The sun is massive. And despite it being so far away, I can’t help but wonder if activity on the sun could possibly effect life on Earth. Enter: solar flares. According to NASA, solar flares are “great bursts of electromagnetic energy and particles that can sometimes stream from the Sun”. Occasionally, solar maximums occur which are essentially massive solar flares. Some worry that a large enough solar flare could potentially disrupt GPS and electronic activity on Earth or even wipe us out entirely. No need to worry though: NASA tells us that these solar maximums occur every 11 years so you’ve likely lived through one already! The flares are not actually strong enough to reach the Earth so you and your electronics are safe!
We constantly hear about climate change in the media. So many political figures and social media users seem to argue about it on the daily. They debate whether it is real or not, whether it matters if it is real, or are we even the ones causing it if it is real? Along with these debates we’ve probably all seen a picture or two like the one above. It’s a simple infographic about how the greenhouse effect works, and in many ways should be an uncontroversial fact when discussing climate change. Scientists understand well how increased greenhouse gases like carbon dioxide increase the amount of energy trapped on the Earth. Yet somehow, this isn’t convincing enough for some people. Even though they know the mechanism by which the Earth warms, they deny it further, insisting that the actions of humans can’t affect the atmosphere that much, and surely the carbon we’re contributing must be minimal. In response to that, I’d like to share another graphic:
This chart shows how the carbon dioxide level in the atmosphere for almost the past 1 million years have never gone above the level of approximately 300 ppm. However, just in the past 70 years, that amount has shot up to over 410 ppm. The previous graphic has already shown us what increasing CO2 amount leads to overtime, and considering these two pieces of information together, it becomes very apparent that humanity’s carbon emissions are going to cause the eventual heating of planet Earth. We may not know how much heating is too much, but we can certainly see the effect when we reach that point by looking towards planets such as Venus. Venus’s atmosphere consists of over 95% CO2, and boasts surface temperatures of almost 900 degrees Fahrenheit. We should begin taking note of the writing on the wall and taking steps in the right direction if we want to secure the long term stability and prosperity of our home and future generations.
Climate change or global warming is understood (or should be) as an environmental issue with serious and concerning human implications relating to both the causes and consequences of the process. The effects of climate change are observed through the emission and build-up of greenhouse gasses in the atmosphere. Air pollutants and greenhouse gases, like water vapor, carbon dioxide, and methane, produced in excess through burning fuel and other human processes, collect and insulate Earth’s atmosphere causing climate temperatures to rise. This process specifically works as sunlight or rather as visible light waves pass through Earth’s atmosphere some of the energy reflects off Earth’s surface and returns to space while a part of the visible light wave is absorbed by the Earth’s surface resulting in Earth emitting infrared light. These emitted infrared light waves combined with increasing levels of greenhouse gasses result in climate change, as rising temperatures are products of the absorption of infrared light by greenhouse gasses. As the infrared light waves are released by the surface they are continually absorbed and reemitted by greenhouse gases effectively slowing down the rate at which the infrared light would otherwise exit Earth’s atmosphere. As greenhouse gases increase within the atmosphere the process in which infrared leaves the atmosphere is slowed, resulting in higher climate temperatures.
However, rising temperatures are not the only or most important consequence of climate change as its effects are largely observed through Earth’s oceans, as the oceans serve to regulate rising climate temperatures. Through water’s much greater heat capacity, the heat produced by climate change is predominantly absorbed by Earth’s oceans, resulting in global sea-level rise through the mechanisms of thermal expansion and glacier melt. The thermal expansion of water produces rising sea levels because as water molecules increase in temperature their electrons gain energy and start moving farther apart, resulting in the molecule gaining in volume and losing in density. This small gain in volume results in a large increase in sea level globally. Lastly, glacier melt is pretty easy to understand, as temperatures of both the oceans and atmosphere rise glaciers and ice above sea level melt creating new water that enters the oceans.
Looking at the picture above, it’s not hard to see why people often travel to observe the grandeur of the Aurora Borealis (aka ‘Northern Lights’). However, some who have seen it claim that alongside the visual spectacle, there’s an added auditory surprise: the Northern Lights make noise!
According to CNN, evidence of sounds from the Northern Lights is largely anecdotal with many scientists believing it to be false, merely coincidental background noise. However, those who have claimed to hear it all describe it similarly: as a pop or snap, “like a piece of meat hitting a frying pan”. Unto K. Laine, a professor at the Aalto University in Espoo, Finland, believes that the noises are caused by something called “temperature inversion”. Temperature inversion occurs on warm summer nights when warm air begins to rise but the ground temperature begins to cool down, leading to a layer of warm air being sandwiched between layers of cold air. The layer ‘sandwich’ accumulates positive charges from above and negative ones from below leading to the proposed popping noises.
