InterStellar

In the article, “When a nearby star goes supernova, scientists will be ready“, by Emily Conover from sciencenews.org, talks about the red giant Betelgeuse is at the end of it’s lifetime and will explode into a supernova any day now. She also mentions that when Betelgeuse explodes, it will be brighter than the moon and visible during daytime. Astronomers were able to tell when Betelgeuse is near the ends of its life due to neutrinos (subatomic particles that stream out of a collapsing star’s center) and gravitational waves.

This article relates to our conceptual objective, “I can describe how stars evolve and die”, because a star that’s really massive will eventually explode into a supernova when the core can’t support nuclear fusion of hydrogen. A star starts out as a protostar and becomes a main sequence star once it reached hydro-static equilibrium. We learned this in our past lecture-tutorial about star formations on pages 119-120. When the main sequence star can no longer support nuclear fusion of hydrogen in their cores will become red giants. Most main sequence stars become red giants, but their specific paths after this stage varies on their mass. A low-mass star will eject it’s outer layers to produce a planetary nebula. The low-mass star’s core in the middle of the planetary nebula is called a white dwarf. A high-mass star such as Betelgeuse mentioned earlier will eventually explode as a type 2 supernova. The supernova will leave behind a neutron star or, if the star was extremely massive, it would create a black hole. We learned this on our most recent lecture-tutorial titled, ” Stella Evolution”. The pages were from 133-134 and they gave a nice introduction to stellar evolution and what happens after these stages occur.

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After reading this article, I found myself really excited about learning about the death of a star since we can actually observe one some day in the near future. It’s a shame we don’t know the exact date when Betelgeuse will explode, but I’ll be looking forward to it. This information can also help astronomers determine the past of some galaxies depending on the white dwarfs and neutron stars it has.

 

Nuclear Fusion

In the article, “First Detailed Image of Accretion Disk Around a Young Star“, by Matt Williams from universetoday.com, talked about about nebula hypothesis which basically means that solar systems are form from huge clouds of gas and dust. When gravitational collapse occurs at the center ( center of the star), the remaining gas and dust creates an accretion disk. A team of astronomers recently captured the first clear image of a young star surrounded by an accretion disk. With this information, astronomers are now able to study it in detail never thought possible with past technology. The star captured in the picture was named HH 212.

This article relates to our conceptual objective, “I can describe how stars form and produce energy in their cores by nuclear fusion”, because it explains the basics of the formation of a star. A star can form when a cloud of gas and dust collapse in a center due to a gravitational force. These gases and dust form the star’s core and gets increasing energy and heat as more matter gets pulled in. The star also gets more dense during this process. This process forms an early stage of a star called a protostar. The remaining matter (gases/dust) forms accretion disk that orbits the star. When the center becomes a certain level of temperature and density, nuclear fusion begins. During the fusion reaction, hydrogen atoms are combined together to form helium atoms. Photons of light are emitted once with fusion occurs. But, once the outward pressure (energy out) balances out with the inward gravitational collapse of gases and dust( energy in), a state of hydro-static equilibrium is achieved. In class, we learned this material through our lecture-tutorial about star formation and lifetimes. These pages were 119-120 and they talked about the energy formed and emitted by stars and how they were created. The energy use to produce nuclear fusion is the material left over after the gravitational collapse of gases and dust in the accretion disk. Once the protostar reaches hydro-static equilibrium, the protostar becomes a main sequence star.

After reading the article, I was surprised we were only recently able to take detailed pictures of this disk. Basically that nebula hypothesis was only a hypothesis after all and now it has been proven true. Learning about the formation of stars can help us determine the past of our solar system and system that will be discovered in the future.

Haven on Earth… (See what I did there)

