The Speed of Light (or so we think)

Posted on January 29, 2022 by Karan Bhardwaj

To measure the speed of anything, the simplest thing to do is to measure how long it takes to travel a known distance. By dividing the distance over the time, we obtain the speed:

Speed = Distance / Time

However, measuring the speed of light is not so easy. Colloquially known as about 3 x 108 m/s, how was the speed of light determined?

Many attempts to measure the speed of light have been thought of, such as having a beam of light travel a distance while having two observers (required as just one observer won’t be able to tell if light reached the end) clock-in, but issues such as synchronization of the two clocks disallow this method from bearing fruit. The method of using a mirror, is much easier, and does not have an issue of stationary vs. moving observers, and might look like this:

Veritasium on YouTube: “Why No One Has Measured the Speed of Light”

By using this method, the speed of light can be determined, as one clock can track how long a beam of light took to travel a distance d and reflect back the same distance d. Thus, what can be seen is the two-way speed of light, or how long it take light to travel 2d.

What Veritasium alludes to is the fact that the one-way speed of light, or the time it takes light to travel a distance d has not been determined. As such, quite a few theories can fit into “our current understanding”:

c ≈ 3 x 108 m/s in both directions < 3 x 108 m/s – x in one direction and x in the opposite < c ≈ 1.5 x 108 in one direction and instant in the opposite

What is more, is that either observer would not notice any difference if the speed of light was not what we thought it to be. I find this rather intriguing, and wonder if the speed of light may not be just a constant. What may be the most interesting case is if light has a speed of c/2 in one direction and instant in the reverse and the implications this solution may have.

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How Big is the Universe?

Posted on January 29, 2022 by jschorr21
image by Pablo Budassi | Map of the Universe

The universe is so big that we can’t even begin to comprehend its true size. First, we can look close to home and realize how big even our own Solar System is. The moon is the furthest place humans have voyaged, sitting at about 200,000 miles away. The next planet over(Mars), however, can be up to 1000x further at about 200 million miles! The furthest space probe we have sent out, Voyager 1, seems to be promising in how well it can reach out and explore the distant universe. It is currently traveling at 11 miles per second, at 14 billion miles from Earth. However, at this rate, Voyager 1 will need to travel for at least 30,000 more years to just leave our Solar System! And to reach the nearest star, Proxima Centauri, it would take over 70,000 years. And let’s say we wanted to drive in a car on some magic road to Proxima Centauri, it wouldn’t take long– only 6x longer than the age of the universe! When we zoom out to the entire observable universe, it gets bigger than we can comprehend or understand. The observable universe is about 93 billion light-years wide, or 1 quadrillion times the distance from the Earth to the Sun. It contains more stars than are grains of sand on all the beaches and deserts of Earth. And this is just what we know and can see. Outside the observable universe could be thousands of times bigger and we would have no idea since the light hasn’t had enough time to reach us. Overall, we must appreciate the outrageous scale to which we can measure our universe and understand that our place in the cosmos, Earth, is extremely random and insignificant. Do you feel small yet?

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blog post 01

Posted on January 29, 2022 by graceward02

Solstices and Equinoxes

The winter/summer solstices are, respectively, the shortest and longest periods of sunlight during the calendar year. The vernal/autumnal equinoxes are days in which the amount of time the day has with sunlight and without are of equal length.

The Seasons, the Equinox, and the Solstices

Days that are solstices/equinoxes demonstrate the formal change in seasons. This occurs because the Earth is positioned at a tilt which differs in position (towards/away from the Sun). If the Earth wasn’t tilted, there would be no solstices/equinoxes because there would not be a noticeable change in seasons as the calendar year progressed (Britannica). The area at which you lived would have the same amount of direct sunlight year-round. Solstices are marked for the beginning of the summer/winter seasons, while equinoxes mark the beginning of spring/fall. These demarcations, however, are opposite on the Northern and Southern Hemispheres. Anyone who lives by or on the Equator of Earth doesn’t have solstices/equinoxes because the amount of sunlight is relatively constant year-round.

