The Cosmic Calendar

Posted on January 21, 2023 by zws42
Source

The Cosmic Calendar is a visualization of the timeline of the Universe that was popularized by astrophysicist Carl Sagan. In this timeline, the entire history of the Universe is scaled down to the length of one Earth year. As you can see from the picture above, January 1st is marked by the Big Bang and the rest of history flows out from there.

There are a few points of interest that I’d like to highlight on this calendar. After the occurrence of the Big Bang in January, our solar system didn’t form until August and life didn’t form until September. After this first appearance of single celled organisms, it took until December 17th for the first animals to appear(based on fossil records). Dinosaurs appeared around the 25th of December and ruled Earth until the 30th. The most striking thing to me however, is that all of human history occurs on the last day of the year. The whole of human evolutionary history happened over the span of a few hours on this cosmic calendar, and the recorded history of our kind occurs in about 20 seconds.

When you look at the universe this way it is extremely humbling to see how very small we are in every sense. Usually we just compare the Earth and the Moon and the solar system to the size of other objects and structures in the Universe, but when we compare our time to the rest of the Universe it’s almost more astounding. In some ways it can be depressing, honestly, to think of the nonexistent blip that your 80ish year life span will leave on this timeline. You would be unnoticeable next to literally anything else on there.

On the flip side of that though, I feel like this perspective can be reassuring in several ways. First, it is a reminder that whatever problems you’re dealing with, no matter how big they seem at the moment, are ultimately insignificant and will fade away and be lost to time. Second, it lets you see the world in a much more positive light, as any prejudices or Earthly conflicts lose meaning when you look down from so high. Lastly, I find it empowering to think that creatures that are insignificantly small in the universe can learn enough to understand how small they are. It’s a level of knowledge and self-awareness that is hard to accept, but we, as a species, have been brave enough to accept that knowledge and go out searching for more. In this way, I find the Cosmic Calendar to be much more uplifting than depressing and I think it is a very useful way to look at the Universe.

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The Vast Size and Scale of The Universe

Posted on January 21, 2023 by theyounesadventure
stars

(Source By Dave Javis)

This following image shows how small the Earth is compared to other stars and how insignificant we are. We keep finding objects that are way bigger than Earth and the objects in our solar system. The universe is full of wonders and mysteries. Furthermore, the scale and vastness of the universe is enormous and hard to understand. First, our galaxy called the Milky Way is home to Earth and our Solar System which is one of 100 billion galaxies in the universe. Not only that but the diameter of our universe is estimated to be around 93 billion light years which is a huge number difficult for the human mind to comprehend. But we can’t see this much of the universe because we are limited to our observable horizon. It is fascinating to me how little we know about our universe.

If you want to learn more about how big our universe is. I recommend reading this article by Vox: 11 images that capture the incredible vastness of space.

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Blog 1 – Changes in Zodiac Signs

Posted on January 21, 2023 by Melanie Marszal

Astrology is a practice that has been around since the 3rd millennium BCE. Most people are familiar with their sun sign, which corresponds to one of the 12 constellations along the ecliptic, or path of the sun throughout the year from our point of view. Your sun sign is the constellation that the sun appeared in front of on the date of your birth.

What some people may not know is that the sun does not always appear in front of the same constellations on each date that it did when astrology was pioneered. The reason for this is precession, which is the gradual wobbling of Earth’s rotation axis. This cycle spans about 26,000 years. Since the tilt of Earth’s rotation axis has changed since the beginning of astrology, the positions of each zodiac constellation from Earth’s view have changed slightly. This results in the sun appearing in front of each constellation at slightly different dates. Additionally, NASA pointed out that technically, there is a 13th constellation along the ecliptic called Ophiuchus. It is said that when the Babylonians created astrology, they decided 12 was a neater number than 13, and so they excluded this constellation.

Taking precession and the 13th constellation into account, the updated signs are shown below. There could be arguments made on either side for whether to use the old or new signs. On the one hand, these new signs more accurately represent the current positions of constellations from our view, but on the other hand, astrology is based more in tradition than in science (although it was not always viewed this way), so it may make more sense to stick with the original signs. What do you think? Do you think your old or new sign describes you more accurately?

Side-by-side of new vs. original sun signs from The U.S. Sun
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Achieving Light Speed: Curvature Propulsion

Posted on January 21, 2023 by alicebyrnes

Space curvature propulsion is a theoretical idea that has been explored through science fiction (including Cixin Liu’s Remembrance of Earth’s Past trilogy) as method of allowing ships to travel through space at or beyond the speed of light.

Image from propulsion through space-time manipulation article, linked in post.

