Fifty newly discovered planets announced September 30, 2011

The largest haul yet of newly discovered extrasolar planets was recently announced.  That alone is news, but the types of planets discovered within said haul makes for even more amazing news.  In addition to numerous Neptune-like planets, scientists have also discovered what they call “super-Earths” that orbit stars very similar to our sun.  One planet in particular, dubbed HD 85512b, lies at the edge of what astronomers have determined to be the star system’s “habitable zone.”

That term deserves a bit of explanation.  Layman and scientist alike clamor for finding a planet that can support life as we know it.  But to do that requires particular conditions that were not discovered outside of our solar system until recently.  Basically, the “habitable zone” is the distance range from a given star in which a planet can orbit and be able to support life.  Too close to the star outside of this zone, and any water — aside from a Nitrogen-Oxygen mix atmosphere, is pretty much the Nummer Eins requirement for complex organisms to survive — will boil away (read:  Venus).  Too far away from the star, and water will perpetually freeze (Mars being a borderline case in that regard).  What scientist have just discovered are some planets within the zone — not too cold, not too hot, but just right.

Another such planet inhabiting its own “Goldilocks zone” is a world dubbed Gliese 581d, though it orbits a red dwarf star, and as such, its habitable zone is much closer to its respective star than Earth’s orbit is to our Sun.  On the other hand, should the system in which the binary Rigel star (a.k.a., Orion’s left foot) have such a zone, it would be much further away.  The reasons could hardly be more obvious.  In addition to being many times the size of our Sun, it also burns much hotter:  it’s temperature is about 11,000 Kelvin, in contrast to the Sun’s comparatively milder 5,778 K emanating from its photosphere.  Translation:  Rigel’s habitable zone, should it even have one, would be a heckuva lot further away from that star than Earth 93 million-mile distance from Sol.

Seeing things in a larger context, it is remarkable how many gas giants have been discovered outside of our solar system, but how very few smaller rock planets we have found.  As Earthlings, it is only natural to see things within the purview of our own star’s system, and as such, we are quite apt to see Jupiter, Neptune, and Saturn as exceptional worlds.  But given the extrasolar gas giant-to-rock planet discovery ratio as of late, these recent developments should serve as a reminder how truly exceptional this third rock from the Sun is.

Much more information on this remarkable finds are offered in great, engaging detail on this National Geographic web pages.  Read on!