Meet Pluto, the dwarf planet.

It is now official. Scientists meeting in Prague have demoted the planet Pluto to the secondary status of dwarf planet. The decision was based on the fact that Pluto’s orbit overlaps with that of Neptune, which disagrees on the third required characteristic of being a planet. In fact, during the same meeting, scientists redefined a planet as a celestial body which

1. is in orbit around the Sun
2. is large enough that it takes on a nearly round shape
3. has cleared its orbit of other objects

We understand the ambiguity when we consider the previous definition of a planet: a celestial body moving in an elliptical orbit round a star. (Oxford Dictionary). A quote from the BBC’s article on the subject explains the history behind the debate:

Pluto’s status has been contested for many years. It is further away and considerably smaller than the eight other “traditional” planets in our Solar System. At just 2,360km (1,467 miles) across, Pluto is smaller even than some moons in the Solar System.

But the real reason for Pluto’s demotion came with a discovery in 2003, which seemed to indicate that if Pluto was in fact a planet, then a number of other celestial bodies should be considered a planet, adding about 20 new planets to our Solar System.

The critical blow for Pluto came with the discovery three years ago of an object currently designated 2003 UB313. After being measured with the Hubble Space Telescope, it was shown to be some 3,000km (1,864 miles) in diameter: it is bigger than Pluto.

One thing is for sure, my kids are now going to have to learn new rhymes for the names of the eight planets of the Solar System: “My Very Expensive Mercedes Just Smashed Up a Nissan”. Or the less common “My Very Elderly Mother Just Sat Upon a Needle”. Gone are the days of ‘New Porches’ and ‘North Poles’. Too sad.

Information on Pluto (From the BBC’s article)

It was named after the god of the underworld in Roman mythology.

Orbits Sun every 248 years
Diameter of 2,360km
Has at least three moons
Rotates every 6.8 days
Gravity about 6% of Earth’s
Surface temperature -233C
Nasa probe visits in 2015

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• A BBC News report on the subject: Pluto loses status as a planet

Fearsome Toothed Whale Fossil Found in Oz

The fossil studied by Erich M. G. Fitzgerald of the School of Geosciences at Monash University, Clayton, Victoria in Australia is surprising to scientist since it belongs to the family of baleen whales. Modern day baleen whale, the humpback and blue whale for example, are all placid, plankton eaters, which means that they do not have huge teeth that are used to eat prey. In fact, some of the fossil whales had teeth, but were inferred to have fed in a similar manner to living whales. The following excerpt from Fitzgerald’s paper [1] explains their conclusion on the subject:

It thus refutes the notions that all stem mysticetes were filter-feeders, and that the origins and initial radiation of mysticetes was linked to the evolution of filter-feeding. Mysticetes evidently radiated into a variety of disparate forms and feeding ecologies before the evolution of baleen or filterfeeding.

This fossil represents a previously unknown species, named after its teenage finder Staumn Hunter, who noticed it in an exposed boulder while surfing in 1997. The species is believed to have lived about 9 to 25 million years ago after the last common ancestor of the toothed and baleen whales. As I pointed out earlier, the previously found fossil whales did not elucidate the origins and early evolution of baleen whales from their lack of a different manner of feeding. So transitional fossils like this one found in Australia can usually explain many hypotheses scientists have on the subject. This one is no exception.

The phylogenetic context of the new whale indicates that basal mysticetes were macrophagous predators that did not employ filter-feeding or echolocation, and that the evolution of characters associated with bulk filter-feeding was gradual.

Finds like these also present scientists with new hypotheses and new questions to be resolved. For example, how did whales evolve drastically different eating habits more than 34 million years ago ? One thing is for sure, this find will clearly make it into the (children) books on the dangerous and mystical monsters of the Pre-historic times.

Age and Paleontogical Information on the Fossil

• ERA: Cenozoic
• PERIOD: Tertiary
• EPOCH: Oligocene
• AGE: 23.8 to 33.7 Million Years Ago

Related Articles

• A Newsvine Seed by Miguel: Whale Fossil Sports Fierce Teeth
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References:

• [1] Fitzgerald, E.M.G. (2006) A bizarre new toothed mysticete (Cetacea) from Australia and the early evolution of baleen whales, Proceedings of the Royal Society B.