I have recently read an article on Space.com titled  “Dying Stars May Transform Frozen Worlds Into Havens For Life” written by Calla Cofield. This article directly relates to our 14th conceptual objective. This article explains how older stars when they reach a time in their celestial life that they being to fade out or run out of energy then surely pass away. These stars when they are beginning to reach this certain climax swell up, almost hundreds of times their actual size. In this process they also take other stars with them by essentially swallowing them up. The research for this article shows that 1.5 billion years from now there will be stars on a march to death and therefore forever expanding the universe. Scientists expect our universe to expand about 200 times the current size it is today, this overtaking with also cause planets like Mercury and Venus to consumed then making our planet essentially unlivable. This research ultimately answers the questions like can planets still support life after avoiding demise? Or can planets near these dying stars still be able to host life? Astronomers have been able to prove that red giants have stability for billions, if not, trillions of years. New work is being constructed that provides in-depth observation on how long planet’s can remain stable living around these red giants, in many cases these planets can live up to nine billion years. Luminosity is the amount of light it emits in any given time, is a big factor in defining the habitable zone for stars. As a star swells up into becoming a red giant its luminosity increases. When stars swell up they lose luminosity, because of the high mass. This high mass gets blasted outward, which can cause a stellar wind. This new work shows that some of the planets, can lose their atmosphere during this evolution. When they are located close to these stars, along with contributing factors like low gravity.

Diving further into the 14th objective, a star’s life after many years collects helium then forms into what scientists call helium ash. The star’s helium core becomes compressed together with electrons with very little limited space for them to go. This then degenerates the amount of pressure resulting in an electron degeneracy. With this degeneracy, the helium flash occurs which can reach upward of 100 mk in the center of the core which allows the helium to fuse together. After this process unfolds a supernova is born which is a neutron star that has three components to its making. This massive star is very dense with an extremely hot core while the supernova explosion rips off the outer layers of the star , thus making the supernova expand forever into eternity. The mass of the star’s core is broken down into three size groups, white dwarf stars which are anything larger than 1.4, a neutron star which is anything larger than 3.0, than anything smaller than that is formed into degenerate pressure because of gravity. Our class reviewed a lecture in our workbook tutorial called “Stellar Evolution” this tutorial showed us which path a star can take after becoming a red giant. If the star has a mass of 8M’s or smaller it then is classified as a planetary nebula. If it is larger than 8M’s it then is classified as a type 2 supernova leaving behind a neutral star or black hole.

This article relates to our 14th objective because it gives a brief summary of how stars evolve and die out. Learning about stars and their evolution it gave me insight as to how remarkable space is. From earth stars seem so small and irrelevant, but on the contrary, stars have a huge impact on the universe and how scientists study astronomy. To me stars are almost like a living organism or object that is in space, that makes me wonder if anything else can survive in space. Overall, I fairly enjoyed this objective because it allowed me to expand my mind a bit and think about major possibilities that could happen with stars and our universe.

 

Physicists create fluid with ‘negative mass’

Assessment 6: Newton’s Laws

Article: link

Physicists at Washington State University have managed to make a fluid that doesn’t follow Newton’s Second Law of Motion. It has “negative mass,” meaning when the liquid is pushed it accelerates backwards. The liquid is made up of rubidium atoms cooled, with lasers, to slightly above absolute zero. The article from United Press International says that the success of the experiment could”[A]llow for exploration of strange phenomena like black holes and neutron stars.”

Newton’s second law states that when a force acts on an object, the object will accelerate in the direction of that force. As we learned from a class lecture, the equation for Newton’s second law is: ΣF (net force)= Mass x acceleration.

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Thinking back to Assessment 6, Newton’s Laws, I can say I will miss this conceptual objective until the day I die. People always talk about Newton’s Laws, but I never could remember what they were. Newton’s first law, or the law of inertia, states that an object will stay at rest or in motion in the same direction and speed unless acted on by an outside force. The second law, as I previously stated, says that when a force acts on an object, the object will accelerate in the direction of that force. The third law states that for every force there is a reaction force that is equal, but in the opposite direction. Well thanks to this conceptual objective, I know I will not be left in the dark when Newton’s laws are brought up in conversation, as this happens quite often.

The Ending Stages of a Star

https://www.seeker.com/doomsday-earth-sun-red-giant-astronomy-alma-eso-stellar-physics-2138112840.html

The fourteenth conceptual objective, “I can describe how stars evolve and die”, has been discussed in class as of late. In order for a star to exist, nuclear fusion must occur in its core. The core must contain enough hydrogen in order to maintain the balance between gravity and pressure and the rate at which energy is generated. However, fusion cannot last forever. When a stars’ core runs out of hydrogen, the star will die. The lifetime of a star is dictated by its size. When all of a stars’ fuel is used up and energy stops, a star will begin to die. The star will then expand into a red giant. Our sun is a relatively low-mass star. At the dying stages of our sun, it will turn into a white dwarf star. A high-mass star will eventually end up being a black hole. In class, we exercised this concept in the Lecture-Tutorial book. In the section titled, “Star Formation and Lifetimes”, we learned that a stars’ lifetime depends on its mass. Different stars with different masses die in different fashions. In the Lecture-Tutorial book we were asked to compare our sun to stars with different masses. The rate of nuclear fusion in a star can also help astronomers determine the stars’ life expectancy as well as how it will evolve and die.

