What’s in a name?: Gonggong & Xiangliu

Posted on April 17, 2021 by wendyyb

Much like many of their small world counterparts, Gonggong and Xianglu are a dwarf planet and moon (respectively) named after characters in mythology. Gonggong, a dwarf planet residing in the scattered disc beyond Neptune, is named after a Chinese water god. Gonggong is depicted as having a copper human head, read hair, and a dragon-like body. He is known for causing chaos and destruction and his stories often end with reprimands from other gods. He is accredited for causing flooding and the Earth’s axial tilt.

Gonggong - Wikipedia
Picture of Gonggong, via Wikipedia

Xianglu, Gonggong’s moon, is named after one of the god Gonggong’s ministers. Xianglu is depicted as a nine-headed eel who caused destruction alongside Gonggong and poisoned everything he touched.

Picture of Xianglu, via Wikipedia

In regards to the actual naming process, certain criteria had to be met for potential names and then these names were voted on. The criteria included: being a ‘creation’-related mythological figure, having counterparts that could be used for moon-naming, and having characteristics similar to that of the world being named. Gonggong was chosen for the god’s relation to water that matched the water-related qualities of the dwarf planet.

If you had to name a dwarf planet or moon, what would you choose?

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The Mythology of Jupiter’s Moons

Posted on April 17, 2021 by bellagoodnight

When I heard about the names of Jupiter’s moons, I immediately wanted to dive into the mythology behind them! The four largest moons of Jupiter, each interesting in their features, are also interesting in their mythological stories as people who were lovers of Zeus. In this post, I will briefly describe the story behind these moon’s names, starting with Io.

Io is a Greek myth and the story of a mortal nymph who was a priestess of Hera, wife of Zeus. Jupiter is the Roman name for the god Zeus, so even though this story originated in Greek mythology, Io was still named as a moon for the planet Jupiter. In this myth, Zeus fell in love, or lust, with Io, and wanted to protect her from his wife Hera before she found out he was cheating on her. To do this, Zeus decided to turn Io into a white cow. Hera, however, saw through this, and convinced her husband to give her the cow (Io). She wanted Io to be watched over so that Zeus could not interact with her further, so she sent Argus, a man with 100 eyes, to keep watch on her. Zeus, unhappy with this development, ordered the god Hermes (Mercury in Roman mythology) to kill Argus. In her anger at Io being free, Hera sent a fly to follow and bother the cow, and Io was stuck traveling across the Earth as a cow. She was eventually turned into a human again by Zeus, and she gave birth to his son.

Next is Europa, another Greek myth, with a similar theme of transformation into an animal. Unlike the story of Io, though, it was Zeus who turned into an animal, specifically a white bull. As a particularly beautiful bull, Zeus approached Europa and her group of friends. After petting and fawning over the animal, Europa eventually got on his back, which led to Zeus promptly speeding away into the sea. After traveling some distance, Zeus explained the situation to her and his apparent love of her. They went to Crete and she eventually had his children.

Thirdly, Ganymede is unique because he was actually a male, whereas the other famous lovers of Zeus were female. Ganymede was a beautiful prince whom Zeus abducted after, once again, turning into an animal – an eagle this time. After being abducted, Ganymede was forced to be a cupbearer on Mount Olympus in addition to being his lover. In this story, the lover taken from their home was punished by Hera, notorious for her rage at Zeus’ infidelity. Ganymede was transformed by Hera into the constellation Aquarius, so technically Ganymede has two famous positions in the sky!

The fourth and final large moon of Jupiter is Callisto. Callisto was a nymph and follower of the goddess Artemis, and in order to be part of Artemis’ hunting team, she had to take a vow of chastity. Zeus, being the not-so-great guy that he was, decided he was in love with her, and used deception in the form of turning into Artemis to lure Callisto and take advantage of her. After this was discovered, she was kicked out of Artemis’ group, and (unsurprisingly) turned into a bear, by either Hera in her rage or by Zeus in an attempt to hide her from Hera. Hera then attempted to get Artemis to slay the now bear, Callisto, but Zeus instead turned her into a constellation where she became Ursa Major. Callisto, like Ganymede, has two spots in our night sky.

