Asteroids, with their varied shapes and sizes, are fascinating objects of the solar system. Their shapes are largely dictated by gravitational forces, with larger asteroids having enough gravity to form into roundish objects. These space rocks are riddled with craters due to many collisions over time. Among them, Ceres stands out as the largest, with a diameter just under 1000 kilometers, about one-fourth that of the Moon. It’s believed that over a million asteroids have diameters exceeding 1 kilometer. To estimate an asteroid’s size, astronomers measure its brightness, which varies based on its size, distance from Earth, and reflectivity. Brightness helps determine size: the brighter the asteroid, the larger it is, assuming equal distance from Earth. This distance is measured by tracking the asteroid’s orbital position, while reflectivity is gauged by comparing the light it reflects from the Sun to its infrared emission, indicating its temperature.
Now, I am from Phoenix, Arizona and it gets pretty hot over there. Which is why I think this is the “coolest” exoplanet. 55 Cancri E. Take a look at this beauty.
This is a planet I can get down with. It looks exactly like Mustafar from Star Wars. This planet is extremely hot, reaching up to temperatures of about 3500 degrees Celsius on the daytime side and about 1400 degrees Celsius on the nighttime side. 55 Cancri E is twice the diameter and eight times the mass of Earth. This planet is super close to its star at 0.01544 AU away. This is partially what makes it so hot on this planet. And because it is so close, it also orbits around its star very quickly. It completes one full orbit in 0.7 Earth days, which is about 17 hours. So a year on 55 Cancri E is not even a DAY on Earth! It is tidally locked with another planet in its system so it is constantly getting cooked on one side because it never spins. The entire surface is covered in volcanoes and seas of lava. The planet also has a very unique atmosphere. There are silicates (salts) in the atmosphere and when clouds are formed, the light from the lava is reflected off the silicates causing the sky to sparkle. This planet is awesome and if my body wouldn’t burn up into a crisp the second I got there, I would totally live here.
As we learned in class/from Dr. Stern’s Pluto talk, we really did not know a whole lot about Pluto until the historic New Horizons flyby in 2015. However, that daring team of scientists allowed us to discover new things about Pluto that people had not even fathomed before. For example, Pluto had been assumed to be a relatively “dead,” or “inactive planet,” but we discovered that Pluto actually has a “heart” of sorts that keeps the planet active. We can tell this through imaging but also through changes we observe on the planets surface. For example, the fact that Pluto’s basin faces Charon, Pluto’s moon is a result of Pluto’s heart, also known as Sputnkik Planitia. Also, Pluto might still be technically active because of the possibility that there is a vast ocean beneath the surface of Pluto, still liquid.
Pluto is not even as big as our Moon. The fascinating part is that Pluto is over 16,000 times farther from Earth than the Moon is, and yet from just one (meticulously calculated) flyby we have learned so much.
Artist’s rendition of what the surface of Titan could look like from: Smithsonian Magazine
Since our class is coming to a close, I have been curious about future astronomical missions. What will the students who take ASTR 2110 learn that we do not have access to yet?
One of NASA’s upcoming missions in partnership with Johns Hopkins Applied Physics Laboratory, is called Dragonfly and it will be observing the surface of Saturn’s moon Titan! Expected to launch in 2028, Dragonfly will journey to Titan and go down through its calm atmosphere to observe the ocean world! This will provide insight as to the kinds of chemical interactions that might have occurred before Earth was inhabitable.
We already have some knowledge of Titan from Voyager II, the Hubble Space Telescope, and the Cassini spacecraft. Cassini taught us about the surface of Titan including lakes, rivers, liquid ethane and methane seas, and sand dunes. It even showed that Titan might have some sort of rain.
Dragonfly is going to sample materials from these different terrains on Titan’s surface to determine if there is or could be habitability on the moon. While in flight Dragonfly will determine more about the contents of Titan’s atmosphere and provide us with images of the surface.
It makes sense why NASA would want to launch a mission like this; it will tell us about a world somewhat similar to ours, one with an ocean. We have been wondering why some planets do not have water and just how much liquid water is important to sustaining life. The Dragonfly mission will give us insight into the conditions needed to sustain life through the presence of liquid water. Dragonfly will no doubt prove to be super helpful to make sense of our own planet.
So what do you think about the Dragonfly mission? Will the results of this in 5 years from now change what we learn about the Giant Planet Moons? I think that the students in ASTR 2110 in the year 2030 are in for some great treats after these missions. It really shows just how fascinating space exploration is, we are always learning more and enhancing our education!
To learn even more about the mission and watch some explainer videos, visit the Dragonfly website here!
