My Last “Hurrah”! (My Favorite Blog Posts + Parting Words on Astronomy 101)

https://jjcastronomy.wordpress.com/2018/04/30/the-theoretical-antithesis-of-one-of-the-weirdest-objects-in-our-universe/

This one has to be one of my favorites just because of how bizarre it is.  This blog post talks about a theoretical source of dark matter.  The thing that makes this post interesting is that the objects that are the focus of this post, white holes,  are objects that repel all light from themselves.  This makes them quite the opposite from the objects they are theorized to come from, black holes.  Also, I found it amazing how old the article estimates a black hole has to be to become a white hole.

This post was for the fourteenth objective, which was on how stars evolve and die.  This objective taught me a little more on how both smaller and larger stars go through their life cycles. While I knew about white dwarfs, supernovas and black holes, I did not know exactly how they formed and why they explode like they do.  Learning about how nuclear fusion in stars eventually makes heavier elements than helium, now I know how these celestial objects form.

https://jjcastronomy.wordpress.com/2018/05/05/our-current-map-of-the-milky-way-one-percent-complete-estimated/

Now, the reason I found this post to be interesting is because it put into perspective how hard it is to map out our own galaxy right now.  I always thought that we, as scientists, had a fairly complete map of our galaxy.  The article within this blog post proves otherwise.  It makes sense, though, seeing as our galaxy has billions of stars, that we only have uncovered a sliver of our galaxy.

That is the main idea that was taught to me through this objective, objective fifteen, which was on describing the dimensions of the Milky Way Galaxy. I never really thought about exactly how massive the Milky Way Galaxy really was, and how hard  it would be to observe it while being within it.  It comes to show how small the Earth is compared to a lot of other objects in space!

Overall, I believe I have learned a fair amount of astronomy through this class.  While I knew some things before this class, like how black holes form and how our Solar System formed, this course gave me even more knowledge on this amazing scientific field.  As I said in the paragraphs pertaining to the blog posts, this course brought me to articles that amazed me with just how massive and complex our Universe is.  If I had not taken this course, I would have never learned about these concepts.  As such, I had an amazing experience with taking Astronomy 101, and I would not hesitate to suggest this course to anyone who has any interest in this field.

Finding Traces of the Earliest Stars in our Universe

http://www.astronomy.com/news/2018/03/fingerprinting-the-very-first-stars

According to Astronomy.com, astronomers have been able to detect the “fingerprints” of the first stars in the Universe.  They accomplished this by using a radio antenna the size of a tabletop in the deserts of Australia. This is quite a feat, as they had to pinpoint the exact frequency of the earliest stars from the entire noise of our Universe.  When they finally did figure out the frequency that the first stars did start emitting frequencies, at about 78 megahertz, they were able to pinpoint the time at which the stars started to form, at about 180 million years from the start of the Universe.

This is pretty big, as it shows the first time stars started to appear in our universe.  However, this is not the first time light appeared in our universe.  As shown by slide 6 on Astronomy-101-Unit4-notes-part2.pptx, the first lights actually came from only around three hundred thousand years after the Big Bang.   The first formation of stars still is an important era of our Universe, though, as after those first few flashes of light, the Universe was dark until stars started forming.  This means that, for around 179 million years, the entire Universe was cold and had no light at all. So, knowing the exact time when light and heat started to appear constantly for the Universe is still a monumental find.  Knowing that they had to find this signal from all the other signals given out throughout the Universe just compounds on how amazing this accomplishment is.

News Article Confirms that Older Galaxies Do, in Fact, Get Flabby

https://www.sciencenews.org/article/young-galaxies-are-flat-old-ones-are-more-blobby

ScienceNews.org had a recent survey to see if the ages of the stars within a galaxy contributed to the shape of the galaxy as a whole.  As it turns out, after looking at the shapes of 843 galaxies, and determining the ages and orbital patterns of the stars within those galaxies, the older the stars within the galaxy, the more round the galaxy is.  This is because as a star gets older, the more random their orbit gets. This shows that spiral galaxies will have a great deal more young stars, that will move in predictable patterns, while elliptical galaxies will have predominantly old stars, which will move pretty much at random.

This confirms our deductions about the differences between elliptical and spiral galaxies that we did in the lecture-tutorial on pages 139-140.  There were some differences in how our class and the scientists came to our conclusions, though.  The biggest difference is that while the lecture-tutorial used the colors of stars to determine the ages of the stars, and by connection the galaxies within them, the article used the orbital patterns of the stars to figure out the ages of the observed galaxies.  Another difference was the pool of galaxies to observe.  While our Lecture-Tutorial booklet only had eight examples to choose from, the astronomers performing the survey used over 800 examples for their data.  Either way, having an expert survey back up the information we had at our class shows that the answers we had in our Lecture-Tutorial were, in fact, correct.  The way the article portrayed elliptical galaxies (as old and flabby) was funnier than our portrayal of elliptical galaxies, though.

