
Dark matter: should we be so sure it exists? Here's how philosophy can help.
More than 50 years since astronomers first proposed "dark matter," we have no idea what it is and nobody has directly seen it or produced it in the lab.
Roughly 80 percent of the mass of the universe appears to be dark matter: an invisible material that seems to interact with ordinary matter only through gravity, without emitting light or energy. Scientists cannot detect dark matter directly and don't yet know what it's made of, but they track its influence based on the motions of stars and galaxies. The presence of dark matter is necessary to explain the universe's current structure.
Related Topics: The Big Bang Theory, Black Holes, The Theory of Relativity in Space, Gravitational Waves