Blog #6: Detecting Extrasolar Planets

Posted on April 9, 2023 by Astro 2110

The photo above features the transit method of detecting extrasolar planets.

Detecting extrasolar planets is a very delicate and challenging task for scientists. The distances between stars and relative sizes of stars compared to planets make it extremely hard to pick them out. Stars are also typically a billion times brighter than planets. There are a number of different methods that have been tried to detect extrasolar planets. Direct imaging is one method used to capture images of the planet using a telescope as it orbits its host star. This method is largely unsuccessful because the light from the planet is often overwhelmed by the much brighter light from the star. This is mainly useful for larger planets. Often times, scientist are forced to infer a planet’s existence by observing gravitational anomalies. Almost all of what we know about extrasolar planets comes as a result of indirect methods either by detecting gravitational or brightness effects on the host star. The next method, the astrometric method, requires measuring the motion of a star caused by the gravitational pull of an orbiting planet. This is useful but often hard to measure because of the very slight effects of a planet’s gravity on the star. Another method is the Doppler Method which involves measuring a red or blue doppler shift on light emitted by a star after being affected by the pull of gravity from a planet. Lastly, the Transit Method also requires a great deal of precision by carefully monitoring the brightness of a star system over an extended period to detect a potential eclipse or transit of a planet. Like other methods, this one has its weaknesses including not being able to detect planets located far away from their host star as there isn’t enough time to see a detectable pattern in the dips in brightness with each orbital period or if the planet is especially small. Scientists typically will try to use multiple methods in order to confirm the existence of an extrasolar planet. We do not know for certain the properties of these extrasolar planets or even if they fall into the terrestrial and jovian categories we have in our solar system. As the powerful James Webb telescope begins operations, we should be able to answer more questions about other planets in the future.

Posted in General, Jovians, Stars, Sun, Terrestrials | Tagged , , , , | Comments Off on Blog #6: Detecting Extrasolar Planets

 New Horizons: Exploring Pluto and Beyond

Posted on April 9, 2023 by 7smessier45

Hello (again), and welcome (back) to my Astronomy Blog! Today we’re picking up where we left off with Pluto and the New Horizons mission. 

The New Horizons Mission
New Horizons Mission Timeline and Trajectory, from NASA

Although NASA approved the mission in 2001, the New Horizons mission officially entered the public conscience when the craft was launched on January 19th, 2006. The speedy spacecraft performed its flybys of Pluto and its largest moon Charon in mid-2015. Several instruments onboard allowed scientists–including Principal Investigator Alan Stern–to gather valuable data that transformed our conception of the Pluto system and the Kuiper Belt. (I have highlighted some of the most important discoveries and a photo from the primary mission in the next section!) New Horizons has completed its primary mission of exploring Pluto and is conducting an “extended mission.” The extended mission has included the most distant flybys of any spacecraft and led to the discovery of a highly unusual Kuiper Belt object that consists of two conjoined bodies and has since been named Arrokoth. As of this post, NASA has extended the New Horizons mission a second time to enable it to explore more of the Kuiper Belt and potentially beyond; the mission clock reads seventeen years, three months, and four days. 

As my political science friends and I like to say, NASA is one of–if not–the best US government agencies because it consistently over-delivers while remaining under budget. So please, give NASA some support (if you can) and read on to learn more about Pluto and the discoveries of the New Horizons team! 

Pluto and Charon, Courtesy of NASA
General information about the “dwarf planet”

Pluto is about half the size of the United States and has five known moons. Charon–the largest of its moons–is about half the size of the “dwarf planet,” and since the two bodies are tidally locked, the moon completes one full orbit of Pluto in the same time it takes the “dwarf planet” to complete one revolution on its axis–153 hours. It takes Pluto 248 years to travel around the sun on its highly elliptical orbit, which takes it from just above 49 astronomical units at its furthest point from the sun to 39 AU at its closest point. 

One consequence of this unusual orbit that was informed by discoveries from the New Horizons mission is that at its near point, Pluto’s surface sublimates–going directly from solid to gas (e.g., dry ice)–causing the atmosphere to thicken. (The atmosphere thins as the dwarf planet moves away from the sun, and the gasses return to solid form.) The New Horizons mission also upended scientific conceptions of Pluto when it relayed data that revealed persistent geological activity on the “dwarf planet.”  Of the features on Pluto’s surface, the mission discovered–including mountains, valleys, and plains–the evidence of craters and filled craters is particularly striking and provides the best evidence for the aforementioned geological activity.  

