Compléter 103-testVersion en ligne 103-test par Farhad Key 1 detect galaxy galaxies substance repels baryonic exists observed impossible The rest of the universe appears to be made of a mysterious , invisible called dark matter ( 25 percent ) and a force that gravity known as dark energy ( 70 percent ) . Scientists have not yet dark matter directly . It doesn't interact with matter and it's completely invisible to light and other forms of electromagnetic radiation , making dark matter to with current instruments . Bust scientists are confident it because of the gravitational effects it appears to have on and clusters .