The Gravitas of Sir Isaac Newton

Posted on February 6, 2022 by parallaxHubble

The astronomer that I am choosing to write about is Sir Isaac Newton. Newton was an important astronomer, mathematician, and physicist and perhaps one of the most important contributors to our current understanding of the solar system and universe today who lived from January 4, 1643 to March 31, 1727. Most notably, his discovery of gravity dictates the motions of everything in the Universe and is able to help us make complex mathematical calculations about the solar system, such as movement, speed, orbits, and more. Secondly, he also created Newton’s 3 laws of motion, which are that an object at rest will remain at rest unless acted upon by an outside force, acceleration depends on mass and force, and for every action there is an equal and opposite reaction. These all heavily impact the movement of celestial bodies and give us good perspective into the framework in which all manner operates in the Universe.

Isaac Newton. Source

Two important events that occurred during Newton’s life that are not astronomy related are the Great Fire of London, which occurred in 1666 and burnt down most of the city. Secondly, the historic document the Bill of Rights, which details important political frameworks in Britain about freedom of speech, royal succession, and the limitations of royal power was passed in 1689.

Another important historical figure who lived alongside Newton was John Locke, English philosopher who lived from August, 29 1632 to October 27, 1704. Locke was important for his thoughts about human nature and the self, ideas which influenced the Founding Fathers of the United States and are firmly chiseled into the Constitution as the right to “life, liberty, and property.”

I think it was interesting to learn more about the context of Newton’s life because it highlighted to me how many important figures existed in the 17th century and also how important their work is. Names like Newton and Locke are still heard today, almost four hundred years later, so they must have discovered something very important that society has been able to build off of and put to good use today.

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Historical Astronomers in Context

Posted on February 6, 2022 by Lindsey
Nicolaus Copernicus - Quotes, Discoveries & Inventions - Biography
Nicholas Copernicus:  February 19, 1473 – May 24, 1543

Nicholas Copernicus was incredibly important to astronomy because he first proposed a model of the universe in which the Sun was at the center and that Earth orbited it (heliocentric model). This was incredibly controversial during his time because most people believed the Earth was at the center of the universe and everything else orbited around it. Another part of his proposal was that the movements we observe in the sky are mainly a result of the movement and rotation of Earth and not the movement of those celestial bodies themselves. Although the Sun is not actually the center of the universe, the idea that Earth was not the center provided an essential push that allowed us to make more accurate analyses and conclusions about what we observed in the sky.

During the lifetime of Nicholas Copernicus, many historically significant events occurred. In 1492, the New World was discovered. Christopher Columbus was given credit for this discovery. The exploration and colonization of the New World led to significant changes in economy and trade/commerce. Additionally, it gave many European nations like Britain, Spain, and France more worldly power and resources than they had before. Additionally, in 1519,  Martin Luther’s 95 theses were published. The main ideas taken from these theses were that the Bible is the main religious authority and that humans cannot reach salvation through their actions (only faith can save them). These ideas ultimately acted as an impetus for the Protestant Reformation.

As stated above, a historically significant figure that lived during Copernicus’s lifetime was Martin Luther (November 10, 1483 – February 18, 1546). His 95 theses sparked the Protestant Reformation.

Overall, learning about the impact of Copernicus’s controversial ideas made me realize how important it was for people to challenge the current way of thinking. If Copernicus had just accepted the socially accepted theory and didn’t question things that were currently seen as fact, we might have been set back years of astronomical progress. Even though the majority of people didn’t accept Copernicus’s heliocentric model and rejected his ideas, the fact that he published it anyway ultimately led to an astronomical revolution. It makes me wonder if there are things we currently consider factual that should be challenged in order to craft a more accurate model of the world we live in.

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Historical Astronomers in Context

Posted on February 6, 2022 by clviggiano

Johannes Kepler (December 27th, 1571 – November 15th, 1630) was a German-born astronomer who carried out much of his scientific research in Prague. Inarguably, Kepler’s most important contributions to astronomy were his three laws of planetary motion, the first two of which he published in 1609, and the third a decade later. The first law states that planets move in elliptical orbits with the Sun stationary; the second, that the radius vector (sun to planet) covers equal areas in equal time; and the third, that the ratio of the square of orbital periods and the cube of elliptic semi-major axises are the same for all planets. He is also recognized for creating the Keplerian telescope, which provided the basis for the modern refractive telescope. 

Just before Kepler publicized his first discoveries, Miguel de Cervantes wrote Don Quixote de la Mancha and published it in 1605. Don Quixote was the first modern novel—its publication marked a literary revolution and the start of a new social writing tradition. Around the time of his second major publication (the third law of planetary motion), the Mayflower landed at Plymouth Rock, delivering the first pilgrims to America in late 1620. 

