Ceres, the Celebrity of the Asteroid Belt

Posted on April 8, 2023 by willems49

Despite comprising almost a third of the asteroid belt’s total mass, Ceres is often left out of dwarf planet discussions. However, Ceres is actually pretty unique and could potentially support life in the future. Because of its relative closeness compared to the likes of Pluto, it was the first dwarf planet to be visited by a spacecraft, called Dawn. While Ceres looks like many asteroids, especially those called C-type asteroids, Ceres contains much more water than anticipated. In fact, it could possibly be almost 25% water, which is more than available on Earth. It also contains ammonia on its surface which is characteristic of objects outside of the ice line. In these ways, Ceres is much more similar to a Kuiper Belt object than an asteroid belt one. There are plenty of theories suggested to explain how these characteristics formed in the asteroid belt, but some scientists believe Ceres actually originated outside the orbit of Saturn. During the early solar system formation, it could have migrated to its current location as giant planets shifted. Learn more about the migration theory here.

Another unique factor separating Ceres from other asteroids is evidence that Ceres was geologically active despite its small size. Ceres could not generate heat like other terrestrial planets or through tidal friction like many giant moons. Instead, it is thought that Ceres was initially cold, and the radioactive decay of elements like uranium and thorium heated the planet up for a period of time before cooling again. This process is called radiogenic heating, and its natural instability would produce unique features across the surface of Ceres. For example, there is a large plateau on one hemisphere with localized fractures that were lacking on the other hemisphere. Physicists simulated this with a model of localized instability on one hemisphere, and the fractures match those observed by the Dawn spacecraft. Read more about the model here. 

This geological activity could have created ice volcanoes which could produce the water vapor found in its thin atmosphere. Additionally, layers of ice could shift and erase large craters while perhaps even a layer of water ice exists below the crust. Because of this, some astronomers are hoping for a rover mission to Ceres to take samples and gather information about the possibility of sustaining life not so far away from home.

An artist’s rendition of Cere’s possible layers is shown below.

Source: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
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Water Beads on the Moon

Posted on April 8, 2023 by willems49

After analyzing Moon samples taken over two years ago, scientists have discovered glass beads of water on the surface of the Moon. The Chinese probe, Chang’e 5, took soil samples from the lunar surface as part of China’s first sample-return mission. These glass beads are thought to be across the entire surface of the Moon and hold potentially 600 trillion pounds in just the top 40ft of the surface. Although it was widely thought that the Moon contains water, it was previously unknown how much of it still existed. 

This discovery also raises the question of how these beads formed, and scientists analyzing the samples have a theory. When asteroids collide with the moon, pieces of the lunar surface are launched into the atmosphere and heated. Under these intense circumstances, silicate particles from the asteroids combine to create tiny glass beads. Water is thought to have formed in the beads through interactions with solar wind. Hydrogen atoms, which match the type released from the Sun, combine with oxygen in the beads to form water molecules. These beads can then release water back into the surface.

This suggests that the moon has an active water cycle and vast amounts of water stored under the surface. Possibly in the future with more lunar explorations and missions, water will not have to be transported. Water weighs over 8 pounds to the gallon which makes it particularly expensive rocket cargo and often the limiting factor for manned missions. Lunar exploration or settlement could be sustainable, and future explorers could possibly extract the water, use it, and recycle it, without needing shipments from Earth. Read more about the finding here.

Glass beads from a lunar sample. Source: Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences

Would you want to try a glass of water from the Moon?

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Titan

Posted on April 8, 2023 by zws42
Artist rendering of Titan’s surface

Titan is Saturn’s largest moon and the second largest moon in the solar system behind Ganymede. It is shrouded in a thick, yellow atmosphere and has standing bodies of liquid on its surface. It is the only place besides Earth(that we know of) that has an atmospheric cycle of precipitation and evaporation. One day on Titan is 15 Earth days and 22 hours long, and one year is about 29 Earth years.