Throughout these myths, there are some recurring themes, such as Zeus being a terrible person, Hera’s punishments, and turning into animals. These are the stories behind the names of Jupiter’s moons!

Image of Jupiter’s moons

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The Depths of Europa

Posted on April 17, 2021 by hunterspiveyastr
Comparison of Earth’s and Europa’s Oceans from NASA

The smallest of Jupiter’s four Galilean Moons, Europa hides a world of fascination below its unassuming icy surface. Europa existed unbeknownst to mankind up until the early seventeenth century when the famous astronomer, Galileo Galilei, was first able to resolve Europa through his telescope at the University of Padua. It wasn’t for another three and a half centuries that Europa would first be able to be explored when Pioneer 10 completed the first flyby of the moon in 1973, shortly followed by Pioneer 11 in 1974. These flybys revealed Europa’s ice covered surface, which was when scientists first began to speculate about the presence of a large subsurface ocean on the moon. Since then subsequent missions including the Galileo orbiter of Jupiter, and the New Horizons flyby have provided us with even further data. In fact, scientists speculate that the subsurface oceans could be as much as 60 miles deep, almost 10 times as deep as the deepest point of Earth’s oceans. While there is still so much that we don’t know about this cold moon of Jupiter, it may not be that much longer before questions about Europa’s mysterious oceans are answered. Is there life in its oceans? As soon as the next couple decades, we may be seeing orbiter missions to Europa as NASA was approved $80 million to continue studying the moon. These orbiters could provide to key to answering all those questions we hold.

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The Oort Cloud

Posted on April 17, 2021 by Mykayla
Image Source

The Oort Cloud is a collection of comets that orbit the Sun far outside our solar system. One estimation of the number of comets in the Oort Cloud is one TRILLION. Unlike the Kuiper Belt, which lies outside the orbit of Neptune, the Oort Cloud neither lies on the same plane as the bodies orbiting the Sun nor has objects that revolve in the same direction. The orbital eccentricities of Oort Cloud comets are also random. This is what makes it a “cloud”––it is not all on the same organized plane as the planets, asteroid belt, and Kuiper Belt. In fact, for this reason, many people have never heard of the Oort Cloud. (If you think about it, this makes sense because diagrams of the solar system would be quite complex if they included it). The distance between the Sun and the Oort Cloud is enormous compared to other objects in the solar system. It extends out to 50,000 astronomical units from the Sun! Because these comets orbit so far away, they can be influenced by the gravity of nearby stars in the Milky Way! These gravitational encounters can cause the comets either to be kept out of reach of the planets OR sent hurtling toward the Sun. Those are the comets that we can sometimes observe from Earth.

I am going to admit, I did not know about the Oort Cloud until taking this class. But now that I have learned about it and seen artists’ representations of it, I am blown away by the sheer vastness of it. I cannot believe that even at that great of a distance, the comets still orbit the Sun! I also think that it is cool that the cloud is nearly spherical due to the varying eccentricities, tilts, and directions of orbit by the comets. What seems to be chaotic actually makes for an orderly sphere that encompasses the solar system.

That reminds me of God. He is in the business of creating order from chaos. He is the great Orderer of the universe! He set the comets in motion and the Oort Cloud in its place. He created the gravity that affects so many of the processes of the universe. He fashioned our solar system, and only He can comprehend the vastness of His creation. We just get the privilege of exploring it, each new discovery pointing toward the peaceful order of our Maker.

“For God is not a God of confusion but of peace.”

1 Corinthians 14:33

Did you know about the Oort Cloud prior to Dr. G’s class? Did this blog help clarify or bring perspective to your understanding of it? Let me know in the comments! Thank you for reading! 🙂

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Europa, and the Possibility of Life

Posted on April 17, 2021 by weatherbysofferings
Europa: Highest Resolution Global Color View
A Beautiful Picture of Europa (Source)

When we discussed the sub-surface oceans of some of the large moon-worlds, I was particularly excited about the idea that these places could potentially contain life, for what could be more exciting than the possibility of life elsewhere in the universe? As such, for my blog post, I wanted to dive into one potential home for alien life, Europa, and explore why it particularly is in contention for the possibility of having life.

