What, exactly, does the “science of reading” mean? The phrase has become popular over the past several years, used as a shorthand for many of the instructional changes schools have adopted to bring ...

The question of what defines a species has vexed scientists across the ages, particularly in conservation, where decisions require a firm understanding of biodiversity. When you purchase through links ...

Astronomers are proposing a new, more quantitative definition of what makes a planet. The new definition looks more directly at the object's mass — but it would still leave Pluto out of the running.