The “Ten”ets of the Universe

Posted on January 22, 2023 by oilrigatoni
Pixabay

Our brains struggle to comprehend the magnitude of our universe. We make comparisons based on that which we can see, yet it is totally inadequate to what reality holds. For example, the average person is just under 2 meters tall. But their size of the Earth when compared to that is substantial. The mean diameter of our planet is 12,742 km (Universe Today). That’s nearly 6400 times in magnitude. (That means in one day, someone at the equator travels a speed of over 330 miles per hour, since the equatorial bulge makes its diameter even longer than the mean.)

The distance from our Sun to Pluto is much larger. At its farthest point, the distance is 50x the distance from the Earth to the Sun (Nasa). The distance to the near the edge of our solar system (the outer edge of the Oort Cloud), is 2000 times (NASA). At a speed of 100 mph, it would take us about 106,000 centuries to make it to that point. One light-year is around 1016 meters. If you think that is a long distance, the Milky Way Galaxy is 100,000 light-years across(Universe Today). But the universe contains many galaxies, spread out amongst the system. The nearest one is 2.5 million light-years away (Astronomy). The universe is such a large expanse our brains can not comprehend its immensity. This video (Powers of Ten) gives a small glimpse into it, by changing the power to which 10 meters is given, yet it can only do so much!

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The Ultimate Race

Posted on January 22, 2023 by jackdoyle25

We take it for granted that the speed of light is the universal speed limit; nothing can go faster than light. The knowledge of light-years is crucial to understanding the images that we see in the night sky. These images are not of the celestial bodies as they currently exist, but as they once were, as light has usually taken thousands of years to reach us. There is, however, one phenomenon that exceeds even the speed of light: the expansion of the universe, which was observed to be far faster than the speed of light shortly after the Big Bang.

This image from BBC Sky at Night Magazine shows the expansion of the universe over time: in it, we see rapid expansion directly following the Big Bang.

This article by BBC Sky at Night Magazine explains the phenomenon. The speed of light is indeed the universal speed limit; however, the universe itself is not bound by this speed limit. The article describes the universe as a “backdrop,” (BBC) rather than a “material thing.” (BBC) Material things within the Universe can not exceed the speed of light, but the backdrop they are on can. This is an extremely abstract concept, but it helps us understand the expansion of the universe.

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The myth of travelling at Light Speed

Posted on January 22, 2023 by Liam Prescott

3*10^8 m/s. Wow. It’s practically impossible to conceptualize something moving 300 thousand Kilometers every single second, but believe it or not photons are doing this as we speak. To put this blistering pace into perspective, the distance from the North Pole to the South Pole is about 20,000 kilometers. Not even close to the length a photon can travel in just a second. It takes light only 66 milliseconds to travel the length of the entire globe! Naturally, it is seen as an incredibly valuable goal for humans to be able to travel at light speed. With current understanding of Physics, using Einstein’s equation of special relativity, it is not possible to do this. Mass, energy, and the constant of light speed are all related to one another, and it would require nearly infinite energy to propel an object with the mass of even a proton to lightspeed. Photons are just so small and energized that they can not compare to even the smallest other particles known to humans.

More Info Here
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The Incredible Size of Our Universe

Posted on January 22, 2023 by sahilreddy2

The image above is an artist’s illustration of everything in the observable universe. I find this image very interesting as it shows the scale increasing starting with our solar system and going out to galaxies, superclusters, our local group and further. This makes me realize how small we truly are in comparison to the universe we are truly just a speck of dust. Furthermore, this currently all we can see because this is all the light that has reached us so far, the universe can be much larger than even this. Currently we can see about 14 billion light years away from the Earth, as time passes we will be able to see more and more of the universe. However, the universe is also constantly expanding so we won’t ever be able to truly tell the full scale of it. I believe that it is important for all of us to understand our place as a miniscule part of everything around us so that we always keep looking forward and expanding the possibilities of all that is left to explore.

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We Already Have a Time Machine

Posted on January 22, 2023 by araceal

People say time traveling doesnt exist. They are skeptical we are able to break every law of physics we grew up learning. But, if we really think about it, we have a time machine right in front of us: a telescope.

What is a light year? Don’t be confused with the word ‘year’ being in this term, because a light year is a measure of distance rather than time. Because our Universe is so large, when we look through a telescope at stars and planets and other objects far away from us, we are really looking back in time. It’s a tricky concept to wrap your mind around at first. When we look at distant objects in our universe, we do not see the objects as they are the moment we look at them, but rather we see them as they were when that specific object released its light. This light then travels the distance (the light years) to our eyes, which takes a great amount of time, hence us looking at the object in its past not in its present state. 

So next time you doubt the idea of time travel, think back to the idea of light years, and how we are able to look in the past with our very own eyes. 

I’ve included a infographic which helps visualize how far some of the closest objects to us are in terms of light year distances. 

From: how far is a light year?
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Up Above The World So High

Posted on January 22, 2023 by reachforthestarsbysam

A blog about observing the night sky over and over.

Wanna read more on this long-exposure picture? Click here!

