Reflection on Astro 2110

Posted on November 25, 2024 by Henry Wang

The most surprising thing I learned in this course is the sheer vastness of space, to the point where there is still a lot about our own solar system that we don’t know. I did know prior that the Universe is infinite, because it is ever expanding, but it’s a lot different to think that the universe is big than to actually learn about what things exist in that infinity, which includes us. There are an unfathomable amount of existence and that thought is both kind of terrifying, but also incredible.

Looping back to our own solar system, one of the coolest things I learned from this class is about the Oort Cloud and a potential ninth planet. Both of these are purely theoretical, but have a lot of evidence supporting their existence, more so the Oort Cloud than planet X. I only really knew about the main 8 planets before this course, and the coolest thing I really knew about was Pluto being declassified as a planet. I am interested to see where the research on the theoretical objects leads, and when we can first observe these objects, assuming they exist at all.

Depiction of the Oort Cloud

One thing I have learned to appreciate more about astronomy is how much ancient astronomers were able to discover. People like Galileo and Hipparchus were able to figure out how celestial objects moved with their naked eye and very primitive magnifying equipment. There are also many ancient structures that perfectly align with certain objects in the sky at certain times, and while we will never know all that much about many of these, it’s really interesting to look at what ancient people were observing.

Something I want to explore further in the future is the advancement of space travel. We are getting closer and closer for it to be possible for humans to start venturing to other planets. With the latest innovation being Starship, which was able to be successfully caught on it’s return to Earth, space travel is looking very bright. We’ve already had the International Space Station for some time, it’s only inevitable that we will get stations in other places, like the Moon, or even Mars. I will definitely keep my eyes peeled for more milestones in the news and maybe one day, go into space myself.

Successful Catch of Starship Booster

My view on an astronomer has definitely changed. While I didn’t really think too much about what an astronomer was, if you asked me before this course I probably would have thought about somebody that looks into a telescope at night. Now, I know there is so much more to that, and nowadays, looking into that telescope is more of the final step than a job. There is so much that goes into astronomy, most of that being theoretical and trying to model how things work. It’s super complicated and observing is really the cherry on top. I see the night sky a little differently now and I tend to think more about what is out there.

Posted in Class | Tagged , , , | Comments Off on Reflection on Astro 2110

Where are the Aliens?

Posted on November 25, 2024 by Henry Wang

One of the most common topics in science fiction (and conspiracy theories) is aliens. The coolest part is that they can be literally anything. There’s terrifying monstrous aliens like the Xenomorph from Alien and there’s much more lovable ones like E.T. It’s fascinating to think about life outside of the (relatively) small planet we call home. Do they look like us? Can they talk? But the most pressing question of all is: why haven’t they found us yet?

Theoretical depiction of aliens

This is the main premise of something called the Fermi Paradox. To understand the paradox, we need to take note of a few things first. First of all, we know there are billions upon billions of stars just in our own Milky Way galaxy. For each of these stars, most if not all of them have planets orbiting them, and some of those planets exist in something called the habitable zone, which is where life can exist. Also consider that the sun is younger than a lot of these stars, which implies that there have been planets where life has a lot longer to develop than we have on Earth. In just the last few thousand years of human history, we have been able to go from sticks and stones to being able to explore space ourselves. Imagine what we could do with a few hundred more years, much less the millions and billions of years other planets have had.

Given all of this, it seems extremely unlikely that we have not found any evidence of alien life, nor have any aliens ever visited us. That is the question proposed by Enrico Fermi, and one we really haven’t been able to answer even 80 years later.

Potential Answers to the Paradox

While there is no definitive way to solve the paradox outside of just finding alien life, there are many reasons why we haven’t found anything yet. Maybe we have been visited by aliens before. Humans have only been on Earth for an extremely tiny amount of time, and it would be really hard to figure out if alien life had visited us millions, if not billions of years ago as there is currently no evidence that we can identify. We might also just not be looking in the correct places, since we are assuming that the only place live can exist is in a planet similar to Earth, when that could be completely false.