Our Current Map of the Milky Way: One Percent Complete (Estimated)!

https://blogs.scientificamerican.com/observations/the-milky-way-revealed-as-never-before/

According to a blog on Scientific American, the most complete map of stars within the Milky Way galaxy has just recently been sent out for observation.  This map, taken by the European Space Agency’s Gaia satellite, is the conglomeration of several year’s observations.  Within the map, there is the recorded brightnesses, colors and motions of over one billion stars within our galaxy!

While one billion stars may seem like a huge number, in the grand scheme of things it is not too impressive, compared with the total number of stars within our galaxy in total.  The article cites that there are one hundred billion stars in the Milky Way, making Gaia’s catalog only one percent complete.  The interesting thing is that this estimate is on the lower end of many estimations, with some going as far as saying that there are 400 billion stars in the Milky Way.

Even though these estimates make Gaia’s catalog seem insignificant at first, Gaia still is a very important step for completing the mapping of our galaxy. Seeing as the Milky way is one hundred thousand light years across, it would be understandable that we currently cannot record every star in our galaxy yet.  In fact, the diagram on page 135 shows perfectly why it is hard to record all the stars in the Milky way at the moment, as our sun is just a tiny dot on one arm in our galaxy, 25000 light years away from the center.  This means that, until we get technology that is powerful enough to record stars 75000 light away from the sun, we will obviously only will be able to record nearby stars. So, knowing that, Gaia’s current catalog is still impressive by our technology’s standards.  Better still, Gaia is still collecting data, so we will likely have an even better understanding of our galaxy when it gives us an updated image!

(It just amazes me on how many stars there are in the Milky Way. The very fact that a map that is only .0025% to .01% complete is considered the most complete map yet further shows this amazement.)

The (Theoretical) Antithesis of One of the Weirdest Objects in Our Universe

https://www.space.com/40422-are-white-holes-dark-matter.html

Space.com posted an article purporting a theory which may explain the presence of dark matter in our universe. In it, it states that white holes may be the objects in our universe that are producing this mysterious substance, which may make up around five-sixths of the entire universe.  The interesting thing about white holes is, if they exist, they could predate our universe, as it takes a long time for white holes to form.

Now, what are white holes? White holes are basically the exact opposite of black holes. While black holes suck all matter into their singularities, white holes do not let anything into them.  Despite these two things being at complete opposites with each other, white holes could possibly be an evolution of black holes! Carlo Rovelli talks about this in the news article, when he states that when black holes die, they could possibly form into white holes. If this is the case, it is incredibly fascinating to know that there is another part to the black hole life cycle.  This means that, if Rovelli is right, we can add another step onto page 134’s diagram, as since a white hole would be an older black hole, it would be the next step in their age.

It does take a while for these white holes to form with this process, however.  The article states that it would take a quadrillion (1,000,000,000,000,000) times the age of the universe (over 13 billion years) to turn a black hole the mass of the sun into a white hole.  This leads scientists to think that if white holes do exist, they could be older than our universe!  This theory just astounds me, as the mere idea of the opposite of a black hole is just crazy!

Merger of Galactic Proportions Shuts Down New Growth of Stars

https://thespacereporter.com/article.php?n=star-formation-in-merging-galaxies-shut-down-by-central-black-holes&id=143832

The Space Reporter put out a news article stating that the fusion of two galaxies is stopping the formation of two stars.  These galaxies, known together as NGC 6240, are currently pulling each other together, forming a butterfly-like shape.  However, unlike a lot of merging galaxies, NGC 6240 is not making a bunch of new stars.  It is actually blowing the components of potential new stars away!

This is due to the huge amounts of stellar wind coming off of the centers of these galaxies, supermassive black holes.  As the two black holes close in on each other, they emit huge jets of gas.  These gases are moving at a high velocity and can blow away the dust within the galaxies.  However, as we learned from panels 42-47 in Astronomy101-Fall2011-Unit3-notes1.ppt, this dust is actually required for new stars to form, as all stars start from this space dust. In effect, the two giant black holes are stopping the first step in the formation of stars, which is the collection of dust into one steadily-growing object, by blowing the dust particles away from each other.  So, until NGC 6240 finally comes together and the stellar winds die down, there will be very little new star formation in this pocket of space.

(The funny thing is, while I knew galaxies merging could make new stars, I had no idea that some merges could actually stop them.)

 

One “Runaway” We Have No Hope of Catching

http://www.skyandtelescope.com/astronomy-news/supergiant-star-caught-fleeing-through-another-galaxy/

Sky and Telescope brought up a couple weeks ago that astronomers have found a very unusual star just outside our own galaxy.  This star, in the Small Magellanic Cloud, was what astronomers call a “runaway” star.  What this means is that the star is moving faster than other stars within the vicinity and could possibly tear away from the area’s gravitational pull.

