if the universe is infinite then why can we measure anything?

Question

any fraction of infinity is also infinity or else it would be measurable. therefore if we can measure anything at all it disbands the theory that the universe is infinite

Answer 1

Your statement that "any fraction of infinity is also infinity" is incorrect. For example, we know that there are an infinite number of integers (1,2,3....), and yet any given number is of course finite.

It would be more correct to say that anything finite is an infinitesimal fraction of infinity, Latest thinking is that the universe in its totality is infinite in extent, since spacetime appears to have "open" curvature. We, however, can only observe a finite piece of it because the speed of light is finite. There is no contradiction.

Answer 2

The universe is finite and is the only reason that we can measure anything.
You are right any fraction of infinity is infinite.
Even the speed of light is limited by the fact that we live in a quantum universe.
Your reasoning is elegant and it should be obvious to anyone.

Answer 3

Just like pi, it does have a value - it converges on a number and in the 'limit' it is real.

An example;

1/1 + 1/2 + 1/3 + 1/4 + 1/5 + .... to infinity = infinity - this 'diverges', if you draw this on a graph you can see what is happening easier.

1/1^2 + 1/2^2 + 1/3^2 + 1/4^2 + 1/5^2........
is the same as -
1 + 1/4 + 1/9 + 1/16 + 1/25 .... to infinity = an actual number (1.59...), - this converges to a number - on a graph you can see it easier.

Answer 4

Well mother nature may of given us a measurement of infinite. What causes a black hole . It is the collapsing of a great star and as it collapses in the pieces are accelerated to the speed of light at which its mass becomes infinite and produces a gravity well that could be 100 light years across .

Answer 5

I'm glad that you asked 'why' instead of how. We can measure anything because we chose to do it. Somebody somewhere (probably Einstein in his first life) came up with the answer to: 'What time is it?' and then 'How far is it to the pub?' A simple answer to an infinity of same.

Answer 6

I agree with Astronomer.

The universe may be infinite, but its parts are not infinite. I can't walk an infinite distance, but I can walk a km to school and I can measure that distance.

Answer 7

The size of the universe is estimated to be about 13.7 Billion Light years in size but based on the Big Bang theory, it is rapidly expanding and speeding up as it goes along.