Things that break all patterns are often the most interesting objects in our solar system. Neptune’s moon Triton is a prime example of breaking general patterns. It is the only large moon in our solar system that orbits in retrograde, opposite the rotation of Neptune (NASA). Originally I was interested in Triton because of its irregular orbital path. Since it likely was a Kuiper Belt object that got pulled in by Neptune’s gravity, it will eventually crash into the surface of Neptune.
The interior of Triton is also extremely intriguing as it is likely a core of rock and metals. It is extremely dense, which leads scientists to believe it has more rock inside than the satellite moons of Saturn and Uranus (NASA). The high density of Triton and its unique orbit leads me to wonder what may occur when it eventually collides with Neptune. Will it destroy the planet or will it leave a large crater on the surface of Neptune?
A picture I took of the eclipse in Nashville at 1:53 PM CST on April 8, 2024.
Around 2 pm today on Apr 8, 2024, I was fortunate enough to see the eclipse reach its peak in Nashville amidst intermittent cloud cover. Although Nashville wasn’t in the path of totality like it was in 2017, it was very close!
For a quick background on solar eclipses, a solar eclipse happens when the Moon passes directly between the Sun and the Earth, and when the Moon completely blocks the sun, it is called a total solar eclipse. A partial eclipse, when the Moon only blocks a part of the Sun, occurred here in Nashville today! Additionally, an annular eclipse is a special type of partial eclipse when the Moon blocks the Sun but leaves a small ring around the edge.
Overall, seeing the eclipse was a fascinating experience and really offered a unique perspective on astronomical events. I hope you all had the chance to see it today too!
OSIRIS-REx was NASA’s mission to collect a sample from the asteroid Bennu. In September 2023, OSIRIS-REx returned to Earth to drop off material from Bennu. OSIRIS-REx continued on a new mission, OSIRIS-APEX. The objective of the new mission is to study Apophis, which the spacecraft will reach in 2029.
NASA lists 10 reasons why scientists wanted to study Bennu. Here a a few of them:
Bennu has been well preserved in the vacuum of space since the formation of the solar system. Bennu is a great asteroid to study to learn more about Earth’s formation.
Bennu might have clues about the origin of life! Through studying Bennu through telescopes (Earth and space based), we know that it is a carbon rich asteroid. This means that Bennu is probably rich in organic molecules. It also might have water!
It can help scientists learn more about the Yarkovsky effect. The Yarkovsky effect is a phenomenon that involves sunlight warming one side of an asteroid and then radiating off the asteroid as heat as the asteroid rotates. Since its discovery, Bennu’s orbit has drifted closer to the Sun by about 280 meters per year. The Yarkovsky effect might be to blame for this because the heat energy pushes Bennu towards the Sun. Studying the Yarkovsky effect can help scientists predict the movement of other asteroids.
Scientists estimated that Bennu could pass closer to Earth than the Moon in 2135 and then pass even closer from 2175 to 2195. Scientists in the next century can use data from OSIRIS-REx to come up with ways to deflect any asteroids that could hit Earth!
The risk of Bennu hitting Earth is very very low: 1 in 1,750 through the year 2300
Being in Nashville, I saw a partial solar eclipse today. It was unfortunate that it was extremely cloudy. Hence, the solar eclipse showed up once in a couple minutes. The clouds proved to be an excellent source of shades. So much so, that the combination of the thick clouds and the eclipse glasses blocked out any sunlight.
Partial Solar Eclipse. Moon is on its path of leaving the sun’s glare. (It didn’t have shades) Credits: Me!
As we can see, the clouds were thick and covering the sky. However, it was still gorgeous. The bright crescent shape outlined through the dark contrasts of the moon made for an beautiful image. The image reminds me of the Crab Nebula image as seen through the telescope, but inverted. The surrounding clouds captured the sunlight brilliantly. The real spectacle was my friend who could only see the eclipse for a couple of seconds as he was trying to answer my texts. Eventually, he got to see it for more than 30 seconds. (I had to tell him to look up.)
Even some of the smallest world in our solar system exhibit (or have exhibited) evidence of volcanism or cryovolcanism. Asteroids like Vesta, with radii of only several hundred kilometers, displays features that indicate that they once exhibited active volcanism and even separation by differentiation. Although their volcanism lasted for periods that were geologically very brief, it is rather surprising that they actually exhibited any volcanism at all. After all one of the best indicators of a planet’s ability to sustain volcanic activity (over any time period) is its size. When we look at current worlds like Mercury, we narrate their tectonic history as being brief and very temporally distant from the present day. If worlds like Mercury can only sustain a little bit of volcanism, how can worlds that are several times smaller sustain any volcanism at all? How can they exhibit mountains that dwarf Earth’s tallest? How small is too small for volcanism and tectonic activity?
We don’t have a definitive answer yet, unfortunately, due to our inability to directly resolve and study very small objects. We have found moons smaller than Vesta that show past evidence of volcanism or cryovolcanism. Mimas, a moon of Saturn, has provided evidence of past cryovolcanism, despite being less than 400 kilometers in diameter. Miranda, a moon of Uranus, has also exhibited evidence of past geologic activity and possible volcanism. Enceladus, an cryovolcanically active moon of Saturn, is only about 500 kilometers in diameter. There are other worlds that we have observed that are much smaller, but we cannot quite determine their level of geological activity due to current optical limitations.
