It's a question that some of us may ask when seeing another breathtaking image of space, this time taken by NASA's Hubble telescope. Last week, we learned about images taken Fermilab's DEC reaching about 66 million light years into space. NASA published an eXtreme Deep Field, or XDF, photograph detailing a tiny portion of the sky, showing about 5,500 galaxies that appear via extreme exposure of 2 million seconds and via the combination of 2,000 individual images.
The XDF goes back 13.2 billion years in time, and close to the believed beginning of universe 13.7 billion years ago. The youngest galaxies in the picture are shown as they existed only 450 million years after the big bang. "The early universe was a time of dramatic birth for galaxies containing brilliant blue stars extraordinarily brighter than our sun. The light from those past events is just arriving at Earth now, and so the XDF is a time tunnel into the distant past."
The farthest galaxies shown in the images are 13.2 billion light years away, which translates to about 2.6 septillion miles.