number of breaks: 2
Is dark matter lighting up the sky with X-rays?
Eighty-five percent of the mass in our Universe is the mysterious substance named dark matter. Besides giving it a name, however, we know little else about it. How can we claim we know dark matter exists if we can't even see it? Through gravity. Just... click to read more
Digging up a dinosaur in a galaxy cluster
Galaxy clusters are the biggest gravitationally-bound objects in the Universe, millions of light years across, some as massive as a quadrillion (10^15) suns. They contain thousands of galaxies and are filled with 100-million-degree plasma, so tenuous it is a million times less dense than the... click to read more