During the same period, other parts of the world were experiencing equally significant political, religious, artistic, and cultural events. In India, Shah Jahan (5 January 1592 – 22 January 1666) claimed the title of the fifth Mughal emperor and reigned from 1628 to 1658. Under Jahan, the empire reached its peak prosperity in terms of territorial expansion, trading, wealth, art, architecture, and education. The commission of the Taj Mahal is regarded as Jahan’s most influential act, and was a testament of the love he had for his favorite wife, Mumtaz Mahal. In 1648, seventeen years after construction first started, builders completed what is now regarded as one of the world’s masterpieces.  

Contextualizing historical figures relative to other famous discoveries, events, people, etc. provides a useful framework for understanding the timeline and evolution of science. I didn’t realize how closely linked a lot of these astronomical discoveries actually were; like how Brahe and Kepler not only lived during the same time, but actively worked together as colleagues. History is incredibly interrelated, and I think it’s easy to forget or overlook that sometimes. To frame these individuals and their contributions against a bigger backdrop provides a really important context through which we can better understand their lives and scientific discoveries. 

Public Domain Image
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The Cosmic Calendar

Posted on February 1, 2022 by jordanekstein

The Cosmic Calendar is a mechanism to help us understand the history of the universe relative to something we can comprehend more easily. This method puts the history of the universe into one calendar year proportionately. Through this it can help us understand in a more conceptual way how long, for example, humans have existed relatively to the rest of the universe or to, say, the dinosaurs. We as humans cannot fathom what billions of years truly is as even a century ago seems like forever. Beyond that it is almost unfathomable to think that in the span of the universe Neanderthals and the very first civilizations were not too far in the past. It is a past that of course to us signifies a beginning but human history is just a blip, about one and a half minutes, on the cosmic calendar as each moth represents over one billion years. While all our lives we learn about human history, the history that surrounds us and that exists beyond our species is far more vast and the universe existed for nearly the entire cosmic calendar before we appeared. This helps to understand and compare periods of time while also acknowledging our own species position in history beyond ourselves.

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My first eclipse

Posted on January 31, 2022 by gcomartin
wikipedia

The solar eclipse of May 20, 2012 is the most spectacular astronomical event I have ever personally experienced. The event was an annular eclipse with the moon only blocking out the center of the sun, resulting in a ring of light around the dark moon. The eclipse occurred less than 48 hours after apogee, so the moon’s diameter looked smaller than typical. Nevertheless, the view from Palo Alto, California was fantastic. My classmates father worked at NASA, and thus wanted to make sure our class was able to properly celebrate the event. He brought it protective goggles for our class to wear, allowing us to in a safe manner observe the eclipse as it formed. The annular phase lasted 4.5 minutes in Northern California, and they will surely be a few minutes I will never forget.

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Blog 1: The Mystery of the Light-Year

Posted on January 31, 2022 by Kaitlyn Lane
How far is a light-year? | Astronomy Essentials | EarthSky
Image Source

People often confuse a light-year for a measure of time instead of a measure of distance. This is understandable since it has “year” in the name. A light-year is NOT a measure of time. The true definition of a light-year can be easily understood with a few simple facts and calculations. First, light travels at a speed of around 300,000,000 meters per second. This immense speed is usually insignificant at small distances, as seen in the diagram. Even though the Moon is 384,000 km away from the Earth, it only takes light 1.3 seconds for light to travel that distance. This can be calculated by dividing the distance by the speed of light, which equals about 1.3. A light-year is the distance that light can travel during one Earth year, or 3.15×10^7 seconds. Since the distance formula is distance = speed x time, if we multiply the speed of light by the seconds in a year, we get the distance of a light-year. This is equivalent to around 9.5×10^19 km or 63,241 AU.

The light-year unit is only applicable for large distances to objects outside of our solar system. Even though an object may only be 4.4 light-years away, like Alpha Centauri, this does not mean that it would only take a little less than 5 years for humans, or even a space telescope to reach this star. The fastest that any humans have traveled was around 40,000 kph, and this speed was achieved by the crew of Apollo 10 as they returned to Earth. This is still not comparable to the speed of light, so humans will not be traveling outside of our solar system in a timely manner anytime soon.

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Moon Phases!

Posted on January 31, 2022 by McKenzieKing
A Timelapse of the Earth’s Moon’s Phases

To start off, I am going to be focusing on our own Earth’s Moon. As we all know, the Moon goes through phases as it orbits the planet. It’s current phase is dependent on where it is in the sky relative to the Sun. For example, the New Moon rises and sets with the Sun and is in the same direction as the Sun. This is why the sunlight is at the back of the Moon and there is no light to illuminate the front face of the Moon. Okay, using the word Moon so much makes it feel like it’s not a real word anymore, so from now on I will be calling the Moon “Steve.” So, as we move through the months, Steve will change positions relative to the Sun. When the Sun is across from him, his face will be fully illuminated and we will have a Full Moon. Between these two phases of fullness and newness, Steve will cycle through many different phases. These are called waxing, meaning increasing, as more of his face becomes illuminated by the Sun’s light and waning, meaning decreasing, and more of his face becomes shadowed. Steve also appears at different times during the day depending on what phase he is in. For example, because Steve must be opposite of the Sun to be fully illuminated, he must rise above the horizon and into view while the Sun is setting on the opposite horizon. So, as the Sun sets in the West, Steve rises in the East. Another example of this is that when Steve’s face is in its ”Third Quarter” phase, then he would need to rise over the horizon and into view around midnight and set around noon of the next day. This is why we can see the Moon during the day sometimes!

