Black hole sun: is there life beyond the event horizon?

Paul Raven @ 11-04-2011

A bit of light reading for the hard sf and cosmology geeks in the audience; via Next Big Future, arXiv has a paper which argues that life – indeed, even complex civilisations – may “inhabit the interiors of supermassive black holes, being invisible from the outside and basking in the light of the central singularity and orbital photons”. Stephen Baxter and Greg Egan, eat your hearts out. 🙂

A little closer to home (and also via Next Big Future), there’s a new start-up kicking around in Silicon Valley. Which isn’t news in itself, of course, but rather than designing the latest portable device or niche-focussed social network, MoonEx has scored a NASA contract that could be worth US$10m with a business model based on building autonomous robotic rovers designed to mine the Moon’s regolith for the increasingly rare metallic elements that our electronic systems depend upon. No doubt they’ll be keeping a close eye on SpaceX’s Falcon Heavy.

[ Any Monday in which you can squeeze a Soundgarden song into a post title is, by definition, a good day. ]


Steppenwolf planets: life in interstellar space?

Paul Raven @ 10-02-2011

Life needs light, right? Without a parent star, a planet stands little chance of developing the conditions under which comples chemistry can bootstrap itself into biological processes.

So goes the conventional wisdom, at any rate, but here’s a paper by two space boffins from the University of Chicago that posits the possibility of “Steppenwolf planets”, roaming the vast tracts of interstellar space with no star to call their own, but of sufficient mass and composition to harbour subsurface oceans heated by the still-active planetary core.

Technovelgy compares this to an old George RR Martin story with which I’m not familiar, but I seem to remember a more recent precedent in the latest Greg Egan collection, though the title of the story eludes me.And then there’s Peter Watts’ Blindsight… can anyone think of any others?

It occurs to me that, short of technological developments of a science fictional scale, the only real use we’ll ever be able to put these hypothetical Steppenwolf planets to would be… well, the settings for science fiction stories, basically. Oh, the irony!

But hey, lookit – I managed to write the whole post without a single “born to be wild” gag!

Ah, nuts.


Nucleotides in Titan’s atmosphere?

Paul Raven @ 06-01-2011

I’m somewhat surprised that I haven’t seen this story all over the place. Perhaps everyone’s taking a while to get back up to speed after the holidays… or perhaps no one wants to get burned the same way they were by the last story about life chemistry that came out of NASA’s press department.

Nonetheless, complete with obligatory “maybe real life is stranger than science fiction after all OMGZ!!” closer, here’s NASA Science News talking about an experiment that demonstrates the possibility of basic life chemistry building blocks in the atmosphere of the Saturnian moon, Titan:

Hörst and her colleagues mixed up a brew of molecules (carbon monoxide(1), molecular nitrogen and methane) found in Titan’s atmosphere. Then they zapped the concoction with radio waves – a proxy for the sun’s radiation.

What happened next didn’t make the scientists shout “it’s alive!” but it was intriguing.

[ There’s good reason to make science journalism accessible, but do we really need shitty little asides like that, NASA? This isn’t Sesame Street, for goodness’ sake… ]

A rich array of complex molecules emerged, including amino acids and nucleotides.

“Our experiment is the first proof that you can make the precursors for life up in an atmosphere, without any liquid water(2). This means life’s building blocks could form in the air and then rain down from the skies!”

[ The metal-head in me now really wants to use Slayer’s “Reign In Blood” as a voice-over bed for this article. Sing along at home! ]

“We didn’t start out to prove we could make ‘life’ in Titan’s skies,” explains Hörst. “We were trying to solve a mystery. The Cassini spacecraft detected large molecules(3) in Titan’s atmosphere, and we wanted to find out what they could be.”

In hopes of obtaining clues to the mystery molecules, Hörst used computer codes to search the lab results for matches to known molecular formulas. She decided, on a whim, to look for nucleotides and amino acids.

[…]

“We had about 5000 molecules containing the right stuff: carbon, nitrogen, hydrogen, and oxygen. We knew we had the elements for organic molecules, but we couldn’t tell how they were arranged. It’s kind of like legos – the more there are, the more possible structures can be made. And they can be put together in many different ways.”

Among the structures identified in the lab experiment so far are five nucleotides found in DNA and RNA, and two amino acids. But she says there could be more amino acids in the mix.

How could those molecules have gotten there? The ice geysers of Enceladus are a possible answer, apparently, though this is all strictly speculative stuff at this point.

Search-for-alien-life bonus material! Antarctica’s massive Lake Vostok may finally give up its secrets (presuming it has any, natch) now that a Russian team has come up with a way to sample the lake’s water without contaminating its effectively closed ecosystem with dirty surface-monkey germs. What mysterious things might we discover lurking miles beneath the ice? Whatever’s down there, it might give us some more clues to what’s going on on Enceladus…


The arsenic aliens that aren’t

Paul Raven @ 03-12-2010

Typical, really; the day I’m away from my desk, a big sf-flavoured story hits the blogosphere. I speak, of course, of NASA’s press conference about the discovery of “alien” life… not at the top of the gravity well, but at the bottom of an arsenic-laced lake in Yosemite National Park. From Wired UK (whose new page layouts are much easier on the eye, but disappointingly similar to their US counterparts):

The bacteria, found in the bed of Mono Lake, are believed to exist as a second form of life — using arsenic in cells in place of the phosphorous found in most living cells.

That suggests that they’ve developed entirely independently from our life, implying that if life has evolved twice on Earth, then it’s far more likely to have evolved off Earth too — especially as it’s believed by astronomers that among stars similar to the Sun, as many as one in four could have small rocky planets like Earth, at least some of which would occupy the same “goldilocks zone” that Earth exists in — neither too hot, nor too cold, for life to emerge.

