The Oort cloud is a mysterious spherical cloud of icy objects that exists beyond our solar system. This collection of icy debris is believed to be left over from the formation of the giant worlds – Jupiter, Neptune, Uranus and Saturn.
Layout of solar system on logarithmic scale. Source: NASA
The Oort cloud starts roughly 1000-2000 AU from the sun and is thought to extend halfway to Alpha Centauri, our nearest star neighbor.
In fact, the comets that visit our inner solar system (every ~200 years) are thought to come from the Oort cloud even though its existence is still hypothetical.
Oort Cloud & Kuiper Belt
Comparison between Oort cloud and Kuiper belt. Source: Sciencenotes.org
The Oort cloud is assumed to be composed of similar objects to that of the Kuiper belt. The Kuiper belt is a flat disk-shaped belt beyond Neptune’s orbit.
As we know today, Pluto resides in the Kuiper belt, but NASA’s New Horizons space probe flew by a dwarf planet called Arrokoth, which is even further than Pluto.
Origin of Long-Period Comets
When it comes to the origin of long-period comets, the Oort Cloud is the most widely-accepted explanation. These comets have orbital periods longer than 200 years!
The Oort cloud was created when the giant worlds of our solar system were formed (~4.5 billion years ago). The movements of these large planets pushed the leftover material past Neptune’s orbit, resulting in the Oort cloud.
Even though it is impossible to directly see the Oort cloud and everything inside of it because of how far away it is, future space missions could help us confirm our theories about this region of the solar system. In fact, the Voyager 1 spacecraft is estimated to reach the Oort cloud’s inner edge in ~300 years, but it will likely have stopped working by then…and the mystery will continue.
This blog is a fun one for me because of the freedom it allows. For this blog post I am going to talk about craters, but not just any crater: one that is right next to my hometown! How cool!
I come from a small town called Eclectic. In the next town over, Wetumpka, Alabama, there is an actual impact crater site that people can go and visit. My class actually took a field trip in middle school to go see this crater- it was an incredible experience!
The Wetumpka Impact Crater hit Earth around 84 million years ago, when the dinosaurs were still alive! The size of this crater is often compared to the size of a football stadium (Bryant-Denny and Jordan-Hare are two very famous football stadiums in the state of Alabama). Scientists who have studied this crater have found that the diameter of the crater, which is about 5 miles wide, is only a small portion of the area that was impacted by this crater. A large expanse of land AND sea was damaged by the crater and both plant and animal life was destroyed. Scientists also calculated the energy that was released in the impact was over 175,000 times that of the energy that was unfortunately released on Japan in the Hiroshima atomic bombing.
What is really interesting about this crater today is that such a classy and cute town was able to build itself up and thrive within the vicinity of a crater!
For this post, I’d like to increase my understanding of global warming because the book introduced to me the major process behind it. First off, I’d like to acknowledge that the climate crisis truly is one of the most difficult things we have globe have faced. We began on this Earth as a species tossed around at the whim of nature but now have developed to the point where we have the ability to destroy the environment that has been here so long before us. Even worse is the lack of consensus of the seriousness and validity of the threat behind climate change.
Here is how the book changed my understanding of this issue. Through learning about the molecular level of the basics of energy and how photons can change the very substance they interact with, I am able to understand the massive effects light can have. We are extremely lucky, as the book mentions, to live in an atmosphere so suitable for life. We have the greenhouse gas effect to thank for this, as without it the temperature on earth would be near freezing on average and freezing in most places.
However, we have the potential to harm this balance and this is why: carbon. CO2 is one of the byproducts of the energy-producing (or maybe I should say transferring, according to Einstein) process we have on Earth. However, CO2 like all greenhouse gasses is suited to absorb the lower infrared energies from the sun. This is good because it allows for our hospitable climate, but dangerous as we produce more and more every year. If we increase the amount of CO2 the greenhouse gas effect will grow and grow, destroying our climate.
I believe all people ought to know the basic mechanics of what exactly our carbon emissions can do, because we are all currently being affected by the crisis as we speak!
It’s a common theme for me within this class to fixate on the possibility of life beyond Earth, and I’m glad to do that once again with today’s blog post. I want to respond to the book’s claim that life on Mars is an “extraordinary claim”.
While it’s true the bold assertion like the one touted by William Herschel about “inhabitants” all over Mars may have little basis, I believe there are several factors that make this claim and subsequent ones a possibility.
