The Moons of the Jovian Planets

Posted on April 17, 2022 by McKenzieKing
Jupiter’s Moons: Io, Europa, Ganymede, and Callisto

Some of the most well known moons in our Solar System, aside from our own, are Jupiter’s Moons. They are known as Io, Europa, Ganymede, and Callisto. However, there are over 170 known moons that orbit all of the Jovian Planets. Jupiter and Saturn both have over 60 each that range greatly in size, and Ganymede and Saturn’s moon Titan are both larger than the terrestrial planet Mercury. The compositions, however, between the terrestrial planets and Jovian moons are very different. The moons contain a lot more ice than the planets, in addition to metal and rock. This is because they formed farther away from the Sun. It is also widely believed that they formed by accretion within the disks of gas that surround each of the giant Jovian planets. This would explain why they orbit in the same direction as their planet’s rotation.

Some of Jupiter’s moons are surprisingly geologically active! Io specifically is volcanically active, even more so than any other celestial object in our solar system. The surface of the moon is so young due to the constant repaving with lava that we cannot find any evidence of any impact craters. The volcanoes are similar to those on Earth and produce outgassing just like on our own planet. This is what makes Io one of the most interesting moons that we have studied, and why it shatters the common idea that all moons are barren and geologically dead.

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Exoplanets

Posted on April 17, 2022 by Kaitlyn Lane
Exoplanets

The words in the above picture are hard to make out, but I really liked the visual of some of the known exoplanets graphed on a plot. The color and appearances of these planets are not truly known since we have not directly seen them, but they are inferred based on density, temperature, metal content, and comparisons to our own solar system. The rings on some planets are just for the aesthetic, but since the large planets of our solar system have some kind of ring formation, it is likely that this pattern exists elsewhere.

Now that I have partially explained the diagram, let’s get into what an exoplanet is. The definition is pretty straightforward: a planet outside of our solar system. Much like our sun, other stars have planetary systems or planets. While the exact number is not known, there are 5,011 confirmed exoplanets, 8,738 candidates, and 3,763 planetary systems (at the time this post was written). While there is currently no proof that life exists beyond Earth, with so many stars and planets in the universe, it is hard to believe we are alone. There are even exoplanets that have similar conditions to those of Earth and are believed to be habitable.

Potentially Habitable Worlds

There is something called the Goldilocks’ Zone where certain conditions that are suitable for life might be met. One of these is a distance from their sun where it is warm enough for liquid water to exist on the surface, like on Earth. Scientists also look for rocky planets, since these are more likely to host life than a gas giant. Different stars have different habitable zones depending on where they are in their lifetime and their temperature. While life on other planets has not been discovered, I believe that there is something out there.

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Using Variable Stars to Find Exoplanets

Posted on April 17, 2022 by alexlitt

One of the preeminent methods for finding exoplanets is tracking periodic variations in stellar brightness. In class, we practiced this technique by examining the light curves of certain variable stars and identifying the presence of orbiting exoplanets. In the real world, scientists must first identify variable stars and then determine which of these variable stars’ brightness fluctuations are actually due to orbiting exoplanets, before they can conduct light curve analysis.

NASA Transiting Exoplanet Visualization

This school year, I have been conducting research on variable stars using data from TESS (Transiting Exoplanet Survey Satellite). My job is to help implement a machine learning algorithm to classify variable stars based on up to 63 stellar characteristics. In the TESS database, each star has information on its mass, radius, period of brightness fluctuation, average luminosity etc. The algorithm’s objective is to analyze existing variable stars (whose types are known) and decipher patterns that differentiate variable star types. Once the algorithm is working effectively, it will be able to process new observations and accurately label each variable star by its type. This type of data processing is vital to identifying exoplanets in the future. As an example, scientists could use this algorithm to effectively ignore all variable star types whose brightness fluctuations are not due to transiting exoplanets. Additionally, if scientists figure out which type of variable star most frequently hosts exoplanets, the algorithm could help scientists focus their time on the stars most likely to be host to exoplanets.

I have not yet completed my research; however, I have been able to create a machine learning algorithm that identifies the most important stellar characteristics for classifying variable star types. Additionally, I have had some success classifying variable stars to a moderate degree of accuracy. While my research is coming to an end, other individuals have (and will) create similar algorithms to help astronomers interpret data from upcoming all-sky surveys. Machine learning algorithms, such as the one that I worked on, will be integral to future astronomical discoveries.

