Hydrogen nucleus + Hydrogen nucleus → Helium nuclei
During fusion, some of the energy trapped inside the hydrogen nuclei is released. All the chemical elements with a larger mass than helium were formed by nuclear fusion in earlier stars.
By seeing how much the light has been red-shifted, you can work out how quickly it’s moving away. The greater the red-shift the faster it’s moving away. From the observations of different red-shifts of different galaxies we know that:
The more DISTANT the galaxy, the FASTER it moves away from us
This provides evidence that the whole universe is EXPANDING.
The Earth and the sun are a similar age. But the universe is about 3x older.
When Scientists trace the paths of galaxies, they all appear to be moving away from the same point. As mentioned in GCSE physics curriculum, the best theory for this is the BIG BANG THEORY, which says that the universe started with a huge explosion 14,000 million years ago.
The ultimate fate of the Universe this is because the future depends on the amount of MASS in the Universe.
If there is NOT ENOUGH MASS, the universe will keep expanding
If there is TOO MUCH MASS, gravity will be strong enough to pull everything back together and the universe will collapse with a big crunch.
Measuring the amount of mass in the Universe is very difficult, so it’s ultimate fate.
End of this section!
Drafted by Gina (Physics)