The average temperature on Titan’s surface is -290 degrees Fahrenheit. Due to these extremely cold temperatures, water ice forms the crust of the planet in much the same way that rock forms Earth’s crust. Titan’s surface is shaped by the flow of methane and ethane, both of which are in the liquid state due to Titan’s extremely cold temperature. These liquids form features we are very familiar with from Earth, such as rivers and lakes. Titan is also thought to have icy volcanism. This would be liquid water erupting as a kind of extremely cold lava equivalent.

Titan’s atmosphere is comprised primarily of nitrogen, much like Earth’s, but extends about ten times further into space due to Titan’s lower gravity. There is also evidence of organic compounds both in Titan’s atmosphere and on its surface. These are thought to be formed when UV from the sun splits particles apart in Titan’s upper atmosphere, which then reform and can fall to the surface. On the surface, these particles form structures reminiscent of sand dunes on Earth.

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Did we really land on the Moon?

Posted on April 8, 2023 by araceal

July 20th, 1969. We landed on the moon. But did we really?

There are many conspiracies on if we really landed on the moon or not. People claim many reasons which prove that the moon landing never actually occurred. Shadows in the moon landing photos are not parallel which shows that they were fake. The astronauts would not have been able to survive Earth’s radiation field. There are no stars in the pictures of astronauts on the moon. The flag set on the moon was waving, but theres no wind on the moon. If we really did land on the moon, way haven’t we been back?

All of these claims are believable, but why aren’t they true. Each of these claims have been debunked by astronomers and researchers, which can be found here. 

Even though all of these claims have so called be “debunked”, do we really believe these explanations, or are the questions of if we really landed on the moon still being contemplated. That is completely to up to you. For me, I think I need to see another moon landing in order to truly believe this. But while you are still contemplating if this achievement really happened or not, maybe this video of the new Apollo 11 landing site being pictured will help skew your decision.

(moon landing picture, History Channel)

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Nemesis: The Ultimate Party (And Ort Cloud) Crasher

Posted on April 8, 2023 by Alex Diefenbach

(Hypothetical Rendition of Nemesis – https://images.app.goo.gl/214dFoRtpLU4LSW59)

There is a theory concerning the orbit of celestial bodies which has been proposed that would explain the extinction of the dinosaurs.

The theory rests on the idea that our sun is part of an astronomical dynamic called a binary system. A binary system resembles the mechanics of satellite and planetary orbital behaviors but it diverges in that it involves the tango of two stars.

The nickname of the sun’s hypothetical companion is Nemesis, dubbed in this fashion for the chaos it causes as it approaches the center of the solar system. Theoretically, it has an orbital period of approximately 26 million years, which is similar to the incidence of mass extinctions like those that ended the reign of reptilians.

When Nemesis transitions toward its perihelion, it is said to pass through The Ort Cloud— a sphere of icy space scraps that surround the solar system. In doing so, it disrupts the potion in its path, sending tons of comets and other junk hurdling toward the inner planets, causing many of them to impact Earth. The period of such destruction would be thought to last around a hundred thousand years or so.

Unfortunately, there hasn’t been any concrete evidence to support this quite interesting astrophysical hypothesis. But even if the theory did turn out to be true, hopefully, the rapid progression of science and technology would help us to combat the consequent destruction of its return.

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Strange Stars (Literally)

Posted on April 8, 2023 by Europa

Neutron stars are the collapsed cores of massive stars of 10-25 solar masses. They are formed when these supergiant stars collapse under their own gravity and undergo a supernova explosion, which compresses the star’s core to the extremely high density of atomic nuclei. In fact, they are called neutron stars because the extreme forces within a neutron star cause the protons and electrons present in normal matter to combine, producing neutrons. Neutron stars are composed almost entirely of neutrons.

Illustration of a neutron star–stellar corpses. (Source)

Aside from black holes, neutron stars are the smallest and densest currently known class of stellar objects, with radii on the order of 10 km and masses of around 1.4 solar masses. This is like compressing twice the mass of the Sun into an object the size of a small city. Also, a teaspoon of neutron star material would weigh around 1 billion tons on Earth!