Should Pluto Be a Planet?

This is a divisive question not just online but in scientific circles as well. Personally, I agree with several prominent (planetary) scientists who argue for Pluto’s reclassification as a planet. Because while the current “dwarf planet” only fulfills two of the International Astronomical Union’s criteria for a planet, it could be argued that several planets in our solar system have not cleared their orbital planes; incidentally, this is the criterion Pluto fails to meet and has been used as justification for its second-class status. Do you think Pluto should be a planet? Or do you think that Pluto deserves to be considered a “dwarf planet?”

 Until next time, 

7smessier45

Posted in Class, Public Policy | Tagged , , , , , , , , , | Comments Off on  New Horizons: Exploring Pluto and Beyond

Solar Eclipse

Posted on April 9, 2023 by niqretnuh

The Sun provides us the most necessary elements for life, and is the reason why we can see whatever surrounds us. The objects reflect sunlight and as those light reaches our eyes, we pick up the signals and “see” the objects. What would the world look like if the sun were to magically disappear?

Solar eclipses happen when the Sun, the Earth, and the moon are aligned with each other. Since the orbits of the moon, Earth, and Sun do not fall on the same plane, these astronomical bodies only meet each other at specific times. A total solar eclipse only happens once in about 18 months, and only at specific points.

In the areas that are completely blocked by the moon’s shadow, a total solar eclipse happens on the Earth. If the Earth is located where the moon only blocks the center of the sun, while the periphery of the sun is exposed, we have an annular solar eclipse. In the case where the moon only blocks a part of the sun, we see a partial solar eclipse.

So, where should you go if you want to see the next total solar eclipse, which is going to happen on Apr. 8, 2024? If you are in the US, you would likely want to be around the belt that day “100%” in the image below. For Vanderbilt Students, we would be able to see this eclipse if we simply drive as far north as Louisville, Kentucky – which is about 3 and a half hours away by car. 

Posted in Class, Sun | Tagged , | Comments Off on Solar Eclipse

James Webb Space Telescope and the Carina Nebula

Posted on April 9, 2023 by lightwyrs
James Webb Telescope by dima_sel via Getty Images

The James Webb Space Telescope is by far the most intricate piece of technology we have ever sent into space. The engineering process for the JWST took nearly 30 years to build with Randy Kimble (who had worked on its predecessor – the Hubble Space Telescope) and had a cost of $10 billion.

The components of the the JWST are as follows:

  • Near-Infrared Camera (NIRCam): this is the primary imager of the JWST that covers an infrared wavelength from 0.6 to 5 microns. This allows the telescope to detect light from the earliest galaxies and stars, young stars in the Milky Way, and Kuiper Belt objects.
  • Near-Infrared Spectrograph (NIRSpec) : this is the instrument used to gather the light collected from the NIRCam into a spectrum. This spectra gathered allows us to know the physical properties like temperature, mass, and chemical composition of deep space objects.
  • Mid-Infrared Instrument (MIRI) : this is both a camera and spectrograph that detects light in the “mid-infrared” region of the electromagnetic spectrum in which the wavelengths are longer than our eyes can see. This has a wavelength range of 5 to 28 microns which allows it to see the redshift of distant galaxies and newly forming stars amongst much more!
  • Fine Guidance Sensor (FGS): this is the instrument that allows for the JWST to take the beautiful high quality images we see as it sends them to us. It also allows for scientists to further discover things like exoplanets and their transit spectroscopy.

Using all of these instruments, on Tuesday, July 12, 2022, we received JWST’s first full color image of the Carina Nebula (left).

This is so significant because it showed the extreme amount of progress given that this image (right) is of the same nebula but taken from the Hubble Telescope in 2008.

The amount of detail present in the JWST photo compared to the Hubble Telescope catapulted astrophotography light years ahead (HA!) of what it used to be.

The Carina Nebula contains the stellar nursery (that is so cute) NGC 3324 – the region in which new stars are formed. The peaks of this region are nearly 7 light years high, and the types of stars created in these regions are usually O- and B- type stars as they are formed by cosmic recycling. The nebula is about 7,500 light years away and coupled with the superior technology of the JWST, will shed light on how stars are formed and evolution of galactic clouds!

