Astronomers today believe the Milky Way was born more than 13 billion years ago as a tiny, slightly denser than average, clump of matter.
Made almost entirely of dark matter, the tiny clump that was the beginning of our galaxy had more gravitational pull than its surrounding neighbors and slowly began to pull more dark matter into its orbit. As it grew in size, so too did its gravitational pull. The Milky Way, and several of its neighboring clumps of dark matter, slowly grew big enough to form stars.
As the size of the Milky Way clump grew, it began devouring the neighboring dark matter clumps. As it reached its proto-galaxy stage, the Milky Way’s enormous gravity pulled in more dark matter and gas. Most of the gas gathered in the center, causing the Milky Way to form into a thin, rapidly rotating disk.
The Milky Way then embarked on a rapid period of star formation hitherto unseen in any other galaxy ? by way of “galactic cannibalism.” Its strong gravity systematically tore up and subsumed smaller galaxies in its vicinity. 13 billion years later, the Milky Way has not stopped and is currently ripping apart the Large and Small Magellanic Clouds.
Larger galaxies swallow up smaller galaxies. But when two major galaxies collide, they merge, with the stars turning “red and dead” as the galaxies run out of gas. The Milky Way has not suffered a merger with a similar-sized galaxy during its 13 billion-year history, but it is on a collision course with the neighboring Andromeda galaxy. The two will collide in about 4 billion years, and when that day comes, the Milky Way that we know will forever disappear.
Alex Kim For The Teen Times
1. What do astronomers today believe about the Milky Way?
2. What were the characteristics of the Milky Way, acording to the second paragraph? How did the Milky Way change?
3. What happened as the size of the Milky Way clump grew? What happened past the proto-galaxy stage?
4. What is “galactic cannibalism”? What happened 13 billion years later?
1. Have you seen pictures of the Milky Way? What does the Milky Way look like?
2. Our solar system is also in the Milky Way. What does this indicate about the Milky Way's size? Are there any other stars or planets in the Milky Way?
3. What are some things that can happen to the Milky Way in the future?
4. What happens when galaxies collide, according to the last paragraph?
Astronomers today believe the Milky Way was born more than 13 billion years ago as a tiny, slightly denser than average, clump of matter.
