06 Feb History
Time travel isn’t possible.
Well, it might be but you may end up in a parallel universe or something. It all gets a bit weird. If you’re interested, look up “the grandfather paradox solved”.
So time travel isn’t possible, at least for people. And I’m not including when you take a pair of twins and send one of them into space, keeping the other on Earth, and one ages faster than the other. That’s relativity or something.
However, technically speaking, looking into the past is possible.
Let’s look at some figures.
The Earth is almost 13,000 km in diameter.
The moon is 384,000 km away.
The sun is 150 million km away.
The nearest star (Proxima Centauri) is 40 million million km away.
(I’m not going to convert these to miles as the numbers are so huge it makes no difference)
Your daily commute suddenly doesn’t seem so bad.
OK, we need to dial these numbers down as I’m getting a headache and you’re probably switching off. Let’s look at the speed of light – it travels at about 300,000 km per second.
300,000 looks similar to 384,000, which is how far away the moon is.
So it takes light just over 1 second to reach us from the moon.
So when you look at the moon, you’re looking at it as it was 1 second ago – you are literally looking 1 second into the past. (one “light second”).
Impressed yet? No? OK…let’s extend this theory to other objects in the night sky.
Look at the Sun (bad idea if you value your sight) – that’s how it was 8 minutes ago. (so it takes light 8 minutes to reach us from the Sun. This means if the Sun were to disappear, we wouldn’t know until 8 minutes later).
Look at the nearest star, Proxima Centauri – that’s how it was over 4 years ago. (physicists would say it is 4 light years away).
Look at the North Star (Polaris) – you’re looking at it 680 years ago.
Generally, on a clear night, any star you can see can be up to 4000 light years away.
So every time you look at the stars you are in fact looking thousands of years into the past. Some of those stars may not even be there any more.
Blows my mind every time. To see the past, all you need to do is look up at the stars.
Funny as I always hated History at school.
*Disclaimer: this blog post is for entertainment purposes only and any opinions contained therein do not necessarily represent those of the author.