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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Blog1: Chinese summer solstice

Posted on January 22, 2023 by lucasliu6

The summer solstice occurs when one of Earth’s poles has its maximum tilt toward the sun. Since prehistory, the summer solstice has been viewed as a significant time of year in lots of cultures, and has been marked by festivals and rituals.

About the Chinese summer solstice: In ancient China, this was the time for people to harvest for wheat. They also offered sacrifices, engaging in prayer in order to show gratitude for the harvest, and prey for a good and productive year free from natural disasters. Thus, people in China celebrated this day with worship ceremonies.

Nowadays, the summer solstice is not considered one of China’s public holidays, but people would also have a big meal with their friends or families. If you are interested in what they usually eat at that specific day, click here!

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Hello,

Posted on January 22, 2023 by Andrew Cascio

I’m Andrew. I study computer science and mathematics here at Vanderbilt. I’ve been watching The Office a lot recently.

Michael Scott Paper Company Inc.
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Happy New Year!

Posted on January 22, 2023 by Trevor Pillow
The lunar phases for 2023

Today marks the start of a new lunar year! There are several key differences between a solar new year and a lunar new year. The most common calendar system in the West, the Gregorian calendar, is based on the Earth’s orbit around the sun. Every New Year, the Earth is more or less in the same position around the sun as one year prior. The lunar new year, however, is based on the cycles of the moon.

There are two types of calendars that use the moon to track time. Purely lunar calendars, such as the Islamic Hijri calendar, do not rely on the sun at all. In the Hijri calendar, the new moon determines the start of the month. As a result, lunar years are shorter than solar years, taking only 354 days. As centuries have passed, the Hijri calendar has deviated from the Gregorian calendar by about 40 years. Also, because the Lunar calendar does not depend on the Earth’s orbit around the sun, the months of the year have no correlation to the seasons. This year, the Hijri calendar starts in July, but years from now it will start in January, the complete opposite season.

The other type of lunar calendar, such as the Chinese calendar, is the lunisolar calendar. Lunisolar calendars, as you might be able to guess, are a combination of solar and lunar calendars. The Chinese calendar starts each month on the new moon, and begins each year at the beginning of the second month after the winter solstice. In order to keep the calendar in check relative to the solar year, occasional leap months are implemented. There are 7 leap months across a cyclical period of 19 years, and they are inserted before the new year.

As I was researching this blog post, I got curious to see how the Western and Chinese zodiacs differ. Since Western zodiac signs are based on the Earth’s orbit around the sun, and the Gregorian calendar is also based on the Earth’s relationship to the sun, I wondered if the Chinese zodiac is somehow related to the moon. As it turns out, Chinese astrology is based on the planets which are visible to the naked eye; Mercury, Venus, Mars, Jupiter, and Saturn. Each of these represent an element, and combining those with your zodiac sign (which is determined by the 7 year cycle) will give you some insight into your personality, apparently.

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Blog 1 – Solstices/Equinoxes

Posted on January 22, 2023 by kevkoppa123

There are 2 solstices: the June and December Solstice.

The June Solstice is the point on the celestial sphere where the ecliptic is farthest north of the celestial equator. Similarly, the December solstice is the point on the celestial sphere where the ecliptic is farthest south of the celestial equator. The June and December Solstice occur around June and December 21st, respectively. During the June and December Solstices, the sun appears directly over the Tropic of Cancer and Tropic of Capricorn, respectively.

Celestial Sphere https://www.pas.rochester.edu/~blackman/ast104/coordinates.html

There are 2 equinoxes: the March and September Equinox. During both equinoxes, each of Earth’s hemispheres receive equal sunlight. The March and September Equinox occur around March and September 21st, respectively. The equinoxes occur when the celestial equator intersects the elliptic.

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