What Is Up There? III
Hey there dear readers,
Have you recommended Yonatan's Talk for TED international? If not, promptly pop over and help us share our story. Thanks!
Now that we got that out of the way, how about we talk a little about our galaxy, as known as The Milky Way?
- The galaxy is a disk of about 120,000 light years diameter with a 12,000 light year diameter of a central bulge. The disk isn't flat, but wrap by the two opposing and pulling forces causeג by the Large Magellanic Cloud from one side and the Small Magellanic Cloud from the other.
- The Milky Way is mostly made of dark matter. To be more on point, the dark matter constitutes of about 90% of all our galaxy's mass, i.e. all visible mass is merely 10% of all the galaxy's mass, at best. Also, gas and dust, floating happily in outer space, make up to 10-15% of all visible matter.
- I should probably mention that the galaxy's mass is estimated at 100-150 billion sollar mass.
- There are between 200 billion and 400 billion stars that make up our galaxy. This is actually not a lot. As galaxies goes, our's is middleweight. Though there are so many stars, only 2500 are visible (Due to gas and dust deflecting light), but not all are the same all the time - stars are lost and born through supernovas.
- At the center of our galaxy, named Sagittarius A*, lies a supermassive black hole with mass of 40,000 suns and with a 14 million miles diameter. Around it orbits the accrestion disk, with estimated mass of 4 million suns, being pulled in by the black hole.
- The age of our galaxy is estimated at about 13.6 billion years, give or take 800 million. To put things in perspective, the age of the Universe is estimated at 13.7 billion years.
- We are not alone! Meaning, our galaxy is a part of the Virgo supercluster, within it many more galaxies (Say, the Andromeda, closest spiral galaxy to ours), or clouds (Such as the Magellanic mentioned above). The Virgo supercluster is 150 million light years across.
- We have a hungry galaxy, eating up other galaxies, as it does nowadays to the Canis Major Dwarf Galaxy.