Infinite Space
In about four billion years, the Milky Way will collide with its nearest neighbor, the Andromeda Galaxy. The two are rushing towards each other at about 70 miles per second . When they collide, they will provide a fresh influx of material that will kick ofF star formation anew.
Our Next Door Neighbor
In about four billion years, the Milky Way will collide with its nearest neighbor, the Andromeda Galaxy. The two are rushing towards each other at about 70 miles per second . When they collide, they will provide a fresh influx of material that will kick ofF star formation anew.
When World's CollideThe Andromeda Galaxy is obviously not the most careful of drivers. It shows signs of having already crashed into another galaxy in the past. Although it is the same age as the Milky Way, it hosts a large ring of dust in its center, and several older stars.
Of course, the imminent collision shouldn't be a problem for inhabitants of Earth. By the time the two galaxies ram, the sun will already have ballooned into a red giant, making our planet uninhabitable. The DebateIn the 1920's, the distant galaxy became part of the Great Debate between American astronomers Harlow, Shapley and Heber Curtis. At the time, astronomers believed the Milky Way completely composed the whole of universe, and the strange patches known as nebulae lay inside of them. Curtis had spotted various nova in Andromeda, and argued instead that it was a separate galaxy.
The discussion wasn't concluded until 1925, when Edwin Hubble identified a special kind of star known as a Cepheid variable - a star whose characteristics allow for precise measurements of distance - within Andromeda. Because Shapley had previously determined that the Milky Way was only 100,000 light-years across, Hubble's Calculations revealed that the fuzzy patch was too far away to lay within the Milky Way. Hubble went on to use his measurements of the Doppler shifts of the galaxies to determined that the universe was expanding. |
FactsA spiral galaxy like the Milky Way, Andromeda contains a concentrated bulge of matter in the middle, surrounded by a disk of Gas, dust, and stars 260,000 light years long, more than 2.5 times as long as the Milky Way. Though Andromeda contains approximately a trillion stars to the quarter to half a billion in the Milky Way, our galaxy is actually more massive, because it is thought to contain more dark matter.
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