One of the most significant aspects of Europa that make it tenable to life is that it has a salty, subsurface ocean. Scientists know this because we have detected a magnetic field coming from it, that could best be explained by such a feature beneath it’s thick ice crust. Moreover, the fact that the icy surface seems to be relatively unmarked in terms of cratering indicate that it is relatively active geologically, since lack of craters means the surface is caused to change often enough for craters to be infrequent. There are also scratches and strange features on its surface that are best explained by the shifting of ice, likely on a large body of water – that same subsurface ocean.

Just as importantly, scientists believe elements like carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur, all of which are essential to life’s formation, were likely on Europa when it formed, and asteroids might still be introducing new carbon now. Significantly, it’s thought that tidal forces – as indicated by the geological activity above – might be heating up part of Europa’s ice enough for it to melt off and provide nutrients, then new liquid becomes ice.

One final issue arises though: how could Europan lifeforms get energy? They could not get it from the sun as most earthly organisms ultimately do. They’d have to be in the pitch black ocean world beneath Europa’s ice! This point can be answered by the idea that there is likely a rocky interior beneath the subsurface ocean, and the tidal heating mentioned above causes this interior to have volcanic activity, spitting out heat and chemical reactions to potentially provide energy for life, albeit life somewhat different from how we know it. It is still, according to some scientists, distinctly possible!

All in all, it is distinctly possible for Europa to have life (albeit likely small, microbial life), and it would be a very unique sort of life that could reveal much about the origins and construction of life as we know it!

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Fomalhaut b: The Planet that Disappeared

Posted on April 17, 2021 by bellagoodnight

What’s more interesting than the story of a planet that disappeared? Fans of Fomalhaut b would argue that nothing tops the tragic story of this exoplanet. What was initially thought to be a large world sitting only 25 light years away was later found out to be nothing but a dispersing cloud of dust. Fomalhaut b, officially named Dagon, was first discovered from Hubble observations, which showed promise of a large exoplanet with a surrounding dust ring. People were ecstatic at this huge discovery of such a large potential exoplanet, and it quickly became well-loved.

Later inspection confirmed something different, however. When new observations were taken with the Hubble Telescope, it had seemingly disappeared. This was not in line with what was expected of this so-called “planet.” It turns out that this structure in the sky was not actually a planet, but the aftermath of a large collision between icy bodies. The brightness is decreasing while the form is expanding, supporting the theory that what was once believed to be a planet was actually just a large dust cloud from a collision. Though it may seem disappointing to fans of Dagon, it is still a fascinating space event that was captured! We were able to see the aftermath of a collision shortly after it occurred, and just because Fomalhaut b didn’t turn out to be a large planet, doesn’t mean that there aren’t any out there. There are still over 4,000 discovered exoplanets, so don’t fret!

Image of Fomalhaut b

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Returning to the Moon: NASA’s Artemis Program

Posted on April 17, 2021 by alliefrymire

It has been nearly fifty years since the last time humanity set foot on the Moon. Now, with NASA’s new Artemis program, humanity may reach the rocky surface of our only natural satellite once again. With a focus on both science and society, NASA’s hope with the Artemis program is to put the first woman and the first person of color on the Moon. Certainly a noble goal given it was exclusively white men, who make up less than five percent of the global population, who had the privilege of exploring the Moon via the Apollo missions half a century ago.

NASA's Artemis project in pics: Why this Moon mission is unique - Oneindia News
You can find this great image here!

Moreover, NASA also aims to collaborate with both industry and academia to make this project a reality. The recent advent of private space exploration companies, most famously SpaceX, makes the role such companies are to play in the future of human space exploration essential. I for one am interested to see how the future of space exploration develops as the public and private sectors partner to make such dreams as the Artemis program a real possibility for humanity. You can read more about NASA’s Artemis Program here.

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What Is A Dwarf Planet, Anyway?