The reality is that we simply don’t know, and whether that is a good or a bad thing is completely up to you. Whether you choose to be afraid of what could possibly be out there, or fascinated at the thought of finding other life, Earth’s eyes will always be peeled for extra-terrestials.

Posted in Aliens, Class | Tagged , , | Comments Off on Where are the Aliens?

Extrasolar Planets and How to Find Them

Posted on November 18, 2024 by Justinc

Extrasolar planets are planets that are found outside the Solar System. Stars are relatively easier to find than extrasolar planets as they are generally bigger and luminous (give off light). But planets, neither generate much light nor are they as big as stars so how do scientists find them?

Well there are four main ways scientists find these planets: Transit method, direct imaging, doppler shift method, and astrometric method.

Direct imaging is the most difficult method for scientists to identify planets. It is especially difficult with the tools currently available as the light from the star generally outshine the planets, causing it to be very difficult to see the planet over the light. However, according to NASA, 82 planets were discovered through this method.

Transit method is one of the most common method for scientists to identify planets. Scientists measure the amount of light a star gives off as the planet orbit around it, dimming the star by a small amount. By measuring how much and how often the star is dimmed, scientists can estimate the size of the planet and its distance away from the star (by calculating the orbit). According to NASA, 4309 planets were discovered through this method.

Doppler Shift method (also known as Radial Velocity method) is measuring the color of light shifting due to movement of the star due to the planet’s gravitational pull on said star. Scientists can measure how much the star is red-shifted or blue-shifted, which can allow scientists to estimate the planet’s information. According to NASA, 1094 planets were discovered through this method.

Astrometric method is measuring the tiny shift in the star’s movement in relation to other stars in the sky to determine information about the planets. This however comes with many difficulties. The movement of the star can (and usually is) be difficult to find as the movement is minuscule and this movement can be caused by many planets (causing the calculation to be very difficult). This method is so difficult in fact, only 3 planets were discovered through this method according to NASA.

The number and types of planets found at the moment. Notice how there’s a lot more “big” planets found compared to terrestrial planets due to the limitations of current modern technology.

Scientists have charted over 200 million stars in the Milky Way galaxy, but only about 5000+ exoplanets have been discovered. This shows the difficult of finding an exoplanet in comparison to finding stars as planets are not as big or bright as stars which make it difficult to locate them (which is also evident by the fact that the planets scientists have found tend to be on the bigger side or close to its star), but as technology improves over time, scientists are finding more and more planets.

Posted in Class, Stars | Tagged , , | Comments Off on Extrasolar Planets and How to Find Them

Are There Planets Outside of Our Solar System?

Posted on November 18, 2024 by Matthew Marcus

The answer to this question is a resounding yes. Before the Copernican Revolution, back when many cultures still believed the Earth to be the center of the universe, the fact that these exoplanets exist would have been largely unthinkable. But today, well over 5,000 exoplanets have been discovered. When these distant bodies have eluded us for so long, how is it that we are finally able to recognize them?

Artist Rendition of Proxima Centauri b

The greatest challenges in detecting exoplanets may be obvious. Primarily, they are extremely far away. The closest one, Proxima Centauri b, is already 4-billion light years away from the Earth. Additionally, the stars that exoplanets orbit are typically a billion times brighter than them, making exoplanets incredibly difficult to distinguish. In order to view exoplanets directly, astronomers use a tool called a coronagraph, which blocks out the light from the star, leaving just light reflecting off the exoplanet. Even with this tool, direct detection is difficult and is usually only applicable when the planet being studied is large and far from its star. Thus, the vast majority of exoplanets have been discovered through indirect methods. These methods rely on observing the changes to a star that must be caused by the existence of an orbiting body. The astrometric method looks for changes in the star’s position in the sky. If a star is moving in the sky, that likely means an exoplanet is exerting a gravitational pull on it, and both bodies are orbiting around their center of mass. The same is true in the doppler method, which measures the shift in star’s spectra over time, implying that it is moving and orbiting with a planet. The final method, the transit method, observes changes in a star’s brightness over time, which could be caused by planets passing in front of or behind it. This method is niche because it requires a planet’s orbit to directly cross over its star from our view on Earth. Additionally, a star’s brightness may waver due to other factors, so a planet detected through this method is usually confirmed by another one. Despite these limitations, the transit method has the advantage of being able to detect smaller bodies than the previous two, and different shifts in brightness at regular periods can reveal detailed information about multiplanetary systems.