The Kuiper Belt was foreign to me before this class. I had never heard of it and because of that it stuck out to me. The basics of the Kuiper Belt is that it is the large region beyond Neptune. It stretches from about 30au-50au from the Sun. So far NASA says that only 2000 objects have been categorized. Which is astonishingly small for how big it is, but they estimate that there are hundreds of thousands of objects in it. Another interesting fact about the Kuiper Belt is that many of its objects have moons. This of course includes Pluto but other objects in it also have moons. The Kuiper Belt remains one of the most interesting but understudied parts of our solar system. I encourage everyone to look it up at some point and see if it interests you as well.
As I read through section 11.1 in our textbook, I realized that I did not comprehend as much as I would have liked about the differences between our Jovian planets. Therefore, I feel as though doing more research about them and writing this blog post will serve as an amazing study tool! This blog post is all about the composition and atmospheric differences between the Jovian planets in our solar system!
We know that all of the Jovian planets have rapid rotation rates, and we measure them by tracking releases from particles in their magnetic fields. Astronomers have discovered something interesting about the rotation rates of these Jovian planets: they vary based on their latitudes! The equatorial regions of Jovian planets rotate faster than the rest of the planet. However, this extremely fast rotation on Jovian planets causes equatorial bulges. The sizes of these equatorial bulges depend on the balance between the inward pull of gravity and the outward push of rotation. This equatorial bulge helps to keep orbiting objects (including moons and rings ) in line with the planet’s equator!
Now that we have covered the most basic differences, we can move on to the differences between the two planets’ compositions! As we learned during class, Jupiter and Saturn are considered gas giants, while Uranus and Neptune are considered ice giants. Therefore, it makes sense that Jupiter and Saturn are composed of mainly hydrogen and helium, while Uranus and Neptune are made of mostly hydrogen compounds, water, methane, and ammonia. As a matter of fact, Jupiter has such vast amounts of hydrogen and helium that it is called a “failed star.” If Jupiter’s gravity were stronger to heat its interior and create extreme levels of density, it would have the potential to generate nuclear fusion! Jupiter has reached the largest possible radius that it can, and thus, whenever any mass is added to it, the mass would not add to its radius, but the planet would just compress and become more dense.
When looking inside the interiors of Jovian planets, you will find rocky cores and ices. Jupiter’s interior layers are extremely interesting and differ from each other in the phase of their hydrogen. Additionally, unlike other Jovian planets, Jupiter’s temperature increases with depth! It has three levels of hydrogen: gaseous hydrogen, liquid hydrogen, and metallic hydrogen. Saturn has a similar interior to Jupiter, but its layers of gaseous and liquid hydrogen are thicker, while its metallic hydrogen is thicker. Uranus and Neptune never have high enough pressures to form liquid or metallic hydrogen, so they only have a gaseous layer of hydrogen.
This was just a glimpse into the differences between all of the Jovian planets, and there is still so much more to learn! With our test coming up, I hope that this taught you some new information and encouraged you to delve more into the topic for your own enjoyment
After learning briefly about asteroids and comets during previous units, I became intrigued by them. I had known a little bit about comets and where they are located within our solar system, but as I was reading about this in our textbook, I realized just how much more there was to learn. Comets are extremely interesting aspects of our solar system above, and in order to gain a complete understanding of the interworking of our universe, understanding the properties of comets is a great place to start.
To begin discussing comets in our solar system, it is beneficial to state the fundamental definition of a comet: a chunk of ice combined with rocky dust and other chemicals. To determine what the majority of comets are composed of, we turn to spectra (which we have discussed in previous units). From analyzing the spectra of various comets, astronomers have concluded that most comets contain hydrogen compounds, water, carbon dioxide, and carbon monoxide. However, these components on comets that make up their ice-rich properties do not necessarily stay in ice form for long…
When the comets are far away from the Sun, they are frozen. Due to the fact that they are not being heated by the Sun’s rays, they are frozen until they move any closer. In this frozen state, the center of the comets is called the nucleus. However, because comets are orbiting the Sun, the closer that they get to the Sun, the faster they go, and as this happens, their temperature increases. As their temperature increases, the ice vaporizes into gas! This gas takes dust particles out of the nucleus and helps to create the comet’s coma. As this coma grows, the comet forms a tail. These tails face away from the Sun for the majority of the time, and they come in two different forms: plasma tails and dust tails.
Plasma tails are made up of ionized gasses (ionized by UV light), and dust tails are dust-size particles that are not affected by the solar wind and are pushed outward by sunlight! During this process, comets cannot stay as big as they originally were forever because their ice is melting. Therefore, it makes logical sense that comets lose .1% of ice every time they pass around the Sun. Additionally, as a comet passes the Sun, the dust particles that are too heavy land on the comet’s surface — darkening it, blocking the outflow of gas, and preventing its tail from growing.
