Is space a perfect vacuum? © Getty Images

Is space a perfect vacuum?

For a perfect vacuum to occur, space would need to be totally devoid of all matter including energy fluctuations which exist even in empty space.

Asked by: Talhah Loonat, Handforth

Advertisement

A vacuum is defined as a space devoid of all matter. In the Solar System, space contains on average five atoms per 1cm3. Interstellar space, between stars, contains around one atom per 1cm3, while intergalactic space, between galaxies, contains 100 times less. Ultimately, a perfect vacuum isn’t possible because quantum theory dictates that energy fluctuations known as ‘virtual particles’ are constantly popping in and out of existence, even in ‘empty’ space.

Read more:


Advertisement

Subscribe to BBC Science Focus Magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun facts.