Exoplanets!

Posted on April 9, 2023 by dromalley
A size comparison of several exoplanets to Earth from Caltech

Over the past several decades, the study of extrasolar planets, or exoplanets, has been one of the most rapidly advancing fields of astronomy and even science in general. With huge leaps forward that have been made in both technology and methodology, the number of exoplanets astronomers have been able to directly observe has exploded, with more than 5000 fully confirmed planets and thousands of candidates which may or may not be. There are a number of ways to identify exoplanets, but the two most common are by observing a transit (measuring how much of a star’s light and exoplanet blocks when it moves between us) or by observing the red and blue shift of the star as it orbits the system’s center of mass.

The radial velocity method relies on measuring the shift in light from the host star

Given the massive number of stars in our galaxy, and the apparent frequency of expo planets around other stars (about 1/5 of sun-like stars) estimates for the number of planets in our galaxy alone can top 100 billion. As we continue exploring the galaxy around us, and especially with new tools like the JWST, that number is sure to grow. With so many planets in our galaxy, its almost certain there are many, many habitable worlds, and it is very possible there may already be life on them.

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Space Potatoes!

Posted on April 9, 2023 by sadiekarr

(Diagram showing various asteroids, very potato shaped, you may notice)

As Dr. G says, “When I say Asteroids, you say Space Potatoes!”

But what exactly does that mean?

The reason we liken asteroids to potatoes is because of their shape (unfortunately, they do not taste as good as those beautiful starchy tubers) (Side note: in case you didn’t know [because I did not], a tuber is kinda like a root but not really. Apparently potatoes are tubers. You learn something new everyday). Because asteroids are so small, they do not hold enough gravitational force to mold themselves into spherical shapes like larger planets do.

You may notice that in the chart above the asteroid Ceres, however, looks very round. Ceres is a special case because it actually is large enough to have the gravitational force to make itself round. It is the largest asteroid in our solar system and accounts for ~1/3 of all mass in the Asteroid Belt. It’s such a large asteroid, it is actually a dwarf planet too!

Maybe now you’ll think of asteroids every time you have potatoes too 😉

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Bog 5 – Chelyabinsk Meteor

Posted on April 9, 2023 by constellationsarentreal

A relatively recent and frightening meteoric event occurred in the quaint city of Chelyabinsk in Russia on February 15, 2013. This incident is rather interesting since damage caused by the meteor was not due to impact, but rather violent shockwaves produced by the airborne-meteor’s explosion over the city. The explosion occurred when the meteor, roughly the size of a house, exploded 14 miles above ground, causing an intense flash of light and sonic boom which not only blew out windows within 200 square miles, but also damaged some buildings. Of the 1,600 people injured in the explosion, most attributed their injuries to shattered glass.

Picture of the meteor’s vapor trail after it plummeted through the atmosphere.

The Chelyabinsk Meteor was also a crucial catalyst for the creation of several agencies geared toward the detection of potential impact asteroids. Programs like The International Asteroid Warning Network (IAWN) and NASA’s Planetary Defense Coordination Office (PDCO) were established after heightened awareness of the Chelyabinsk incident. Even still, several programs at NASA, most notably the Near Earth Objects Observation Program, received more funding and attention. Since then, NASA has detected, identified, and continuously tracked thousands of asteroids. NASA also worked with the US Government to develop planetary defense plans against an imminent asteroid impact. In addition to the testing of computer simulations, NASA’s Double Asteroid Redirection Test (DART) space-flight mission successfully altered the orbit of an asteroid by butting it off course through kinetic-impact. Learn more about DART here.

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Lightning on Jupiter

Posted on April 9, 2023 by sadiekarr

How fitting that mysterious lightning has been observed on the planet named after the god of sky and storms!

Lightning on Jupiter has been reported multiple times over the years during multiple space missions: the 1979 Voyager mission, 1990s Galileo Jupiter mission, and again during the 2007 New Horizons mission. Now that we’ve got Juno (orbiter spacecraft) to keep an eye on Jupiter, more lightning and new information have been observed!

Besides being super freaking cool, Juno’s observations of lightning on Jupiter have revealed ammonia (rather than just water) in the planets storm clouds. For the longest time, we assumed that the lightning on Jupiter occurred in the same manner as lightning on Earth (convection). And that is mostly the case, but the observation of “shallow lightning” means that something a little different is going on.

Shallow lightning is a “form of electrical discharge [that originates] from clouds containing an ammonia-water solution,” rather than only water, like on Earth.

This video (which we viewed in class) simulates going through the clouds on Jupiter as bursts of shallow lightning occur. Pretty cool!

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The Frozen World: Pluto

Posted on April 9, 2023 by sahilreddy2

Pluto’s Icey Surface taken from the New Horizons Spacecraft

Pluto is one of the most interesting “planets” in our solar system and for decades now has had constant debate surrounding it. Pluto has an extremely thin atmosphere, one that is a lot thinner than ours on earth that is made up of primarily nitrogen. Its surface temperature is around -400 degrees Fahrenheit because of its location in the Kuiper belt which is very far away from the sun. Also, since Pluto exists in the Kuiper belt it takes 248 Earth Years to orbit around the sun because of the distance. Before 2015 we never had acquired proper pictures of Pluto, this all changed when the New Horizons spacecraft reached Pluto and was able to take revolutionary pictures. Through images like the one above humanity was able to learn about extremely large mountains that are on the surface and a heart-shaped region that covers the dwarf planet. Furthermore, from New Horizons we were able to get more detailed information on Pluto’s moons such as Charon (the largest) and learn from data that there is possibly an ocean underneath its surface. Conducting missions such as New Horizons to visit objects around our solar system is crucial for us as we are able to learn more about our place in the universe.

