Reflected Light from First True Exoplanet Observed

The first exoplanet ever discovered was 51 Pegasi b in 1995.  It kicked marked the slow beginning of what would soon become the ‘exoplanet gold rush.’  It meant that for the first time, we had the technological capacity to discover new worlds, and science fiction soon became science fact.  51 Pegasi b was also a very strange planet.  A massive Jupiter sized world orbiting very close to its home star.  On one hand it was this characteristic that made it much easier to detect.  On the other, it showed us that we did not understand planetary system formation as well...

Hubble’s Best View of a Planetary Disk

At one point in history, let’s say around 1994, astronomers were fairly confident in their understanding of the formation of planetary systems.  Even though at the time we hadn’t found any planets orbiting other stars, they had long been theorized, and we figured that systems would form much like our own solar system.  Rocky planets in the interior, gaseous giants further out, and a huge icy debris field at the outer edges. And then along came 51 Pegasi b.  Half the mass of Jupiter, it orbits its star in only 4 days, far closer than Mercury.  It was considered a...