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How many AU is the nearest Galaxy from the milkyway?

Answer 1

John Alexander

It depends what you mean by nearest galaxy, but the conversion factor between light years and AU is about #63000#

Let's work out a conversion factor between light years and AU first.

The Sun is roughly #93000000# miles from the Earth and light travels at about #186000# miles per second.

So #1# AU is about #500# light seconds.

There are #86400# seconds in a day and about #365.25# days per year, hence:

#86400 * 365.25 = 31557600" "# seconds per year.

Dividing this by #500# we arrive at:

#31557600/500 = 63115.2 ~~ 63000" "# AU per light year.

#color(white)()# How far away is the nearest galaxy from the Milky Way?

The very nearest galaxy would be one of the small satellite galaxies.

There are about #50# galaxies within about #1.4# million light years of the Milky Way. The closest are about #1000# light years from the edge, which by our reckoning would be about #63000000 = 6.3 xx 10^7# AU from the edge.

Perhaps of more interest is the distance to the Andromeda galaxy, our largest neighbour in the Local Group. This is about #2.5# million light years away, which would make it about #160# billion AU away.

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Answer 2

Ian Aitchison

The nearest galaxy to the Milky Way is the Andromeda Galaxy, which is approximately 2.537 million light-years away from us, or about 0.76 megaparsecs. In astronomical units (AU), this distance is roughly 23.8 quintillion AU.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.