The Oort Cloud In 1932 the Estonian astronomer Ernst Opik (1893-1985) proposed that long-period comets came from an orbiting cloud at the outer […]

The Hunt For Distant Worlds Historically, the quest to detect remote planets, inhabiting the families of alien stars beyond our […]

Galaxy Wonderland Galaxies are gravitationally bound systems of stars, dust, gas, stellar relics, and mysterious non-atomic dark matter. Galaxies come […]

The Magellanic Clouds Both the LMC and SMC were named after the Portuguese explorer Ferdinand Magellan (1480-1521) who mistakenly believed they were clouds. While […]

The Dark Side The mysterious dark matter is believed to consist of exotic non-atomic particles that do not interact with electromagnetic radiation. […]

Solar Nursery Our Solar System emerged from mixed fragments composed of lingering relics from the long-dead, nuclear-fusing furnaces of older […]