#2217 - Brian Cox

5797.467 - 5816.1 Brian Cox

And the sun shines by making helium from hydrogen. So by measuring the amount of helium in the core, by looking at basically sound waves, it's like an earthquake that sunquakes. You can measure how much helium is in there so you can get an estimate of the age of the sun. And then you can get an estimate of the age of the universe by measuring how it's expanding and using Einstein's theory.