First off, after further research of this “extraordinary claim” I discovered the Labeled release experiment to find life on Mars in 1973. I cannot believe the book didn’t mention this finding because it was at first found that there were possible signs of some simple life forms on Mars, and it was only from a further lack of evidence this finding faded away. I personally think we should be focused on gathering more evidence to this possible finding as it is imperative to identify possible life should we decide we want to ensure the future of our civilization. Moreover, I think it’s important to consider the other evidence that the possibility of life is something we cannot rule out. This includes the existence of water, the substance of life as we know it. The environment is also suitable for life due to its atmosphere’s ability to shield harmful radiation from the Sun that would end life. Lastly consider the presence of methane on Mars which can be produced by biological processes. This may be a sign of life, as explained in this article.
Climate Change is for real. That is true, without a doubt. Like no cap. Furthermore, all evidence points to the species Homo sapiens as the culprit. Due to our overuse of fossil fuels, releasing previously sequestered carbon into the atmosphere, our industrial and agricultural practices releasing other greenhouse gases into the atmosphere, and the total destruction of our planet-healing ecosystems, we have led our Earth into a nightmare where we are slowly killing that which sustains our societies. This post will not dive into the specifics of the causes, nor the symptoms, but rather more specific ways we as individuals can help improve our planet’s situation. To learn more, NASA has some brilliant information on the subject. I find the argument that because corporations and mass factories are the main culprit, individual choices are irrelevant, a very weak one. Despite the fact that these large entities do create much of the problem, there are two reasons why the second clause of the above argument is incorrect: for one, these corporations are fueled by profit, so if the customers cease to purchase their products or financially support their efforts, these companies will close up shop. Furthermore, current consumerist practices of individuals do contribute in non-negligible amounts to climate changes. Think of our beautiful coral reefs. You can help to save them, with relatively simple (though maybe not easy) practices.
Ways in which we can reduce our impact on the environment are innumerable. These suggestions come from the book Is It Really Green? Everyday Eco-dilemmas Answered by Georgina Wilson-Powell. More specifically, this post will deal with ways our food choices could reduce our environmental impact.
First, a diet of reduced meat consumption, a vegetarian diet, or even vegan diet can make a difference. Especially in the Western world, our meat-heavy diet has created an agricultural system in which meat and dairy take up 77% of farming land usage, yet as the book says, ” these foods provide just 17% of the calories we eat.” It is a brilliant example of the trophic period, in which through each level of energy transfer 10% of energy is lost. For example, if we were to eat plants, we get the fullest possible energy sourced from the sun. Furthermore, it is the least water and other nutrient input relative to higher on the trophic levels. But if we eat the cattle raised on the plants we could have eaten (or an alternative, as we will not eat hay), than on average only 10% of that original energy is then available for them. And since we then eat that trophic level of cattle, 10 times less energy is available for us through cattle consumption than through a plant diet.
This does not mean a diet of all plants is wholly good as well. For example, eating a diet of crops imported from afar can have a considerable environmental impact as well since the transportation can use fuel. The opinion of this writer is to not remove meat entirely from the market, but rather reduce its usage and switch to more sustainable and healthy alternatives.
A more specific example is dairy alternatives as well. These beverages have grown in popularity in recent years, mainly due to their claims of being more environmentally friendly. (The dairy industry alone is associated with 3-4% of greenhouse gas emissions.) For example, soy milk is a popular option. However, not all of the alternatives are as sustainable as they claim to be. Soy and rice milk are associated with practices not considered good for the environment. Almond milk also does not live up to their claims, as its farming practices have devastated pollinator communities and used water sources year-round in drought-stricken areas. Oat, hemp, pea-protein, and coconut milk seem to be the best alternatives for those truly seeking to reduce their environmental impact.
There are a number of other small ways to reduce our individual impact. Simple ways include wrapping food in beeswax, soy wax, or foil for storage instead of plastic wraps. Reducing very processed foods is beneficial as well, because of their long supply chains and heavy chemical input.
We as stewards of the Earth have a duty to protect that which sustains us. Not only for our future generations, but also an ethical obligation to protect its beauty and goodness today. More can be done, individually and as a society, and I highly recommend the book used for this blog post.
Nuclear fusion is the process that drives star light formation and prevents the force of gravity of the star from collapsing into itself. In a nuclear fusion reaction, two smaller nuclei, typically hydrogen isotopes, bond together to form a helium atom while immense amounts of energy are released. The fusion between smaller atoms continues to release energy until the iron atom is formed in which case the fusion bonds now require more energy than is released by the reaction. This is why many stars begin to die once it’s core transitions to iron. The difference in mass between the old and new matter created is equivalent to the that times the speed of light squared or e=mc^2. These reactions as far as we know require an immense amount of heat to occur such as at the heart of a star and enables massive amounts of energy to be released. Although scientists would love to have cold fusion available on Earth for easy energy production, unfortunately there is no known way to cause nuclear fusion without immense amounts of heat and energy to start.
