Month: May 2010

What’s Wrong With Jupiter?

Jupiter loses a stripe – 11 May 2010 – New Scientist.

Losing a stripe seems rather careless for a Giant Planet, but that’s what Jupiter has done. Why? First let’s look at what Jupiter’s bands are made of. The white, almost featureless cloud deck that has replaced the stripe is composed probably of ammonia ice-clouds and virtually all the cloud on Jupiter is the same. Neither hydrogen or helium can condense as clouds on Jupiter so most of the atmosphere is actually clear gas. The small fraction of gases that can condense do all the colouring and feature-making on all the gas giants.

Neptune & Uranus generally show very few clouds because they’re too cold for hydrogen compounds like methane, ammonia and water to condense at visible levels – only occasional methane ice clouds provide most of the visible features. Saturn is a bit warmer, but it seems to be “blanded out” because of the cold too. More visible clouds appear, but deeper in the atmosphere and so they’re more obscure.

Jupiter has a richer palette because it is warmer. We’ve met the immense ammonia ice-cloud canvas, but adding colour are trace organic, phosphorus and sulfur compounds. These produce the sometime vivid colours dredged up from deep down in Jupiter’s innards. Now it seems the source of colour has shifted or has been depleted and one of Jupiter’s colour bands is gone.

SO why the shift? We really don’t know. Jupiter is being mysterious and any “explanation” is currently just speculation, informed or otherwise. No doubt wacky theories will emerge to ‘muddy’ the picture, but there’s no way of knowing without actually going…

Opik-Oort Cloud (Mostly) Not of the Sun?

Is Halley’s comet an alien interloper? – space – 10 May 2010 – New Scientist.

New simulations of the evolution of the Opik-Oort Cloud indicate it might be anomalously heavy for its cometoids to have come from our Sun’s forming Outer Planet disk. Instead the majority of OOC objects formed in the same star-forming nebula as the Sun and followed it as the nebula dispersed. Thus they’re captured. Simulations of the Scattered Disk produce only 10 times as many OOC objects as SD objects, but observations of long-period comets, like Halley’s, indicate 700 times as many OOC objects as SDOs.

Doesn’t mean there’s more out there, just that most of them aren’t from the same material as the Sun’s planets. Does mean that many, many more ended up as free-floating objects between the stars. Thus star-travellers may find way-stations strung out between here and their destinations, a common “Galactic Swarm” of comets.

Fast Ignition of Boron-Proton Fusion

Heinrich Hora is a fusion researcher at UNSW here in Oz who works with George Miley, Leif Holmlid and other alternative fusion researchers. He has several very interesting papers on using lasers to induce “fast ignition” of solid boron-hydride. Fast ignition is when a sufficiently sharp energy pulse is used to set off a self-powering fusion detonation wave in the target, and a recent advance in producing very narrow pulses of laser energy has raised the prospect of igniting p+11B fusion with an energy input just x10 that needed for D+T. That’s really good news and Hora is obviously very enthusiastic about the idea.

Here’s his web-page… Heinrich Hora
And a representative paper… Laser-optical path to nuclear energy without radioactivity: Fusion of hydrogen–boron by nonlinear force driven plasma blocks

…so fast laser ignition will be worth investigating for “Project Icarus” too.

Neanderthal Man is… Us!

NEANDERTALS LIVE! from Assoc. Prof. John Hawks’ weblog.

John Hawks discusses how Neanderthals have survived to the present day, as recently revealed by their sequenced genomes. More interestingly it means the Neanderthals were the same species as Homo sapiens – they really were Homo sapiens neanderthalis, a sub-species variant, as a lot of older paleoanthropologists insisted c.30-40 years ago. We didn’t evolve from them, but they have contributed genes to our common humanity. All us non-Africans, and probably many living Africans, owe them a debt of ancestry. Our expanding population of African-originated variant Homo swallowed up the smaller population of regional variants that was ‘Neanderthal Man’, some 50-40,000 years ago…

DAWN’s slow crawl…

Getting between the planets isn’t easy if you want to stop at multiple destinations on one tank of propellant. Currently the only probe able to do so – unless they do some orbital gymnastics with Cassini – is NASA’s DAWN. Currently DAWN is seemingly within spitting distance (~0.48 AU) of Vesta, its first port-of-call, but both are going too fast to stop. That maneuver is approximately 439 days away according to the count-down clock.

Vesta is an interesting little world – surprisingly an asteroid covered in lava/basalt. Interestingly we already have samples of it available for study, in the form of the HED meteorites, which are the many scattered remains of an immense collision that ripped off a huge chunk of Vestan crust ~1 Gya.

Question: Why did Vesta melt and spew lava, but so many of its asteroidal siblings didn’t too?

More on ARMAN

Weird, Ultra-small Microbes Turn Up in Acidic Mine Drainage …at On Orbit
…a reiteration of this Astrobiology Magazine piece …itself a re-echo of this U.Cal Berkeley News Bite. Basically the ARMAN (Archaeal Richmond Mine Acidophilic Nanoorganisms) microbes, classified with the Archaea, are very small, but still independently subsisting organisms, perhaps even predated upon by Thermoplasma archaea they share their habitat with. Their genomes are very small, a mere million base-pairs – smaller than the genome of the giant Mimivirus family of amoeba infecting viruses. More interestingly the code is stripped back, with its genes averaging a mere 774 base-pairs long – i.e. not a lot of unexpressed material. Human genes can be very large, even when the proteins coded by the gene aren’t themselves so large. The ARMAN microbes are virtually the “minimal lifeform” sought after by artificial life researchers, living in quite extreme environments – more acidic than battery acid is the description. Interestingly, for astrobiology, the clouds of Venus are similarly acidic…

Latest paper: Enigmatic, ultrasmall, uncultivated Archaea