As seen on the Cosmos TV series featured in 2014, the Milky Way galaxy and the nearby Andromeda galaxy will collide and merge 4 billion years from now. Check out this video from the Hubble Space Telescope news center to see the predicted merger between our two titan spiral galaxies, as seen in Earth’s sky.
But what about Earth? Will it survive long enough to see this merger of galaxies? Chances are that the Earth might but as far as life on Earth goes, probably not. Astronomers say that the luminosity, or intrinsic brightness, of our Sun will steadily increase over the next 4 billion years. As the Sun’s luminosity increases, the amount of solar radiation reaching the Earth will also increase. It’s possible that – around 4 billion years from now – the increase in the Earth’s surface temperature will cause a runaway greenhouse effect, perhaps similar to that going on now on Venus, whose surface is hot enough to melt lead. No one expects to find life on Venus. Likewise, life on Earth will probably not exist 4 billion years from now. What’s more, our Sun is expected to become a red giant star eventually. A probable fate of the Earth is absorption by the Sun in about 7.5 billion years, after our Sun has entered the red giant phase and expanded to cross Earth’s current orbit.
The bottom line is that as our Milky Way galaxy and the Andromeda galaxy merge, beings who live in either galaxy will have a spectacular view in our night sky.
Read the full story on the EarthSky website.