In 1995, NASA’s Hubble Space Telescope spent 10 days looking at a seemingly empty pinpoint in the sky.
Instead of darkness, what Hubble found changed our understanding of the universe...
The Hubble Space Telescope is an outstanding time machine, in a sense, because of course in
astronomy anything we look at in space we're seeing it as it was when the light from that
object, be it a planet, a star, or a galaxy began its journey to us.
Now, normally we don't really think about that when we're just looking at the night sky,
but it's incredibly important for our studies with the Hubble Space Telescope to realize that
when we're looking at a galaxy, we're seeing it as it was millions of years
ago, sometimes billions of years ago. It's taken that long for the light to get to us.
In 2004, the Hubble Ultra Deep Field revealed over 3 times more galaxies than the Hubble Deep Field.
Further Hubble deep fields have shown us that there are hundreds of billions of galaxies in the universe.
One of the neat things about the Hubble Ultra Deep field, and one of the things that made it so unique
was how long it took us to take that image. There's an exposure time that's expressed, I think it's
11.2 days. it's a very. very long exposure time. But probably what's more important is how many orbits
it took us to do that. 400 orbits of Hubble data to take that image, that's a lot of orbits! It was
a lot of Hubble time, you only get 15 orbits a day, to take 400 orbits and say we're going to observe
this one spot in the sky for 400 orbits, and I think the results from the science, I mean it was
amazing, what they saw was spectacular.
We see some of the faintest objects showing up in these images
and those faint objects are often distant galaxies. These deep fields have revealed visually to us
a universe absolutely teeming with galaxies, hundreds of billions of galaxies. In one deep
field alone we can see a thousand of these little smudges of light which are distant galaxies.
By doing that we can compare galaxies that are shining to us from billions of light years away
with galaxies closer to us, or even to our own Milky Way and see if they're similar or different.
What Hubble has revealed is that the universe has in fact changed over these billions of years of time.
We looked at the darkest part of the sky, very small part of that, and we
were amazed at how many galaxies we found. And we continued to go back to that portion of the sky
to even increase that visibility, and we've seen tens of thousands of galaxies, just it's amazing.
Hubble spent two weeks taking pictures of empty places in the sky,
and they saw they weren't empty at all there were thousands and thousands of galaxies. In astronomy,
there's what we knew before Hubble and now there's what we know after Hubble, they're so different.
Basically every page of an astronomy textbook now
says something about discoveries made with Hubble, every page.
Hubble has given us this picture of the universe evolving over billions of years of time
into a place where now we have galaxies with plenty of stars and interesting chemical makeup,
so this is something that I'm grateful to the Hubble Space Telescope for opening our eyes to.
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