Now that we know a lot about these comets, only one more question remains: where do they come from? Astronomers trace the orbits of comets backward to find out where they originate from, and they determine that most comets must come from the Oort Cloud! The Oort Cloud is thought to have around one trillion comets. Some comets also come from the Kuiper Belt, a region with fewer comets.
This post provided a lot of information about comets, and I hope that you all learned something valuable from it. Knowing about comets is crucial to understanding our solar system as a whole, and I can’t wait to hear your questions about them!
If I am going to be honest, my decision to dedicate this blog post to the Alpha Centauri system comes from a TV show that I watched a few years ago. Netflix’s remake ofLost in Space follows a family as they travel across the universe to Alpha Centauri to start a colony there. Captured by the idea of a habitable planet other than Earth, my fascination with exoplanets can be attributed to this show. If you have not yet seen it, I highly recommend giving it a watch!
In the vast expanse of outer space, it is a miracle that we have the technology to discover stars and planets that are trillions of miles away. Located 23.5 trillion miles away, the Alpha Centauri System is the closest star system to our solar system. It is comprised of three stars, two of which are gravitationally locked in a binary system: Alpha Centauri A (Rigil Kentaraus) and Alpha Centauri B (Toliman).Yes, it is confusing: the entire star system is referred to as Alpha Centauri as well as the individual stars. To ease this confusion, I will refer to these stars by the names in the parentheses. Rigil Kentaraus is slightly more massive than our sun and 1.5 times brighter (EarthSky)!
The real fascination with the Alpha Centauri star system comes from the third star, Alpha Centauri C (Proxima Centauri). Out of all three stars, Proxima Centauri is the closest to Earth at 4.2 light years away. Unlike our Sun which will begin to die in 5 billion years, Proxima Centauri still has another 4 trillion years left. Even more remarkable, three planets have been detected to orbit it. Of these three, Proxima Centauri b is the most fascinating because it lies within Proxima Centauri’s habitable zone. Since Proxima Centauri is a red dwarf star and gives off much less energy than our Sun, its habitable zone spans much closer to the star than ours. Therefore, even though Proxima Centauri b is “at a distance about 5% of the distance between Earth and the sun”, it is sill within the habitable zone (Space.com).
Although the exoplanet is located in a region where liquid water seems possible, the planet itself may seem less hospitable. According to Universe Today, it seems that the chaotic nature of red dwarf stars like Proxima Centauri, coupled with the short distance between it and its exoplanet, Proxima Centauri b, may leave a world that receives 1000 times more solar wind radiation than Earth. Further, even though Alpha Centauri is the closest system to Earth, at speeds of 17,500 mph, it would still take more than 148,000 years to travel there (Space.com). Even if Proxima Centauri b may not be as hospitable as we had initially thought, and that we cannot reach Alpha Centauri with our current technology, studying this system reveals that our planet Earth may not be the only planet with the potential for life!
The SpaceTech industry is filled with companies attempting to reduce costs and drive innovation in the world of space exploration. In this blog post, I will cover a few leading companies in this space.
True Anomaly
True Anomaly is a SpaceTech based out of the United States. They are building a vehicle called Jackal, which is designed to maneuver in any orbit – GEO, MEO, or cislunar. The team at True Anomaly plans their missions extremely carefully with very specific goals. They have recently integrated AI into their vehicle to help it give off alerts.
Rea Space
Rea Space is an Italian company in the SpaceTech industry. They make a bionic spacesuit that interacts with muscles, thus, counteracting low gravity effects. They incorporate EMSI sensors to analyze the effect on gravity on the astronauts body. It also stimulates the body to prevent muscle loss and maintain cardiovascular function.
Apex
Apex, another US based startup, offers standardized satellite buses. Each of these manufactured buses are created and produced for specific missions, each with their own requirements. The buses range from 100 to 500kg in mass. They are based out of Los Angeles, California, and were founded within the last year and a half!
Pluto, situated 40 astronomical units (AU) from the Sun, orbits the Sun every 248 years. Its path stands out due to its highly elliptical shape and inclination relative to the ecliptic plane, distinguishing it from the other planets. Pluto is orbited by five moons, with Charon being the largest and most notable. Charon orbits Pluto at a distance of 20,000 kilometers, which is significantly closer than the Earth-Moon distance of 400,000 kilometers. Furthermore, Charon is relatively large, being one-eighth the mass of Pluto, unlike the Moon, which is only 1/80th the mass of Earth. The creation of Charon, as well as Pluto’s other moons, is thought to have been the result of a giant impact event, similar to the theory of our Moon’s formation. A large comet colliding with Pluto could have released its less dense outer layers, forming a ring of debris surrounding Pluto. It is hypothesized that this debris re-accreted and formed Charon and Pluto’s other moons. This hypothesis also could explain why Pluto orbits on its side around the Sun. It’s interesting to think about how Pluto and its moons came to be!
