter and Saturn are more easily visible this month. Jupiter is perfectly visible once it rises after midnight, and Saturn is in opposition on August 27th. Opposition means the planet is opposite the Sun in our sky. Saturn will rise at sunset, and set at sunrise, meaning it will be visible all night.

As always, the ice giants Uranus and Neptune are difficult to observe without binoculars or a telescope. Uranus rises just past midnight, only slightly to the east of Jupiter for the whole month. Neptune rises at 10 pm, and will be found between Jupiter and Saturn in the constellation Pisces

The most useful constellations for night sky navigation are the Big and Little Dippers. In Ohio, and further north, the Dippers never set below the horizon. They are in the northern sky all night long and all year long. Stars that never set are called circumpolar stars. Polaris, the North Star, is in line with Earth’s north pole. As Earth rotates, Polaris stays still in the northern sky, and all the stars appear to move around it. This becomes apparent when astrophotographers take exposures of the sky that last hours; the stars leave a trail that show their path around Polaris. Because of this, constellations like Draco and Ursa Major/Minor are useful all year round.

The Big Dipper is likely the most common constellation in the northern sky; however it is not a constellation. There are only 88 officially recognized constellations, but anyone can connect the dots in the sky to make a shape. These shapes are called asterisms. Ursa Major is a recognized constellation, but the ladle of the Big Dipper is only a section of the constellation that has been given a nickname, therefore it is an asterism. The Big Dipper is notable because it is made up of bright stars that can be seen even in light polluted cities, and its stars are helpful to guide a stargazer to other constellations. For instance, the two stars at the edge of the ladle point directly to Polaris, which is the tip of the handle of the Little Dipper. Winding between the two Dippers is Draco the Dragon. Another example is that the handle of the Big Dipper arcs over to the bright star Arcturus in the constellation Böotes (pronounced Boh-oh-teez). These are only a few examples of using guide stars to navigate through the sky.

 

Sources:

https://www.timeanddate.com/sun/@5165418?month=8&year=2023

http://www.seasky.org/astronomy/astronomy-calendar-2023.html

https://www.britannica.com/science/blue-moon-astronomy

https://earthsky.org/astronomy-essentials/everything-you-need-to-know-perseid-meteor-shower/

https://www.timeanddate.com/astronomy/night/usa/columbus

https://stellarium-web.org/

 

Images:

Sturgeon Moon: https://www.bbc.com/news/uk-england-nottinghamshire-62517894

Image Credit: Graham Wiffem

Blue Moon: https://www.space.com/15455-blue-moon.html

Image Credit: Herken Herken

Position Diagram: http://alicesastroinfo.com/2007/01/mercury-at-greatest-elongation-2007/

Saturn: https://solarsystem.nasa.gov/planets/saturn/overview/

Perseids Radiant Point: https://earthsky.org/astronomy-essentials/everything-you-need-to-know-perseid-meteor-shower/

Big Dipper/Little Dipper/Draco/Bootes: https://stellarium-web.org/

Star Trails: https://fuzzy.photos/astrophotos/42-star-trails-at-the-celestial-pole

Image credit: Frederick Steiling

 

What’s Up? – July, 2023

Constellations, Planets, and Astronomical Events Visible in July 2023

-written and compiled by Alyssa Whalen

Now that the solstice has passed, it is now officially summertime! Enjoy the long days and warm weather, and hopefully the summer nights will be clear enough to go out and observe. The sun will rise around 6:15 am, and set near 9:00 pm everyday; although the days will now begin to slowly grow shorter. Since we are still in the height of summer, we are losing daylight at a rate of only 1 minute and 20 seconds per day, but that rate will increase as we approach the autumnal equinox in September.

The full moon this month is a supermoon! Supermoons are full moons that occur when the moon is at its closest approach to Earth. This is only possible because of the slight ellipticity in the moon’s orbit around Earth. When the full moon is at perigee and full in the same night, it is called a supermoon. The July supermoon occurs the evening of July 3rd. It is often nicknamed the Buck moon, as this is the time of year that male deer grow their antlers. The new moon occurs on July 17th. With clear skies and some luck, this will be the best time to observe during the month.

There is a meteor shower this month! The Delta Aquarids meteor shower runs annually from mid-July to late August. This year, the shower peaks the night of July 29th with a peak rate of around 20 meteors per hour. While the shower peaks on the 29th, the rate of meteors should be fairly constant throughout the shower’s duration. The radiant point of the meteor shower is in the constellation Aquarius, though it will be possible for meteors to appear anywhere. Aquarius will be slightly southward from the eastern horizon around 11 pm the night of the 29th, but the best time to view the meteor shower will be during the early morning of the 30th between 2-4 am when the constellation is higher in the sky. There is a full moon in early August that will make viewing the fainter meteors difficult, so finding a dark sky in the earlier days of the shower (or later in mid-August) when the moon is nearly new might prove to be a better strategy. With enough patience, there should be a number of bright meteors that make a good show even during the full moon.

Mars and Venus are in conjunction this month. On July 1st, the two planets will make their closest approach to one another. The conjunction will be visible in the evening for a few hours after sundown, and the planets will remain close together in the sky. Both planets will be visible at sundown; Venus will set first around 11:20 pm on July 1st, with Mars disappearing below the horizon shortly after at 11:35 pm. They will both set earlier in the night as the month goes on.

Mercury is too close to the sun to be visible at the beginning of the month, but, in the later days of the month, it will begin to appear slightly above the western horizon after sunset. Jupiter continues to rise earlier in the night; now it is above the horizon around 1:45 am. Saturn is becoming more easily observable, as it now rises around 11 pm. Uranus is difficult to observe this month since it does not rise above the horizon until 2:15 am. Neptune rises near midnight; however, both ice giants are not visible without the aid of a telescope or binoculars due to their distance from Earth.

While Ursa Major and Ursa Minor are always above the northern horizon to help guide our stargazing, this time of year there is another popular way to get around. The Summer Triangle is an asterism (a group of stars that form a shape/pattern, but are not officially recognized constellations) made up of the bright stars of three constellations in the summer sky: Vega in the constellation Lyra, Deneb, in the constellation Cygnus, and Altair in the constellation Aquila.These stars are very bright, and can even be seen clearly in light polluted cities, which makes them popular guide stars. The name ‘Summer Triangle’ comes from the fact that these constellations are nearly directly overhead at sundown, and are visible all night during the summer months.

Sources:

https://www.timeanddate.com/sun/@5165418?month=7&year=2023

http://www.seasky.org/astronomy/astronomy-calendar-2023.html

https://earthsky.org/astronomy-essentials/everything-you-need-to-know-delta-aquarid-meteor-shower/

https://www.timeanddate.com/astronomy/night/usa/columbus

https://stellarium-web.org/

 

Image Credits:

Sunset: Alyssa Whalen

Buck Moon: https://science.howstuffworks.com/buck-moon.htm

Credit: JOHN FINNEY PHOTOGRAPHY/GETTY IMAGES

Meteor Shower Radiant: https://earthsky.org/astronomy-essentials/everything-you-need-to-know-delta-aquarid-meteor-shower/

Mars/Venus: https://www.businessinsider.com/see-mars-venus-align-planetary-conjunction-2021-7

Aquarius/Pegasus: https://stellarium-web.org/

Cygnus/Lyra/Aquila: https://owlcation.com/stem/Exploring-the-Summer-Triangle-in-the-Night-Sky