While this idea currently resides firmly in the realm of science fiction, the theoretical basis is rooted in fact. Space is curved due to the effects of gravity, and flattening out the space behind a ship could accelerate it up to the speed of light. A device capable of doing this is called a warp drive. Some people speculate that space could further be warped through the use of dark energy and higher dimensions to accelerate ships beyond the speed of light. This type of propulsion would enable interstellar travel, or a “193-second flight to Mars”. This information is sourced from and further discussed in Javier Yanes’ 2018 article (also the image source).

Several barriers are preventing this idea from materializing, beyond the massive leaps and bounds human society would need to make in technology development. Dark matter and dark energy are mysterious entities we don’t even know are possible harness, and the energy requirements for such a device would be massive. But, nobody knows what the future will look like, and it’s certainly exciting to explore the possibilities!

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Legitimate and Illegitimate Cases of Exceeding Light Speed

Posted on January 21, 2023 by 88bw

This image of CERN provided by TIME was taken at the peak of the 2012 craze over the facility’s discovery of neutrino particles breaking light speed. Since the barrier of light speed has been such an insurmountable rock and cornerstone of physics, the neutrino’s clocked speed increase of 0.0025% was groundbreaking. Although I was only 12 at the time, I remember hearing rumblings about the neutrino’s beyond-light speed record, and I suspect that it had entered the sphere of pop discussions as well due to the gravity of such news.

Unfortunately (or fortunately), the neutrino particles’ unprecedented speed was the result of a loose cable in the GPS system in the CERN facility, and the neutrinos fell into a long line of illegitimate phenomenon of breaking light speed.

However, one known instance of light speed being broken is the expansion of the universe. There is a sphere known as the Hubble volume; it is not a fixed region in the universe, but it is an area around an observer within the universe where any objects beyond the Hubble volume boundaries are receding away from the observer faster than the speed of light. I’m not the most well-versed in universe expansion, but I wonder what this Hubble volume suggests about the limits of our observation of space. Assuming that there were no celestial obstacles blocking our vision of the full universe, the Hubble volume seems to suggest that there are some celestial bodies whose light will never reach us due to the region between us and the object expanding faster than light can travel; I think of it like climbing (us being the light) at a slower velocity against the trajectory of an escalator (being the universe) – this thought experiment confirms that we would never reach the top of the escalator, much in the same way that an object’s light that begins outside of the Hubble volume would never reach the observer.

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Blog Post 1

Posted on January 21, 2023 by Myles7235
Macmillan

When I was in elementary school, I never understood why Pluto was called a dwarf planet. I called Pluto a “baby planet” because it looked so tiny compared to the rest of the planets. I thought the reason that it was called a dwarf planet was because of its smaller size. The International Astronomical Union is the organization that created the 3 criteria that an object must meet in order to be considered a planet. This object must orbit a star, be large enough for gravity to force it to maintain a spherical shape, and be large enough to where its gravity clears its pathway when orbiting around the Sun. Pluto satisfies these first two requirements, but unfortunately fails to fulfill the third requirement. Therefore, the IAU decided to demote Pluto to be a dwarf planet. There was backlash from people all around the world since Pluto had been considered a planet for many years. Despite all of the backlash , the IAU stood firm in its decision. Although Pluto is a dwarf planet by definition, it will always be a regular planet in our hearts!

Sources:

Why Pluto is No Longer a Planet

What is a Planet?

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Identifying Jupiter and Mars

Posted on January 21, 2023 by Europa

Last night, I was looking up at the night sky while walking to dinner. I noticed a few constellations, as well as two brighter points of light that I was pretty sure were Mars and Jupiter. Normally, I can identify them, but for some reason Mars didn’t look as red to me as it normally does, and Jupiter looked a bit brighter to me than it normally does. In order to verify their identities, I tried to think logically about Earth’s rotation and its position in its orbit around the Sun.

First, I thought about how I knew that I was walking southwest, just from my spatial awareness of Vanderbilt’s campus. While facing southwest, I knew that the west was toward right, so I knew that that was where the Sun had just set. It was about 6pm, so I knew that I was positioned on the part of the Earth that was looking out 90 degrees counterclockwise away from the part of the Earth facing the Sun directly (as in, looking in the direction of a first-quarter moon). Now that I knew where in the Solar System I was facing, I looked at my Apple Watch. I use the Apple Watch face that is configured to display the current position of each planet in the Solar System relative to the Sun, although it is not to scale. I could see on the image that my part of the Earth, which was experiencing 6pm, was looking out toward Jupiter, while Mars was more eastern. Sure enough, when I looked up at the sky while facing southwest, I saw that the bright point that I had predicted to be Jupiter was almost straight ahead, and when I turned my head eastward, I saw the bright point that I had predicted to be Mars.