What keeps neutron stars from collapsing further is neutron degeneracy pressure. As a star collapses, it eventually reaches a point where it cannot collapse any further due to the Pauli exclusion principle. The principle states that no two fermions (a category of quantum particles that includes protons, neutrons, quarks, and leptons) can occupy the same quantum state. The interior of a neutron star is so densely packed that there is physically no room for additional particles. This causes an outward pressure against the collapse of additional material. Thus, equilibrium is maintained between the inward force of gravity and the outward force of the neutron degeneracy pressure. It takes immense gravity, caused by an immense mass, to overcome the neutron degeneracy pressure, which is what happens when the mass of a neutron star exceeds the Tolman-Oppenheimer-Volkoff limit and the neutron star collapses into a denser form.

The inward force of gravity is counteracted by the outward force of neutron degeneracy pressure in a neutron star. (Source)

The most likely denser form is a black hole. However, at even more extreme temperature and pressure conditions, it is hypothesized that when the neutron degeneracy pressure is overcome, the object might not become a black hole, but might establish a new equilibrium. In this scenario, the neutrons would merge together and dissolve into a sea of their constituent quarks. This would represent an entirely different, ultra-dense phase of matter–quark matter. A new equilibrium would be reached–one between the inward force of gravity and the outward force of quark degeneracy pressure, which is analogous to neutron degeneracy pressure. This stellar object would be called a quark star, and is considered an intermediate stellar category between neutron stars and black holes. Alternatively, it is possible that quark matter exists in the inner cores of some neutron stars.

To take this one step further, or perhaps, stranger, we must discuss the different types of quarks. There are six types of quarks: up, down, charm, strange, top, and bottom. Normal matter is composed of up and down quarks, since they are stable at the temperature and pressure conditions of the majority of the universe. For example, protons are made of two up quarks and a down quark, and neutrons are made of two down quarks and an up quark. The other four quarks are unstable at normal pressure and temperature conditions and will decay into up and down quarks. However, under the intense pressures at the interior of a quark star, it is strange quarks that would be the most stable, so up and down quarks may transform into strange quarks and form strange matter.

The six types of quarks. (Source)

Thus, we have a new variation of quark star: the hypothetical strange star, composed of up, down, and strange quarks. It is possible that we have already detected such objects–astronomers have found stellar objects that appear to be neutron star adjacent, but are a bit unusual. For example, the star at the center of the supernova remnant HESS J1731-347 seems like it should be a neutron star, but its mass is only 0.77 solar masses–significantly lower than the minimum neutron star mass predicted by theory. Is there a gap in our understanding of neutron stars? Are we looking at a strange star? Are we looking at something completely different? More research is necessary, but the idea of stars composed of forms of matter entirely unknown on Earth is an exciting possibility!

The supernova remnant HESS J1731-347. (Source)
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Comets

Posted on April 8, 2023 by zws42
Source

Comets are Kuiper Belt objects composed of chunks of rock and various ices. For the majority of their orbits they are a long way away from the Sun and don’t have the characteristic tail that we are used to seeing. However, as the comet dives back into the inner solar system, the radiation from the sun causes the tail of gas and dust to form in the wake of the comet’s passage. These tails can stretch for millions of miles behind the comet, and when one of these tails cross over Earth’s orbit it can cause meteor showers on Earth.

There are currently 3,865 known comets, but astronomers estimate that there are billions in orbit within the Kuiper Belt and Oort Cloud. As I touched on above, these objects would not have the long, bright tails that we associate with comets due to their great distance from the Sun, which makes them much harder to see. This, coupled with our small number of missions to the outer solar system, accounts for the small number of comets we have discovered relative to the total estimated amount.

