Perhaps the greatest and most fiercely contested race in modern science is the search for dark matter.
Physicists cannot see this stuff, hence the name. However, they infer its existence because they can see its gravitational influence on the structure of galaxies and clusters of galaxies. It implies that the universe is filled with dark matter, much more of it than the visible matter we can see
If they're right, dark matter must fill our galaxy and our Solar System. At this very instant, we ought to be ploughing our way through a dense sea of dark matter as the Sun moves towards the constellation of Cygnus as it orbits the galactic centre.