Currently, man has only observed 1 universe that contains all that which we can see, including a trillion other galaxies each containing roughly 100 billion stars or so each, but theoretically, our universe may be only 1 of an infinite number of other universes that we can not see or detect (yet...).
To make it easier to comprehend the theoretical, imagine our entire universe is a bubble among an infinite number of bubbles floating in a vast ocean. The distances between the bubbles may be so great, that we are incapable of detecting or seeing them or possibly we just can't see beyond the edge of our own bubble or maybe we exist on the inside of the bubble's surface which curves back upon itself, so if you looked far enough, you might just ee the back of your own head. :) (look up Mobius Strip for a better description of this)
Another idea, is that there are an infinite number of universes that are not so far away, but which exist entirely in another dimension or time that we can not detect. (Imagine a universe that exists 1 minute in the past from ours. We could never see it as we are always existing one minute ahead of it and it could never see us as we were are always traveling a minute ahead of them. (this is an over simplification, but you get the theoretical idea.)
Is your mind blown yet?
yes, we are one of the trillions and trillions of galaxies!
Canada is totally real. It is a country. The country is locatd above another country named the United States of America. There are many countries. They form continents and oceans surround these continents. So these continents and oceans make the planet we live on which is called Earth. There are many different planets in our galaxy and there are many galaxies. Galaxies are in universes and there a lot of universes. Beyond universes....... no one knows. Maybe someday someone will find out.
I believe that that is true even though we can not travel there.
No stars are actually a galaxy. All stars are stars and all galaxies are galaxies. Stars are found in galaxies. Some galaxies look like tiny dots in our night sky, so might look like a star, but they are not stars; they are galaxies.
With the trillions of stars that make up just our own galaxy, and the trillions of galaxies we can see, there is little chance that some other star out there has life. We do not yet know what is needed for life, just what is needed for life "as we know it" so our efforts are hindered by only being able to look for life as we know it.
so people can make out in diffrent galaxies
The millions, then the Ten Millions, then the Hundred Millions, then the Billions, the Ten Billions, the Hundred Billions, the Trillions, the Ten Trillions, the Hundred trillions, the Quadrillions, the Ten Quadrillions, the Hundred Quadrillions, the Quintillions and so on.
Trillions would be a minuscule percentage of all the planets in our solar system, let alone the universe No. There are more then 8 plants for sure because scientist's discovered them but I am sure that in other universes they are there(if only are space probes can go to other universes.Oops, when I said solar system I was meaning galaxy, serves me right for not proof reading, ether way I agree with Charlieberzak and find it unfortunate our understanding of such things is so small
Parallel universes fall under the study of Quantum Physics.
An alien is a person from another country that is in your country and you don't really like him being there (here). The term is also been used for 'an alien being from a distant planet'. The possibility of those are at best only fair.
2/3 of the earth's land mass is desert so that means trillions upon trillions of gallons of sand
There are only 6,000 stars in the night sky which are viewable with the naked eye. But there are billions if not trillions of stars in the universe. Remember one star in every solar systen, millions to billions of stars in each galaxy, and billions of galaxies in the universe.