Star Lifetimes and Energy Production

I found an article at,  http://www.space.com/22471-red-giant-stars.html     . It talks about how the red giant star is a star that is dying. It reaches a size of 100 million to 1 billion kilometers, which is 100 to 1,000 times the size of today’s sun. It’s because the energy is spread across larger areas. The surface temperature reach up to 2,200 to 3,200 degrees Celsius. Stars spend approximately 3,000 to 1 billion years as a red giant. The star shrinks until a new helium shell reaches the core.

When the helium ignites, outer layers are blown off in huge clouds filled with gas and dust which is called planetary nebulae. The core collapses on itself and the smaller stars such as the sun end their lives as white dwarfs. The sun will begin the helium-burning process which takes place in around 5 billion years.

After it expands, its outer layers will consume the planets, including Earth. When stars turn into red giants, it can actually become habitable for other planets. Habitable zones is a region that water can exist in. A red giant can exist for a billion years which is a possibility that life can form. My personal opinion of this article is overall good because it has a lot of interesting facts. I would recommend people to read it. This article connects to what I have learned in class because it talks about the stars lifetimes and energy production which is what we went over in class. I learned in class that most energy released by fusion starts its journey out of the solar core in the form of protons. The clicker questions also helped out.

Distance and Size of the Stars

I found an article at, https://www.universetoday.com/25331/size-of-stars/ , which talks about the sizes of stars. Stars can be smaller and they can be even bigger than our Sun. Red dwarfs are the smallest stars out there and there are no more than 50 percent of the mass of the Sun. They could also have little as 7.5 percent the mass of the Sun.

That is the minimum mass that a star needs to hold in order to support its nuclear fusion in the core. Below that mass it is a brown dwarfs. One example of a red dwarf is Proxima Centauri which is the closest star to Earth. This star has 12 percent of mass of the Sun and about 14 percent the size of the Sun. It’s about approximately 200,000 km across which is a little larger than jupiter.

Our Sun has a diameter of 1.4 million kilometers. When the Sun hits the end of its life it will become a red giant and will grow 300 times its original size and will consume the inner planets, including Earth. A larger star than our Sun is the blue supergiant Rigel which is in the constellation Orion. The star is 17 times the mass of our Sun. It has 66,000 times as much energy. It 62 times as big as our Sun.

Let’s talk even bigger. For example Betelgeuse which is 20 times the mass of the Sun. Astronomers think that Betelgeuse might explode within the 1,000 years. It has increased out to more 1,000 times the size of our Sun. The monster VY Canis Majoris is the biggest star in the Universe so far. It’s thought to be as 1,800 times the size of the Sun. If this star was in our solar system, it would touch the orbit of Saturn. My overall personal opinion of the article was very good because I learned so much about the stars. I would recommend that people should read it because it is pretty fascinating. This article relates to what I have done in class because it talks about the size and distance of stars which is what we talked about in class. I learned from class that atoms are widely spaced about 1 molecule per cm3 a nearly perfect vacuum. Convection cycle is the same with the sun. The sun is energy balanced. The clicker questions helped too when study the material.

Stellar Evolution and Deaths

I found an article at, https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve    , It talks about how the stars are the building blocks of our galaxy. They are born within dusty clouds and are scattered through galaxies. The gas and dust begin to collapse under its own gravitational attraction. The cloud then collapses and the material begins to heat up.

This is known as a protostar, which the material of the center of this collapsing cloud becomes a star. A prediction is made through three-dimensional computer models about how the spinning clouds of collapsing gas, including dust, breaks up into two or three blobs which explains why most of the stars in our Milky Way are in groups of multiple stars.

When the cloud collapses, a core that is hot begins to gather gas and dust. Note not all the material ends up as part of the star. It could end up as, comets, planets, asteroids, or stay as dust. Sometimes the clown wouldn’t collapse at a steady pace.

There was a star which was approximately the size of our Sun required about 50 million years year for it to mature. Beginning of the collapse all the way into adulthood. For our Sun, it will stay at its mature phase for about 10 billion years. Stars, we know, are indeed filled with nuclear fusion of hydrogen in which it forms helium deep in the stars interiors. Hypergiants, which is the most massive star, is 100 or more times greater than the Sun. It could have a surface temperature of 30,000 k or more. They do emit more energy by hundreds of thousands more than our Sun but may have only have a lifetime of only 3 million years.

