It’s interesting to think about the formation of the solar system and how the gasses that originally created it are still a part of our solar system. The origins of the solar system can be explained by the nebular theory. The nebular theory suggests that our solar system was formed from the gravitational collapse of an interstellar cloud of gas. This cloud formed the Sun and the planets that then formed around the Sun.
Going back further, the gas from the solar nebula was the product of galactic recycling. The Big bang produced hydrogen and helium, and then, some heavier elements were produced. These heavier elements were either made by nuclear fusion or nuclear reactions.
This shows how much of our solar system’s formation was based upon galactic recycling and how old the elements that created us are.
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The storm scene in The Martian is one of the movie’s few inaccuracies
The Martian is one of my favorite books, and the movie adaptation was fantastic as well (mild spoilers ahead). As someone who enjoys science and science fiction, I loved the realism and accurate technical problems that Mark Watney faces. The fundamentals of life on Mars—the time needed to travel there, delays and difficulties communicating with Earth, the length of martian days, and the weaker gravity—are all portrayed accurately in the novel and the movie. The design of the HAB is accurate as well, and Mark Watney’s idea to grow potatoes on martian soil with human waste as fertilizer is indeed possible. The biggest (and only glaring) inaccuracy in The Martian is one that everyone in this class should know: Mars has a very thin atmosphere, and violent wind storms like the one that blows over the astronauts’ spacecraft at the beginning of the story are not possible. This is what kicks the story off, as the storm forces Mark’s crew mates to leave the surface of Mars without him (believing Mark to be dead). While this inaccuracy is regrettable, the rest of the movie certainly makes up for it.
Nuclear fusion is a reaction between molecules where nuclei are combined to form different atomic nuclei and particles, releasing energy. This process powers main sequence stars through stellar nucleosynthesis. Stellar nucleosynthesis can only occur at extremely high temperatures in the cores of stars. Depending on the mass of the stars, i.e. the pressure and temperature in the cores, either the proton-proton chain or the CNO cycle (or both) will take place. In the proton-proton chain, hydrogen is combined to produce energy and helium. The CNO cycle essentially does the same thing with the help of carbon, nitrogen, and oxygen. Lower mass stars, including the Sun, primarily do fusion with the proton-proton chain, while more massive stars use the CNO cycle.
As with most impressionable children growing up, the fascination of space and the many wonders it holds stems from watching certain movies or television shows that help portray these wonders. I was no exception to this as I was completely awestruck when I watched Christopher Nolan’s brilliant film, Interstellar. Despite containing a masterfully crafted story and amazing acting performances, this space adventure depicted these wonders with high levels of scientific accuracy. While I could drone on for hours regarding the films plot and emotional scenes, I will instead focus on one particular part of the movie that got me interested in the cosmos.
This particular phenomenon that intrigued me is time dilation. The film shows a scene involving time dilation and how only an hour spent on a planet that revolved around a black hole, equated to over 20 years back on the space craft’s orbit and on Earth. As a 13-year-old boy watching this scene, I do not think any movie scene has ever peaked my curiosity more. Time dilation as shown in Albert Einstein’s theory of special relativity, is the “slowing down” of time on a clock by an observer who is in motion relative to the clock. In the movie, since the planet the astronauts landed on was orbiting a black hole, its gravity warped time to such an extent that almost every second equated to a day on Earth. This is interesting in that it can almost be seen as a form of time travel. When the main character reunited with those living on Earth, he was even younger than his daughter due to time dilation. This idea of time dilation and watching it unfold on a screen is what caused my own interest in learning more about the universe around us.
Gamma ray bursts are extremely energetic spouts of energy, and similar to visible light, are part of the electromagnetic spectrum. Unlike visible light however, gamma rays have significantly higher energy — a single gamma ray photon is more energetic than 1,000,000 photons from the visible light spectrum. This makes gamma rays a form of ionizing radiation: radiation that is strong enough to break chemical bonds.
Gamma rays were first discovered by a satellite sent into space by DARPA, with an original use-case of detecting Soviet nuclear space tests. While no bombs were detected, slight gamma bursts were, and a few years later they were found to be coming from distant galaxies.
There are two sources of gamma ray bursts. The first releases a ‘long gamma ray burst’ when the core of a massive star collapses to create a supernova. The second ‘short gamma ray burst’ occurs when a pair of neutron stars merge. Gamma ray bursts occur in jets as the magnetic fields of the objects forces material into cone like jets, and if the Earth were in one’s path, it would devastate the current state of life on the planet. With our current technology, we could do little to nothing to stop one from obliterating through the atmosphere, but the likelihood of getting hit with a jet-like stream is slim.
