In approximately what year will the Andromeda Galaxy impact our Earth?

Question

Astrophysicists say that the Andromeda Galaxy is raveling toward us at 200,000 miles per hour or about 55.55 miles per second. If Andromeda is 2.5 million light years away how many years will it take for it to impact with our Milky Way Galaxy?

OK guys, to help you a little:
Light travels in one year 5,865,696,000,000
X 2.5 million light years
That means that Andromeda is 1466424 to the power of 13 miles away or
14,664,240,000,000,000,000 miles from Earth

Does that help any?

Answer 1

Assuming that the Andromeda Galaxy is on a collision course with the Milky Way Galaxy - which I doubt is actually the case - and your figures are correct, we can calculate the time until collision by dividing the distance by the speed of approach. However, we must convert our units of distance and speed so that the units of distance cancel and the units of time come out in years.

One light year is the distance that light travels in one year in a vacuum. Light travels

186282 mi/sec * 60 sec / 1 min * 60 min / 1 hr * 24 hr / 1 da * 365.2422 da / 1 yr.

This gives a speed for light of 5.87819e12 mi / yr. When written in nonscientific notation, this is 5,878,190,000,000 miles in a year.

The Andromeda Galaxy is 2.5e6 light years distant. When multiplied by 5.87819e12 mi per light year, this gives 1.47e19 miles and is moving towards us at 2.00e5 miles per hour * 24 hr/da * 365.2422 da/yr = 1.75e9 mi/yr.

1.47e19 mi / 1.75e9 mi/yr = 8.38e9 yr or 8.4 billion years, give or take a minute or two. :)

Answer 2

The whole of the Andromeda Galaxy is not going to impact on one tiny little Earth, stuck out on the spiral arm known as the Orion spur, 26,000 light years from Galactic Centre, is it?

Collision will be with the Milky Way as a whole. We already have an idea of the process involved in two galaxies merging as a number of smaller satellite galaxies are currently merging with the Milky Way.

Space is mostly that: space with stars occurring every few light years or so (except for binary and trinary systems where two or more stars rotate around one another). So merging does not necessarily mean collision for any star you might mention. For one thing, the Andromeda Galaxy may mostly merge with the other end of the Milky Way, not our end.

Figures between 5 and 8 billion years have been suggested as a timescale. (There was an idiot on here, clutching a Mayan calendar, a few weeks back, who believed that Andromeda was going to hit us in 2012. not grasping that going 2.5 million light years in the space of 5 years was 500,000 times as fast as light travels!)

To get a figure of 5-8 billion years in perspective, we need to remember that the timescale in which the Sun will swell up and become a Red Giant (once it has fused all its hydrogen to make helium) is 4-5 billion years. i.e. life will have become impossible on earth before Andromeda arrives and we will need to have upped sticks and moved elsewhere afore then.

Answer 3

When 2 galaxies collide, that doesn't mean that the stars themselves collide. A galaxy has a lot more empty space than stars, so its not likely the merger of Andromeda and the Milky Way will actually affect the Earth at all.

Answer 4

Around the year 5,000,002,008, since it has already been estimated at taking around 5 billion years for the two galaxies to collide.(more or less)

Answer 5

It will come close in about 5 billion years and seriously distort both galaxys. It will come back and merge about 2 billion years later.

Answer 6

I read that it's something like 5 million years... I think. I forgot. :P

Answer 7

102 years, 29 days, and approximately 4hours..

Answer 8

Im stupid i dont know, lol.