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Post 6

Posted on April 9, 2023 by berlinbe

Many people may remember the last total solar eclipse that was visible from North America. It occurred on August 21, 2017. The next total solar eclipse that covers North America, and the only one for the next 20 years, will occur on April 8, 2024—almost one year from today. Total solar eclipses are a fascinating sight for humans, but beyond that, what is their utility?

It turns out that total solar eclipses are of significant scientific value, as they provide an opportunity to study our earth and atmosphere when it isn’t receiving its usual amount of solar energy. In fact, the last total solar eclipse in 2017 saw 11 NASA-funded studies that aimed to take advantage of the conditions. Many of these studies seek to better understand the sun’s corona (which is normally relatively hidden), as well as the outer layers of our atmosphere where the sun normally ionizes particles.  

So, when North America witnesses the amazing sight of the total solar eclipse on April 8, 2024, consider the useful scientific discoveries that may arise from the event.

This diagram from NASA shows where the 2024 total solar eclipse will be visible in North America.

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Blog #5: Pluto

Posted on April 9, 2023 by Astro 2110

The above photo was captured by the New Horizons Spacecraft and enhanced by NASA in 2015.

Pluto is classified as a dwarf planet and is located in the Kuiper Belt in the far reaches of the Solar System. The average surface temperature on Pluto is around -233°C. This is because Pluto receives very little sunlight due to its distance from the Sun. Pluto orbits the sun about once every 248 years and remarkably also has five moons surrounding it on its highly elliptical orbit around the Sun. The largest of the moons, Charon, was discovered in 1978 and is considered a turning point because it allowed astronomers to calculate the mass of Pluto for the first time. Pluto had been known to exist since its discovery in 1930 by astronomer Clyde Tombaugh, but it was hard to study until extremely powerful telescopes were developed to capture its small size. The hypothetical view of outer space from Pluto would be incredible with the moon Charon taking up much of the sky and the unobstructed view of light from the rest of the universe. Charon and Pluto are tidally locked and have a binary orbital pattern around a center of mass slightly outside of Pluto. Much of what the scientific community knows about Pluto was discovered during the New Horizons mission which launched in 2006 and finally arrived at Pluto in 2015. We now know that Pluto once had active geologic activity and its surface contains mountains as big as the Rockies in the United States, bewildering scientists. Pluto is not known to have any source of internal heat powering this activity. We still have much to learn about Pluto and its origins which could make it an appealing target for an orbital mission in the future. Considering the success of the New Horizons flyby, the orbital mission could provide groundbreaking new information to learn more about all planetary activity even beyond our solar system.

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Blog 6 – Io

Posted on April 9, 2023 by kevkoppa123

Io is one of the 4 Galilean moons of Jupiter and it is the most volcanically active body in our solar system, continually repaving its surface with volcanic eruptions. Consequently, there are no craters on Io, indicating that its surface is extremely young. The outgassing of sulfur dioxide from Io’s volcanoes strengthens Jupiter’s magnetosphere, creates the small atmosphere of Io, and supplies the ionized gas for Io’s torus. Volcano plumes can blanket large areas. The reason for Io’s geological activity is tidal heating, where Jupiter’s tidal forces stretch Io in many different directions during Io’s very elliptical orbit. This results in the energy being transformed into friction, which heats up the moon.

Jupiter’s moon Io is the most volcanically active world in the solar system. This high-resolution image of Jupiter’s fifth moon was captured by NASA’s Galileo spacecraft and was published on 18, Dec. 1997.
Io

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Blog 5 – Pluto

Posted on April 9, 2023 by kevkoppa123

Pluto is a dwarf planet located in the Kuiper belt with an orbit time of roughly 248 years, as it is about 40 AU from the Sun on average. Relative to the eight planets on our solar system, its orbit is much more elliptical and inclined to the ecliptic plane, allowing it to get closer to the Sun than Neptune during certain parts of its orbit. Although Pluto is a small-ice rich dwarf planet, it remains very geologically active. Additionally, Pluto has a small atmosphere created from the vaporization of its ice crust and has very large ice mountains. Pluto’s moon, Charon, has a large canyon comparable to Earth’s Grand Canyon. The first spacecraft to make a flyby to Pluto and its five moons was the New Horizons mission in 2015, which collected data on Pluto.

Pluto in True Color - High-Res.jpg

Pluto

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Post 5

Posted on April 9, 2023 by berlinbe

In 2006, the International Astronomical Union (IAU) declared that Pluto was not a planet, but rather a dwarf planet. This was largely because Pluto is relatively small (smaller than our moon) and it belongs to the Kuiper Belt—a body of comets/large objects that orbit the sun on the outer edges of the solar system. This presented a problem for the IAU; but to see why, we must first see how the IAU defines a regular, full-size planet.

The three main criteria for a full-size planet are that it orbits the sun, is (almost) spherical in shape, and has “cleared its neighborhood.” By “clearing its neighborhood,” the IAU means that a planet must not orbit in sync with nearby, similar objects. Rather, all such objects must be gravitationally attracted to the planet. This is where Pluto fails. Because there are other, relatively similarly-sized objects in the Kuiper Belt that are not affected by Pluto’s gravity, it has not “cleared its neighborhood.”

While the IAU maintains this important distinction between regular planets and dwarf planets, planetary scientist Alan Stern offers an interesting perspective—that the title is merely semantics. He states how, according to planetary scientists, all dwarf planets are planets by nature. A dwarf planet is simply a small planet. Therefore, it is irrelevant and misguided to characterize Pluto as “not a planet.”

Here is a diagram from ESA Hubble comparing the sizes of the largest Kuiper Belt objects, emphasizing how Pluto has not “cleared its neighborhood” of comparably-sized objects.

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