[BRIEF NOTE] Might life exist thanks to the cold?
Robert Frost's 1920 poem "Fire and Ice", is simple, short, and stunning.
Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great,
And would suffice.
The poem can be taken to refer relatively directly to the likely fates of the Earth--will it be engulfed by a Sol turned red giants, or will it freeze?--and more abstracts connects to the human heart's ability to wreck the world. I was surprised to find out, via Not Rocket Science, that ice might in fact have fostered the emergence of life on Earth.
Some of the most popular theories suggest that life began in a hellish setting, in rocky undersea vents that churn out superheated water from deep within the earth. But a new paper suggests an alternative backdrop, and one that seems like the polar opposite (pun intended) of the hot vents -ice.
[. . .]
RNA can store information, speed up chemical reactions, and make copies of itself without any outside help. It evolves too - stick it in a test tube with the right raw materials and a source of energy and it eventually gets better and better at copying itself. This ability was first demonstrated in 1972 by Sol Spiegelman and the brutally efficient RNA strand that resulted was melodramatically known as Spiegelman’s monster.
[. . .]
But RNA’s unique physical properties aren’t enough. The molecule is also very fragile and it would rapidly degrade under all but the gentlest environmental conditions. It also needs to be concentrated in some way. A molecule that makes copies of itself needs to be kept in the same place as its constituent chemicals; if the parts are allowed to disperse, the whole will never come together. So RNA may have the right qualities, but it needs a stable and confined space to make the RNA world a reality. Attwater thinks that ice provides just such a space.
At first glance, this seems like a bizarre idea. For a start, cold temperatures can slow many chemical reactions to a crawl. Proteins that piece together RNA molecules stop working when they’re frozen. But remember, RNA in the form of ribozymes can speed up its own creation without any proteins. And Attwater found that one such ribozyme called R18 is still active at subzero temperatures. In fact, ice actually stabilised the ribozyme, preventing it from breaking down. On ice, the ribozyme was slower than at room temperature but it also carried on working for longer. As a result, it was actually more productive, creating longer lengths of RNA with no less accuracy.
That’s one problem down, but there’s also the fact that ice is solid. You might think that this would prevent molecules from meeting each other with ease, but ice isn’t completely solid. At a microscopic level, weaving their way between the crystals, there’s a complicated network of channels and spaces that haven’t frozen completely.
The water in these spaces is salty; as the surrounding molecules froze, any dissolved impurities were pushed away and became concentrated in the remaining liquid. Attwater found that this process boosts the concentration of ions, nucleotides and other chemicals in the liquid compartments by over 200 times. That accelerates the work of the ribozymes, and more than compensates for the slowing effects of the cold.
The blog concludes that this theory works only if the early Earth was icy. Some recent evidence suggests so, and certainly the dimness of early Sol relative to today--Sol was only 70% as bright as it is now--might facilitate this chill.
This model also has serious implications for life on other worlds. It's reasonably well-known that many moons--Jupiter's Europa, Saturn's Enceladus--almost certainly harbour oceans of liquid water under their icy surfaces, and that this water could theoretically support life. Might the fact that these worlds have so much ice say interesting things about the prospect of Europan and Enceladean biospheres?
Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great,
And would suffice.
The poem can be taken to refer relatively directly to the likely fates of the Earth--will it be engulfed by a Sol turned red giants, or will it freeze?--and more abstracts connects to the human heart's ability to wreck the world. I was surprised to find out, via Not Rocket Science, that ice might in fact have fostered the emergence of life on Earth.
Some of the most popular theories suggest that life began in a hellish setting, in rocky undersea vents that churn out superheated water from deep within the earth. But a new paper suggests an alternative backdrop, and one that seems like the polar opposite (pun intended) of the hot vents -ice.
[. . .]
RNA can store information, speed up chemical reactions, and make copies of itself without any outside help. It evolves too - stick it in a test tube with the right raw materials and a source of energy and it eventually gets better and better at copying itself. This ability was first demonstrated in 1972 by Sol Spiegelman and the brutally efficient RNA strand that resulted was melodramatically known as Spiegelman’s monster.
[. . .]
But RNA’s unique physical properties aren’t enough. The molecule is also very fragile and it would rapidly degrade under all but the gentlest environmental conditions. It also needs to be concentrated in some way. A molecule that makes copies of itself needs to be kept in the same place as its constituent chemicals; if the parts are allowed to disperse, the whole will never come together. So RNA may have the right qualities, but it needs a stable and confined space to make the RNA world a reality. Attwater thinks that ice provides just such a space.
At first glance, this seems like a bizarre idea. For a start, cold temperatures can slow many chemical reactions to a crawl. Proteins that piece together RNA molecules stop working when they’re frozen. But remember, RNA in the form of ribozymes can speed up its own creation without any proteins. And Attwater found that one such ribozyme called R18 is still active at subzero temperatures. In fact, ice actually stabilised the ribozyme, preventing it from breaking down. On ice, the ribozyme was slower than at room temperature but it also carried on working for longer. As a result, it was actually more productive, creating longer lengths of RNA with no less accuracy.
That’s one problem down, but there’s also the fact that ice is solid. You might think that this would prevent molecules from meeting each other with ease, but ice isn’t completely solid. At a microscopic level, weaving their way between the crystals, there’s a complicated network of channels and spaces that haven’t frozen completely.
The water in these spaces is salty; as the surrounding molecules froze, any dissolved impurities were pushed away and became concentrated in the remaining liquid. Attwater found that this process boosts the concentration of ions, nucleotides and other chemicals in the liquid compartments by over 200 times. That accelerates the work of the ribozymes, and more than compensates for the slowing effects of the cold.
The blog concludes that this theory works only if the early Earth was icy. Some recent evidence suggests so, and certainly the dimness of early Sol relative to today--Sol was only 70% as bright as it is now--might facilitate this chill.
This model also has serious implications for life on other worlds. It's reasonably well-known that many moons--Jupiter's Europa, Saturn's Enceladus--almost certainly harbour oceans of liquid water under their icy surfaces, and that this water could theoretically support life. Might the fact that these worlds have so much ice say interesting things about the prospect of Europan and Enceladean biospheres?