In order to further investigate, volunteers at the Hankasalmi Observatory will launch an experiment this summer utilizing microphones and antennas in an attempt to prove or disprove Laine’s theory. What do you think? Have you ever heard noises from the Northern Lights? Do you think they’re real or merely someone stepping on a branch? Let me know (:
Us residents of the Earth take our atmosphere for granted. We constantly bombard it with harmful chemicals and pollute it with manmade substances that can permanently damage our “forcefield” around Earth. After all, it is responsible from keeping us safe against the harmful rays of the sun and provides us with the oxygen we need to live.
So, how did our shield in the sky come about? When Earth first formed, it was giant rock floating in space. Because of its mass and density, gravity caused the core of Earth to grow hot and this molten core created volcanoes. Such volcanoes emitted H20, C02, and N2, known as volcanic degassing, into the air, creating our initial atmosphere.
So how did we get to where we are today? Sometime and somewhere, life formed on Earth as a simple bacteria in the oceans. As the heavy CO2 sunk and was absorbed by the ocean, this bacteria (precursor to modern plants) was able to live off it and produce the O2 we know and love today as a waste product. Over time, this O2 accumulated and the atmosphere we have today was finally formed.
Images from NASA’s Hubble Space Telescope show changing seasons on the gas giant, Saturn. Saturn has a slower orbit than Earth (29 years to orbit the sun!), which makes each “season” on the planet over 7 years long. Similar to Earth, Saturn is tilted on an axis, which affects the intensity of sunlight on sides of the planet, causing seasons and other atmospheric changes. Saturn’s long seasons produce small changes in photographs of Saturn’s bands taken in consecutive years:
Saturn in 2018 (left), 2019 (center), and 2020 (right) taken by NASA’s Hubble
From 2018 to 2020, the equator grew almost 10% brighter, and wind speeds near the equator have gotten significantly higher in the last decade (now about 1,600 kilometers per hour).
Saturn’s northern hemisphere is approaching Fall, so polar and equatorial regions are changing. Differences can be seen in color, winds, and cloud height, according to Amy Simon, a scientist at NASA’s Goddard Space Flight Center.
Over a longer timescale, more significant changes will be visible on Saturn, thanks to Hubble.
It is no secret that space travel is a risky and dangerous endeavor for all involved. As of 2021, 19 astronauts (including cosmonauts) have died in in-flight accidents. Only one accident, however, occurred in space—over 100 kilometers above the Earth.
Three Soviets (called cosmonauts) were aboard the Soyuz 11 in June of 1971, which was docked to space station Salyut I. For 23 days, the cosmonauts carried out experiments on the ship, keeping precise records and logs of all results, particularly about weather on Earth. On the last day, one of the cosmonauts undocked Soyuz 11 as planned, and notified officials on Earth that they were on their descent back to Earth. At some point during the ship’s descent, the cosmonauts stopped responding to ground control’s messages. The ship landed on Earth in Kazakhstan, and the three cosmonauts were discovered dead with no signs of struggle.
While the official statement read that a seal failure caused a rapid decrease in pressure in the ship, many other theories for the accident were debated by experts. Some thought that humans could simply not survive prolonged time in space, that it caused heart problems. Others thought that a toxic substance had been released. Regardless of the reason, the deaths caused concern among Americans preparing for the launch of Apollo 15.
There is now a memorial where the ship landed, commemorating the tragic deaths of Georgy Dobrovolsky, Viktor Patsayev, and Vladislav Volkov.
An artistic rendition of the Parker Solar Probe (via NASA)
Kevin Durant, a two-time NBA champion, once tweeted: “I’m wondering how do these people kno what’s goin on on the the sun.. ain’t nobody ever been.” Like his tweet from 2010, I too wondered how humans have been able to study the Sun’s surface and what discoveries have been made to determine the surface’s characteristics.
Astronomers since Galileo have used telescopes and, more recently, satellites to view the surface of our Sun, known as the photosphere. Using filters, they could observe the surface to discover that the Sun does not have a solid surface like Earth. Instead, the Sun has a massive plasma sphere that has a temperature of 5500 degrees Celsius. Underneath the gaseous photosphere, scientists in the 1970s began to use helioseismology which is a method that could be used to investigate the structure of the Sun and discover its interior features. Using helioseismology, astronomers study oscillations of particles under the surface, allowing them to understand the Sun’s dense where nuclear reactions produce the star’s fuel.
Observing from far away using telescopes and satellites has been adequate to understand the Sun, but astronomers needed a more modern approach to researching the star. The result is a 2018 NASA probe called the Parker Solar Probe that will come closer to the Sun than any other human instrument. Its mission is to use the gravitational pull of Venus to orbit closer and closer to the surface, all while taking detailed measurements of our star. In all, the probe will orbit 24 times around the Sun and will begin its return to Earth in 2025. From telescopes to Sun probes, astronomers have come a long way in their ability to study the Sun’s characteristics.
