The things in our daily life have height, width and length.
According to many researchers, we can't see the fourth dimension, or any other dimension beyond that.
Physicists work under the assumption that there are at least 10 dimensions, but the majority of us will never "see" them. Because we only know life in 3-D, our brains don't understand how to look for anything more.
In physics, spacetime is any mathematical model that combines space and time into a single continuum.
Spacetime is usually interpreted with space as being three-dimensional and time playing the role of a fourth dimension that is of a different sort from the spatial dimensions.
By combining space and time into a single manifold, physicists have significantly simplified a large number of physical theories, as well as described in a more uniform way the workings of the universe at both the super galactic and subatomic levels.
Light travels at about 300,000 kilometers per second (186,000 miles per second) -- that's pretty fast.
We see the moon as it was 1.3 seconds ago; the sun as it was 8.3 minutes ago; the nearest star 4.2 years ago; the most distant galaxy as it was about 13.3 billion years ago. The most distant object you can see with your naked eye is the Andromeda Galaxy and even that is about 2.3 million light-years away, which means you see it as it was 2.3 million years ago.
“ Some theories, most notably special and general relativity, suggest that suitable geometries of space-time, or specific types of motion in space, might allow time travel into the past and future if these geometries or motions are possible.
Now imagine an object with such an enormous concentration of mass in such a small radius that its escape velocity was greater than the velocity of light. Then, since nothing can go faster than light, nothing can escape the object's gravitational field. Even a beam of light would be pulled back by gravity and would be unable to escape.
A wormhole is a hypothetical topological feature of spacetime that would be, fundamentally, a "shortcut" through spacetime.
The interior of a charged or rotating black hole can "join up" with a corresponding white hole in such a way that you can fall into the black hole and pop out of the white hole. This combination of black and white holes is called a wormhole.
The multiverse is a theory in which our universe is not the only one, but states that many universes exist parallel to each other. These distinct universes within the multiverse theory are called parallel universes.
Parallel universes basically say that space is so big that the rules of probability imply that surely, somewhere else out there, are other planets exactly like Earth.
In fact, an infinite universe would have infinitely many planets, and on some of them, the events that play out would be virtually identical to those on our own Earth.
The “false vacuum” began to decay, creating amazing amounts of particles. These particles are the same as those which began our universe.
There are two main ideas as to what these different universes may contain. The first is that these universes are the same in matter and physical laws as our universe . For example, the oceans would be where our continents are and vice versa, on and on.
The second idea is that the other worlds would potentially be different in that they may not operate in the same way as ours does . A three dimensional world may not be what the norm is.
Nothing in the world is supposed to travel faster than light.
But some neutrinos set off from Geneva and reached a lab beneath the mountains in Italy 60 nanoseconds (billionth of a second) faster than light would have, travelling a distance of 730 km. (I.e. About 12 Billion kms /sec)