Posted on April 17, 2021 by alliefrymire

Given all our discussions of Pluto and the other “dwarf planets” of our solar system, you may be interested in just how astronomers differentiate a dwarf planet from a “regular” planet. According to the ever-reliable Wikipedia (not being sarcastic, Wikipedia is generally very trustworthy these days!), there are three characteristics that define a dwarf planet. First, the object must orbit around the Sun. Second, the object must be massive enough to maintain a nearly-round shape. Third, the object must not have “cleared the neighborhood” around its orbit.

Dwarf planets
This awesome composite of all our dwarf planets can be found here!

It’s this third characteristic that seems to be the most important in differentiating planets and dwarf planets. “Clearing the neighborhood” of an object’s orbit means that the object must be the gravitationally dominant object in its path of orbit, and there must be no other object of significant size other than the object’s natural satellites. So, what do you think about the official definition of a dwarf planet? Do you think it’s valid, and why or why not? I’d love to hear your thoughts in the comments!

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Han Solo Is Working Too Hard

Posted on April 17, 2021 by brandonlipper
Star Wars Protocol

While science-fiction flicks like Star Wars produce some exhilarating and high-stakes chase scenes with the help of treacherous asteroid fields/belts, in reality, you could probably navigate these asteroid belts blind-folded. With all due respect to Han Solo’s piloting skills and his less than twelve parsecs Kessel run, he would not actually have needed to utilize those skills when traveling through an asteroid field. In fact, each time we send a spacecraft to the outer solar system, the craft must pass through the asteroid belt between Mars and Jupiter. These unmanned crafts have never collided with a significant object. In fact, Sol Alan Stern said of the New Horizons mission that the odds of collision were “almost vanishingly small — far less than one in one billion.” This is a very noteworthy contrast to C3PO’s assertion that “the possibility of successfully navigating an asteroid field is approximately 3,720 to 1.” Unlike in the popular arcade game Asteroids, real asteroids that are about 1 km in size are millions of km apart.1 One of these average sized asteroids will only collide with another asteroid about every few billion years. Thus, if they were truly as close as they appear to be in movies, asteroids would collide constantly and break one another up into tiny pieces.

While it is true that asteroids in an asteroid belt are relatively concentrated, the space they occupy is so expansive that it would be more likely for Han Solo and the gang to pass through an asteroid field without even seeing an asteroid than to have to duck and weave around them. In our own solar system, planetesimals are concentrated in a belt between Mars and Jupiter because of Jupiter’s orbital resonances.1 However, these asteroids are so far apart that if you were on an asteroid, you would need a telescope to see another asteroid.2 Han Solo and the others would have had a lot more trouble hiding in an asteroid field if each asteroid was shown as being the true distance of millions of km apart.

[1] Bennett, Jeffery, et al. The Cosmic Perspective: The Solar System. 9th ed., Pearson, 2020.

[2] Grundstrom, Erika. SolSysLTs-AsterImp-SmayKortz

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Triton: Neptune’s Interesting Moon

Posted on April 17, 2021 by captivatingcomet

Triton is Neptune’s largest moon with a diameter of 1,680 miles (2,700 kilometers). It was discovered in 1846 by astronomer William Lassell a little over two weeks after Neptune’s discovery. Triton is named after one of Poseidon’s sons; Poseidon is the Greek god equivalent of the Roman god Neptune. Triton is unique in that it is the only large moon in our solar system with a retrograde orbit. This means it orbits in the opposite direction of Neptune’s rotation. Due to this, scientists believe that Triton is a captured moon. Triton is mostly covered with volcanic plains, mounds, and round pits. Its volcanic activity leads it to have a thin atmosphere mainly comprised of nitrogen with little bit of methane. Also, Triton has some active geysers and very few craters on its surface. It has a metal and rock core, an icy mantle, and a frozen nitrogen crust. Triton’s density is about twice the density of water and is very cold with a surface temperature around -391 ℉ (-235 ℃). Triton could possibly have a subsurface liquid water ocean as well. Currently, there is the proposed Trident mission that will utilize a flyby to explore Triton and its unusual features. I hope this proposal gets selected, so we can learn more about this intriguing and special moon!

Image of Triton taken by the Voyager 2 spacecraft in 1989 (taken from NASA Science)

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