March 4th, 2010
Two new interesting news items, both discovered via Synthetic Aperture Radar (SAR) scanning by orbital space-vehicles. First target is the Moon… Water Ice Found on Moon’s North Pole …some 600 million tons of the stuff, found as ice a couple of metres thick lining the floors of 40 or so small craters around the Moon’s North Pole. The India moon-probe Chandrayaan-1 carried an American SAR instrument into Lunar orbit and successfully scanned the Moon before the probe packed it in. Now data analysis is producing these sort of reports, more which will appear thanks to the 41st Lunar & Planetary Sciences conference that is currently happening in the USA.
The next target is Mars… JPL News Buried Martian Ice …which has even more ice present than first imagined, buried under regolith so it doesn’t evaporate away to the Poles. Very handy for future colonists. Discovered via a Shallow Radar system on the Mars Reconnaisance Orbiter mission. A lot of it is very clearly associated with erosional basins, thus some kind of water/ice based weathering created the features and eventually trapped the ice there.
Buzz Aldrin has recently come down on the side of the Obama administration’s axing of the “Return to the Moon” program GWB began in the wake of “Columbia” burning-up in 2003. For a Moon-Walker that might seem a strange position to take, but Buzz’s position is more ambitious than the apparently “purposeless” (i.e. non-vote related) program of NASA. He wants commercial space-vehicles servicing the ISS while NASA builds a real space-ship, the XM, a space-ship ultimately bound for Mars. And he thinks we should use all the remaining bits of Shuttle etc. to do it.
I agree with the spirit of his plan, but I have one reservation. The Moon has a long-term resource that Mars doesn’t seem to have. Mars is the destination for colonization and ultimate transformation, sure, but the Moon has about ~2.5 million tons of 3He in its regolith, and I believe that will be vital to building high-speed fusion propelled space-ships. But we need to “ground truth” those proposed solar-wind deposited resources of the Moon. And there will be more than just 3He, which is very rare. All that lunar hydrogen, bound up as water-ice, will contain deuterium, another fusion fuel and vital for CANDU natural uranium reactors.
But here’s where Mars has an advantage – deuterium. Mars is enriched in the stuff, at least the water we can see is. Ideally we need both worlds, something only serious propulsion systems, like fusion, can give us.
Posted in Carnival, Sol Space, Starflight, Super-Tech | 1 Comment »
February 20th, 2010
Hi All
My first reaction to the “New Scientist” reporting the conclusions of William & Arthur Edelstein was to write an angry blog-post, but then I realised that such gamma-factors (~5,000) run up against the thermal glow of the galaxy and the CMB red-shifted into a white-hot blaze. It’s not just the proton radiation we have to worry about too. Dust, cosmic-rays and so on, all get focussed & intensified by relativistic aberration as well as the blue-shift. Essentially a “hard wall of light” forms, making such extreme speeds unhealthy. So I’m inclined to agree with the Edelsteins, though James Essig’s suggestion of ultra-dense matter shielding may well be the ‘unobtainium’ miracle needed to ultimately achieve such. However since the intensity falls off rapidly at lower gamma factors, this really isn’t an impediment to more modest ranges – a gamma-factor of ~50 would experience a much more benign radiation field.
Interestingly Alastair Reynold’s fictional “House of Suns” deep future view has maximum speeds of a mere 0.9999 c, even though they’re protected via some kind of space-time ‘interdict’ shield – though it’s hard to imagine what could power million ton starships doing 1200 gees at 0.999c…
Posted in Carnival | No Comments »
February 18th, 2010
Interstellar travel, in case you didn’t realise, is a passion of mine, so when it gets asinine press coverage I get pissed. Here’s an egregious example…
Read the rest of this entry »
Posted in Cosmos, SETI, Starflight, Super-Tech | 5 Comments »
February 14th, 2010
Happy Valentine’s Day to all you loveable Blog-ghosts who read this page.
I’ve been working on the dynamics of laser pushed reflectors – i.e. super-reflectors which can ‘reuse’ the beam thousands of times before it is absorbed and lost as heat. The concept was AFAIK originally discussed by Robert Metzger & Geoff Landis, but Young K. Bae has used it experimentally in a mock-up of a low-power position system for space-vehicles. Ignoring relativity, for now, and staying at close range to minimise diffraction loses, the final velocity over a range from Xo to X is pretty easily solved as…
v = sqrt[2.E/m*ln(X/Xo)]
…but then integrating, care of the Online Integrator from Wolfram’s Mathematica, to find the trip-time produces this horror…
t = 2.X.F{sqrt[ln(X/Xo)]}.sqrt[m/2E]
…F{…} is Dawson’s Function or Integral which is related to the Error Function that produces the Bell Curve. In otherwords there’s no easy way of computing the rotten thing.
