When you look up, how far back in time do you see?

Description

Our senses are stuck in the past. There’s a flash of lightning, and then seconds pass until we hear the rumble of distant thunder. We hear the past.

We are seeing into the past too.

While sound travels about a kilometre every three seconds, light travels 300,000 kilometres every second. When we see a flash of lighting three kilometres away, we are seeing something that happened a hundredth of a millisecond ago. That’s not exactly the distant past.

But as we look further afield, we can peer further back. We can see seconds, minutes, hours and years into the past with our own eyes. Looking through a telescope, we can look even further into the past.