While there are only a few of these “runaway” stars that are known, what is especially interesting about the star covered by this article is that it is a yellow supergiant. This means that the star in question is a very large, hot star, like star D on page 117 of our lecture tutorials, but hotter Not only that, but it turns out, it is still growing.  As mentioned in the article, this phase will only last for ten to one hundred thousand years, before it cools and becomes a red supergiant, like star G on the same diagram in our lecture-tutorials.   Before this article, I had never even heard of “runaway” stars, nonetheless supergiant “runaway” stars!

One of the Universe’s Oldest Objects has Had its Distance From Earth Determined by a Simple Method

https://www.space.com/40222-wobbles-ancient-stars-cosmic-yardstick.html

 

Space.com reports that astronomers have been able to determine the distance between the Earth and one of the universe’s oldest celestial objects. The celestial objects, A group consisting of hundreds of thousands of stars in the constellation Ara known as NGC 6397, is only a short 7800 light years from earth, and is considered to be over 13 billion years old.  This estimation is considered extremely precise, with only a 3% margin of error, as opposed to the 10-20% margin other measurements had.

Now, how did these scientists figure out this distance and age? Surprisingly, they used the parallax method of determining distance! Using years of images taken by the Hubble Space Telescope, they measured the tiniest wobbles stars would make, which were often only the fraction of a pixel on a normal camera, to determine what the parallax angle was. Then, they could do problem-solving to determine the distance that the object was away from the Earth.

Normally, using parallax angles to find the distance between the Earth and a celestial object is only used for relatively close objects.  The problems we did on pages 37-43 were of this sort, only going as far as eight parsecs.  The very fact that astronomers were able to use this simple method of determining the distance between our planet and one of the oldest objects in our universe just amazes me.

The Oldest Historian in the Solar System is Actually a Rock!

https://phys.org/news/2018-04-oldest-magnetic-solar-meteorite.html

Phys.org posted an article stating that they have found a certain material in meteors that could help scientists explain how our Solar System could have formed. This material, known as dusty olivine, is rich in iron, which can be magnetized. The odd thing about dusty olivine in particular is that even though it is non-uniform in magnetization, which is considered poor in most magnets for keeping history of magnetic fields, it still is a great keeper of magnetic history.

The way magnets take in history is quite interesting. First, they have to be heated up to an incredible degree, 300 degrees Celsius for the dusty olivine particles talked about in the article.  Then, while heated up, they take in the magnetic fields they are experiencing at the time. Once they are allowed to cool off, they retain the magnetic patterns they took in, keeping them in the same way they experienced them for billions of years. Once scientists find these magnets, they can look at the bands in the material to see what magnetic fields they were in.

This way of finding out our Solar System’s history seems to purport the nebular theory of Solar System formation. As shown by panel 4 of Astronomy101-Fall2011-Unit2-notes.ppt, the nebular theory of Solar System formation states that a star forms from a giant cloud of gas, and the leftover gases go through a process that changes them from a protoplanetary disk to proper planets.  With the magnetic fields recorded by the dusty olivine in meteors, it shows that this theory could have some merit.  Only time and more research will tell if this is true.  It still is interesting to find out that magnetic material in meteors could help us find the origins of our solar system!

Giant, Infrared-Detecting Telescope’s Launch Postponed… Again

https://www.space.com/40102-james-webb-space-telescope-launch-delay-2020.html

Space.com recently put out an article stating that NASA has decided to postpone the launch of the James Webb Space Telescope until the year 2020.  This is the second time that this telescope’s launch was postponed, with the first one being September of last year. The reason why the telescope is not being launched is because of several technical difficulties, including several large tears in the telescope’s sun shield.  Sadly, because of this delay, the overall price of the project is expected to rise as well, even though it has already gone over its initial budget of 8 billion dollars.

When the James Webb Space Telescope finally gets launched, however, it will be a great help for astronomers looking for infrared light. This telescope, the largest space observatory ever, is designed to look for and collect data from infrared radiation, which can com from stars that are from the earliest parts of the universe.

Even though getting this telescope up into space has been a pain for NASA for years, it makes sense that it has to be up in space. As shown on page 51 in our Lecture-Tutorial booklet, only trace amounts of infrared light can penetrate to the Earth’s surface, and even then, it can only reach tall mountain tops. This makes it impractical to have an infrared telescope down on Earth. With the telescope in orbit, it has access to the entire amount of infrared light, allowing it to get the best recordings of celestial objects giving off infrared energy. While I knew of the postponing of the James Webb Space Telescope from our classes, I did not know that it was specifically designed for finding infrared radiation.