M45 – The Seven Sisters

Posted on February 28, 2023 by 7smessier45

Hey, y’all, and welcome back! 

Today, we’re taking a quick jaunt outside our solar system to visit the Pleiades. This grouping of stars–commonly referred to as Messier 45 (M45)–is one of my favorite observables and can be best viewed in January–but the cluster is easily visible from late fall through the winter. The cluster is currently moving through a cloud of interstellar dust and is located about 440 light-years outside of our solar system. Interacts between the light from the stars and the dust give the appearance of a wispy haze around some of the cluster’s hottest and most luminous stars–the brightest of which is about 1000 times more luminous than our sun.  But from our vantage point on Earth, we can view (with the naked eye) about six or seven stars of the over 1000 stars found within this open star cluster by looking towards the constellation Taurus or by using Orion’s shield and Aldebran as pointer stars.

M45 by Joel Tonyan   

As one of the brightest star clusters in the night sky, numerous cultures have their own names and mythologies associated with m45. In Japan, for example, the cluster is known as Subaru. (Sound familiar?) 

But the story I am most familiar with is one of at least two from Ancient Greece. For seven long years, the hunter Orion chased the seven daughters of Atlas throughout the known world. Just before the giant could seize the sisters, Zeus changed them into the brilliant stars that adorn the sky to this day. But for Orion, the hunt continues. His constellation pursues the seven sisters across the sky, and every night their eternal chase begins anew. 

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What will happen to our solar system when we collide with Andromeda?

Posted on February 28, 2023 by Melanie Marszal

You may be familiar with Andromeda, our closest neighboring galaxy. You may have also heard that Andromeda and our Milky Way are moving towards each other. But what will happen to Earth and the rest of our solar system when these two galaxies collide? Will Earth even still be around by then?

The answer to the second question is likely yes, at least based on the projected lifetime of the Sun. The Sun should live for about 10 billion more years. However, in about 5 billion, it will turn into a red giant and expand into Earth, burning it up. Humans will not be around to see that, unless we relocate to a different planet. Earth will stop being able to sustain human life in about 1 billion years, due to the Sun increasing in brightness and drying up the oceans.

As for Andromeda, it is expected to collide with us in about 4 billion years. With this timing, the Sun will not be a red giant yet, and therefore all the planets will still be intact unless something else happens to them. While a collision of galaxies sounds very catastrophic, scientists agree that it is unlikely that our solar system would be harmed in any way, due to how spread out stars are in each galaxy. The odds of any two stars in either galaxy crashing into each other are extremely low. The black holes at the centers of each galaxy would merge, with Andromeda’s black hole of 100 million solar masses swallowing ours, which is only 4 million solar masses. After this merge, computer simulations from Hubble data predict that it will take about 2 billion years for the contents of each galaxy to completely merge and reshape into one elliptical galaxy. While this reshaping takes place, it is predicted that our solar system will be thrown much further from the center of the galaxy than we are right now.

Although this collision of galaxies would be unlikely to affect the lives of anyone living in either galaxy, astronomers could have a pretty good time with the event. As Andromeda and the Milky way get really close together, it may be fun for any intelligent lifeforms to observe another galaxy so close up, especially since from Earth, much of our view of our own galaxy is obstructed by dust. Would you want to live through an event like this?

A rendering from NASA of what Andromeda (left) and the Milky Way (right) may look like from Earth in about 3.75 billion years when they are closely approaching collision.
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Dark Matter

Posted on February 27, 2023 by zws42
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In studies of galaxies and star clusters, astronomers have found that many of these bodies appear to move in ways that don’t reflect the amount of visible matter in the system. For instance, some galaxies appear to orbit much faster than they should be based on the amount of stuff we can see within them. This fact, in the absence of any other explanation, has led astronomers to the conclusion that there are large amounts of matter in the universe that we can’t see. Hence the name dark matter. This hypothetical form of matter doesn’t interact with the electromagnetic field at all. This means that we can’t measure it or detect it in any of the conventional ways that we find other things in space. Despite the lack of direct evidence for its existence, dark matter is estimated to account for about 85% of mass in the universe[1].

This is obviously a massive amount of stuff, and it’s kind of hard to accept that such a high percentage of matter in the universe is invisible to all of our instruments. The first thought in my mind when I see that number is that we have to be missing something, and that there can’t possibly be that much in the universe that we can’t see. That’s the human response that I have, but I think it’s important to step back and look at it objectively. While we obviously haven’t found and perfected every technique of investigating the cosmos, we have done pretty well with our tools so far and they have been effective in investigating a large number of astronomical phenomena. All of our observational evidence points to the existence of a large amount of matter that is currently invisible to us, and we have to accept that that must be true unless we want to discount all our proven laws of physics and methods of observation. So despite that initial reaction of disbelief, I think it probable that there is a very large percentage of mass in the universe that we can’t see, but I do believe that we may be able to develop some instrument or method that allows us to more directly detect this matter. Either way, it is a very cool concept, and it will be exciting to see what new information comes out about dark matter as we make new astronomical discoveries.