There are two main types of comets: short period and long period. Short period comets come from the Kuiper Belt and typically have predictable orbits, due the fact that we have seen them come by before. These have orbits that are typically less than 200 years long. A well known example would be Halley’s comet, which has an orbital period of about 75 years. Long period comets are thought to come from the Oort Cloud and are much less predictable than short period comets. Part of this unpredictability comes from the fact that these comets can come from any direction; not just the plane of the solar system. The larger factor however, is that these orbits can last up to 30 million years due to the extreme distances they travel. This makes it extremely hard to predict when they will come through the inner solar system, and therefore probably poses the largest risk of unforeseen impact with Earth.

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The Dwarf Planet Debate

Posted on April 8, 2023 by araceal

(picture of the colorization of Pluto)

We all know the controversy that Pluto causes. Should it be a planet? Should it not be one? Why should or shouldn’t it be? 

Although astronomers and other scientists claim that Pluto should not be considered a planet, some researches believe that this decision was unfair and incorrect and that we should reconsider Pluto to be a planet in our solar system. 

So why isn’t Pluto considered a planet? Well, according to Tom Metcalfe, a Planet must have three requirements: 1. Must be spherical, 2. Must orbit the sun, and 3. Must have gravitationally “cleared its orbit” of others planets. Pluto fulfills 2/3 of these requirements, but it does not fulfill the last requirement. Pluto shares its orbit with other objects (“plutinos”).

So if this is true, and Pluto does not fulfill the requirements for having the title of a planet, then why do researchers believe that Pluto should be considered a planet again? These researchers state that a previous definition, created in the 16th century, of a planet being “any geological active body in space”. But if this definition was used to classify “planets” rather than the previous three requirements, this would mean that over 150 objects in our solar system would be our “planets”.

So many things need to be considered before making this decision. Will Pluto become our 9th planet again, or will it stay outcasted as just a Dwarf Planet?

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Ocean Worlds of Supercritical Fluid

Posted on April 7, 2023 by Europa

In class, we learned about various categories of exoplanets, including Super-Earths, terrestrials, ice giants, gas giants, and hot Jupiters. One other category that was mentioned was “water worlds,” an ill-defined and not entirely proven category of planets. This category would describe planets that are on the border between terrestrials and ice giants, or terrestrial worlds right near the frost line.

I did some more research into water worlds and found the Wikipedia page for “ocean worlds.” However, this isn’t necessarily exactly what I was looking for–the page describes a planet that contains a significant amount of water in the form of oceans, either subsurface or on the surface of the planet. This is not a very narrow definition–it includes Earth, with our surface oceans, and some icy satellites, like Europa and Enceladus. While the latter two are exciting prospects for life due to the presence of water and recent geological activity, they don’t fit the definition of water worlds that I was looking for.

I read on and found a more narrow discussion of one type of ocean worlds. To preface, water accounts for only 0.05% of Earth’s mass. Imagine an exoplanet with a much higher percentage of water–if the ocean is deeper and denser, the pressure could be extremely high at the bottom. Think about how much pressure you feel in your ears when you swim to the bottom of a diving well–that’s about 12 feet. Earth’s ocean gets to almost 7 miles deep. The exoplanets Kepler-138 c and Kepler-138 d appear to have oceans 1,000 miles deep.

An illustration comparing the interior of Earth, with its thin oceans, to the potential interior of Kepler-138 d, with its predicted thicker oceans. (Source)

At such immense pressures, ice could exist, even at the high temperatures of a planet’s interior. One form of ice that can form under these conditions is ice V (read “ice five”), a specific crystalline phase of water with a notably complicated molecular structure. Ganymede is thought to have such ice at the base of its potential liquid water ocean. Ice V could make up the mantles of such ocean worlds.

The structure of ordinary ice, ice XI. (Source)
The structure of ice V. (Source)

Taking this a step further, what if the ocean world is close enough to its star that water reaches its boiling point? The water would become a supercritical fluid, which means that it is at a temperature and pressure above its critical point but below the pressure required to compress it into a solid, and thus distinct liquid and gas phases do not exist. The exoplanet would lack a well-defined surface. The atmosphere would be thick and mostly water vapor, leading to a greenhouse effect.