When the area you live is tilted its maximum toward the Sun, you will have summer solstice. If it is at its maximum tilt away from the Sun, you will be experiencing the winter solstice. The vernal/autumnal equinoxes, however, occur when the Earth’s tilt is relatively straight up and down (neither toward nor away from the Sun).

If the Earth wasn’t tilted, and we had no seasons, how would our lives be different?

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Blog 1 – Solar and Lunar Eclipses

Posted on January 29, 2022 by parallaxHubble

Hello everyone, the topic that I am choosing to blog about this week is the similarities and differences between solar eclipses and lunar eclipses. Firstly, we can define an eclipse as a moment in time in which one celestial body, be it a moon, planet, asteroid, or star, effectively blocks out a significant portion of light (usually light generated from a star) from reaching another entity. It is important to note that Earth is not the only planet in our solar system that experiences eclipses, as other planets, such as Jupiter, experience them as well as they also have the moons that are necessary to create such conditions. A solar eclipse can be defined as when the moon appears to cover the Sun, getting in between the Earth and the Sun. A solar eclipse is experienced on Earth as a short period of darkness, lasting up to a couple minutes, during the daytime. Depicted below is a solar eclipse.

Image Source

On the other hand, a lunar eclipse occurs when the moon is covered by Earth’s shadow. This happens when the Earth intersects the light between the moon and the sun. Since the Earth is so much larger in volume and surface area than the moon, it can cast a much larger shadow than the moon is capable of producing on Earth, meaning that while solar eclipses are relatively short lived, lunar eclipses can last up to 90 minutes. A lunar eclipse is viewed on Earth as a phenomena known as a blood moon, when the moon turns a orange and red color. This happens because the most of the light reaching the moon is actually reflected from Earth’s atmosphere, not the sun, which gives the moon a unique orange color. Below is how a lunar eclipse works.

Image Source

Now that we understand what an eclipse is, the different types of eclipses, and how they vary, the next question would seem to be do eclipses happen in other solar systems beyond our own, and how would we be able to measure such eclipses? Although we do not have quantitative proof of any occurrences yet, I personally think that it is very likely that eclipses would occur in other solar systems besides our own because the only factors really necessary to make them happen is the existence of a star, a planet, and a sizable moon, which to me doesn’t appear to be that demanding to ask for.

Let me know below in the comments what your thoughts are about the possibility of eclipses in other solar systems.

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What’s your real zodiac sign?

Posted on January 29, 2022 by evang914

If you ask anyone what their zodiac sign is, chances are they will be able to give you a quick response. I happen to be an Aquarius, which makes me both assertive and easy-going…? At least according to this Cosmopolitan article, I am. Anyway, most people probably don’t know that their zodiac sign, which is meant to represent the constellation that appears behind the sun on the day they were born, is actually wrong… kinda. It would be right if you were born nearly 2400 years earlier in 400 BC around when the zodiac system was created. But because of the cyclic rotation of the Earth’s axis (also known as precession) that takes 26,000 years to complete, the direction of the Earth’s axis changes over time. It also explains why the current North Star, Polaris, will not always be the North Star. Eventually, our precessional wobble will orient a new star to appear to be located at our Northern celestial pole. If you’re a visual learner like me, check out this video to see the process in motion. The first person to notice this movement was the Greek astronomer Hipparchus who realized when he was cataloging stars that their positions had all shifted slightly from earlier Babylonian records.

So, what should your actual zodiac be then? Your correct zodiac is probably the sign that precedes the one assigned to you by the static zodiac calendar. As you can see from the picture below, the sun was firmly set in front of Capricornus on the day I was born in 2000, not Aquarius.

Sky on February 9, 2000 via Stellarium
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Galactic Time Travel

Posted on January 29, 2022 by timmyshaheen
Leia imagines her home world has not yet been destroyed. (Marvel)

In the picture above, Leia looks towards the night sky and the lights of the stars from her Galaxy. She remarks how the light from the destruction of her planet has yet to reach them yet, and she imagines that she could just get into a spaceship and go see her planet alive and well.

While it may have been impossible for her to travel through hyperspace and go back to her planet, theoretically, if she had gotten an immensely powerful telescope, she actually would have been able to see her planet, years in the past.

