Most of the Universe is missing

What is dark matter?

We normally detect matter in space, such as stars, dust clouds or planets, by its interaction with the electromagnetic force. Stars emit electromagnetic radiation, dust clouds absorb it and planets reflect it. One way or another, we can "see" it. A great deal of evidence, which has been building up for 75 years, suggests that this is just the tip of the iceberg.

A view along a section of the 27km long LHC tunnel and collider

It seems that 85-90% of the mass in the universe does not interact with the electromagnetic force, so we can't observe it directly. This dark matter only gives itself away through its gravitational effect.

So what is it?

For this assignment, you will research the latest scientific thinking about dark matter and how the experiments at the LHC might or might not help crack this mystery. Your teacher will tell you how they would like you to present your findings.

Key things to find out:

What are galactic rotation curves? How do they provide evidence for the existence of dark matter?
What is gravitational lensing?
Can you find an example of gravitational lensing providing evidence for the existence of dark matter?
What are gravitational waves? What might cause them?
One explanation for dark matter is that it is some sort of non-baryonic matter, that isn't made of protons, neutrons and electrons at all. Hypothetical supersymmetry particles are a strong candidate, and they are looking for these with the LHC. But what are they?
What are WIMPS and MACHOs?