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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the cosmic calendar

Posted on January 19, 2023 by Emma Williams
Image from The Steam Project

The history of the universe is tough to wrap our heads around, much less to place in the context of our own lives!

When studying astronomy, we are presented with so many large numbers — that the distance between earth and sun is 150,000,000 km, the universe is 14 billion years old, and the Milky Way is 100,000 light-years wide. It becomes easy to lose ourselves in the magnitude of the universe, and it becomes necessary that we find tools to help contextualize these numbers.

One such tool is the Cosmic Calendar, adapted from a version put forth by astronomer Carl Sagan (yes, the same Carl Sagan who so famously said that “we are star stuff“!). The Cosmic Calendar compresses the entire 14 billion year history of the universe into 365 days, beginning with the Big Bang and ending with you reading this right now! Throughout the year are marks made to indicate important events such as the formation of the Milky Way (February) and the rise of the dinosaurs (December 26).

Although it seems that our earth has been around forever, the calendar shows us that it was a relatively recent development — the earth formed in September, during the last third of the year. By the end of the month, life was flourishing on earth. Still, animals recognizable to us didn’t become prominent until mid-December, and early hominids didn’t stand upright until the final 3 hours of the year!

The entirety of human civilization– from the Mesopotamians to Renaissance thinkers to us today– falls within the last 30 seconds. Our lifetimes are merely the blink of an eye, becoming smaller and smaller in the timeline of the universe with every passing second.

When confronting this reality, it is easy to become apathetic and nihilistic; after all, if everything we do is basically nothing in the grand scheme of things, why care at all?

But this sentiment can also be freeing. After all, if everything we do is nothing, why care so much? Why place large amounts of stress and pressure on ourselves for matters that are nothing to the universe? The impetus is on us to pack our blink’s worth of a life with as much meaning as possible since our mistakes and struggles really don’t matter.

The cosmic calendar is just that: a calendar. But, more importantly, it is a way for us reframe our way of thinking about life and an opportunity to explore our very, very, very distant past.

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Moon Phases in the Southern Hemisphere

Posted on January 18, 2023 by willems49

While reading Chapter 2 in the textbook, I realized how much of a difference living in the southern hemisphere would affect the way you view space. I think we generally tend to think of things as being similar if not the same in the southern hemisphere, especially something as universal as the stars in the sky or phases of the moon. However this is not the case, and although the textbook doesn’t mention explicitly the differences in moon phases, I did some extra research. 

When I learned about the phases of the moon in elementary or middle school, I was taught to identify a waning crescent vs. a waxing crescent based on which side of the moon was lit. For a waxing crescent, the moon was lit on the right side and vice versa for a waning crescent; therefore, I always associated waxing with the right-direction. However, this logic actually only applies in the northern hemisphere. In the southern hemisphere, the moon appears “upside down,” but the name of the phase the moon is in remains the same no matter which hemisphere you are in. Thus, the moon is lit on the left side while waxing and the right side while waning. The part of the moon lit by the sun grows from right to left in the northern hemisphere and left to right in the southern hemisphere. This is a similar concept to stars appearing to rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. Like most things in astronomy, it is all a matter of perspective. As a result, to tell which phase the moon is in from a single picture, the first question you should ask is which hemisphere the photo was taken from. That being said, no matter which hemisphere you are in, if the moon appears to grow in size (perhaps over a series of pictures), it is waxing, and waning if shrinking. I use the mnemonic, “wax on, wane off” to remember.

The picture below shows the difference between hemispheres, and this website does a good job of explaining further.

Image from Primary Homework Help authored by Mandy Barrow
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Blog 0: Introducing Me

Posted on January 17, 2023 by groblesnieles727

By Me

Hey everyone! Here’s a picture of me at the Audubon Aquarium in New Orleans from a road trip I took in May 2022 . Though not particularly astronomical, penguins have always been some of my favorite animals; plus this picture was more fun than some of the others.

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Welcome to Mo’s Astronomy Blog!

Posted on January 17, 2023 by mothuso

The beautiful night sky as seen from South Africa!

To find more stargazing spots in Africa, visit:

Top Stargazing Spots Africa | Find The Best Spots In Africa (pemburytours.com)

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