The nearest star, Proxima Centauri , is 4,29 lightyears away. A decent daytrip by car is 300 km. A lightsecond 300 000 km..... Three hundred thousand kilometers.
There are 3600 seconds on an hour and 24 hours a day and 365 (or so) days a year. So yeah,it's quite a bit away. And that's the nearest star. Just one out of many. How many,you ask,well we don't know.
But imagine this, Proxima Centauri is really really close to Earth on a galaxy scale. Stars clump up in galaxies. Ours is called The Milky Way.
It is roughly 100 000 lightyears across. Probably a bit more but let's not dilly dally. It's 25 000 times larger than the distance to our nearest star. 25 000 times. If that's not large even on a mind blowing scale,i don't know what is. Of course our galaxy is just one among several. The nearest one,the Andromeda Galaxy,is 2.5 million lightyears away.
Now if your mind isn't blown already,imagine this: there are galaxy clusters. They are structures of hundreds of galaxies bound by gravity. Not only that,there's plenty of them too. To avoid a complete headexplosion, let's not go into superclusters, which are clusters of galaxy clusters,mkay ?
In fact i talked to a radioastronomer the other day and i asked if there's anything pointing to the Universe having a limit at all. He answered: As far as we can tell,it's spherical, which apparently is radioastronomer speech for: from what we can observe it's endless. So if you could imagine a supercluster without your head exploding,it's probably quite a bit bigger than that. Of course there are more than one supercluster but still. It's way larger than that. From what we can observe it seems to be endless.
Now we don't know that for sure but that what it looks like. If that is the case and if it has an endless amount of mass (which we don't know either but that's what it looks like) by sheer mathematical coincidence there is going to be a planet that is exactly like this one. Exactly, down to the position of every single atom. And others, almost exactly like this one. In fact,mathematically every single possible combination of earths and every possible permutation of what could have happened since the beginning of time must exist. Simultaneously.
Now where have we heard this before ? Well the multiverse theory that seemed so improbable and a figment of a heavy pot-smokers mind. Hmmm it might just be that way after all.
Another interesting concept is,if i were to go to such a planet and meet the other me,that is exactly the same composition of molecules as me, he would not be me,right ? So what is me ? Do i exist of something more than what is observable ? If i'm not "just" the cluster of molecules clumped up together that is my body,then what am i ? Wow i might just have gotten religious after all! Who would have imagined ?