Time Immortal

…although the idea that an inbound meteorite might have catalyzed the eventual “dominance” of so-called “left-handed” amino acids (a pre-requisite for the evolution of life on Earth) is, if nothing else, interesting.

I could do without the metaphysical leap at the end of the article, though:

“This work is related to the probability that there is life somewhere else,” said Breslow. “Everything that is going on on Earth occurred because the meteorites happened to land here. But they are obviously landing in other places. If there is another planet that has the water and all of the things that are needed for life, you should be able to get the same process rolling.”

I suppose its entirely possible that meteor impacts had the effect that Ronald Breslow (Ph.D., Columbia University) and his team is proposing, and if so it is certainly a most interesting path by which some of the necessary pre-conditions for the emergence of life on Earth were set up. Of course, if it did happen that way, it doesn’t really tell us all that much about the probability of life anywhere else in the galaxy, or the Universe (I’ve said before that in articles such as this, the discussion tends to jump all too quickly to the issue of alien life) — the meteor and the amino acids it brought with it would still have had to land on a planet that had all the other pre-requisites for life already in place (i.e. a certain climate, water, ample light but controlled exposure to harsher radiation spectra, etc.). For all we know there is a scarcity of planets on which such conditions arose (we also lack any assurance that such conditions would persist; for all we know, there may be a very tiny window in a planet’s evolutionary cycle in which the potential for the emergence of life exists).

But as I said, the article ends with Breslow making a bit of a metaphysical leap in claiming that the meteor just “happened to land here.” That’s certainly one interpretation, but an equally valid interpretation would be to observe the somewhat poetic metaphor that exists in the meteor “touching” down on Earth, kindling the first necessary reactions that brought about life on this world (think: finger of God). Either way, it’s a metaphysical leap, not a scientific statement, and seems out of place in the article as a whole.

Which leaves unanswered, I suppose, the question of why warming trends analogous to trends observed on Earth have been observed on other planets in the Solar System, most notably Mars. It also leaves unanswered, one must note, the question of why most of the observed global average temperature increases have been undone in recent months, corresponding to the observation that the Sun, having finished one sunspot cycle, has not begun another one (contrary to expectations).

The article’s headline is a bit misleading, methinks. The specific solar radiation under discussion is what are called cosmic rays, the really intense radiation that the Sun gives off. Most of that stuff gets blocked by the Earth’s magnetic field anyhow — one of those beautifully-designed things, you know? Of course, cosmic rays are not the only sort of radiation emitted by the Sun, and radiation in other parts of the spectrum can penetrate the magnetic field (ultraviolet radiation would be an easy example to point to here).

The fact is, we can be fairly certain that what solar radiation does penetrate the magnetic field must be responsible for warming the Earth, because we are fairly certain that were the Sun to suddenly stop emitting said radiation, the Earth would become a frozen wasteland. Whatever solar radiation gets through the magnetic field is responsible, in large measure, for the fact that the temperature in most places on the Earth’s surface is in a range that humans find liveable. It still seems reasonable, even in light of findings which suggest that Henrik Svensmark may have been wrong in his theories about cosmic rays, that variations in the Sun’s output in other spectra still do produce changes in the Earth’s climate and average temperature.

Especially, I note again, since similar trends have been observed on other orbital bodies in the Solar System which, last time I checked, were not home to advanced, industrialized societies.