Hello everyone, I will post a few fun facts about Physics (and Astrophysics) every Tuesday!
Facts!!
Scientists use detectors that are about the size of buildings to capture the products made by particle colliders. These detectors can pick up just about all particles created in these collisions.
A big question that is still asked today, is the nature of Dark Matter and Dark Energy. Dark Energy is about 68% of the Universe and 27% of the Universe is Dark Matter, and the rest is what we have only observed so far!
The Voyager 1 spacecraft which was launched on September 5, 1977, is the farthest human sent object from Earth and has entered interstellar space, which means that it is in the process of leaving the influence of the Sun’s solar winds.
Image of the Day! 1/23/2024 Deep Nebulas: From Seagull to California
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The Powers of 10 is a video meant to help you understand the Universe’s relative size. After doing several exercises in class that dealt with relative sizes and distances, I realized I did not have a strong understanding of the scale of outer space. The video linked begins with an image of a man on Earth and proceeds to zoom out 1024 meters (it also zooms into the subatomic level, but for this blog, I was more focused on space). By the time we are at 107 meters, the entire Earth fits in the frame, and by 1013 meters, the whole solar system. Now, these numbers are already almost incomprehensible (1013 m = 10,000,000,000,000m), yet I was shocked to learn that the celestial sky still hasn’t moved from this perspective. Even 1015 meters zoomed out from Earth, where our sun is merely a dot, the same constellations observed from Earth still look the same. This helped put in perspective how far away the stars in our night sky are. Lastly, I know it’s pretty common knowledge that space is mostly empty, but once you get to the galactic scale, how much emptiness there is becomes even clearer. At a zoom out of 1021 meters, there were practically three light spots on the screen with an abyss of darkness in between. I seriously recommend anybody interested take a look at this video, as it helped me grasp the size of some of the things we discuss in class.
In elementary school, my library teacher always had the Farmers’ Almanac for the year on her desk. The Farmers’ Almanac has a forecaster who works under the pseudonym Caleb Weatherbee. Weatherbee’s predictions are based on a formula that takes many things into account including the Moon phases. Every fall, my classmates and I looked forward to the class when our teacher told us what the Farmers’ Almanac predicted for winter. I either left that class excited about the prospect of snow days or defeated from hearing it would be a mild winter.
I was recently reminded of the Farmers’ Almanac when I watched a TikTok where a farmer explained that she weans her foals based on days suggested by the book. These days are based on what phase the Moon is in and what constellation it is closest to. I found this especially interesting after reading the textbook chapter about the Moon. The special topic section titled “Does the Moon Influence Human Behavior?” mentions that the physiological patterns of many species follow the Moon’s phases. I think it is cool that even though the Moon’s impact on weaning foals might not be explained scientifically many farmers still swear by the Farmers’ Almanacs’ suggestions.
Many people know that the laws of physics dictate that nothing – and I mean nothing – can travel faster than the speed of light. It is not possible for any object, nor any information, to exceed 299,000,000 meters per second. At first, this seems to be an incredibly high number… and to be fair, on an Earthly scale, the speed of light is enormous. But, as we zoom out into our Solar System, and even just to our planet and moon, it becomes apparent that the speed of light isn’t all that fast, relatively speaking.
James O’Donoghue
Examine the gif above. 1.255 seconds for the fastest possible interaction between the Earth and the moon! “But they are so far away!” Yes and no. Relative to myself, sitting on the couch, and the TV remote, 10 feet away, indeed the moon is far. But the solar system is large – larger than we tend to think. This website might help to open our eyes as to the true scale of our solar system. With this added perspective, our speed limit begins to feel smaller than ever before. Personally, I can’t help but feel the isolating effect of being so far away from everything, not simply in distance, but in time itself.
On April 8, 2024, a total solar eclipse will happen in North America. For those in Nashville, a mere 2-3 hour drive will allow viewers to witness it. For some, it is worth the journey to witness this rare occurrence, and for others perhaps not. For a select few, however, it is always worth the journey. These people are called eclipse chasers, and they have devoted their lives to reliving the spectacle of the eclipse as many times as they can. For eclipse chasers, being in the moon’s shadow for the few minutes in which the total eclipse takes place is an addiction. They plan trips years, even decades ahead in order to witness as many eclipses as they possibly can. You may think that this is crazy – a waste of time, money and energy just to see what they have already seen many times before. However, eclipse chasers are a large community, many of whom talk about their experiences here. There is clearly a somewhat addicting aspect to witnessing eclipses, something that those who have not been lucky enough to see one may not be able to grasp. The next eclipse is on a Monday, and to view it in its totality, a decently long drive is required. That being said, an eclipse chaser wouldn’t bat an eye at a 2 hour drive to witness this astronomical spectacle, and maybe you shouldn’t either!
