ANU has just posted this for our edification:
Did you know we can only see 15% of the universe? The other 85% is known as dark matter and cannot be observed directly. So how do we study something we can’t see?
In this video, Suryashree Aniyan condenses her PhD down to three minutes for the Three Minute Thesis competition, explaining how she searches for clues on dark matter by observing things that we can observe, such as gravity.