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Nuclear Fusion

Posted on February 27, 2023 by zws42
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Nuclear fusion is the process that powers our sun, as well as all the other stars in the Universe. At the most basic level, nuclear fusion is the combination of two light atomic nuclei to form a heavier one along with a release of energy. This reaction is governed by Einstein’s E=mc^2 equation, where some of the mass from the initial part of the reaction is converted to energy. Since the total mass of the resulting particle is less than the total mass of the initial particles, the energy released from the reaction is equal to the difference between the initial and final masses, multiplied by the speed of light squared[1]. For reference, if one kilogram of matter was fully converted to energy, it would release about 8.99 x 10^16 joules of energy. This is enough energy to power the entire city of New York for over a month[2]. As you can see, fusion reactions can produce enormous amounts of energy at a time, and the sun experiences about 9.3 x 10^37 such reactions per second.

Now, it is important to note that a kilogram of mass is never instantaneously converted to energy as mentioned above, at least not in any process that we know of today. The masses being converted to energy per reaction in the sun are around 4.8 x 10^-29 kilograms[3]. A reaction with this amount of mass conversion releases 4.3 x 10^-12 joules of energy. Taken alone this is quite a small amount of energy, but if you multiply it by the number of reactions per second in the sun it becomes very large. Overall, fusion reactions produce about four times more energy than the fission reactions currently achieved in nuclear reactors on Earth, and would therefore be the preferable form of nuclear energy once the technology becomes available.

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Comparing the Atmospheres of Mercury, Venus, Earth, and Mars

Posted on February 27, 2023 by Melanie Marszal

We may not think much about the presence of Earth’s atmosphere in our day-to-day lives, but it has an immense impact on us. Earth’s atmosphere contains the oxygen we need to breathe, protects us from many of the Sun’s harmful ultraviolet (UV) rays, helps stabilize the Earth’s temperature, and is responsible for weather patterns. If the composition or thickness of our atmosphere were any different, we would likely not survive.

Mercury, Venus, and Mars are the other terrestrial planets in our solar system, meaning they have rocky surfaces resembling Earth. However, one of the reasons they end up seeming so distinct from Earth is their differing atmospheres.

The first aspect of each atmosphere that differs is the chemical composition. You may know that Earth is composed of 78% nitrogen and 21% oxygen (and 1% argon). Mercury has an even higher composition of oxygen than Earth, with oxygen comprising 42% of its atmosphere. The other elements present in Mercury’s atmosphere include sodium, hydrogen, and helium. On the other hand, the atmospheres of Venus and Mars are comprised almost entirely of carbon dioxide, with it making up 96% and 95% of their atmospheres, respectively. Nitrogen is also present in these 2 atmospheres.

The other extremely important way each of these atmospheres differ is in thickness. Earth’s atmosphere is thick enough to keep the temperature somewhat regulated and to keep out harmful UV rays. On the other hand, Mercury has virtually no atmosphere, which causes major temperature variability. The reason Mercury has so little atmosphere may be that since it is so close to the Sun, particles in the atmosphere are frequently heated enough for them to escape the planet’s gravitational pull, leaving the atmosphere. Solar winds likely also contribute. Mars has a relatively thin atmosphere as well, but not as thin as that of Mercury. Venus is on the other side of the spectrum, with an incredibly thick atmosphere, which traps heat.

Another difference between atmospheres is clouds. On Earth, we often see white clouds of water vapor form (a.k.a. clouds). On Venus, clouds of sulfuric acid often form. Thin clouds of water and carbon dioxide form on Mars.

The four terrestrial planets in our solar system: Mercury, Venus, Earth, and Mars (image from Wikipedia)
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Solar Flares and the Carrington Event

Posted on February 26, 2023 by sydneyastr2110

We heard a little bit about the Carrington Event in class, and I wanted to know more about it. A solar flare is essentially a burst of energy on the Sun which sends electrified gas and subatomic particles toward Earth.

In 1859, there was an abnormally large solar flare caused two geomagnetic storms known as the Carrington Event. The name is from the last name of an astronomer, Richard Carrington, who observed the event through his telescope. While observing the Sun, he noticed intense, white light bursting from the sunspots.

A few hours later, the world experienced telegraph communication failures. Basically, extremely powerful of currents were traveling through the wires. According to writer Christopher Klein, “the atmosphere was so charged… that they [telegraph operators] could unplug their batteries and still transmit messages,” (Klein). Accounts from the time mention the incredible bright red sky caused by the event. You can check out a more in-depth description of the event here.

This event was certainly unusual in size as it was “twice as big as any other solar storm in the last 500 years,” (Klein).

This was over 160 years ago, so why do we care? On January 5, 2023, there was an X1.2 solar flare. The X is representative of a classification for the most intense flares. While this was intense, the 1.2 indicates that it was nowhere close to the size of the Carrington Event. The classification and images are available from NASA. The image below is from NASA and shows the solar flare on the left side of the Sun.