This is due to the immense distances that light has to travel to reach different solar systems. One of the closest stars to earth, Alpha Centauri, is a little over four light-years from us, meaning that while we observe the star on Earth, we are technically seeing the star and its planets four years in the past.

While we do not have the ability to travel faster than the speed of light like the characters from Star Wars, if we could all it would take is a quick trip to another corner of the galaxy to see ourselves in the past.

Sources: EarthySky.org

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Eclipses of the Past

Posted on January 29, 2022 by isaiandrade01
Pictured are 19th Century Chinese Astronomers Observing an Eclipse

Due to advancements in technology, we can easily explain the scientific reasoning behind astronomical events such as lunar and solar eclipses. We understand solar eclipses occur in the new moon phase when the Moon passes between the Sun and Earth, appearing to cover the Sun and cast its shadow on the Earth. The opposite is true for lunar eclipses as they only occur in the full moon phase as the Earth will come in between the Sun and the Moon and cast its shadow on the Moon. While total solar eclipses themselves are not extremely rare, “occurring approximately every 18 months,” what is extremely rare is the occurrence of a total solar eclipse in a specific location on Earth. A total solar eclipse occurs when the Moon appears to completely block out the Sun, only leaving the corona visible to observers. Astronomers estimate that a total solar eclipse in a specific location will, “occur approximately once every 375 years.” This rarity helps us understand why ancient civilizations understood these astronomical events as abnormal and chose to interpret them in their own way.

In the article linked through the caption, many total solar eclipses throughout history are described, each having different meanings within the varying cultures of civilizations. For example, in Ancient China, astronomers believed that an invisible dragon would appear and battle the Sun during an eclipse. The ruling emperor would then gather an army to shoot arrows in the air and beat drums to scare it away. As well, in Ancient Greece (648 BCE), poet Archilochus described the occurrence as a direct result of Zeus’ power, “since Zeus father of the Olympians made night from midday, hiding the light of the shining sun, and sore fear came upon men.” Presently, we understand why these eclipses occur; however, it’s understandable that an ancient civilization, especially with far less technological advancements, would interpret eclipses as symbols of greater power, simply due to how rare it was to observe them.

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Phases of the Earth

Posted on January 28, 2022 by jesszhang782
If you live on Earth, you can probably picture the Moon cycling through its different phases in the sky. But have you ever thought about what it would look like if you lived on the Moon and saw Earth in the sky? Turns out Earth has phases too. Similar to the Moon, half of Earth […]
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Blog 1: Chinese Zodiac

Posted on January 28, 2022 by sissichen17
Illustration from Britannica

Zodiac is a belt-shaped region of the sky that extends approximately 8° north or south of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. In astronomy, the zodiac is divided into 12 signs, each occupying 30° of celestial longitude and corresponding to one constellation. 

In Chinese culture, it is similar that the zodiac belt is classified into 12 classes. Each division is named after an animal (rat, ox, tiger, rabbit, dragon, snake, horse, ram, monkey, rooster, dog, pig) to represent a month based on the Lunar calendar. Zodiac animals are associated with certain characteristics. For example, if a person is born in June, his/her zodiac animal sign will be Wu (house), and he/she is expected to be energetic and cheerful. Apart from Chinese zodiac signs for the month, there is a zodiac year, which is also represented by the 12 zodiac animals. 

Zodiac animals are always associated with “Fengshui”(study of looking at the movement of heavenly bodies in relation to people’s birthdate). Along with other elements, zodiac animals reveal personality archetypes and compatibility. Fortune tellers can also figure out people’s potential destiny and fate by knowing their zodiac animals.

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Cosmic Calendar Explained

Posted on January 28, 2022 by Natalie_paige

Birthday’s are one of the most significant days for humans, it signifies the day that we’re born, and became really apart of the universe. But do we know the universe’s birthday? when was the universe created? to answer that question astrophysicists have been able to figure out that the age of the universe since the Big Bang is around 13.7 billion years. In order to get some perspective of all of the events that occurred within the Big Bang and now they created the Cosmic Calendar. Compressing every event within a year, starting with the Big Bang as December 31st

Cosmic Calendar as a typical calendar you could buy in the store http://visav.phys.uvic.ca/~babul/AstroCourses/P303/BB-slide.htm
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