Trawlling the Web produces some interesting finds, courtesy of the University of Arizona Press, a whole book online by Carl Sagan & James Pollack (both sadly deceased), Planetary Engineering ,which covers all the big questions of remaking the planets. Cool.
Sagan was a heavy-hitter in astrobiology & SETI – he worked on even while battling his ultimately fatal cancer and produced this paper, one of his last…
Scintillation-induced Intermittency in SETI
…which covers the fade & amplify effect that interstellar plasma can have on radio signals. Thus we might occasionally receive a signal from much further away, thanks to random drifts of plasma in the intervening void. Makes it very hard to get a repeat performance from such signal sources and the full implications are discussed here by his co-writer…
Now You See Them, Now You Don’t
…on his web-site (John Lazio’s page.)
Mentioned by the 1997 paper is an earlier SETI results paper, by Paul Horowitz & Sagan (again) from 1993…
Five years of Project META – an all-sky narrow-band radio search for extraterrestrial signals
…which reports a tantalising set of signals. Benford3 reference the paper in their duology…
Searching for Cost Optimized Interstellar Beacons
Messaging with Cost Optimized Interstellar Beacons
…which are deserving of a more detailed discussion next time.
Posted in Cosmos, SETI, Super-Tech | 5 Comments »
February 12th, 2010
Theology and theodicy are fraught with pitfalls and surprises. Amateur theology even more so. Here’s a review that is a case in point…
A caring God would not have designed us like this
…discussing a review of a new book, Inside the Human Genome: A case for non-intelligent design by John C. Avise, which argues the genome is such a demonic mess that it had no Designer. The reviewer makes the interesting point – perhaps we have a moral imperative to then fix the mess.
But what of the Designer? With a hat-tip to Anne Rice I wrote this…
Perhaps the Designer intended for biochemical Life to remain as ‘immortal’ archea & eubacteria, and was taken by surprise when they ganged together, made eukaryotes, then sex & death at the same time. After a billion years of watching the carnage S/He decided “enough is enough” and chose to intervene by developing an Intelligent Watchmaker who could fix the biosphere… but we’re just not finished yet. The Designer is still struggling with how to handle “junk memes” and is working on new software to upgrade us to Humanity 2.0…
As believeable as any religion, just more up-to-date.
…tongue firmly in cheek, but the point is that perhaps God didn’t know how the world would turn out – until it turned out this way. Even a “god outside time” has to let events occur to foreknow them, else they’re all being directly orchestrated by god and any “freedom” and “free-will”, as well as any evil and sin, is written into the Script of the cosmos, and God really is just a mask for the Devil. So even a God outside time must be surprised, from time to time, but eternally surprised.
And why should we be surprised by that fact? A number of mathematical arguments imply that knowledge, even perfect knowledge, of a system is only possible by letting that system ‘run’ when it is past a certain level of complexity. God took a cosmic risk when S/He created space-time and all else that followed.
Posted in Anthropology, Belief or Not, Biology, Cosmos | 5 Comments »
February 12th, 2010
Two recent arXiv preprints discuss capture of Dark Matter and limits on its self-annihilation inside white dwarfs…
Capture of Inelastic Dark Matter in White Dwarves
Inelastic Dark Matter As An Efficient Fuel For Compact Stars
…the first discusses limits for inelastic Dark Matter capture inside the white dwarfs of globular cluster M4, while the second discusses capture in general. PhysicsWorld.com has a commentary news-piece on the limits and the putative inelastic DM signal from the DAMA/LIBRA experiment… Warm white dwarfs could reveal ‘inelastic’ dark matter …and mentions white dwarfs maintaining an even 7000 K temperature, rather than cooling towards ~3000 K (what the coolest WDs radiate at.)
What does that mean, in the long term, I wondered? Consider the average white dwarf, which is about 0.7 solar masses and about 0.0093 solar radii. Call it 0.01 size of the Sun. At 7000 K each square metre is radiating x2.15 times the Sun’s 5780 K, thus the white dwarf is putting out about 0.0002 Solar luminosities – i.e. about 5000 white dwarfs would equal the Sun. Since the galaxy is expected to evolve to a state of being either white dwarfs or brown, then there will be about ~20 million solar luminosities worth of Dark Matter annihilation energy radiating from them until the Dark Matter runs out some time between 1019 – 1020 years from now.
The SETI implications are interesting – does it imply that civilizations with an extremely long-view will ultimately move into residence around white dwarfs? Such would live ~1-10 million times longer than red-dwarf based societies, which is quite impressive. Of course a mere 1020 years is nothing compared to eternity…
Posted in Carnival, Cosmos, Energy futures, SETI | 1 Comment »
February 7th, 2010
Every gun that is made, every warship launched, every rocket fired signifies, in the final sense, a theft from those who hunger and are not fed, those who are cold and not clothed. This world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children. This is not a way of life at all in any true sense. Under the cloud of threatening war, it is humanity hanging from a cross of iron.