Trajectory of NASA’s Parker Solar Probe (via Wikipedia)
Radiometric dating, or radioactive dating, is a method astronomers use to study a rock’s age. This method is critical in learning about the Solar System’s formation, as rocks from the Solar System can be studied to find how long ago the rock was formed and how old the Solar System is. When billions of atoms collect into a rock, the chemical composition of the atoms change. At that time, any isotopes in the rock begin decaying into a different isotope with new characteristics. By determining the original isotope and the rate the decaying process occurs within the rock, the rock’s formation’s date can be extrapolated. The rates are typically shown in half-life units, or the time it takes for exactly half of the isotope to decay. For example, if the formation occurred at time 0 with 16 radioactive atoms of a particular isotope, there will be 8 radioactive atoms after one half-life. If there were only one atom left today, we would know that the rock was formed four half-lives ago.
Using this process, the oldest known rock on Earth, Acasta Gneiss (shown above), was found in Canada and determined to be just over 4 billion years old. Others collected from the Moon are close in age to Acasta Gneiss. Some non-terrestrial meteorites such as the Murchison meteorite in Australia have been determined to be over 7 billion years old (older than our Solar System!!). Ultimately, without radiometric dating, none of these discoveries would have been possible, and the history of the Solar System would still be a mystery.
Astronomy is awesome. It lets us make cool observations (e.g., things that inform our understanding of the foundations of the universe, like the Cosmic Microwave Background), helps us ask big questions (e.g., why does the universe exist?), and reminds us that not all questions have answers (e.g., we can’t really expect an answer to the question of why the universe exists according to theoretical physicist Sean Carroll).
Astronomy, however, is not a “self-substantiated” entity: it’s based on an assumption we apply to all our observations. The assumption is called the Cosmological Principle, and it has three parts (according to Weintraub, How Old Is the Universe?, pages 228-229):
-Universality: the laws of physics are the same everywhere
-Isotropy: the universe looks the same in all directions to observers everywhere in the universe
-Homogeneity: the average contents of a large enough chunk of the universe will be the same for any chunk of the universe (i.e., the contents of the universe are relatively similar everywhere over large enough volumes)
From the Cosmological Principle, we can apply our understanding of physics to the rest of the universe: we can make claims about the creation of the universe, the size of the universe, how stars work, whether extraterrestrial life may exist, etc. Virtually all of astronomy is based on the Cosmological Principle; without it, we wouldn’t be able to make sense of our measurements of the universe.
Learning about the Cosmological Principle opened my eyes to how lots of analyses are based on some key assumptions, and I’ve carried that lesson with me as I’ve progressed through coursework for my economics and political science majors.
Economics is based around the assumption that producers and consumers are rational, meaning they “maximiz[e] objectives within constraints” (Conley, Microeconomics for Smarter Students, April 2020 draft version, page 24). In other words, we make some key assumptions that consumers, for example, can rank bundles of goods against each other by preference (e.g., I would rather eat two slices of pizza than one… who wouldn’t?). If consumers were to be irrational, though, we wouldn’t necessarily be able to predict and analyze how they would act. If our underlying assumption of rationality were to fail, so too would our analysis fail.
Political science is based on some similar assumptions, and I’m going to zone in on one specific realm of poli-sci right now: understanding the nature of war. When historians and anthropologists study past civilizations, they collect data about things like cracked skulls, the presence of spears, and battle fortifications – they look for signs of warfare. When political scientists come in, we analyze all that data, and we draw conclusions about warfare in older societies from our analyses. Similar to astronomy and the Cosmological Principle, however, this entire analysis is based on a key assumption: the bits of evidence from different societies are manifestations of the same pattern. Think about it: if different societies made spears for entirely different reasons (e.g., one society did it for war and one did it purely for decoration), the constructions of spears would not be related, so we would be incorrect to claim that all old societies with spears were violent. If our underlying assumption of different societies doing the same things for the same reasons were to fail (i.e., if our assumed pattern were to fail), so too would our analysis fail.
So, just like astronomy, it’s easy to see that other analyses are also dependent on some key assumptions. While astronomy assumes the validity of the Cosmological Principle, economics assumes rationality, and political science’s analysis of warfare assumes independent events are related to each other through patterns.
All this leads to two questions I’d like to pose to you: what are the underlying assumptions serving as the foundations of the belief systems with which you’re familiar, and what would happen if those assumptions were to fail?
Expansion of the universe, a phenomenon we understand as a result of assuming the validity of the Cosmological Principle. Image courtesy of Wikipedia.