A colorized image of the young surface of Miranda (also known as Uranus V) captured by NASA’s Voyager 2 mission. Courtesy of zelario12 on Flickr, under the CC BY-SA 2.0 DEED license.
Another problem (besides our compromised ability to study very small objects) that arises when trying to figure out a minimum size for volcanism or cryovolcanism is our lack of precise knowledge of bodies’ past sizes. Mimas may be 400 kilometers in diameter now, but may very well have been larger (or smaller) when it was cryovolcanically active. To be able to empirically determine a minimum size for volcanic or cryovolcanic activity, we would need to be able to estimate planetary radii from billions of years ago with extreme precision, which is extremely difficult.
As our resolving abilities improve and we expand our horizons in physical exploration, we may find new world that are even smaller than those observed currently. Until then our question will have to remain unanswered.
We first landed on the moon over 50 years ago, but despite the relative feasibility of going back to the moon, we have only conducted a few missions since then for people to travel to our closest celestial neighbor. Why is that? Going to the moon is incredibly expensive, and there’s always been little reason to go back given its lack of resources that don’t already exist on Earth. This changed in 1994, however, when it was discovered that water ice exists on the poles of the moon. Since then, there has been an increased push to go back to the moon, as this water ice could potentially be harvested and used to produce fuel. This mission, from harvest, to storage, to turning the harvested materials into something we can use, is incredibly expensive. Plans are currently being proposed in order to find out more about this extraterrestrial water and how it can be used, but it is still unclear at this point the extent to which it would be worth it to undergo an expedition of this nature given the costs. You can find more about this here. For me, this idea is intriguing because of the future implications. We are still so early in our quest to discover what exists on the moon and Mars, and perhaps further research will uncover more resources that could assist humanity than we currently are aware of. Given the current state of climate change, perhaps it will be sooner than we think that we will have to venture outside our own planet in order to acquire what we need to survive.
Kepler-186F is an exoplanet that exhibits strikingly similar characteristics to Earth. The planet is roughly the size of Earth, and is within the “habitable zone” of its red dwarf star, Kepler-186. The habitable zone implies that due to its distance from its star, it’s very possible that the exoplanet could have liquid water on its surface. It is the outermost of 5 similar planets that were discovered roughly a decade ago, which together make up the “Kepler System.” This discovery is absolutely fascinating, for the potential existence of liquid water and other Earth-like qualities means that there is a very good chance that extraterrestrial life exists here. Unfortunately, the planet is over 500 light years away, a distance we have not come remotely close to being able to reach with current technology. While it’s unlikely that we will be able to see what exists on Kepler-186F in our lifetime, it is fun to imagine what could exist on a world like this. Could life exist, or perhaps be much further developed than life as we know it? If you’re curious, you can find out more about the planet here.
One of the most interesting bodies in the universe is the brown dwarf, a small world a few times the size of Jupiter. These are interesting because they do not fit cleanly into our definitions of stars and planets. They are technically under the category of star, but this is due in most part to the way in which they form. They form just as stars do, by accumulating gas in space following a disturbance in a nebula, rather than from the debris surrounding a star. However, because of their lack of gravity from their small mass, they have limited fusion in their core, meaning they are kept rather cool, and so, do not glow particularly bright. This is where they get their namesake, and also why they were not discovered until 1994.
Triton stands out amongst most moons. Usually a moon is made of the leftovers from when the solar system was being formed, ideally becoming large enough to force itself into a spherical shape. More ambitious moons are made directly from planet material cast off in an accident. Triton sticks out; it is theorized to have been thrown out of its original orbit in the kuiper belt. The high inclination it cycles Neptune’s equator is largely unique to it, and it orbits in the opposite direction Neptune spins. As a side effect to its origins, Triton was once far more geologically active than most moons of its size. This can be attributed to the once elliptical orbit Triton had, which affected the tidal forces on it, and the faster rotation it surely used to have.
When someone mentions Pluto, most people’s minds instantly go to the “Is Pluto a planet debate”. In fact, all I knew about Pluto before reading these chapters was that it was too small to be a planet. If you asked me to picture Pluto, I would have said something akin to our moon – rocky, filled with craters, and relatively boring. However Looking at the images of Pluto taken by New Horizons tells a different story. Filled with vibrant red patches, towering mountains, and massive glaciers, Pluto is the opposite of boring. In addition, un-cratered areas found on Pluto show that there is actually geologic activity happening, unlike the moon. Even Pluto’s moon Charon is much more interesting than our moon, as it too shows signs of geologic activity and a lack of craters on its plains. Finally, scientists now believe Pluto has a massive ocean running underneath it, similar to Jupiter’s moon Europa. Regardless of it’s contested planetary status, Pluto remains one of the most interesting bodies in our Solar System, and I hope we send another satellite back to do further research.
Four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with color data from the spacecraft’s Ralph instrument to create this enhanced color global view of Pluto. Source