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The Moons of Saturn

Posted on April 17, 2022 by AndreaS
Saturn’s moon Titan

There are many moons of Saturn, but the two largest are Titan and Enceladus. Titan is an enormous moon, the second largest in the Solar System after Jupiter’s Ganymede. It is notable for its thick atmosphere, which is made up of mostly Nitrogen compounds. Its surface is characterized as geologically young, with evidence of lakes and other surface liquid features that are likely made up of hydrocarbons.

Saturn’s moon Enceladus

Enceladus is a much smaller moon, about 1/10 the size of Titan. It has a snowy and icy surface that contains both very old and very young terrains. Heated by tidal heating, there is evidence of recent ice volcanoes, and the fresh material makes Enceladus the most reflective object known in the Solar System. Enceladus is also thought to have a liquid interior, further evidence for a source of heating and active geological processes on the moon such as tectonic activity that produces the large rifts and scars that can be seen along the surface.

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Blog 5: Comets

Posted on April 17, 2022 by Kaitlyn Lane
Comet Hale-Bopp

Comets are relatively small bodies in our solar system comprised of dust, rock, gases, and ice. They are remnants from the formation of the solar system, and their solid bodies, or nuclei, can range from a few miles to dozens of miles wide. When its orbit gets close to the sun, this nucleus heats up and forms an atmosphere, called a coma, and a tail made of gas and dust particles facing away from the sun that can be millions of miles long. There are currently 3,743 known comets in our solar system, but it is estimated that billions exist in the Kuiper Belt and Oort Cloud. We can usually only detect comets whose orbits come near the sun since this is when the coma and tail form. The comets in the outer solar system are too cold to release this large stream of gas and dust, so they are harder to detect. Despite this, comets have been discovered near other stars in the Milky Way, and probably exist throughout the universe.

Comet Orbit: 67P/Churyumov-Gerasimenko
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Black Holes

Posted on April 17, 2022 by alexbawa

If you’re like me, you’ve heard plenty about black holes, but your only real understanding comes from a couple Interstellar screenings. The movie does a pretty great job being accurate, but even the excessively brilliant characters don’t know whats going on behind the scenes. This blog is an exploration of the phenomena, equal parts for curiosity and so I can stand my ground when I mention I have a minor in astronomy.

To me, the name “black hole” is somewhat misleading. There’s no expanse or hole to fill, but rather an excess of mass that is super tightly packed. The hole in question is actually what all of that mass does to spacetime, our way of conceptualizing the intersection of time and space. The intensely concentrated gravity drags down that fabric of reality, creating a deep pit that even light can’t climb out of, earning the “black” of black hole.

Visualization of effect on spacetime

Due to the trap that black holes set for light, they’re difficult to detect. It turns out one of the easiest ways to pick up on them is to recognize what they’re known for: gravity. Observing inconsistencies in orbits and trajectories can sound the alarm for a black hole pulling the strings behind the scenes.

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Wormholes

Posted on April 17, 2022 by jadonroy
The Conversation. com

One of the many wonders of our cosmos that peaked my curiosity to the world of astrophysics was the concept of the wormhole. After seeing a wormhole being used in one of my favorite movies, Interstellar , I became even more fascinated with this topic as it I was given a cinematic and visual example of how one could theoretically be utilized by humans. In the film, humans from the future discovered a way to create and place wormholes and in turn placed one in the present world’s solar system so that they could escape their dying planet. This has always been an interesting debate amongst humans. In the event the Earth was no longer a viable option for humans, we then could turn to the stars to find a more suitable home. As shown in the movie, a wormhole could be a way for us to reach worlds far beyond our own solar system. To explain the concept behind wormholes in a very basic way, imagine two points on separate ends of a piece of paper represent two points in space. The distance all the way across is far too long in relation to space. But what if there was a way to reduce this distance. Now imagine folding the piece of paper and the two points on the pieces of paper are on top of each other. Then you can reach far distances in a shorter period of time. Despite being a very obvious over simplification, this is the main concept behind their benefits for us. Unfortunately for us though, wormholes are not possible for at the moment and only an interesting topic in science fiction. However, some scientists believe that we may soon be able to prove that wormholes are a real part of the universe. The scientific way of describing such phenomenon is known as the Einstein-Rosen bridge. An Einstein-Rosen bridge is rooted in Albert Einstein’s general theory of relativity, a work that caused us to change the way we viewed gravity. Fortunately for humans, there is no need to leave our planet at the moment, but it still is intriguing to know our possible options in the future. Ultimately, movies such as Interstellar teach us that instead of looking for new planets, we should be focused on protecting and preserving our own.

