Extra-solar planetary milestones

Two exciting announcements for astronomy enthusiasts have been made nearly at the same time. Not only have the first direct observations of an extra-solar planet have been made in visible light, there has also been the first direct observations of a multi-planet system around a normal star.

While it's not the first time that direct images have been taken of planets outside our Solar System, which were in infrared, it is the first time that such images were taken in visible light. Not only that, astronomers have actually managed to see it moving over a two-year interval. Fomalhaut was suspected to harbor such a planet back in 2005 when its lopsided dust belt was discovered, and the Hubble Space Telescope managed to directly observe the planet by blocking out the bright parent star's light.

Fomalhaut b orbiting its parent star, Fomalhaut
Fomalhaut b orbiting its parent star, Fomalhaut

And if that's not enough to stir some excitement, the Gemini Telescope and the Keck Telescope have for the first time managed to take direct infrared images of a solar system not our own that harbors multiple planets. Initially two planets were discovered orbiting the parent star, but followup observations revealed yet a third planet much closer to the star.

Planetary system HR 8799 showing all three planets
Planetary system HR 8799 showing all three planets

One of the things that direct observation of planets allows is the measurement of spectrographic properties of the planets, which can tell us what kind of stuff they are made of, something that was not very feasible, although not entirely impossible, with indirect methods of observation.