Dwight D. Eisenhower
Posted in Carnival | 3 Comments »
February 6th, 2010
Nick Lane is a prolific writer and has some very interesting pieces available at “New Scientist” as well as his own web-pages. Very readable work from a biochemist. Here’s a sampler from “New Scientist”…
The Big O …not orgasm, but Oxygen and its variations through geological time. During the Carboniferous it was 35% of the atmosphere (just 21% today), yet a few million years later it was just 12% at the end of the Permian. How did Life respond?
Has the mystery of sex been explained at last? …why do we have sex when some animals get along without it just fine? Or do they? The old explanation is that sex helps defend against external parasites… BUT that doesn’t quite work. What about genomic ‘parasites’?
What’s the point of being warm-blooded? …maintaining a high, constant body temperature is what burns most of our calories in a day, and that’s true for almost all mammals and birds. Why the waste heat? Why not burn slower like our reptilian ancestors?
Was our oldest ancestor a proton-powered rock? …Think ‘Chemiosmosis’ and you’ll get the idea. The LUCA (Last Universal Common Ancestor) was a cell in a ‘rock’… read more for details and an engrossingly told story. A summary in 10 Steps is available too.
Finally, not from Nick Lane, is this ABC News item…
Cell’s Power Packs Came from Within
…which studies how mitochondria – the common energy factory of all eukaryotes – came to be converted from a free-living bacterium to energy centre. Apparently the transfer molecular machinery that shuttles materials from mitochondrion to host cell came together from diverse bacterial parts organised in those first eukaryotes, and the researchers recreated just how.
Posted in Biology, Carnival, Cosmos, SETI, Super-Tech | No Comments »
February 6th, 2010
Not the opener to “Voltron”, but the latest synthetic palaeo-news.
First, appropriately enough, the first tracks of the First Crawling Things…
Found: The first ever animal trails …reported by “New Scientist”, some rock-hounds have discovered 565 million year old anemone trails. Well… they look like anemone trails at least. Older ‘trackways’ are known, but they’re not obviously animal tracks since things like gas-bubbles under algal mats can leave similar markings. These are the real deal.
But why then? The Ediacaran/Vendian came just after the last Big Glaciation (Snowball Earth) and a multitude of squishy, shelly Things appeared and left fossils. Why not earlier?
The next news item answers that…
First breath: Earth’s billion-year struggle for oxygen …seems cyanobacteria, the oxygen-making variety, didn’t appear until c.2.7 billion years ago, took 300 myr to oxygenate the air, then collapsed during the subsequent Ice Age, caused by oxidation of the methane greenhouse of the time. The first series case of climate change due to Life’s by-products, perhaps. An earlier one might’ve been caused by the methanogens themselves, who warmed the Archean Earth.
After the end Archean Ice Age, the Earth languished in an epoch of smelly oceans – hydrogen sulphide and sulfate dominated – but finally something shifted, probably the Greening of Rodinia about 800 mya. This mass erosion event caused by lichens and terrestrial algaes, set the Earth for the Snowball Earth events and the subsequent explosion of animal Life. Or so the story goes as told by Nick Lane. Like all such Proterozoic Tales, there’s a lot we just don’t know.
The implications are interesting. Where did the oxygen making bacteria come from? Could they have drifted in from Venus as its oceans were wafted into the stratosphere and photolysed? That’s my pet theory – we’re all Venusians. Of course Panspermia implies all the suitable solar planets and moons are really one common biosphere.
Posted in Biology, Cosmos, SETI, Sol Space | No Comments »
February 6th, 2010
Marc Buie, Pluto guru, has spent several years of computer time – or scrapings of time over several years – to process observations of Pluto done with the HST…
Unusually Rapid Changes on Pluto
…reported with panache, by Paul Gilster at Centauri Dreams and all over the web. Pluto has rather dramatic seasons it seems. And, c.14 July 2015 we’ll know a lot more as “New Horizons” flings past at very high speed, snapping at a resolution of ~100 metres (i.e. really HIGH.) While chasing this news item I ran into a very handy web-page…
New Horizons Real-Time Simulation
…which gives a live countdown to arrival and a count-up from Launch, plus positional data. A companion page is here…
Spacecraft Leaving Our Solar System
…with similar data for “Voyager” 1 & 2 and “Pioneer” 10 & 11 on display. Our first Interstellar probes, “Voyager” 1 & 2 are expected to be signalling until 2025 or so. Maybe 2027… the first 50 year Mission?
Posted in Sol Space, Starflight, Super-Tech | 1 Comment »