How far back in time can we see in space?

submitted a year ago by

We see objects whose light only arrives just now. But we see them as they were in the past: when that now-arriving light was first emitted.

Key Takeaways

In this Universe, we can see a whole slew of objects both near and far; anything is visible so long as the light signals it emitted in the past is arriving at our eyes/instruments right now.
We don’t see those objects as they are right now, but rather as they were in the past, when that now-arriving light was first emitted, because it only traveled at a finite speed: the speed of light.
While the Sun’s light is only a few minutes old and the light from stars is up to a few thousand years old, extragalactic light is millions or even billions of years old. Here’s how far we can see into the past.