Posted in Class | Tagged , , | Comments Off on James Webb Space Telescope and the Carina Nebula

Sky News

Posted on April 9, 2023 by thisisntzenon

For my “any astronomy” blog posts, I like to somewhat link them to my personal life. Last time, I shared my hometown planetarium, the Adler Planetarium. This time, I wanted to focus on this week’s astronomy-related event as my birthday is this Thursday. I found this amazing website called This Week’s Sky at a Glance. Almost like a weather forecast, it shares what telescope users should expect to see when they look in the sky.

Mock up of the April 7th Sky by Sky & Telescope

For those who have yet to do any observing this semester, I think this could be a helpful tool to see what could potentially be seen the day you observe. To my fellow Aries, our constellation will have been visible tonight. Additionally, throughout the week we shall see Mercury and Venus, with brief and faint appearances from Mars and Saturn.

Picture of Kochab retrieved from StarFacts

The key sky news for my birthday, April 13th, is the visibility of the star Kochab or Beta Ursae Minoris, which will appear at the right of Polaris. According to Star Facts (2022), Kochab is the second brightest star in the Ursa Minor and apart of the Little Dipper. At this point in the year, most of the Little Dipper is not visible but it would be wonderful to see a component of it.

As corny as it may sound, there will be many stars visible from Nashville on April 13th. I encourage you all, to find some time to discover a day whose night sky intrigues you!

Posted in Observables | Tagged , , | Comments Off on Sky News

Pluto: New Horizon

Posted on April 9, 2023 by niqretnuh

Pluto, a dwarf planet farther out than Neptune in the Kuiper Belt, was once thought to be the ninth planet of our solar system. However, the discovery of Pluto’s moon, Charon, led to the revision of calculations on Pluto’s mass, and the redefinition of planets finally “kicked” Pluto out of the solar system planets since it is not massive enough to clear its surrounding asteroids’ orbits. After that, Pluto was assumed to be an uninteresting dwarf planet because it is thought to be too small and far from the sun to have any geological activities that are of interest to us.

However, this notion was completely changed after the New Horizon mission launched in 2006. On Earth, it is exceedingly difficult to identify specific features on Pluto since it is so far from us, and in light of the newly discovered Kuiper Belt, scientists wanted an opportunity to take a close look at these outer astronomical bodies in our solar system. In this attempt to uncover the mysteries of Pluto and the Kuiper asteroid belt, New Horizons mission was selected; it was launched in 2006 and remained inactive until it got to the proximity of Pluto in 2015.

The information uncovered by this mission was shocking to many. Pluto showed much evidence for geological activities – the lack of craters on its surfaces, the ice volcanoes, mountains made of ice, and the biggest grand canyon in our solar system. How Pluto gains its internal heat for these activities when so far from a heat source and so small in mass it is still a myth to us today. However, the New Horizons mission has really opened our eyes to a metaphoric “new horizon”.

Posted in Class, Dwarf Planets | Tagged , , | Comments Off on Pluto: New Horizon

Ganymede, Aurorae, and the Potential for Life Outside of Earth

Posted on April 9, 2023 by groblesnieles727

Artist’s conception of Ganymede and Jupiter. Image by NASA

Although by visible light and upon first glance Ganymede might seem like an unassuming satellite, further inspection and deeper exploration demonstrates that this view is both tired and untrue.

Simply by size alone, Ganymede is a headliner. As the largest moon in our solar system, it exceeds in size Earth’s moon (obviously), but it’s also larger than both Pluto and Mercury–bodies which either have been, or are currently classified as planets. Though Ganymede doesn’t meet the three criteria to be classified as a planet (thanks, Jupiter), the size of this satellite is quite remarkable.

Beyond the matter of size, Ganymede is an anomaly within our system, in that it is the only moon known to have a magnetic field of its own.

Hubble image of Ganymede, with its auroral belts colorized in blue. Image by NASA/ESA

As demonstrated in the image above, the Hubble Space Telescope captured auroral belts on Ganymede, and what’s more, it noted that the aurorae are “rocking” back and forth to a degree that supports the conclusion that a massive salt-water ocean lies beneath the surface of the moon. This ocean, which is estimated to be ten times deeper than Earth’s oceans and contain more water than the entire surface of the Earth, was an exciting discovery in the search for life-sustaining worlds and life beyond Earth. According to NASA, a previously created model supports the idea that it would be possible for primitive life to develop in this ocean.

