Extrasolar Planets

Until a couple of decades ago, the only planets we knew existed were the nine in our Solar System. In the last twenty-five years, we’ve lost one of the local ones (Pluto, now classified as a “minor planet”) and gained about three thousand...

The desire to discover distant, rare, and strange objects dominated twentieth-century astronomy, for which increasingly larger and more sensitive telescopes were constructed. 

The act of carrying out this objective has brought enormous—and...

The stability of the solar system is one of the oldest problems in theoretical physics, dating back to Isaac Newton. After Newton discovered his famous laws of motion and gravity, he used these to determine the motion of a single planet around ...

Why is the expansion of the universe speeding up, instead of being slowed by the gravitational attraction of galaxies and dark matter? What is the history of the Milky Way galaxy and of the chemical elements in its stars? Why are the planetary...