The article I chose, “Dying Star Offers Glimpse of Earth’s Doomsday”, compares a dying star to our sun. L2 Puppis is a dying star that is located over 200 light-years from Earth. Our sun is expected to enter its dying stages in five billion years from now. After our sun runs out of hydrogen fuel, it will expand into a red giant and eventually die and become a white dwarf. This news story attempts to foresee the future of Earth when the sun dies. There is no doubt that life would cease to exist on Earth, but would our planet still exist? The L2 Puppis star will help astronomers foresee the future. L2 Puppis is closely related to our sun, however it is in its dying stages. Like L2 Puppis, eventually our sun will transform into a red giant then a white dwarf.

This article provides an insight of the future of our solar system. In five billion years from now, our sun will begin its dying stages. It will first expand into a red giant. It then will eventually become a white dwarf star, about the same size of Earth but much more dense. This article clearly demonstrates the fourteenth conceptual objective by comparing a star to our sun. This star is so similar to our sun, it gives astronomers an idea of what the future has in store for Earth. Although life will cease to exist n Earth, astronomers are still trying to determine if Earth will be in existence. This article was very interesting to me. I am always intrigued to learn about the future of Earth. This article portrays what we exercised in class relating to how stars evolve and die.

My Very Educated Mother Just Studied Under NASA’s Professors… and now she knows how the solar system was born!

It all begins with a star. When a star is born, it undergoes a gravitational collapse that leaves behind dust, clouds, and other planet-forming debris. This debris orbits around the star and is known as an accretion disk or a planetary nebula. The nebula is referred to as an emissions nebula once its components radiate enough heat to illuminate the gaseous dust cloud. The cloud thought to have formed our own solar system 4.5 billion years ago is referred to as a solar nebula.

Once you have a star and a nebula, the next step in the birth of a solar system involves the nebula’s collapse. Our solar nebula, according to the theory described in our text book, was probably so spread out that it required more than just gravitational forces to initiate its collapse. An example of an outside force large enough instigate this would be a nearby star explosion (specifically, the formation of a supernova.)

As the nebula collapses in on itself, several forces are at work producing various results. First, gravity pulls all of the particles in all directions inwards towards the center. As gravity pulls the nebula inwards, it begins to shrink and heat up. Most of the heat and density is concentrated in the center, which is where our sun formed. The solar nebula also spun and flattened into a disk as it heated up and collapsed in on itself. This disk is referred to as a protoplanetary disk. At some point, the extra gas is blown away, leaving only solid material in the nebula. These tiny particles of material that are leftover orbiting the star are what will eventually make up the planets, moons, and comets of the solar system.

The gravitational forces, forces caused by rotation, temperature, and the characteristic of being a flat plane each contribute to the formation of planets, moons, and comets. As the particles of material continue rotating, they collide with each other and begin to clump together, especially so at lower temperatures. The temperature drops the farther a particle is from the center of the nebula. After innumerable collisions, these clumps slowly gain more and more particles, and eventually they turn into comets, which smash into each other to become dwarf planets, which smash into each other to become larger planets.

The distance of each planet from the sun affects its composition. Mercury, Venus, Earth, and Mars were all close enough to the sun to develop into terrestrial planets, which are warm and have a solid, tangible surface. Jupiter, Saturn, Uranus, and Neptune (and Pluto) are all known as “Jovian” planets, which means that they are cooler, gaseous planets.

There are several pieces of evidence to support this theory of our solar system’s formation. The general motion and behavior of our solar system fits the bill. The planets rotate around the sun in a flat plane, with all planets and most of their moons going in the same direction. And all planets (except Venus) rotate in the same direction as their orbit. Research into other, similar solar systems throughout various stages of their development also supports this theory.