Venus lacks a magnetic field. Its ionosphere separates it from outer space and the sun’s wind.
4 Billion Years Ago it is assumed that the atmosphere of Venus was a lot like earth’s atmosphere. There could have been liquid water. The area 50-65 km above the surface of Venus is the most Earth-like place in the solar system with breathable air that is like helium.
Troposphere
The troposphere is the densest part of the atmosphere. The troposphere has an atmospheric pressure strong enough that carbon dioxide turns into a supercritical fluid. A large amount of carbon dioxide and water vapor help create a strong greenhouse effect. This traps solar energy and increases the temperature.
Venus has an ionosphere. The ionosphere is related to temperature. The high ionization occurs on the dayside of the planet.
Venus has an induced magnetosphere. It is caused by the sun carrying solar wind.
Nuclear fusion is an incredibly interesting topic by which one of the most important parts of our solar system and cosmos utilizes constantly. In the core of our very own sun, hydrogen is converted into helium in a process known as nuclear fusion. In the sun and other stars, Nuclear Fusion reactions power this process by making the two lighter nuclei form into a single heavier nucleus. This then releases energy since the total mass of the resulting single nucleus becomes less than the mass of the two original nuclei. Albert Einstein’s famous equation (E=mc^2) helps to explain why and how this process happens. His equations partly states that energy and mass can be converted into one and other which further shows how this occurs. Nuclear fusion is also incredibly important in that it could be the future form and method that we utilize energy here on Earth. It is a far cleaner energy option than that of oil as it emits no greenhouse gases and could be a bright step in the future to taking care of our Earth. By safely using fusion reactions we can eliminate toxins and pollutants from our atmosphere and take care of our wonderful planet.
Radioactive decay is one of the processes by which Earth produces heat. Radioactive isotopes start off unstable (these are called the parent isotopes), and so they decay into other, more stable daughter/progeny isotopes. The decay produces alpha, beta, or gamma radiation which is then converted into thermal energy. The decay of isotopes like uranium, thorium, and potassium provides a continuous heat source for heat, despite the fact that our planet has cooled since its formation. We can actually measure the rate at which these radiogenic decay processes are emitting energy through geoneutrino measurements! Geoneutrinos are the same as normal neutrinos except that they come from earth, and they can tell us information about which isotopes they were emitted by. Through neutrino geophysics we have found that about half all of Earth’s total heat flux comes from radioactive decay. (Gando et al., 2011)
We also use uranium, thorium, and potassium for our most common radiometric dating of Earth’s rocks. U-Pb is the most refined method of radiometric dating and is most often used to date zircon, as it can provide accurate ages for a span of 1 million to 4.5 billion years. Zircon is an incredibly durable mineral that can survive extremely high temperatures and practically any earth event. This and the fact that Zirconium does not form with lead (Pb) in it’s initial crystallization, makes U-Pb dating of zircon very accurate, and helpful for understanding the true age of a magmatic system. The oldest earth materials that we have found are the Jack Hills Zircons, found in a quartz conglomerate in western Australia, these zircons are 4.0 – 4.4 Ga!
Jack Hills Zircon showing zoning and U-Pb ages. (Research Gate)
We can also use K-Ar dating (potassium-argon) to find the crystallization age of igneous and volcanic rocks. This provides viable ages for 100,000 to 4 billion years. K-Ar dating is also pretty useful for archaeological dating of the rock record above or below artifacts because neither of the isotopes in the process are a product of human activity.
This graphic explains the general process of the formation of our solar system
Our solar system has many characteristics that can seem like odd coincidences. Why are all of the planets in the same orbital plane? Why are their orbits all nearly circular instead of being more eccentric? Why do they all orbit in the same direction around the Sun? The nebular theory of solar system formation, as well as the process of heating, spinning, and flattening, explain these coincidences using the simple, fundamental laws of physics. Starting with a large, low-density cloud of gas, it logically follows that it will collapse in on itself over time due to gravity. Because of conservation of energy, gravitational potential energy is converted into kinetic energy during the collapse, which is converted into heat as particles begin to collide. The center, being hot and dense, is where the Sun forms. Due to conservation of angular momentum, the once imperceptible rotation of the cloud speeds up as the cloud shrinks, and due to gravity and collisions, nearly all of the material spins in the same direction. Finally, collisions between clouds regulates the orbit of the materials and flattens the lump into a disk. We now have a flat disk of material spinning in nearly circular orbits in one direction. This explains the three “coincidences” that I mentioned at the start, and shows how you can often explain strange characteristics of the universe using basic laws of physics.