Leaving aside the actual story for a moment, the meta-story – namely how excited the public can get about the possible announcement of alien life – is worth considering as well. I’ve got no criticism for NASA over the way they framed their announcement; it’s no more duplicitous than the PR operations of the average corporation or government, and I know which I’d rather be paying attention to. But as New Scientist points out, the possibility of actual evidence for extraterrestrial life – which is what a lot of people thought (or hoped) was on the cards – was embraced with a cheery enthusiasm by all sorts of news outlets. Perhaps the world’s gotten so weird lately that nothing can surprise us any more… or perhaps we’re still secretly hoping that sentient ET(s) will turn up, Intervention-style, and pull our collective homo sapiens backsides out of the frying pan we’ve been cheerfully heating up for ourselves. (The writer – and reader! – in me would still quite like the latter to happen, not because I think we actually deserve a species-level bailout, but because the frying pan would doubtless be succeeded by a very interesting succession of fires.)

Anyway, the important thing about the arsenic-alien-life story is that it’s not quite as big a deal as the headlines would have it. It’s still pretty fascinating stuff that connects to extremophile life, but – as explained by Paul Gilster at Centauri Dreams – it’s not evidence for “shadow biospheres”, and doesn’t really tell us anything about extraterrestrial life that we haven’t already hypothesised.

Let’s leave the astrobiology aside for the moment and simply focus on the fact that life is fantastically adaptable in terms of biochemistry, and can pull off surprises at every turn. That’s always a result worth trumpeting, even if it leaves the wilder press speculations in the dust. After all, it’s long been assumed that the six elements that underlay the basic chemistry of life are carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur. Despite persistent speculation, few thought life could exist without them.

[…]

Can these bacteria replace phosphate with arsenic naturally? Wolfe-Simon herself says thirty years of work remain to figure out exactly what’s going on, a comment on the preliminary nature of this work, which remains controversial in some quarters and is in obvious need of extensive follow-up. No shadow biosphere yet, but obviously the quest is ongoing because of its implications, and we’ve now received one very tantalizing piece of evidence that such things may be possible.

If life really did start here more than once — a finding that is not remotely demonstrated by this work — then we can talk about how likely it will have done the same thing on distant planets, upping the chances that we live in a universe where life emerges whenever given the chance.

And here’s PZ Myers, taking a break from being Dawkins’ bulldog to dig into the actual science of the paper:

You’d predict just from looking at the [periodic] table that arsenic ought to have some chemical similarities to phosphorus, and you’d be right. Arsenic can substitute for phosphorus in many chemical reactions.

This is, in fact, one of the reasons arsenic is toxic. It’s similar, but not identical, to phosphorus, and can take its place in chemical reactions fundamental to life, for instance in the glycolytic pathway of basic metabolism. That it’s not identical, though, means that it actually gums up the process and brings it to a halt, blocking respiration and killing the cell by starving it of ATP.

Got it? Arsenic already participates in earthly chemistry, badly. It’s just off enough from phosphorus to bollix up the biology, so it’s generally bad for us to have it around.

[…]

So what does it all mean? It means that researchers have found that some earthly bacteria that live in literally poisonous environments are adapted to find the presence of arsenic dramatically less lethal, and that they can even incorporate arsenic into their routine, familiar chemistry.

It doesn’t say a lot about evolutionary history, I’m afraid. These are derived forms of bacteria that are adapting to artificially stringent environmental conditions, and they were found in a geologically young lake — so no, this is not the bacterium primeval. This lake also happens to be on Earth, not Saturn, although maybe being in California gives them extra weirdness points, so I don’t know that it can even say much about extraterrestrial life. It does say that life can survive in a surprisingly broad range of conditions, but we already knew that.

I can’t help but feel a twinge of disappointment myself, really; cynical I may be (YA RLY) but I’d still love to hear we’d found solid evidence of truly alien life. But you know what? News that the life we already know works in weirder and more tenacious ways than we previously thought is enough to give me a sensawunda kick. I suspect that if you’re not continually astonished by nature’s diversity, you probably don’t yet know enough about it*.

[ * Yeah, I’ve been binging on documentaries from the BBC’s iPlayer service on these chilly evenings; so sue me. I might as well enjoy bachelordom to the full, no? 😉 ]


Taking the air on the moons of Saturn

Paul Raven @ 26-11-2010

Sounds like something out of an Edwin Morgan* poem… but what are poems but dreams of possible truths, eh? From io9, suggestions based on Cassini probe data that Rhea, one Saturn’s many moons, might have a breathable oxygen-rich atmosphere:

It seems oxygen is far more abundant than we ever suspected, particularly on moons that seem to be completely frozen solid. We recently found evidence of oxygen on Jupiter’s moons Europa and Ganymede, and now this finding on Europa. In fact, because the region of space surrounding Saturn’s rings has an oxygen atmosphere, it’s thought even more of the icy moons within the gas giant’s magnetosphere likely have little atmospheres of their own.

According to new data from the Cassini probe, the moon’s thin atmosphere is kept up by the constant chemical decomposition of ice water on the surface of Rhea. It’s likely that Saturn’s fierce magnetosphere is continually irradiating this ice water, which is what helps to maintain the atmosphere. Researchers suspect a lot of Rhea’s oxygen isn’t actually free right now, but is instead trapped inside Rhea’s frozen oceans.

The last couple of years have seen the Rare Earth hypothesis take a number of serious body-blows, what with moons with atmospheres and oceans, and the sudden rash of exoplanet discoveries; I doubt I’m the only person here who isn’t too sad about that. 🙂

[ * Probably my favourite poet, and a trailbreaker in sf and concrete poetry right back in the Sputnik era, Edwin Morgan is already much missed. Rest in peace, sir. ]


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