So Close, Yet From So Far ☄️

Comet Atlas, captured on March 16th, 2020 by Steve Pauken

The above image is of Comet Atlas, which is a comet that has been getting closer and much, much brighter over the past few weeks. If it doesn’t fizzle out, Comet Atlas will be able to be seen by the naked eye in as little time as a couple of weeks, at places without much light pollution.

Comets are indeed very pretty to look at in the night sky, but sometimes we ponder the question of where they come from. It turns out that these balls of gas, dust, rock, and ice largely come from an area on the edge of our solar system; the Kuiper Belt and the Oort Cloud. Haven’t heard of these two before? They mostly consist of clouds of small, icy bodies. Sometimes, these objects get gravitationally pulled a little too close to the rest of the solar system, and this changes their orbit slightly which passes by the inner solar system and straight into the Sun, where it’ll never be seen again. However, most of the time, we are able to spot them through binoculars and telescopes or even just our eyes, and we call them comets.

The Kuiper Belt is closer to us than the Oort Cloud, but the Oort Cloud’s existence is based merely on speculation and we don’t really know how big it is, or exactly how far away it lies. However, we believe that long period comets, comets that take 200 years or more to complete one orbit, come from the Oort Cloud, and short period comets mostly come from the Kuiper Belt.

The Kuiper Belt and the Oort Cloud were created when the solar system first formed. The remaining gas, dust, and rocks that didn’t coalese into planets were slingshotted away by gravitational force and formed parts of these spherical clouds. Some material was too far away from any of the planets, but not too far to escape the solar system, so it continues to reside in the Kuiper Belt.

Both the Kuiper Belt and Oort Cloud are constantly changing and even diminishing, since objects continually collide with one another and turn into smaller, dustier fragments, then get blown away by the solar wind. Some comets burn up on their orbit into the inner solar system, and never return. Though we’re not sure of all the details yet, it’s still fascinating to find that beyond the commonly known orbits of our planets, we are surrounded by bits of our solar system’s nursery.

How’s the Weather Up There? ⛅

A beautiful picture of our weatherless Moon!
Captured by u/ajamesmccarthy

On an especially brutally stormy day, you may have thought to yourself, “Why does it have to be this way? Why do we have to be so inconvenienced? Why can’t we just have no changing weather?” Well, if we colonize Mars or the Moon someday, your wish may come true. That’s because weather stems from the presence of an atmosphere! Weather is mostly caused by heat from the Sun and movement of air.

Without an atmosphere, there are no air molecules to be affected by the planet’s heating. Without these moving particles due to temperature differentials, there is nothing to cause wind. In fact, wind simply cannot occur without an atmosphere because it IS air. Clouds would also be unable to form, because they are masses of liquid droplets suspended in the atmosphere. (There’s the additional problem of requiring water to evaporate!) Even if clouds could form without an atmosphere, they would be blown away by the solar wind due to the lack of protection an atmosphere would normally provide. Thus, rain cannot occur, nor snow, sleet, and other precipitation.

Though, that would probably be the least of your problems, since you’d be physically unable to breathe in such a place without assistance of some kind. Earth’s atmosphere is made of precisely the right amounts of nitrogen, oxygen, and other gases that we need to survive normally. (Probably because we have only ever known living on Earth, and developed on Earth as a species.) Oh, and the lack of atmospheric pressure on your body would quickly start making your insides feel like they’re becoming your outsides…

Long story short, while not having to deal with rainy day traffic may seem like a blessing, not having an atmosphere at all makes things much, much worse!

The Trouble With Astronomy 🤔

“The most distant galaxy ever discovered in the known Universe, GN-z11, has its light come to us from 13.4 billion years ago: when the Universe was only 3% its current age: 407 million years old. But there are even more distant galaxies out there, and we at last have direct evidence for it.”

“Space,” it says, “is big. Really big. You just won’t believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.”

— Douglas Adams, The Hitchhiker’s Guide to the Galaxy

So you want to study space?

Now, how exactly are you going to do that?

Astronomers over the ages have struggled with that exact problem for even longer than astronomy was recognized as a field. We can’t exactly walk over to the Sun and collect a few samples, nor can we travel millions of light years away, or even see what stars at that distance look like with the naked eye. With our most basic abilities, our five senses, we can normally barely use one, our sense of sight, to gather information from space. To imagine that we have grown from believing that the sky was a enclosed, spinning dome surrounding the Earth, to sending humans onto the Moon, to exploring the depths of our solar system and beyond with probes, and now, capturing spectacular imagery of stars and planets that are impossibly far away from us using the strongest telescopes.

One of the most famous early astronomers, Tycho Brahe, was known for his extremely precise naked-eye astronomical observations. He lived in the 16th century, before telescopes were invented and used. Even then, using only his eyesight, he was able to record data accurate to one arcminute, which is 1/60 of a degree! Besides proving that comets and supernovas were much farther away from us than the Moon, the data he collected also proved invaluable to future astronomical models. Even without a telescope, past astronomers were able to prove that the space around us was not merely a projected dome, surrounding us at the same distance away.

In the grand scheme of human history, the “common” knowledge that the planets in our solar system revolve around the Sun hadn’t been widely accepted until after Galileo had solidified arguments against an Earth-centered one, which was in the late 16th to early 17th centuries. That is a mere, give or take, 400 years ago that people used to believe the Earth was the center of the universe! Even public opinion and religious authorities were hurdles to overcome in the history of astronomy.

