Hubble vs. Webb - How Far Back Will They See?

Roland Piquepaille writes "According to Forbes, reporting in "Peering Back At The Universe's Past," space telescopes are really acting as time machines. They can watch objects which are so far from us that light has taken billions of years before reaching their mirrors. The Hubble telescope is able to look at events that took place 13.3 billion light-years ago. But the James E. Webb space telescope, currently under construction, and scheduled to be launched in 2011, will be able to see even further and catch phenomena which happened 13.5 billion light-years ago. The astronomers think the Webb telescope might even be able to see up to 13.7 billion light-years ago, when our universe was just 200 or 300 million years old. We are used to see fantastic images from Hubble, without paying too much attention to the characteristics of the telescope itself. So here is a thorough comparison between the two space telescopes."

Comments

Distance Units?

[davew666]

13.5 billion light years ago? Maybe I am being stupid, but I always thought that a light year was a measurement of distance?

Re:It's spacetime, man

[kmac06]

Why is this modded imformative? No, distance and time are not the same thing. When you're dealing with space-time, time can be thought of as a dimension in the same way the other 3 coordinates we all know and love are, but its not the same thing.

Also, you're perception of the past is wrong. If I'm a light-year away from something and see something happening, I can say that in my reference frame, that happened a year ago. Someone travelling at speeds approaching c might disagree, but that's another story.

And a light-year is a measure of distance. If you specify "the time it takes for light to travel a light-year" than you have a measure of time, but that was not what the original story poster wrote (although you could assume it since the telescopes are recieving light).