Source: the Cosmic Perspective by Bennet, Donahue, Schneider & Voit

Posted in Class, Exoplanets | Tagged , | Comments Off on Are There Planets Outside of Our Solar System?

All About Comets

Posted on November 18, 2024 by Matthew Marcus

In popular media, comets are often depicted as huge balls of fire streaking across the sky. See Sozin’s Comet from Avatar the Last Airbender as an example:

Sozin’s Comet

Comet Hale-Bopp

It may then be surprising to learn that asteroids are small, ice-rich bodies that are completely frozen for the majority of their life cycles. Comets tend to have highly elliptical orbits, and spend most of their time far from the sun in the Kuiper Belt or theorized Oort Cloud. When a comet does reach the inner solar system, heating from the sun vaporizes particles on the surface of the comet, creating a dusty atmosphere around it called a coma. Some of these particles are then pushed away by the sun creating its tails. A comet actually has two distinct tails: a plasma tail, and a dust tail. The plasma tail consists of gas particles ionized by ultraviolet light, and the dust tail contains small solid particles. We often think of comet tails as trailing behind them, but in reality these tails are usually directed away from the sun, as the solar wind blows gas particles away, and sunlight pushes dust particles outward. As a comet orbits over and over again, it loses material each time and eventually will eventually die by running out of ice to vaporize, being unable to outgas through a layer of dust, or breaking apart entirely.

Source: the Cosmic Perspective by Bennet, Donahue, Schneider & Voit

Posted in Class, Small SS Objects, SolarSystem | Tagged , , , , | Comments Off on All About Comets

What Exactly is Pluto?

Posted on November 18, 2024 by Justinc

Did you know, Pluto isn’t considered to be a planet? Well you might’ve known that because of widespread media covering this information, but you may not know the reason why.

There’s three qualifications of being officially considered a planet: it needs to orbit the sun; it needs to be big enough to be a spherical shape; it needs to clear its orbit of debris. Pluto however, does not meet the third requirement from this list. Being in the outer part of the Solar System called the Kuiper Belt, it is constantly surrounded by icy asteroids, and thus, its orbit is filled with rocks in the way. So Pluto goes into the category of “dwarf planet”.

Why is pluto not a planet? [Infographic]
The three conditions of being regarded as a planet, and what requirement Pluto does not meet.

Pluto also has more similarities to other dwarf planets than it does with planets. For example, when compared with its mass vs semi-major axis and high orbital inclination, Pluto is grouped with other dwarf planets.

Now you know why Pluto is no longer regarded as a planet!

Posted in Class | Tagged , , , | Comments Off on What Exactly is Pluto?

The Europa Clipper Mission

Posted on November 17, 2024 by Ian Vasquez

Artist’s concept of Europa Clipper orbiting Europa.

On October 14th, 2024 the Europa Clipper Mission was launched into space on a SpaceX Falcon 9 Heavy Rocket. It is now on a 6 year journey of 1.8 billion miles to circle the icy surface of Jupiter’s moon, Europa.

The Europa Clipper blasts into space on a SpaceX rocket.

What exactly is the Europa Clipper’s mission? The goal of the Europa Clipper is to perform a detailed study of Europa because of the scientific evidence that there may be the conditions needed on the planet to host life. It is believed that under Europa’s icy crust lies an ocean of liquid water capable of hosting life as we know it. The spacecraft will perform around 50 flybys of Europa, capturing images and data of almost the entire planet before the mission is over.