Fast forward to modern day astronomy, where we have all these amazing tools to help us learn more about how vast space is, what is out there, and how it all connects together. Even now, astronomers struggle with problems such as the Milky Way blocking us from viewing what’s behind its arms, or the length of time it takes for our space probes to reach the farther planets in our solar system, such as Uranus and Neptune, and collect data for us. Though we are able to image planets and galaxies millions of light years away, we still don’t know everything about our own solar system, our home.

These are truly some of humanity’s greatest achievements to be able to learn so much about things that are so far away from us. We’re able to determine the temperature and composition of stars that we’d never be able to get remotely close to, much less touch. We’re able to predict galactic collisions 4.5 billion years from now. (Hello, Andromeda!) We have equations that tell us about how the same physical principles that we use on Earth can explain phenomena in space. We’re even able to establish a timeline of major events from 13.8 BILLION years ago, which was the beginning of our universe, A.K.A. everything, ever!

It’s truly mindblowing, if you think about it.
Let’s pat our astronomers on the back.

A Tidal Boat Dance 🌊

Compiled by Reddit User u/Spiritgreen from Hall’s Harbour webcams
(Right click on video and select “loop” while playing to continuously loop)

The above GIF shows the changing tides in a unique manner, by splicing together pictures taken throughout an entire day, at 20 minute intervals! The resulting effect is that it looks as if time is spiraling around the image. You can also see both pairs of high and low tides, one set during the day and one set during the night.

Unless you’ve lived by or frequently visited shores, you’ve probably never had to think about the tides much. Sure, the concept of tides is fairly well known by many, but how much of a difference does it make?

Well, as the video shows, quite a lot! Before I had watched time-lapses of tidal behavior, I had assumed that the water level difference between high tide and low tide wasn’t more than a meter or so. The reality is that in some places, like at Hall’s Harbour in Nova Scotia, Canada, the difference can be up to 14 meters! The rate at which it rises is about 2.5 centimeters a minute, escapable unless you were wading far out at sea.

After realizing how much more water is present in one area at high tide, I got to thinking. Where does all the water go when it recedes? Surely it can’t just… disappear? Then, I realized that at any one point in time on Earth, if it is high tide somewhere, then it is low tide elsewhere. So, the water is pulled towards those continuously moving (at least, relative to the surface of the Earth) points at which high tide exists, and thus, low tide exists.

Thankfully, there aren’t mystical forces drinking the ocean up away from shores, or we’d have bigger problems to deal with.

Another thing about tides that I didn’t know about until just a few days ago was that yes, the moon causes tides, but in what way? It turns out that tides are caused by the magnitude of the difference in gravitational force felt on opposite sides of a body, not necessarily the magnitude of the forces themselves. I had always accepted that the Moon’s gravitational force somehow caused tides since that’s what I was told since I was very young, but I also figured that the gravitational force on the Earth from the Sun must be stronger than the Moon’s, or we’d probably crash into the Moon. I had never put two and two together, and wondered why it was the Moon that caused much larger tides, even though the Sun pulls the Earth with much greater force.

The secret is that gravitational force drops proportionally to the square of the distance from the object, so the difference between gravitational force felt at two points separated by a constant distance is higher when they are closer to the massive object than if they were farther away. In this case, the two points are opposite sides of Earth, and the objects causing a force to be felt are the Moon and the Sun.

It was thanks to a recent Astronomy homework assignment that it was made apparent to me! See, you really do learn things in school. 😂 I’m looking forward to the next astronomical epiphany, but until then, enjoy this spiraling tidal time-lapse! 🌊

Feeling Dizzy Yet? 💫

This isn’t your everyday Milky Way time lapse video.

Video Captured by Eric Brummel

This video, captured by Eric Brummel, is sky-stabilized with the Earth in view to show our planet’s daily rotations.

It’s amazing, isn’t it?

We don’t think about it often during our daily lives, but every single second, we’re moving vast distances across space. Your glass on the edge of the counter or the monitor you’re reading this blog on might seem motionless, but in reality, we’re spinning around at a speed of about 460 m/s (approximately 1,000 mph), and that’s only counting Earth’s rotation!

If we were to factor in our actual orbit around the Sun, we’re moving at about 30,400 m/s, and if we were to factor in the solar system’s orbit in the Milky Way galaxy, about 220,000 m/s!

How come we can’t feel this motion though? To me, I’m only sitting back, enjoying the peace and quiet. That’s because everything on Earth is rotating at the same speed as us, including the atmosphere, the buildings, and the glass on your counter. Everything has been spinning ever since the Solar System was formed out of a collapsing dust cloud, and it’s never stopped since. We’d only feel it if Earth suddenly stopped, like if a car suddenly stopped. Just thank inertia for keeping your drink on the table.

When we look up at the sky and see the Sun rise, then later on, set, or the stars travel overhead, it can be easy to forget that we aren’t stationary and that our own planet’s rotation and orbit around the Sun cause these objects to move relative to us. To an outside observer’s perspective, we may as well be flying through space at incredible speeds on a wobbling top, which sounds more fun anyways.

Enjoy the rest of your orbit around the Sun! 😊

Meet (Astrono)me! ⭐

by me

Thank you for visiting my blog! 😊

Hello! My name is Vivian Li, and I’m just now starting my blog about my studies on the solar system this upcoming semester.

I’m a junior undergraduate student in Vanderbilt University, and looking forward to great things this semester in ASTR2110!

Though I’m a computer science major and pursuing a minor in mathematics, I’m taking this astronomy course to learn more diverse topics during my time in college.