NASA’s plans to return astronauts to the Moon through the Artemis program and ultimately send humans to Mars highlight just how far space exploration has come. Yet while the Moon and Mars remain compelling destinations filled with scientific mysteries, looking beyond our solar system raises even deeper questions about the universe itself.
Among the biggest of those mysteries is matter – the substance that makes up everything around us. Surprisingly, most of the matter in the universe is invisible, and astronomers still do not know what it is.