Most people understand that the earth moves around the sun and rotates on its axis. However the earth moves more than just around the sun. In fact, our entire actually orbits around the center of the Milky Way at over 500,000 miles per hour. So why don’t we crash into anything? The answer is that everything in our galaxy, and especially in our universe, is really, really, far apart, so it will be a long (billions of years) time before we even come close to something that could hit is. In addition, all the galaxies around the Milky Way are actually moving apart from us. Furthermore, the farther a galaxy is away from us, the faster it is moving away. By solving for the rate of expansion using big telescopes, we can determine the approximate age of the universe by extrapolating the growth rate backward. So we know that the universe is about 14 billion years old! This is super cool!
This is a side-by-side comparion of the near and far sides (left and right respectively) of the moon.
By looking at the image above, it’s clear to see that the dark splotches we’ve come to associate with our closest cosmic neighbor, the Moon, are only seen on one side! The farside of the moon is much more uniform with a lot more craters than the side we see. This stark difference has puzzled scientists in the decades following the first lunar orbiter, but with advancing technology they believe they’ve reached an explanation!
While scientists across the field may not agree on all the details, it seems that a general consensus has been reached that because of the nearside’s thinner crust and higher concentration of “heat-producing and radioactive elements,” more mantle material was able to reach the surface, creating the dark spots, called maria, we see today. How these elements came to be more abundant on the nearside is still debated. There are two prevailing ideas. One is that a major impact event on the Moon’s south pole led to these elements being dispersed within the nearside mantle. The other is that due to early Earth’s emanating heat, the near side stayed molten longer, allowing it to accumulate more of these elements. Future missions are in the works to gather more samples from various sites to try and refine this hypothesis.
If you’re interested in learning more about this, feel free to ask questions via comments or check out these articles by the Planetary Society and Brown University!
It is difficult to truly grasp the size and scale of our universe. And while using units like light years might be helpful in some cases, it can also be helpful to put things in a scale that is more common in everyday life. This image helps me understand the scale of the universe in terms of units in meters. The smallest unit femtometers (fm) is equal to 10^-15m. Each subsequent photo is 1000x bigger than the last ending with Ym which is 10^24m. It is interesting to see that in terms of scale, the smallest picture, which is the nucleus of an oxygen atom, is to us, as we are to an Oort cloud. In other words, there is a 10^15x difference between an oxygen nucleus and us, and a 10^15x difference between us and an Oort cloud. Even with this aid, I still struggle to grasp the sheer size of it all. I am interested in what others think about this, and what ways you try to put everything into perspective to understand it.
By me – this is a photo of my sister and I at our favorite beach in Nantucket Island. This is where I first became fascinated with space; there is little light pollution here and for as far back as I can remember, I have stared at the night sky for hours at a time in awe of the complexity of the universe. While I have never been there, this is a link to an observatory on Nantucket that discusses the island’s beauty and amazing conditions for stargazing.
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In 1905, Albert Einstein took the first crack at the Newtonian foundational physics. In his paper on special relativity, Albert Einstein postulated that the speed of light, c, is constant in all inertial reference frames. Assume that a person on a bicycle is holding a flashlight and moving at a constant speed relative to someone who is standing still on the sidewalk. Then, both people measure the speed of light, c, to be approximately 300,000 km/s. Relative to the person standing still on the sidewalk, the light coming out the flashlight still moves at 300,000 km/s, not 300,000 km/s plus the velocity of the person holding a flashlight while cycling. This turns out to be extremely important consequences. By keeping the speed of light the same, the only two variables that can change are the distance and time that is traveled. The longer the distance, the longer the time it takes for the light to traverse the distance. The shorter the distance, the shorter the time it takes for light to travel. If there is any distance between you, the observer, and the object, then it will take some time for the immediately emitted light to travel from the object and in to your eyes. Essentially, there is a time lag between the observer and what you observe. Therefore, the light that reaches you is in fact light that was emitted some time ago. Therefore, you’re actually peering into the past! By observing different types of light that is radiated in the universe, we can learn about the origins of the universe. The oldest light that is observed is Cosmic Microwave Background (CMB).
The CMB, as it turns out, is a relic of the early universe. The CMB tells us how much baryonic matter and dark matter there was in the early universe. The CMB also helps us model how stars and galaxies formed, a crucial step in understanding our cosmic address.
The constancy of the speed of light has enabled us to peer back into the past to observe, analyze, and theorize about our ever elusive origins. Perhaps in another blog I might discuss the philosophical implications of light. But as it stands, a universal constant speed and its ability to shed light on the birth of our galaxy is mind-blowing enough for one blog post.
(1977)
