Ever wondered how we got to see photos of stars and galaxies from the past? There is a photo from NASA which chose the state of the universe which is apparently after the big bang. And it is very close to the event of the Big bang, say a few billion years after the big bang. Obviously we didn't exist back then. Our very own galaxy was far away from being formed. So how did we get that? This is where the most fascinating theory comes in the fact that time machines exist and it is something we already know, the telescope.
We know how a telescope works. The most basic description is that it zooms into stuff. Suppose it can zoom into Saturn and then we can see its rings which we cannot see with the naked eye at least in the cities. And we also understand how we see things in order to see something. The light needs to travel from that object to our eyes. And only then we can see the object. So the event where you are seeing Saturn through the telescope light from Saturn travels to you, you and then you see it. Now a bit more technicality. We know light has a speed. Of around 300,000 km per second. So Saturn is billions and billions in trillions of kilometers away from you. So the light that comes from Saturn obviously takes a substantial amount of time as light can only travel up to 300,000 km per second. So even if you have a distance of 1 million km it will require light 3.33 seconds to reach you. I suppose you're now understanding what is happening here. For example, it takes 8 minutes for the sunlight to reach us from the surface of the Sun to the Earth. So when we look at the Sun we see an image of the sun which is constructed by the light that came from the Sun. So the image constructed in our eyes at a certain moment of the Sun is actually transmitted 8 minutes before that time when you're seeing the Sun. By this theory, scientists have come up with giant telescopes like the James Webb, the Hubble telescope.
These giant telescopes can see things that are many billions of light years away from us. So light has to travel all these billion years from those objects to us in order for us to see them. And this is how we get pictures of things that are billions and billions of years old. So next time when you think time travel is not possible. Remember, this time travel has been happening for eternity. We can't see the future, but we can certainly see the past very vividly.