    I would like to leave you with this fun fact! Most people believe that the side of the Moon that is always facing away from the Earth is the “Dark Side,” but this is not true. The other side of the Moon actually goes through phases as well, we just can’t see them because the Moon rotates completely on a rate that roughly equals one month. This is why we always see the same face of the Moon facing toward us. Think of it like this: Steve wants to keep his eyes on us, so we never see the back of his head!

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Blog 1 – Initial Review of SkyView Lite

Posted on January 31, 2022 by Jack Walton

SkyView Lite is an iPhone application that allows the user to point their phone at different parts of the sky and see an overlay of constellations in the direction that they point. I downloaded the app and tried it out. This post is going to be about my experience using the app.

The app works by using a combination of your GPS location and iPhone orientation to calculate what portion of the sky you can see when you point your phone in any given direction. This application is great for inexperienced sky-watchers to learn the about the constellations, planets, and satellites. While using it for a few minutes, I was able to find the North star, locations of the 12 Zodiac constellations, many planets, the ISS and the Hubble space telescope. I noticed that just like in the textbook, the zodiac constellations formed a ring around the Earth going from East to overhead, to West to straight down.

Screenshot from within the Skyview App

In the app, I could see that the Sun is in Capricorn, even though according to the Astrology signs, the Sun is currently in Aquarius. This lines up with what we learned in class, which is that due to the Earth’s precession, the sun is now one sign “behind” of where the original astrologists of star signs saw them 2000 or so years ago.

I am looking forward to going stargazing and using this app to learn more about the sky. I also can’t wait to learn more about the night sky through this astronomy class!

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The speed of light and what it means for the Earth-Sun system.

Posted on January 31, 2022 by alexlitt

The speed of light is one of the most important laws (or principles) in our Universe. The speed of light determines what we see and when we see it, as well as providing a universal “speed-limit” for countless celestial objects that zoom throughout the universe. I find it illuminating to consider the speed of light in regards to how it affects my (or humans in general) everyday life. Principles such as special relativity and time-dilation don’t manifest at the relatively sluggish pace of even the fastest man-made contraptions such as cars, trains or planes. On the other hand, the Sun, affects nearly everything that we as humans do, and the Sun’s light is greatly affected by the speed of light. The Sun dictates what we wear each day, when we go to sleep, whether we will go swimming today, or whether we will go ice skating. Because the Sun is located approximately 150 million kilometers from Earth (on average), and because the speed of light is around 300,000 km per second, the light that we observe from the Sun is not the light that is currently being emitted from the Sun, but light that was emitted some time ago. Using some rough math, we can calculate how long ago the Sun emitted the light that we are observing on Earth. (150 * 106 km) / (300 * 103 km/s) = 0.5 * 103 seconds = 500 seconds = 8 minutes and 20 seconds. This means that if the Sun suddenly stopped emitting light, or if a large passing celestial object obstructed the Sun’s light from reaching Earth (or parts of Earth), we would still receive the Sun’s light/heat for more than eight minutes!

Video From NASA: Information about the Sun, solar wind, and the Parker Solar Probe. Info about the Sun begins at 0:38. For more information about the Parker Solar Probe visit the NASA page linked here.
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“Powers of Ten” and the Scale of the Universe

Posted on January 30, 2022 by Brian
The famous Hubble Ultra Deep Field image, which illustrates the scale of the universe by showing countless galaxies in a region of space previously thought to be nearly empty

I didn’t remember until I started the video, but I had seen “Powers of Ten” before in some science class many years ago. This staying power, evidenced by my recollection and the countless Youtube comments saying similar things, is proof of how mind-blowing the concept of scale is.

Scale determines what we can comprehend and the shape that reality takes for us, but because it is so inherent to our everyday lives, it is very difficult to understand this. That is why videos like “Powers of Ten” are so important: they open our eyes to the fact that there is so much more out there than human-sized things. This is part of why I study physics and astronomy. Yes, human-sized problems are particularly relevant to our lives, but physics deals with the smallest and largest scales. There is so much richness in places that we don’t see everyday that other academic disciplines simply don’t touch. For example, this course focuses only on the Solar System and still has so much content to cover— about the Sun, the planets and their interactions, the moons, and so on. Yet, the Solar System was only at the 13th power of ten in the video, 100 billion times smaller than the upper limit of 24. That is what makes physics and astronomy different from other subjects.

I’d also like to touch on a question that is invoked by thinking deeply about scale: do you think that scale goes on infinitely in either direction? I personally think that the universe should be scale invariant because there is no reason that things should stop existing once they get very big or very small. The video discusses how there is a pattern of “alternation between great activity and relative inactivity” as you zoom in and out, and in my mind this should go on forever. However, that concept of infinite scale also has logical issues. What do you think?

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