A new space telescope designed to peer into some of the farthest regions of the universe could finally answer one of the most puzzling questions surrounding Albert Einstein’s general theory of relativity.
The Euclid mission, which is due to be launched by the European Space Agency in 2021, will capture images of billions of distant galaxies to provide new insights into how gravity works in the depths of space. Einstein’s famous theory, which he published in 1915, is widely considered to be the best way of explaining gravity. It essentially says that massive objects cause the fabric of space and time to curve, which causes other objects to fall towards them.
But while general relativity appears to be consistent with how scientists observe gravity behaving in our own solar system and galaxy, it begins to look less convincing on larger scales.
Observations of distant supernovae suggest that our universe is accelerating as it expands, although some scientists dispute this. For accelerated expansion to happen under general relativity requires the universe to be permeated by a mysterious, and so far undiscovered, ‘dark energy’ that is needed to drive the process.
While many physicists are convinced by the existence of dark energy, others are searching for alternative explanations. Prof. Koyama leads a project called CosTesGrav, which is using observations of distant galaxies to help develop new theories that modify general relativity so it works on large scales. The data gathered by Euclid when it launches will be vital to help them do this.