The larger the star is, the shorter its life is. After a star has fused all its hydrogen in its core, it becomes even hotter because hydrogen is still available outside the core. It then pushes outer layers of the star outward which causes them to expand and cool. This star becomes a red giant. The collapsing core may become hot enough to support more exotic nuclear reactions if the star is sufficiently massive. As time goes on, the star’s internal nuclear fires becoming unstable. Sometimes it burns furiously or just dies down. Everything depends on its core.

Personally I enjoyed reading about this article because I found it pretty fascinating. There is in my opinion a lot of good information on the article. I have learned that stars are born when gravity causes the collapse of molecular clouds, they shine for millions and billions of years with energy produced by nuclear fusion, and in their deaths they ultimately return much of their material back to the interstellar medium. This article relates to the main objective because the article talks about the life cycle of the stars.

 

HR Diagram

I found an article at,https://www.universetoday.com/52252/main-sequence/ , which talks about the HR diagram. Most of the dots on the Hertzsprung-Russell diagram is on a nearly diagonal, straight, line, which went faint and red to blue and bright. The discovery of the main sequence was required to wait until the distance to a minimum of a few hundred stars which can be reasonably estimated. This all happened early 20th century

Going back to the 19th century it would be impossible to answer the following questions. Why do most stars seem to lie on the main sequence? Why don’t we find stars all over the Hertzsprung-Russell diagram. They could not answer these question back then because the quantum theory was not created yet. Also they did not know about nuclear fusion or what powered the Sun.

As the answers became closer to us, the stars on the main sequence is just a sequence of mass. Stars on the Hertzsprung Russell diagram that were elsewhere, their positions reflect what nuclear reactions powered them. There are so many stars on the main sequence because stars spend a lot of their lives by burning hydrogen than they do in other ways producing energy.

Working out the details of stellar evolution took many decades. How some stars can live on long after it should be white dwarfs, how the size of a star reflects its internal composition and structure, what nuclear reactions for what exactly what composition and mass of a star, etc. There is still many unanswered questions in this day and age. My personal opinion of this article is over all good because I feel that I really learned a lot from it and I would recommend people should read this.I learned that cool stars on the main sequence are dim and small, most stars are on a line called the main sequence, giant stars are stars that are brighter than expected are large and are called giants or supergiants. This article connects to what I have learned in class because this article talks about the H-R diagram and I learned all about it in my class.

The Other Galaxies

I’ve found an article at,https://www.universetoday.com/30525/other-galaxies/  , which talks about how the Milky Way we live in a spiral galaxy which measures about 100,000 light years across. These galaxies are pretty much the same as the Milky Way. Some are a tiny bit larger. Many galaxies are indeed out there. Some are smaller and younger.

There are elliptical galaxies in which they can be dwarf galaxies. These dwarf galaxies can be a fraction of the mass and size of the Milky way. Ultracompact dwarfs are the smallest known galaxies to us. They have this elliptical shape to them. Galaxies that are elliptical could also be the largest galaxies in just the small ones.

There are also irregular galaxies in which they do not have an elliptical or spiral shape to them at all. They could have started off as a known shape but after gravitational interactions with other galaxies, they could of just reshaped into a more unique structure. The Canis Major Dwarf Galaxy which is located 25,000 light-years away from Earth is closest galaxy to the Milky Way.

My personal opinion of this article is overall pretty good because it gets into detail about the other kind of galaxies near and afar from our Milky Way. I think it’s a good article to share with everybody because if you’re the kind of person who wants to know more about galaxies, well this is the right article for you to view.

I learned in class all about how galaxies are attracted to each other by gravity. As an elliptical passes through, the stars do not collide and the increased density and gravity creates new stars. Elliptical shaped galaxies were mentioned in the article and learned in class. I’ve also found the clicker questions that I did in class were pretty fun to do and the lecture tutorial helped a lot. The slideshow in class was also very effective when learning the main objective.