Posted in Instruments, Moons | Tagged , , , , | Comments Off on Ganymede, Aurorae, and the Potential for Life Outside of Earth

I want to belive.. but I can’t!

Posted on April 9, 2023 by dougkyles422111
A poster popularized by The X Files

As I do so often, I would like to talk about the possibility of extraterrestrial life within the Universe. I will take this last blog as an opportunity to reflect on the things which I have been able to learn from the course as a whole as it relates to one of the topics I am most interested in. Ultimately, I hate to make this conclusion, but I believe that extraterrestrial life is likley, but we will most likely never reach any meaningful contact with them. I believe that it is likely simply from the vast scale of the universe. It is said by many leading astronomers that there are “billions” of planets like Earth. There is no reason we should be one of the only ones to possibly harbor life. While Earth’s situation is highly unlikely as a planet, the almost mathematically, and in reality practically, infinite number of systems suggests there are at least a handful of places similar to Earth in their ability to harbor life.  

While the possibilities for life are limitless, there are two main reasons I do not believe we will experience meaningful contact. First is the massive scale of the universe in general. The idea of physically transporting probes and even spaceships the distance to other stars, much less galaxies is a task that is seemingly impossible. Likely, if there was life somewhere out there, it wouldn’t have developed at the same time as our civilization. There would be a large portion that would have developed sooner, and these beings would have most likely discovered a way to communicate with us within their billions of years of development. So the second reason is the fact that we haven’t heard from anyone out there yet, because if they were truly out there, ​​someone would’ve most likely figured it out.

Posted in Aliens | Tagged , , | Comments Off on I want to belive.. but I can’t!

The Cosmic Microwave Background

Posted on April 9, 2023 by constellationsarentreal

One of the pillars that the Big Bang Theory Model rests on is the existence and characteristics of the Cosmic Microwave Background (CMB). The CMB is an observed cosmic glow of radiation seen everywhere, filling the universe like a sea. Roughly 380,000 years after the Big Bang, the universe cooled enough (~3,000K) for free-roaming electrons to bind into atoms of Hydrogen and Helium, allowing photons to travel unhindered. As a result, light shot out everywhere, allowing the universe to become transparent.

Since then the universe has expanded in size by 1,000 times, meaning the CMB should appear 1,000 times cooler. Accidentally discovered in 1956, the CMB appeared to come from every direction. The measured thermal spectrum of the CMB revealed a temperature of exactly 2.73K, roughly 1,000 times less than the ancient temperature of the CMB, thereby supporting the Big Bang Theory. Even still, models of the Big Bang Theory predict a 7:1 H-He ratio in the era of nucleosynthesis (the first three minutes of the universe). Models predict that the current ratio should be 3:1. Observed amounts of H-He content in the current CMB show 75% H, 25% He, providing yet another line of evidence.

The above image was taken by the Planck Space Telescope and depicts the map of cosmic radiation left over from the Big Bang: the CBM! The image was gathered over several months from the oldest light in the universe. The map depicts slight temperature variations that correlate to denser regions of space during the early years of the universe. In other words, the CMB maps out all the dense regions that would later become stars and galaxies!

Posted in Class, Physics, Universe | Tagged , , , | Comments Off on The Cosmic Microwave Background

Blog Post 6: Gravitational Slingshot

Posted on April 9, 2023 by Myles7235
Gravitational Slingshot

Have you ever played with a slingshot to shoot small items such as pebbles as a kid? Astronomers can also tap into their inner child by using a gravitational slingshot in space. A gravitational slingshot happens when a small object uses the gravitational pull of a larger object to speed itself up. Take a spacecraft as the smaller body and a planet as the larger body. When a spacecraft passes by a planet at a certain angle and encounters the planet’s gravitational attraction, the spacecraft can be shot forward with greater speed. It’s as if the planet is the slingshot and the spacecraft is the pebble. The key difference between a regular slingshot and a gravitational slingshot is that the spacecraft is stealing momentum from the spinning planet. Since the spacecraft ends up stealing some of the momentum of the spinning planet, the rotation of the planet slows down. The planets slows down by an extremely insignificant amount since it is much more massive than the spacecraft. To our eyes, the planet looks like it is moving the exact same speed as it did before. Although your traditional slingshot may not be as cool, you may one day be able to contribute to a space mission that uses a gravitational slingshot if you pursue astronomy!

Posted in Class | Tagged , , , , | Comments Off on Blog Post 6: Gravitational Slingshot