The speed of light, c, is not just a very large number. In modern physics it is a structural constant: the conversion factor ...

Two black holes merged together 2.4 billion light years away from Earth, and scientists have just figured out how fast the newborn ricocheted, and in which direction.

At just 25, Cecilia Payne-Gaposchkin applied quantum physics to a treasure trove of astronomical observations to show that stars are mostly hydrogen and helium.