Facts About Home

I found an article at,http://www.space.com/19915-milky-way-galaxy.html   Our Galaxy (the Milky Way) is the most known galaxy to us because we live there. The Milky Way is a barred spiral, like billions of galaxies in space. When people from ancient times looked up, they seen space like a river, as milk, and also a path among other things out there. Our Milky Way is a spiral galaxy which is approximately 100,000 light-years away.

A barred spiral contains a bar across its center region which is unlike a regular spiral. Our Milky Way contains 2 major arms, also including 2 smaller spurs. The Orion Arm is one of the spurs which contains the solar system and the sun. Our Milky Way is constantly rotating. It basically never stays still. The arms are also moving through space. The solar system travels 515,000 miles per hour on average which is 828,000 kilometers per hour.

The spiral arms possesses a high amount of gas and dust. These newly stars are forming constantly within the arms. The Arms contained what is called a disk of the galaxy. It’s about 1,000 light-years thick. The center of the galaxy is called the galactic bulge. The milky way is compact of gas, dust, and stars.

In the center of the galaxy is a powerful black hole which is billions of times, massive as the sun. This massive black hole possibly started off smaller in size. The gas and dust caused the black hole to grow. Most galaxies have black holes in the center of the galaxy as scientist claim. The most obvious components of the Milky Way is the bulge and the arms. The most visible ingredients in the galaxy is the, stars, dust, and gas. It is also made up of dark matter. Scientist directly cannot detect this material. Similar to black holes, scientists can measure it basically by the the objects around it.

The milky Way is not just spinning, but is indeed expanding throughout the universe. Space is always filled with gas and dust. Scientists say that the milky will run into its neighbor, the Andromeda Galaxy. Those to galaxies are running toward each other at about 70 miles per second. When they collide, they will provide a fresh influx material.

The milky Way has over 200 billion stars and definitely has enough gas and dust to make billions of more stars. Solar system lies approximately 30,000 light-years from the center. More than half of the stars in the Milky Way are older than 4.5 billion years old. Red dwarfs are the most common stars in the galaxy.

In the 1920’s, astronomers thought that all the stars are contained in the milky way. Well, we know that that’s not true. The thought about that didn’t change until Edwin Hubble discovered a Cepheid variable, which helped him to measure precise distances. Astronomers realised that the fuzzy patches were classified as nebula were separate galaxies. My personal opinion of this article is overall good. I would recommend people should read it because it had a bunch of interesting facts about the Milky Way.

I learned about Galaxy classification. Bigger Galaxies have more stars. I learned from the clicker questions. For example, I learned why the arms of spiral galaxies are typically blue in color, it’s because stars are forming in the spiral arms which has a high mass and are very hot. That’s the reason. I learned about dark matter which is also mentioned in the article that I have presented. Also I learned about quasars and that if a quasar is a certain distance a away, it’s equivalent to how many years ago you were seeing it.

Size of the Universe

I read an article at,https://www.universetoday.com/113786/how-big-is-the-universe-2/  , it talks about how the universe is expanding. The light takes time to travel from these distant galaxies that are far way. The problem is talking about how big these galaxies are. A lot astronomers don’t worry at all about the distance of galaxies.

They mostly focus on redshift in which they measure it by z. Bigger the z, the more redshift, which means the more distant the galaxy is. The most distant galaxies that they have measured has a redshift of 7.5. By using this, they can now determine the distance by calculating the length of the light from the other galaxy.

A red shift of 7.5, comes out to be approximately 13 billion years. It’s not 13 billion light years away, its 13 billion years ago the universe was smaller, which was actually closer at the time. Calculating that distance, it is only 3.4 billion light years away. The galaxy is of course a lot more further than that. The galaxy keeps moving away from us. The co-moving distance of the cosmic background is around 46 billion light years. The observable universe had a diameter of around 92 billion years.With the observed distance, it even extends more than that. It has a diameter of about 92 billion light years.

This article relates to this objective because it talks about the main objective about the size of the universe. I personally like this article I feel that I learned a lot of good facts from it. I learned from the article that there are some ways of calculating it. I also learned a lot in my class in fact I learned about how all galaxies move away from us which it also explains the same thing in the article. I learned that all galaxies are attracted to each other by gravity. As an elliptical passes through, the stars do not collide. The increased density and gravity creates new stars which I found pretty fascinating.