Nisi cognitio finitas, infinitum sit necesse est ignoratio
Hopefully in your fave news-source, but here’s a few more…
NASA – HST news
New Scientist news-bite
Scientific American
BBC News
From the ExtraSolar Planet Encyclopedia…
Fomalhaut and planet …only 25 lightyears away.
Hr 8799 and retinue …some 128.5 ly away. A bit far, but at least we know it has planets.
…enjoy!
Seems Edgeworth-Kuiper Belts are more common than regular star-systems, at least around A stars…
Universe may abound with icy planets (from COSMOS magazine.)
…A stars are like Sirius A and Fomalhaut (stellar celebrity with a planet now spotted by the HST), substantially brighter than the Sun, not heavy enough to get dramatic and go SuperNova. Instead they race through the Main Sequence and become Red Giants in less than a billion years. So while the belts of Icy Planets are currently chilled, eventually they will melt down and become rather nice for a few million years before their stars sputter out.
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.
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…
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!
Every so often I try to revive interest in odd papers. Here’s one… SETA and 1991 VG …plus its ADS Entry.
Basically Duncan Steel, NEO astronomer and expert, asks the not-too-crazy question that if a small, highly reflective object on a near Earth orbit isn’t a (known) man-made vehicle, nor dull like a meteoroid, then what is it? SETA – the Search for ExtraTerrestrial Artefacts – is exactly what its name implies, looking for products of intelligent behaviour on Earth and in space. And 1991 VG might be an example.
Question is: alien space-junk or a working probe?
And if it is a probe, then why is it suddenly becoming visible? Based on our primitive attempts at invisibility cloaks using meta-materials I suspect any advanced technological species will be able to remain unseen by primitive eyes… yet here we have a probe making itself blatant. Hmmm…
It’s up… Carnival of Space #77 at Tomorrow Is Here Blog…
…Paul Gilster scooped me with a better discussion piece on the Benfords’ papers. I chucked in a comment about my favourite star HD 157881 or Gliese 673 as it is otherwise known. In 1990 – according to an interview I saw on an ABC Science Doco in 1992 – a Western Australian radio telescope picked up a really strong signal (like the “Wow!” signal of 1978) from Gliese 673 but didn’t get another ‘scope on it before it faded. According to the Benfords that’s exactly what we should expect from economically practical beacons. Not saying it really was a signal from ETIs, but it’d be so cool if it was. The star itself is a K7V, with an absolute visual magnitude of 8.1 and an effective temperature of 4020 K. A planet could easily exist in its habitable zone – the extended habitable zone of James Kasting, not Michael Hart’s ultra-tight hab-zone that is.
Addendum
Data on stars to 30 parsecs (about 100 ly) can be found HERE… and our star in question is #76 in Tables 1 & 2 (dwarf Main Sequence stars). According to their computations the Teff is 4115 K – for “cool” stars it’s really hard for computations to get closer than ~100 K working from different empirical formulae. The luminosity is ~0.11, so the HabZone is between 0.32 AU and 0.64 AU. Tidally locked planets have issues keeping an even temperature, so how far out does an Earth-sized planet have to be to avoid tide-lock? For the Sun it’s about 0.5 AU. Assuming stellar mass is ~1/4 power of the luminosity we get ~ 0.58 Msol for GJ 673. The tide-lock scales to the 1/3 power of the mass, thus ~0.41 is the new tide-lock radius, which HD 157881 dodges neatly. It really could host an exo-earth with ETIs… could…
At 25.2 ly away that’s 50.4 years round trip for signalling. Since high-powered RADAR were used extensively during the “Battle of Britain” in 1940 what’s the minimum time-span for ETIs to signal back with what they received? Just like Ron Bracewell first suggested – send back the signal you receive to get noticed. Well 1940 plus 50.4 is… 1990!
The Search for ExtraTerrestrial Intelligence and Messaging ExtraTerrestrial Intelligence are about 50 years old as a proper scientific endeavour – the first published paper was in 1958 and the first SETI was in 1960. But the Search has come up empty handed. However before we conclude ETIs are rare to non-existent we should ask ourselves if we’re conducting the Search in a reasonable manner? Have we considered the best strategy? Or has SETI been driven by wishful thinking divorced from economics?
Twin brothers James & Gregory Benford, plus Dominic Benford, have argued that Searching and Messaging driven by cost considerations (in a very general sense) won’t look anything like the hoped for (and unseen) Great Blindingly Obvious beacons, and will look a lot like the brief flashes of radio-energy seen so far…
Cost Optimized Interstellar Beacons: SETI
Cost Optimized Interstellar Beacons: METI
…following the current work on the Galactic Habitable Zone, and the Extra-Galactic Cosmic-Ray Periodic Death Scenario, the authors argue that searching and messaging should focus on the Galactic Core and stick to the Galactic Plane. This also reduces the total energy needed and increases the odds of a message finding a receiver.
All quiet here in “Crowlspace” but elsewhere in the Blogoverse is the latest Carnival of Space. And the BlogHost IS normally in Swedish, in case you’re bleary eyed and feeling a touch out-of-it.
As the World licks its collective wounds after the Financial Meltdown and we all watch the storm clouds gather, consider the Egyptians suffering under the Plagues of Moses way back in c.1500 BC (1300 BC?) Usually written off as fiction, the perfervid imaginings of a pious scribe or two, a recent analysis by Colin J. Humphreys lends the account some credibility when the details are matched against the internal calendar of the account…
| The Plagues of Egypt | ||
| Plague | Cause | Time of Year |
| Nile turned to Blood and fish died | Red soil particles and red algal blooms | September |
| Frogs/Toads | Pollution forces frogs ashore where starvation and dehydration cause mass die-off | September-October |
| Gnats | Biting Midge, Culicoides carnithorix. Predators all died causing population boom. | October-November |
| Flies | Stable Fly, Stomoxys calcitrans. Population explosion as above (slower life-cycle.) | November |
| Livestock mass-deaths | Culicoides spread Bluetongue and African Horse Sickness viruses. | November-December |
| Boils | Stomoxys spread skin infection. | December-January |
| Hail | Exceptionally severe hailstorm. | February-March |
| Locusts | Damp sand from hail attracts the Desert Locust to lay eggs. | February-March |
| Darkness for 3 days | First annual khamsin produces a dark, dense dust-storm. | March |
| Death of Firstborn (males) | Mycotoxin on grains, due to grain being contaminated and damp after hail and locusts, and stores being sealed by sand from sandstorms. | late March-early April |
All these events occurred at the correct time of year and follow logically one after the other. Thus it’s a coherent whole account, not a pastiche of scribal bits and pieces as several venerable compositional theories hold. Either the scribes who wrote it were keen observers of Egyptian natural disasters, and they pieced them together correctly, or the account is describing an actual historical catastrophe. But was it caused by the God of Moses? Or did Moses somehow see it coming and skilfully used the opportunity to march his people into the land of Midian to found a new nation? Is there a difference?
For more on Colin Humphreys’ ideas check out his book The Miracles of Exodus. He’s a physicist by training who became keen on the historicity of the Exodus tale after a trip to the Levant. Not initially a believer in the accuracy of the account his research eventually produced a convincingly coherent reconstruction of Moses’ tale. Annoyingly, direct evidence for Moses remains elusive.