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Landing site of Apollo 14, as seen from Moon orbit by the Lunar Reconnaissance Orbiter If you love talking about Solar System science (and if you read this blog, it seems statistically likely), consider applying to become a Solar System Ambassador. In this program, sponsored by NASA’s Jet Propulsion Laboratory (JPL), volunteers speak about current research in their communities.
- We haven’t found life on any other world (yet), but there are plenty of alien-to-human environments here on Earth. Caleb Scharf describes organisms found near a “white smoker”, an undersea volcanic vent that produces carbon dioxide so highly compressed that it’s a liquid.
- From the Annals of Improbable Research: the physics of ducks’ feet, based on a paper entitled “Characteristics of vortex formation and thrust performance in drag-based paddling propulsion”. Be kind to your web-footed friends.
- Did the Solar System originally have a fifth Jovian planet? (podcast) Planet formation simulations have had some difficulty in reproducing the number and location of planets we actually have, but one model found if you load the dice to make five big planets, one gets ejected from the Solar System to wander forever alone through the galaxy.
On that note, we don’t have a good name for planet-like objects that aren’t currently orbiting a star — even though these objects are now known to be very common. Ironically, “planet” is derived from the Greek word for “wanderer”, since they wander across the field of stars in the geocentric model. Now astronomers have found objects that really fit the definition of a wanderer, but calling them “planets” seems inappropriate, since orbiting a star (not just the Sun) is a common requirement in modern definitions for planets. So, what do we call these objects? “Planet-like object” is too clunky; “planetoid” is already in use. Any suggestions?
Galileo's Pendulum 
4 responses to “Tuesday Linkses, My Precioussss”
The term generally used for planets not orbiting any star is “rogue planets.” That makes sense, as compositionally, they still are planets and what they are hasn’t changed. This may be one of many new categories we have to create with an adjective in front of the word “planet.” Chances are these bodies at one time orbited a star only to somehow be ejected from that orbit. A good precedent is the classification of brown dwarfs on the lowest end of the stellar category. If an object ever conducted hydrogen fusion, even if it is not doing so now, it is considered a type of star.
These objects discovered by Sumi et al (MOA group) are not necessarily planets at all. Rather they are unbound planetary-mass objects.
A good and more accurate acronym might be:
UPMOs
Unbound Planetary-Mass Objects.
Or USOs, for Unbound Substellar Objects.
They could be primordial black holes. All we currently know is their approximate mass range, and that is only a “ballpark figure”.
RLO
Discrete Fractal Cosmology
Caleb Scharf puts in a vote for “vagabond” for planets not orbiting any star. I like that idea: it’s a one-word name (like exoplanet), and very descriptive. (Source: http://bit.ly/oKmlae)
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