Through reading the textbook this past week, I was enlightened about what it would be like to observe the night sky hour after hour, night after night, and year after year. Before taking this course (and one other last year), I did not know much about what it would be like to observe the night sky, nor had I taken the time to stare at the night sky over and over. However, I now know that there are crystal clear and recognizable patterns that one would notice after repeated observation. In particular, the star patterns within the constellations of the sky that we recognize, such as Orion and Cassiopeia, are star patterns that have been constant in both shape and location for thousands of years. The Ancient Greeks looked up at the sky and saw the same patterns as we do to this very day. This will however change eventually, as both our galaxy and other stars/galaxies move, change, and die. But until that happens, I find it comforting that on Tuesday of this week I will look up and see the same stars I will see next Tuesday and the same stars the Ancient Greeks saw on their Tuesdays!

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Eclipses & Wildlife

Posted on January 22, 2023 by brandodan

During our discussion of solar eclipses in last Thursday’s lecture, we focused mostly on the astronomical concepts behind how and why they occur. As well, there was a brief discussion on what one would experience inside the path of totality for those short 7 or so minutes during a total solar eclipse.

Following this lecture, I was curious about how wildlife would react to such an event. As humans, we understand the non-threatening and incredibly brief impact of eclipses, but what about animals?

I decided to dig into this a little deeper. Here is an article I found: Eclipses!

Birds During Solar Eclipse 2019 (Source: Express UK)

The article references research being conducted regarding many solar eclipses throughout the last few centuries and their impact on wildlife.

Here are the summarized findings:

Hippos were disturbed and took time to adjust whereas lions didn’t seem to mind.

Crickets became excessively chirpy, cicadas stopped singing, and mosquitoes stepped up their activity.

Birds go quiet, owls hoot, hens stand still, swallows act normally, and pigeons become agitated and aggressive during totality.

Interestingly, some bats were even found to wake up and become active, mistaking totality for night time.

All in all, eclipses in general are incredibly fascinating, and it’s really interesting to see how such a brief moment of darkness during the day can have varying impacts on wildlife.

I wonder what other animals are affected by solar eclipses and also how the change in temperature might affect the general ecosystem and possibly plants!

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Blog 1 – The “Great American Eclipse” Experience

Posted on January 22, 2023 by constellationsarentreal

Back in 2017, my school allotted class time for observing the total solar eclipse that (conveniently) passed through Nashville. Many of my classmates (including me) didn’t fully realize how significant this was until our observation. The brief two and a half minutes of totality was awe inspiring. What struck me most was the terrestrial reaction to the event. Birds and other animals suddenly stopped making noises, and insects started buzzing and chirping (since they thought it was night time). The sky became darker with a haunting orange glow on the ground. It also got noticeably cooler. While totality was more than profound, I also felt it to be surreal and somewhat unnerving.

2017 Total Solar Eclipse, NASA.

With regards to astronomy, solar eclipses are truly special and rare. From our perspective, the moon fully or partially engulfs the sun. But in order to see a total solar eclipse, the moon must not only be positioned close to earth between the sun, but it must also cross through a node, the intersection between the moon’s orbital incline and the ecliptic (otherwise, the moon will not engulf the entirety of the sun and we see a partial eclipse). Since this occurs only twice a year, solar eclipses are quite rare. The moon casts its full shadow (umbra) in a smear across the earth. A total solar eclipse can only be seen in this umbra, but you can still see a partial solar eclipse in the moon’s partial shadow (penumbra), which covers a wider area along the umbra. Even still, the moon’s shadow is conic, so these regions are quite contained.

Remarkably, another total solar eclipse will pass through North America (somewhat near Nashville) on April 8th of 2024. If you’ve never seen one, please do yourself a favor and go see totality. You won’t regret it.

2024 Solar Eclipse Path, NASA.

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The Scale of the Universe and Us

Posted on January 22, 2023 by cuia2
As demonstrated here in this picture from a fellow WordPress blog, we are an infinitesimally small part of the universe.

     Reading the graphic in the textbook called “Our Cosmic Address”, I got a sense for the first time of how small of a planet we live on. Earth is a typical planet rotating by a typical star we call the Sun which is only one of billions of stars in the Milky Way which is only one of the billion galaxies in the universe. Earth is only 10^4 km big whereas the local supercluster the Milky Way is in is 10^21 km big which is about equal to 100 million ly. Reading the essay by Neil deGrasse Tyson called “The Meaning of the Cosmos”, I got a sense of what the two reactions to the vastness of the cosmos was like. One professor said it made him feel small and insignificant, whereas Tyson said it made him feel alive and very much significant for humans to possess this knowledge in the first place. I could see where both professors are coming from, but I agree most with Tyson’s quote: “We are not simply in the universe. The universe is in us.”

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Minutes and seconds of arc

Posted on January 22, 2023 by Andrew Cascio

Similar to a light-year, an arcminute can be mistaken for a unit of time. An arcminute is 1/60th of a degree and an arcsecond is 1/60th of an arcminute. For example, “12 degrees, 50 arcminutes, and 29 arcseconds” is written as 12° 50′ 29”. As units of angular measurement, arcminutes and arcseconds allow for more precise measurements of the angular size of objects in space. Angular size alone, however, tells us little about the actual size of a far away object. The photo below depicts the angular size of the planets in our solar system as perceived from Earth at the time of writing in arcseconds.

Angular size of planets relative to Earth

Note that the angular size of Neptune and Uranus are a fraction of that of Mars, Venus, and Mercury despite being many times larger in actual size.

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