How full is the universe?

I was lucky enough to experience an extremely clear night on the Isle of Wight recently. The stars were clear, the milky way stretched overhead, and in just an hour I saw nearly 20 satellites and 6 shooting stars.

I was reminded of one of my favorite images. The Hubble Deep Field.


This is an image of a small region in the constellation Ursa Major, constructed from a series of observations by the Hubble Space Telescope. It covers an area about one 24-millionth of the whole sky, which is equivalent to a tennis ball at a distance of 100 meters.

The image was assembled from 342 separate exposures taken with the Space Telescope’s Wide Field and planetary camera 2, over ten consecutive days between December 18 and December 28, 1995.

The field is so small that only a few foreground stars in the Milky Way (our Galaxy) lie within it.

So, almost all of the 3,000 objects in the image are galaxies.

Our Sun is just one star of millions in our galaxy, so each of the galaxies in this image are made up of millions of stars just like our Sun.

And remember, just a tennis ball at 100 meters….



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