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Gurbhej Singh wrote:

How many galaxies do we know of; how large are they and what is their distance from our galaxy?

Astronomer William Georgevich replies:

Astronomers estimate there are approx. 150 billion galaxies that we can account for that we can see in visible light. Our own Milky Way which is an average-sized galaxy stretches about 100,000 light years from extreme end to end. Compare that distance with the the intergalactic distance between the Milky Way and the Andromeda Galaxy some 2.2 million light years away and you get some notion of scale in the Universe. That is the closest galaxy to our own Milky Way. This scale extends into billions of light years and the Universe expands toward the wavefront of energy that cosmologists call the Big Bang. The most distant objects are quasi-stellar objects that are somewhere between 10 and 2.

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