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The Moons of Jupiter

Posted on April 17, 2022 by AndreaS
Jupiter’s moon Ganymede

Jupiter has many moons, but the largest of them are the Galilean moon, Ganymede, Callisto, Europa, and Io. This post will explore the defining features of these Jovian moons.

The largest of Jupiter’s moons is Ganymede, the largest moon in the Solar System. In fact, Ganymede is larger than Mercury. This moon has a liquid core that produces the only known magnetic field in the moons of the Solar System. It is thought that there is a liquid water ocean beneath the surface of Ganymede, something that is thought to occur on other moons as well. The surface of Ganymede is heavily cratered and therefore very old. The moons Ganymede, Europa, and Io are in 1:2:4 resonance, which influences the level of tidal heating on each world.

Jupiter’s moon Io

Slightly larger than Earth’s moon, Io is the innermost of Jupiter’s moons and is extremely geologically active. There are over 400 active volcanoes on Io, a feat that is caused by friction due to tidal heating between Jupiter and the other large moons. The surface of Io is largely coated in Sulfur, which gives it a distinct yellowish color. Volcanism is a key feature of Io that also impact Jupiter as well. Emissions from Io’s atmosphere have inflated Jupiter’s magnetic field, making it much stronger than it would be without Io.

Jupiter’s moon Europa

Europa is slightly smaller than Earth’s moon and has a smooth surface largely made out of water ice. The lack of cratering suggests geological activity on Europa such as plate tectonic-like activity that recycles water ice from the subsurface to the surface and back again. Another interesting feature of Europa is its internal ocean, which is likely heated by vents and sustained by tidal heating. The discovery of such conditions has opened the door to questions about the possibility of finding life on Europa.

Jupiter’s moon Callisto

Finally, there is Callisto, the second largest of Jupiter’s moons. The surface of Callisto is nearly all covered in craters and is therefore extremely old, aided by the fact that it does not experience much tidal heating. This moon is also thought to have an ocean deep below the surface.

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Neptune’s Triton’s Origins

Posted on April 17, 2022 by Sheila Chau

As compared to other moons, Neptune’s Triton was captured into Neptune’s orbit. This was found out due to its backward rotation and how it rotates at a high inclination to Neptune’s equator. Rather than being formed in the disk of gas around Neptune, Triton was most likely captured into Neptune’s orbit. 

There is one way as to how this happened: Triton could have been a member of a binary Kuiper belt object that passed close to Neptune and lost energy and was soon captured. Triton shares many similarities with Pluto, the most well known world of the Kuipter belt. They are both very cold worlds with similar sizes and proportions of ice and rock. 

Neptune and Triton

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Jupiter’s Great Red Spot

Posted on April 17, 2022 by alexbawa

Growing up, I grew to recognize Jupiter’s distinctive birthmark, but I never attempted to understand it. I figured their were clever astronomers out there who knew what was going on and I’d end up absorbing what they know from a TED talk at 1.5x speed. After looking into it though, it turns out the Great Red Spot is largely a mystery.

It’s well established that the Great Red Spot is a weather system in Jupiter’s atmosphere. It is massive – spanning roughly three Earths across in the late 1970’s. It is fast – reaching up to 425 mph on the edges, nearly 200 mph faster than the fastest hurricane wind ever recorded on Earth. Past that, not much more is known. Experts guess at things like its composition and what makes it red, but there isn’t anything conclusive yet.

The Great Red Spot + Europa

There’s still much to be learned about what goes on in the vast storm that sits in Jupiter’s atmosphere. More missions to the outer solar system, better equipped to explore the red expanse, are essential to figuring out its mysteries.

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