Matter is defined as that which 1) has mass and 2) has volume or takes up space. Mass is an intrinsic property whose base SI unit is the kilogram (kg).

Invisible dark matter makes up most of the mass in the universe, far outweighing the amount of matter we can see. (Image credit: Dark matter, R. Caputo et al. 2016; background, Axel Mellinger ...

Dark matter, the mysterious form of unobserved matter which could make up 85% of the mass of the known universe, is one of science's biggest manhunts.

With 10 times the mass of the Milky Way, this filamentary structure accounts for much of the universe's "missing matter," the search for which has baffled scientists for decades.

NASA's James Webb Space Telescope recently zeroed in on the Bullet Cluster—delivering highly detailed images that show a greater abundance of extremely faint and distant galaxies than ever before.

Scientists believe that if a nuclear clock is developed – one that uses the atomic nucleus to measure time with extreme precision – even the tiniest irregularities in its ticking could reveal dark ...