Dark matter is hypothesized to outweigh "ordinary matter" in the universe by a factor of five. That means all the stuff we ...

Astronomers tallying up all the normal matter—stars, galaxies and gas—in the universe today have come up embarrassingly short ...

Physicist Richard Lieu first explored the idea that gravity could exist without mass—now he’s got a new cosmological model ...

Galaxies may not be as simple as "young and blue" or "old and red." A new idea from astrophysicist Charles Steinhardt proposes a third type: red star-forming galaxies that break the mold. These galaxi ...