Day: November 8, 2008

The Hobbit Challenge

We were not Alone. Less than 12,000 years ago we shared the planet with Homo floresiensis – the Hobbits. Aunty (the Australian Broadcasting Corporation) screened an updated documentary on the Hobbits, with some seriously teasing ideas… The Hobbit Enigma …which is fully downloadable. Well worth a look. It gives a voice to the sceptics as well as the believers, but makes a strong case that the Hobbits really are small-bodied, small-brained hominids unlike anything previously imagined.

But what are they? Two possibilities –

(i) a different evolutionary track from Australopithecus roots. Bill Jungers backs this idea, especially after he fit together near perfectly the hip bones of the Hobbit (LB-1) to the sacrum of Australopithecus afarensis (“Lucy”).

(ii) a dwarfed version of Homo georgicus – the 1.8-1.7 million year old hominids from Dmanisi in Georgia, which have much smaller brains than Homo erectus plus some post-cranial features uniquely their own.

But did the ancestors of Homo floresiensis migrate to Indonesia? Or did our ancestors migrate to Africa from Asia?

Notes:

Some links –

Were the Hobbits Cretins? …medically cretins i.e. deficient in iodine. Very unlikely as the main source of iodine, fish, were found amongst the food remains in the cave.

John Hawks’ Hobbit cretin FAQ …more reasons why that analysis is wrong.

Is the Homo floresiensis phenotype due to mutations in the PCNT gene? …a rare condition causes an otherwise normal person to grow to half-size – including an otherwise normal, but small brain. A very ascerbic Anthropology blogger’s take on the matter. Science is about scepticism…

Bradshaw Foundation page on the Hobbits …initially what drove Mike Moorwood and colleagues to Flores was 30,000 year old Asian paintings in the Kimberlies, Northern Territory.

More Exoplanets!

Yes… there’s more now listed at the Extrasolar Planets Encyclopedia, bringing the grand total to 322. Except a few of the new ones are border-line brown-dwarfs – itself a dubious distinction. Anthony Whitworth and his various colleagues have been modelling the formation of brown-dwarfs for years, and their latest model forms a bunch of brown-dwarfs, low mass stars and even planets in a heavy disk around a solar mass star. The heavy disk fragments under its own gravity, but is too far from the central star to be disrupted by shockwave heating, thus allowing a whole bunch of Jeans Mass clumps to condense. Most are scattered by their mutual interactions, but some get captured by the central star.

Thus in this model there’s no real distinction between stars, brown-dwarfs and planets, except the obvious “Does it fuse hydrogen, deuterium or nothing?”

A related model even more explicitly makes planets… Formation of Massive Exoplanets by Fragmentation of the Protostellar Cloud …in the same way as low-mass stars and BDs. Another e-print this year produces another eeriely familiar model… Planet Formation by ConCurrent Collapse …with many of the same features.

But most venerable of all is Michael M. Woolfson’s Capture Theory, an ADS bibliography for which (many downloadable) is here.

As Woolfson himself has said, there’s more than enough room for several different scenarios to successfully make planets…

Carnival of Space #78

Is at Simostronomy… and chock full of goodies. A surprising amount of space-bloggers have picked up on the magnetic shield experiments that hit the presses during the week. Not a new idea, but no one has tested a magnetic field in a stiff plasma wind before, and the results were pretty cool! But I won’t link to it… go visit a Space-Blogger or two!