miércoles, 15 de junio de 2011

Basic space-time explanation



It's hard to understand correctly the concept of space-time. Think of a very large ball. Even though you look at the ball in three space dimensions, the outer surface of the ball has the geometry of a sphere in two dimensions, because there are only two independent directions of motion along the surface. If you were very small and lived on the surface of the ball you might think you weren't on a ball at all, but on a big flat two-dimensional plane. But if you were to carefully measure distances on the sphere, you would discover that you were not living on a flat surface but on the curved surface of a large sphere.
    The idea of the curvature of the surface of the ball can apply to the whole Universe at once. That was the great breakthrough in Einstein's theory of general relativity. Space and time are unified into a single geometric entity called spacetime, and the spacetime has a geometry, spacetime can be curved just like the surface of a large ball is curved.
    When you look at or feel the surface of a large ball as a whole thing, you are experiencing the whole space of a sphere at once. The way mathematicians prefer to define the surface of that sphere is to describe the entire sphere, not just a part of it. One of the tricky aspects of describing a spacetime geometry is that we need to describe the whole of space and the whole of time. That means everywhere and forever at once. Spacetime geometry is the geometry of all space and all time together as one mathematical entity.
I'm preparing an entry about worm holes. I hope it'll be finished by tomorrow.

10 comentarios:

  1. Very intriguing, eagerly awaiting the wormhole entry!

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  2. More man, this is really neat stuff!!

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  3. Where did you learn all of this? In formal education or did you just pick all of this up on your own? Either way, very impressive knowledge right here.

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  4. Good explanation! Looking forward to your next entry.

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  5. i thought space was the lack of matter, were i taught wrong?

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  6. That picture looks really familiar. I swear I had that same illustration on my final last week.

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  7. That is well explained, I wait for the worm holes

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  8. This all went right over my head...haha.

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  9. damn this is an interasting blog, i really enjoy reading everything here. i like science, even have the basics in quantum physics, so it's fun to learn more

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