The pressure vs. temperature graph for water, showing the supercritical phase at high temperature and pressure. (Source)

Such exoplanets must not be very massive or must be close to their star. Otherwise, they would have retained a thick atmosphere of hydrogen and helium, making them more similar to their cousins–ice giants like Uranus and Neptune.

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“Mars Will Come to Fear My Botany Powers”

Posted on April 7, 2023 by oilrigatoni
This image has an empty alt attribute; its file name is pexels-kristina-paukshtite-712876-1.jpg
Pexels

While this line was a comical hit in the box-office hit “The Martian,” it also emphasizes a particular problem that we are experiencing as we explore new worlds. It is very heavy, cumbersome, and expensive to send all the food we need on space missions, and for a prolonged colonization mission, it just isn’t feasible. Therefore, the strategy is to use the field of astro-botany to farm food for the colonization missions.

There are a number of problems with farming in space, whether it be on space stations or on other planets. Firstly, in conditions where gravity is absent or extremely low, water behaves in funky ways. Cohesion and adhesion has more power relative to the force of gravity. (See this video to see an example). It’s difficult to provide the plants with the correct amount of water if water isn’t behaving in a predictable manner, so specialized irrigation techniques are necessary.

Another problem is that plants are evolved to Earth. They have not developed in the lower gravity’s of other planets, nor the lack of gravity of space. This may not be a huge problem, or it may cause plants to lack effective development, affecting their methods of gravitropism. Current tests in the ISS are looking at genetic modification of these plants to change their levels of lignin, which gives plants their stiffness. Ultimately, it remains to be seen if this will cause significant problems on our celestial plants.

There are even more problems with obtaining the necessary resources for growing plants. Sunlight, water, atmosphere, and nutrients are all needed. Firstly, plants are evolved to receive specific wavelengths on Earth. Different types of light reach planets’ surfaces in different quantities due to the varying compositions of their atmospheres. But this likely isn’t too big of a problem, especially with the use of artificial light or greenhouse roofs that screen the excessive harmful wavelengths.

A bigger problem is our old friend dihydrogen monoxide. Water is difficult to obtain, as it is far too dense to take into large quantities into space. Currently, the ISS uses recycled water from the urine, sweat, and showers, but since that is just being used for drinking and other small tasks, it is extremely cyclical with very little being removed from the system. But plants need lots of water, so they would be a massive drain on the cycle. Thus, we’d need to produce more water than we bring to a new frontier in space. This can be done in several ways: first of all, the ISS is trying out a new advanced Sabatier system. This will turn the hydrogen and carbon dioxide waste of the space station into methane and water, which will help the ISS to reduce waste and provide more water for the astronauts. On a planet like Mars, this is an option, but there is another one as well. The soil is about 3% frozen water, with more ice content being found below the surface. This ice can be extracted and turned to liquid water for human (and plant) use.

For soil nutrition, scientists have been developing new ways to garner the necessary nutrients for the plants on other worlds. Like water, it isn’t feasible to send tons of Earth dirt to other planets, so we have to use the soil we find there. The problem is, most of these soils lack any “nutritional” value. Soil without any nutrients can not provide support for plants. Furthermore, Martian soil, for example, has toxic chemicals like perchlorates which can even be harmful if we can consume, posing another barrier to effective farming. Yet we have made some headway. Cyanobacteria were shown to be able to survive harsh radiation from space, similar to what they’d experience on Mars. Their interaction with regolith on Mars could provide nutrients for the plants in the same soil.

Astrobotany is an emerging science as we approach our goal of colonizing Mars. Having the ability to grow crops on another planet frees up room on a rocket for other equipment and supplies, as well as bringing a more balanced diet to the astronauts. It is certainly very interesting the ways that space explorations makes us think of possibilities we had never before thought of.

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