The Apple Watch’s Solar System display as it appeared when I used it to locate Mars and Jupiter. (Source: taken by me)

This was a gratifying moment, since I would not have been readily able to run through this thought experiment had we not talked about the Moon phases at different times of day, as well as done the Lecture Tutorial about “Motion.” Has anyone else found themselves looking up at the sky a bit more scientifically since starting this course?

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Pondering Scale

Posted on January 20, 2023 by dougkyles422111
This Image is the beginning of the Powers of 10 Video created in 1977 by Eames Office LLC

The Video “Powers of 10” impacted me so profoundly as I viewed it for the first time that I took a minute after watching to consider how insignificant we technically are in this universe. Earth may be the setting for every idea, individual or event that we know of, but there are infinite bounds of empty space and unfamiliar galaxies all around us. Does this neccesarily mean we are in any way significant, just because we are quite infinitley small? I belive not. As Neil DeGrasse Tyson mentioned in is foreword to our Solar System textbook, the fact our 3 pound primate brains can discover the mysteries and truths of the universe confirms there in fact is something unique about our place in the Universe. Overall, while this video does give an accurate view of the scale of our universe, it’s misleading in my opinion for one’s takeaway to be that we matter any less because of this size.

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The Upcoming Total Solar Eclipse

Posted on January 20, 2023 by sydneyastr2110

One year, two months, and eighteen days: this is the time from the writing of this blog until a total solar eclipse will occur in North America. I’ll save you from doing the math, the date of this solar eclipse is April 8, 2024. The sky along the path of totality will become dark for a few minutes on that day. As we discussed in class, totality occurs when the Moon complete blocks the Sun from viewers on Earth. You may be wondering where you can view this rare astronomical event. Unfortunately, it does not pass through Nashville, so experiencing the path of totality will require a little bit of travel. The following image marks the path which begins in Mexico crosses through the United States and finally ends in Canada.

Image credit: Great American Eclipse, LLC

While it may be over a year away, it is never too early to start planning where you will be for this event. If you will still be a Vandy student in Spring 2024, I believe the closest part of the path of totality to Nashville is Paducah, Kentucky which is about a two-hour drive from campus. In Paducah, totality will begin at about 2 p.m. so you could even attend your morning classes and still make it on time. If you don’t want to drive, the best flight is probably to Dallas, Texas. This is less than a two-hour flight and since the eclipse happens on a Monday, you could even make it a three-day weekend. One factor that we won’t be able to prepare until closer to the event is weather. Clouds significantly inhibit your ability to view the Moon.

Now that I have discussed location and weather, I want to mention how rare this event is. According to NASA, the next total solar eclipse to pass through the United States will not be until 2044. All you need to do is get some eclipse sunglasses and decide where along the path is most convenient for you.

If you want to learn more about specific times of totality, what to expect during the eclipse, or pictures of eclipses, I recommend taking a look at the 2024 Total Eclipse by NASA.

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Blog #1 – Observing the moon

Posted on January 20, 2023 by 02yrstu

As a part of one of the courses I took last semester, we observed the phenomenon of the phases of the moon. We were instructed to record what the moon looked like for one month, noting which area of the moon was illuminated at what time. When the data collection process was completed and we all examined our observation papers, we were struck with multiple questions about why the moon looked like what we saw.

For example, one of the phenomenons regarding the phases of the moon that came up in our discussion was why the moon seemed to rise approximately an hour later each day. After creating multiple models and filling in the blanks of areas we were uncertain of, we came to a conclusion that it strongly had to do with the fact that the Moon takes less time to complete a full orbit compared to Earth. Because the Moon takes around one month (or 30 days) to rotate the Earth, it means that it moves approximately 10 degrees each day. With this movement, it takes longer for the Earth to ‘catch up to’ the moon’s orbit and therefore has to rotate more for the Moon to be visible from the same location. This difference, is around one hour.
This event was particularly interesting because it allowed me to view the phenomenon, gain curiosity about it, and find answers to our questions as a “scientist” would do.
Another phenomenon of the moon that I still do not have the answer to that I would like to know more about is the perception of the moon. Looking at other people’s data, it seemed like the way the moon looked like differed depending on the person. For instance, one student saw a crescent moon where the bottom right side was illuminated. However, another student saw a crescent moon illuminating the upper right side the same day and similar time. The way in which the moon’s illuminated portion seemed to rotate depending on the person was very mysterious and interesting to me.

Image of the phases of the moon through a one month cycle from Penn State

The image above is a calendar showing the estimated phases of the moon in the span of one month. It was an interest finding for me that despite having a concrete estimate, the way the moon looks like may not accurately reflect the calendar depending on how you perceive it, where you are looking at the moon from, and the time.

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