Dark Energy & Dark Matter (AQA GCSE Physics): Revision Note

Dark Energy & Dark Matter

• Over the past two or three decades, astronomers have gathered plenty of evidence helping us to understand the universe much better

• However, there are still many observations that are still not understood, including:

  • Evidence from the rotation and motion of galaxies suggests that there is much more matter in the Universe than we are able to account for

  • This unseen matter is given the name dark matter and its nature is not currently known

• Measurements of the expansion of the Universe using supernovae suggest that the Universe is starting to expand at a faster rate

  • It has been suggested that this accelerated motion is caused by dark energy pushing everything in the Universe apart

• If gravity is present everywhere in the Universe, it might be expected that everything will one day become closer together, but that is the opposite of what we see

  • This is another reason why dark energy is a possible solution which could be counteracting gravity and expanding the Universe instead