Image Credit: NASA/GSFC/SDO

Could an event like the Carrington Event happen again? Yes, absolutely. A study in 2020 from the University of Warwick and the British Antarctic Survey determined, “that on average there is a 0.7% chance of a Carrington class storm per year.” If you want to know more about the results of this study, check it out here. This type of storm could be detrimental to modern infrastructure as it would impact power grids and satellites with estimated losses of $1 trillion to $2 trillion (Klein).

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The Coolest Telescope

Posted on February 15, 2023 by Liam Prescott

The James Webb telescope, unveiled on December 25 2021, is by far the coolest telescope. Webb has the power to view infrared light rays from exoplanets that are potentially habitable. Also the innovative technological achievement can better observe our own solar system and the first galaxies that were formed 13.5 billion years ago. It has a 6.5 meter mirror that is the largest NASA has ever built, and this allows it to view more further objects in greater detail and accuracy. The telescope is designed for space and is 60 times larger than previous space telescopes too.

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Evidence for Understanding

Posted on February 13, 2023 by dougkyles422111

I want to talk about an aspect of light that doesn’t make the most sense to me, and that is how we receive it. Thinking about sight abstractly, we cannot really comprehend at all times what we are seeing are particles of light. To us, our visual environment is our reality. Learning about how the reality around us is really just electrical signals being received by our brain from light-sensitive particles is a concept that is hard to wrap one’s head around. This is part of chapter 6 that was most interesting to me. 

Even further, light can be considered energy- as small as on the electron level. Receiving light can be broken down as photons giving ionization energy to electrons within the atoms within the cells of our eyes. The understanding the previous chapter on light and energy provides allows one to go so deep into the idea of the reality of our world that the knowledge is in my opinion unbelievable. This is what I’d like to discuss. While I don’t believe there’s enough information or evidence for me to doubt the science behind chapters 5 and 6, I find that subconsciously I question how we know so much about things that cannot exactly be observed. Coupled with chapter 3 on historical astronomers I wonder if we have possibly a system that is outdated and will be changed soon with time. The following article is one I read that helped slightly with my understanding of how we know what we know about the atom.

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Blog 2 – Tides: my thoughts from the anime Avatar: the Last Airbender

Posted on February 13, 2023 by niqretnuh

One of my favorite poetic interpretations of tides comes from the anime “Avatar–the last airbender”. In the episode “The Siege of the North”, the root of the mysterious power of “water-bending” is explained to stem from the moon, and the power of tides. The goddesses “tui (推)” and “la (拉)” (“push” and “pull”) directs the motion of the tides, symbolizing the  “yin-yang” balance behind everything in life. Born and raised in a coastal city, watching the bright, white moon rise over the horizon always reminds me of this beautiful and philosophical episode.

In astronomy, we learned that tides result from the gravitational force from the moon. The differences in the force received from the two opposite sides of the Earth causes its shape to deform, causing tides to occur. However, unlike portrayed in the anime, tidal forces do not disappear in day time – in fact, the sun’s gravitational difference, although very limited compared to that of the moon, still contributes to tidal phenomena on the Earth. 

Although not entirely scientifically accurate, the anime still sparks a lot of discussions over the moon tides, and the philosophical meaning we can derive from this phenomenon. In my childhood, this episode in Avatar provided me with endless imagination over this mysterious, powerful phenomenon.

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The Wave-Particle Duality of Light

Posted on February 13, 2023 by jackdoyle25

In common perception, most things in our universe fall into two fundamental categories: energy and matter. Energy could be electricity, heat, sound waves, or kinetic motion. Matter is generally a descriptor of things made up from atoms, such as planets or stars or humans ourselves. However, looking at these on a more fundamental level, the lines between energy and matter are blurred. Take kinetic energy, which is stored in the matter of the object which is in motion, or stars, which are full of constantly occurring chemical reactions to create energy. The so-called “fundamental” distinction between matter and energy is, in fact, a flawed idea.

Nowhere is the ambiguity of this distinction more significant than in the nature of light itself. Our previous examples involve intersections between what we think of as energy and matter. Light, however, can present itself as both. To be more specific, light can behave as a wave or as a particle.

An example of an experiment which provides evidence for the wave-particle duality of light.

Particles of light are called photons, each of which can be observed as their own individual particle and contain energy. Waves of light are inseparable from the concept of photons, as photons have their own wavelengths and frequencies, which are the defining properties of waves.

The idea that light can be both a wave and a particle at the same time is conceptually unwieldy, but it is necessary to our understanding of how light works. This understanding allows us to reframe the distinctions between matter and energy. Light is an example of a particle acting as energy, and of a wave acting as matter. The destruction of such a simple dichotomy confounds logic, and in doing so, opens up a world of possibilities. This principle of wave-particle duality is crucial to one of the most fascinating fields of modern scientific study: the theory of quantum mechanics.

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