X marks the spot at the center of the Milky Way galaxy

A large X-shaped structure of stars has been theorized to exist in the center bulge of our galaxy, the Milky Way. The article, “X marks the spot at the center of the Milky Way galaxy”  mentions Dustin Lang, a research associate at the Dunlap Institute for Astronomy and Astrophysics states that there has always been controversy whether the X-shaped structure really does exist. He believes that their is finally strong evidence to prove that it is there. The Milky Way is a barred spiral galaxy, containing dust, gas, and billions of stars expanding about 100,000 light-years in diameter. The Milky Way is composed of two spiral arms with a bar shaped center bulge housing many stars. The theorized X-shaped structure is an important component of the center bulge. Their are two ideas of how the bulge could have formed; the Milky Way merged with other galaxies, or it may have formed without external influences as an outgrowth of the bar, which forms from the evolving disk. Lang noticed the X-shape when re-analyzing previous data from the Wide-Field Infrared Survey Explorer (WISE) which is surveyed the entire sky in infrared in 2011, imaging three-quarters of a billion galaxies, stars and asteroids. Lang’s partner Melissa Ness believes the bulge is the main factor of how our galaxy formed, that if we understand the bulge then we can figure out the processes that formed and shaped our galaxy. The X-shaped structure is clearly seen from the WISE image suggesting that internal formation processes are the reasons of the bulge formation. This is also evidence that no major merging events have occurred since the formation of the bulge, other wise the X-shape would have been disrupted.

It is interesting to think that their is an enormous X-shaped structure of stars in the center of our galaxy. I am very curious to how they formed like that. What I don’t understand from this article though is how exactly did this X-shape structure our galaxy. It was mentioned a few times in the article that the structure could be the reason that our galaxy is a barred spiral but it is never mentioned why or how. I find it funny that this X-shaped turned down by many scientists yet according to Lang the X-shape is very clear in the infrared picture WISE took. That was back in 2011 so if it was so clear to see its odd it was just noticed about six years later. However, its neat that scientists are finding out more about our galaxy and how it really formed.  This article corresponds well with our 15th conceptual objective: I can describe the structure and size of the Milky Way galaxy. I always thought of our solar system being a large area, but I never knew how large our galaxy was until this chapter of class. 100,000 light-years is enormous. I didn’t grasp the size until we did “Milky Way Scales” from our Lecture-tutorial notes.20170427_202847

It shows that it is about 100,000 light years long. To scale, one centimeter is about 10,000 light years while one millimeter is 1,000 light years. I began to grasp the concept when completing question 2, that the stars; Sirius, Vega, Spica, Rigel, and Deneb all would be at point A, even though they are several light years away from the sun. I also found it unbelievable that the third closest galaxy to us is 2,500,000 light years away, which would have been 250cm off the page.20170425_115020This clicker question taught how far away we are from the center of the Milky Way. The Earth is about 25,000 light years away. This is a long distance and crazy to think if we could travel at the speed of like it would take 25,000 years to reach it.


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