The Europa Clipper will take a very interesting route to get to its destination. First, the spacecraft will sling past Mars back to Earth and use the two planets as a gravity slingshot to gain speed to make it over to Jupiter. The spacecraft will then make big orbits around Jupiter, crossing paths with Europa as it does so. This is to keep the spacecraft out of the damaging magnetic field that Jupiter has surrounding it that could potentially fry the spacecraft and its instruments.

Europa Clipper’s odd path to Jupiter

, , , , , ,
, ,

Posted in Class, Instruments | Tagged , , , , , , , , , | Comments Off on The Europa Clipper Mission

Halley’s Comet

Posted on November 17, 2024 by Ian Vasquez

Halley’s Comet

In 1705, Edmund Halley, an English astronomer, used Isaac Newton’s theories to chart the paths of 24 comets. In doing so he discovered that three comets that were seen in 1531, 1607, and 1682 were the exact same comet: Halley’s Comet. He then predicted that the same comet should appear again in the year 1758. Edmund Halley sadly died in 1742 and never got to see his hypothesis proven true as the comet appeared in the sky on Christmas night of 1758 just as he predicted. This comet was the object of many superstitions, curses, omens, and victories throughout human history. It is said the comet inspired Genghis Khan and the Mongols to invade Europe in 1222, and its appearance overlapped with the Ottoman Empire’s invasion of the Balkans in 1456. Although the comet was looked at with a more scientific eye starting during the Renaissance, it was unable to be studied with sophisticated technology until 1986. Five probes were sent on flybys and took high quality images that confirmed that its core was a solid mass of ice and dust. Powerful telescopes were also aimed at it from down here on Earth. The comet is currently starting its way back towards Earth, out past Neptune in the Kuiper Belt, and is expected to be back in view in the year 2061.

,
, ,
Posted in Class, Small SS Objects | Tagged , , , , | Comments Off on Halley’s Comet

Space Weather and Technology

Posted on November 17, 2024 by Michael
Space weather threats

The field of space physics is becoming extremely important due to society’s increasing reliance on technologies that can be affected by space weather. Aviation, GPS, internet, and the power grid are just a few examples of infrastructure that may be damaged or even destroyed in a large-scale space weather event. Posing potentially lethal hazards, this is a serious situation to address and showcases the vital need for research in this field.

Currently, institutions such as NASA and NOAA work to publish forecast data and can correctly predict arrival times of large scale space weather events but are unable to predict specific information such as the precise location of affected areas. However, it is possible that with scientific advancement, we may receive specific solar forecasts in the future.

Something you may not know is that space weather forecasting is very important for space missions, both manned and unmanned. The solar wind can damage electronics, and satellites must be specifically designed with specialized components. As for humans, space weather presents a significant radiation hazard or could endanger them in other ways, such as affecting their spacecraft.

, , ,
, ,
Posted in Class, Physics | Tagged , , , , , , | Comments Off on Space Weather and Technology

How Do Spacecraft Move?

Posted on November 17, 2024 by Henry Wang

We’ve all seen videos of spacecraft launching: 3, 2, 1, Blastoff! The main booster rocket burns a tremendous amount of energy to escape Earth’s gravity, reaching terminal velocity.

Rocket Launch

But when they enter space, this much force is wholly unnecessary, there is no gravitational field to escape, so how do spaceships move? The main way is actually just by doing nothing. Since there is no gravity in outer space an negligible air resistance, simply escaping Earth’s gravitational pull will have enough inertia to continue moving with minimal adjustments. This is how probes like Voyager 1, the furthest travelled man-made object, move most of the time.

Another interesting maneuver is called a gravitational slingshot. Essentially, when something passes through the gravitational field of a planet, if you enter and travel through it at the right angle, you can use the force of gravity to increase speed and “slingshot” to change direction.

Granted, while 99% of the time traveling through space doing nothing is generally the most effective option, spacecraft are still equipped with smaller thrusters to make small adjustments. Currently our technology is not like the massive sci-fi spaceships that are constantly using extremely advanced thrusters to zip around, but maybe, sometime sooner than one might think, we can fly through space as easily as we fly through our own atmosphere.

Posted in Class, Space Travel | Tagged , , | Comments Off on How Do Spacecraft Move?