Whenever we look up at night, we see the same side the Moon, the side that has faced us for billions of years and will continue facing Earth for billions of years. Humans have sent probes and spacecraft to see what’s on the far (not dark) side of the moon. Soviet Union spacecraft Luna 3 took the first photographs of the far side of the Moon. Astronauts on the Apollo 8 mission were the first humans to see the far side of the Moon. The first probe to ever achieve soft-landing on the far side of the Moon is the Chinese spacecraft Chang’e 4 on Jan 3, 2019.
Chang’e 4, named after the Moon goddess in traditional Chinese culture, is the fourth spacecraft bearing the name Chang’e, and made a great leap in lunar exploration for both China and mankind. It’s true that the crater-filled surface makes landing on the far side harder, but the crucial thing is communications, since no signal from Earth can get to a probe on the far side directly. So before Chang’e was launched, a comms relay satellite, Queqiao, had to be launched into lunar orbit beforehand to enable communications with the probe.
Chang’e 4 landed in Von Karman, an impact crater in the Aitken basin in the southern hemisphere of the Moon, where it sent out a lunar rover to measure and analyze lunar rocks and soils. The Aitken basin is thought to be a huge impact crater, where mantle and crust materials are likely exposed on the surface. Aside from providing a lot more insight on the inner structure of the Moon, landing on the far side provides a significant advantage on using radio telescopes, since there is much less undesired interference. Chang’e 4 also conducted research on cosmic rays and coronal mass ejections.
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To begin with, some background is necessary. The Earth has a magnetic field surrounding it, which enables our planet to deflect cosmic rays and incoming particles. This in turn protects our atmosphere and allows us to maintain it at a stable temperature and pressure. In essence, it is essential for the maintenance of most life on Earth. This magnetic field is created by the convection circles and fluidity of the Earth’s mantle and core, which due to its large quantity of heavy metals, creates an electromagnetic “wall.”
Research has shown that the Earth’s magnetic field is a bit more complex than some magical forcefield, however. It seems it has two parts: one, the axial dipole, which is the traditionally depicted field that stems from the magnetic poles and loops around the planet. It is created throughout the mantle and the core. But the second part is a much weaker field around our planet, created by the outer layer of the outer core. It seems this smaller, unpolarized (non-directional) field is what emerges when the magnetic poles flip. (LiveScience)
(Pole flipping: what you mean? Well, we’re not entirely sure why it happens. The primary theory is that the “storms” of fluid within the planet are sometimes enough to cause a flip in the polarity of the Earth’s magnetic field. This makes the magnetic north turn south, and vice versa)
We as a planet are due for another flip in the magnetic field, and it seems as if one is coming. There have been increasing disruptions around the poles. However, there will likely be minimal damage due to it. (There is some possibility of damage due to more exposure to cosmic rays.) In fact, some scientists are excited to observe this event, as it will allow the more precise observation of the secondary field that is usually overpowered by the axial dipole. Do not fret about the animals; evolution of animals has lived through a number of these flips, and natural selection likely selected for species not overly affected by them. (Discover)
The magnetic field is extraordinarily interesting, and it is not entirely understood. It is still an area of active research, and could better help us to see possibility of life supporting planets in other planetary systems in the Milky Way.
The formation of the Solar System is truly a testament to our good fortune of life being possible on a planet located in the “Goldilocks Zone” near the Sun. The initial conditions allowed for not only Earth to be composed of rocky elements such as carbon but for the Earth to be protected from flying space debris by larger Jovian planets composed of mainly hydrogen and helium located a further distance from the Sun. For countless reasons Earth is lucky, and the orbits we observe today indicate the early Solar System happened to have a composition of rocks and metals located closer to the Sun where temperatures were well-suited for them to condense. Lighter elements like hydrogen and helium tended to be absorbed into the larger clumps of matter located a large distance from the Sun because the temperatures allowed for more accretion.
Our Solar System, the Milky Way, was created from a dense could of interstellar dust and gas that collapsed and turned into a swirling, spinning nebula.
This nebular is made up of hydrogen and helium, and a little amount of other elements, which combined together and reacted in order to create other materials which in turn created the planets of our solar system we know today.
Only rocky materials could survive the heat of the sun, which is why the closet planets, Terrestrials, to the sun in our solar system are made up of rocks and metals. On the other hand, the outer planets of our solar system, the Jovian planets, are made up of ice, liquid, and/or gas because gravity was able to pull these materials together.
Fun fact! The reason our Milky Way has its names is because it appears as a “milky band of light” in the night sky.
