4 June 2014
While you search for within the night time sky, there are areas of the sky that seem darkish. That’s as a result of there may be nothing in that area vivid sufficient for us to see with the bare eye. In case you regarded upon this area with a telescope, you’ll discover dim stars and galaxies, however you’ll nonetheless see areas that appeared darkish to you. How far may you are taking this? In case you stored smaller and smaller darkish areas with ever extra highly effective telescopes, what would you see?
Beginning in 2003, we’ve put this concept to the take a look at when the Hubble telescope was geared toward one of many darkest patches of sky we may discover, within the Fornax constellation. It’s an space so small, it’s the obvious measurement of a grain of sand held at arm’s size. On and off over the following 9 years, the Hubble noticed this area, gathering ever extra mild to see particulars within the picture. Hubble gathered mild at infrared and visual wavelengths, and most just lately gathered ultraviolet wavelengths as nicely. After gathering mild for about 1200 hours whole, what you get is that this:
There are about 10,000 galaxies on this picture. 10,000 galaxies within the space of a sand grain. That is what lies throughout the darkish of night time.
From this picture we’ve estimated that there are 100 billion galaxies within the seen universe. That’s greater than 10 galaxies for each man, lady and youngster on Earth. These galaxies may need a median of about 100 billion stars. Round most of these stars is likely to be tens of planets. It’s a huge sea in the dead of night of night time.