Scientists created the solar nebula theory (and continue to find clues on how our solar system was formed) by studying the various components of it. An article I found on spacedaily.com titled “How comets are born” explains how an in-depth study of Comet 67P/C-G reveals information on how our solar system came to be. The fragile, porous structure of this specific comet has lead the researchers to believe that the collisions of particles forming the comet happened at low speeds, since high speeds would have compromised its structure. Through spectral analysis of this comet, they have determined that the surface of the comet came into contact with very little or no water during its formation, and they discovered the comet is chemically comprised of carbon monoxide, nitrogen, hydrogen, and carbon. The presence of these elements leads the researchers to believe that the comet formed in cold temperatures. Researchers conclude that this comet and others like it must have formed slowly, over the entirety of our solar system’s existence, accumulating mass from leftover particles on the very outskirts of it. (Talk about living on the edge!)

This all relates back to the conceptual objective because the study gives us insight into how our solar system was formed. Dating the material that the comet is made of and determining its age helps us figure out the age of our own solar system. Testing its chemical composition unveiled remnants of ice, indicating that formation tempratures must have been freezing. Testing  the chemical composition also tells us that the comet formed on its own, and not of something called TNO’s (trans-Neptunian objects.)

A comet building slowly in cold temperatures very far away from our star backs up the entire nebula-theory of solar system formation. The theory says that particles accumulated over many collisions over time, and that the temperature and speed of these rotating particles decreases as distance from the sun increases.

The article also mentions that the study forced scientists to reconsider how TNO’s formed, since some of these are as far out in the solar system as comets like Comet 67P/C-G, yet show evidence of being heated by short-lived radioactive substances while comets do not show any signs of being heated. After careful consideration, the researchers determined that TNO’s must have formed “rapidly within the first one million years of the solar nebula.” As you can see, the study of this one comet has provided the science community with an abundance of information on the formation of the solar system, which is why I chose to include this article in this blog post.

REFLECTION: I really liked this article because I find it fascinating how scientists are able to piece together the little information that they have in order to draw conclusions (or at least develop plausible theories for further research) on things they are still trying to figure out. I thought the study of this comet was really important because they found out a ton of information on the formation and chemical composition of comets, the approximate age of larger/more distant TNO’s, and the formation of our solar system, all from just from this one study.

A White Dwarf Acts Like a Pulsar

I recently read an article titled, “Astronomers Discover a White Dwarf That Acts Like a Pulsar” written by Alison Klesman. This article correlates with the conceptual objective 12 “I can explain how astronomers use the Hertzsprung-Russell diagram to study properties of stars.” This article, by Alison Klesman, states “a pulsar is a type of neutron star that emits focused beams of radiation from its poles as it spins.” Astronomers have discovered a pulsar that is not a neutron star at all; instead, it is a white dwarf! It is the first white dwarf pulsar to ever be discovered. Professors Tom Marsh and Boris Gänsicke at the University of Warwick’s Astrophysics Group, and Dr. David Buckley of the South African Astronomical Observatory discovered it! They found that AR Scorpio, a binary system that sits in the constellation Scorpius, contains a white dwarf pulsar. AR Scorpio system contains a white dwarf and a red dwarf that orbit each other every 3.6 hours with a distance of 1.4 million kilometers between them. Every two minutes the white dwarf rotates around its axis and blasts the red dwarf with a beam of radiation. The white dwarf pulsar in AR Scorpio is 200,000 times as massive as Earth, and has an electromagnetic field that is 100 million times the strength of Earth’s. This is why the white dwarf emits beams of radiation as a pulsar.

I am able to connect this article to our conceptual objective because of what I have learned during the lectures during our class. As I learned in the class discussion and from the power point slides, white dwarfs are hot stars that are dim and have a very small radius; they are not on the main sequence line of the H-R diagram. Therefore, the white dwarf, as discussed in the article above, would reside in left-hand side of the diagram, probably in the lower left corner. We did a lecture tutorial titled “H-R Diagram,” in which I learned how to read a H-R diagram, and where certain stars belong on the diagram. Because of this tutorial, I know where the white dwarf would be placed on the diagram.FullSizeRender-1.jpg

This article was very interesting to read about because I didn’t know what a pulsar was and this article explained it well. After learning about pulsars, i thought they were very interesting and this article explains everything clearly. I was excited to find such an interesting article that referenced a white dwarf and was ecstatic to connect this to the H-R Diagram with my new-found knowledge on this topic. With the information i received from our class and from this article it helps me better understand this conceptual objective.