Our galaxy, the Milky Way, is isolated in space but it is not alone. The galaxy closest to us is Andromeda, M31. It is 2.5 million light-years away, which is more than twenty times the diameter of the Milky Way!
Between the two there is nothing, it is emptiness. And since there are no stars, no air, no wind, in short nothing at all, it is freezing cold, -270 ° C! It’s the lowest temperature in the world, what do I say about the Universe.
On the other hand, near nebulae or stars it can be very hot, more than 10000 ° C. As you can see, the emptiness of the Universe is really a very inhospitable place where life is not good.
Beyond the Milky Way and Messier 31, there are hundreds of billions of other galaxies. Some are located billions of light-years away, so far they look like orange, red or blue stars a little blurry in a powerful telescope.
We even discovered galaxies billions of light years away! They are so pale and small that only telescopes put into orbit (like the Hubble Space Telescope) can see them and often only by photography!