When it comes to extrasolar planets, appearances can be deceiving. Astronomers have imaged a new planet, and it appears nearly identical to one of the best studied gas-giant planets. But this ...

The Solar System does not have a clear border. The influence of the Sun in certain domains is small enough for the Voyager probes to have escaped into interstellar space, but there are comets and ...

Beginning in late November during the waning phases of the Moon, and then again in late December, you can investigate the possibility of a curious optical phenomenon. It involves a bright planet ...