APOD: 2017 November 22 Oumuamua: Interstellar Asteroid
22.11.2017

Nothing like it has ever been seen before. The unusual space rock 'Oumuamua is so intriguing mainly because it is the first asteroid ever detected from outside our Solar System -- although likely many more are to follow given modern computer-driven sky monitoring.

Periodic Comet Swift-Tuttle
19.02.1996

Comet Swift-Tuttle, shown above in false color, is the largest object known to make repeated passes near the Earth. It is also one of the oldest known periodic comets with sightings spanning two millennia.

Gliese 876 System Includes Large Terrestrial Planet
14.06.2005

Is our Earth unique? In continuing efforts to answer this question, astronomers have now discovered an Earth-like planet orbiting a distant normal star. Previously over 150 gas-giant planets like Jupiter had been so discovered.

Dark Matter Ring Modeled around Galaxy Cluster CL0024 17
16.05.2007

How do we know that dark matter isn't just normal matter exhibiting strange gravity? A new observation of gravitationally magnified faint galaxies far in the distance behind a massive cluster of galaxies is shedding new dark on the subject.

Moon Over Eugenia
14.10.1999

Eugenia is an asteroid with a moon! This animation was constructed from infrared discovery images of the Eugenia-moon system taken in November 1998 using the Canada-France-Hawaii Telescope (CFHT). Main belt asteroid Eugenia, represented here as a central white patch, is a mere 215 kilometers in diameter.

25 Years Ago: Vikings on Mars
21.07.2001

On July 20, 1976, NASA's Viking 1 lander become the first spacecraft to land on Mars, followed weeks later by its twin robot explorer, the Viking 2 lander. Operating on the Martian surface...