23 December 2007

Why Is There Nothing Instead of Something?

While scanning the spectral emissions of the universe, astronomers must ask themselves that question. Why is there no evidence of anything beyond a raw, untamed cosmos? Earth's solar system is only 5 billion years old, whereas the universe appears to be 15 billion years old, give or take 5 billion. Where are all the old, wise civilisations of intelligent beings that evolved in other galaxies? The universe does, after all, have a long history that precedes us.

Centauri Dreams blog's Paul Gilster wonders the same thing.
We’re beginning to learn that planets are abundant around stars in our region of the disk, with the encouraging expectation that habitats for evolving lifeforms must be widespread. But maybe there are natural caps other than technological suicide that could end a civilization’s dreams.

You can’t help pondering this when you run into the recent news about a long duration gamma-ray burst (GRB) that took astronomers by surprise. GRBs are normally thought to flag the death of a massive star, but in this case the burst seems to come out of nowhere. What caused the event in a region of space where the nearest galaxy is 88,000 light years away? [ed: see photo above--the long tail of the Tadpole Galaxy. Some such tails--the result of galactic collisions--are too faint to see]

...Of course, where gamma-ray bursts are concerned, the farther away, the better. But there are other interesting sources of trouble besides GRBs. Consider 3C321....Both these galaxies, according to Chandra X-ray Observatory data, contain supermassive black holes, but the larger galaxy shows a jet that seems to be pointed right at the smaller. That could make things interesting indeed at the receiving end
Centauri Dreams

Gamma ray bursts (GRBs) are highly focused events of generally short duration--usually no more than a few seconds, but occasionally lasting minutes. If you are not directly in the path of a GRB in that time period, you are probably safe from its furious energies. But if you are in the path of the jet of an active galactic nucleus, as is the companion galaxy described above, you may be in for a long and deadly bombardment of lethal energy.

There is protection in numbers, even for star systems, however. The same way that the solar wind of our star protects us from extra-solar radiation, the "galactic wind" from the Milky Way Galaxy protects its member star systems from extra-galactic radiation. But there is a limit to its protection, and a sufficiently powerful extragalactic jet--or an intra-galactic jet within 500 light years of earth aimed in our direction--could mean lights out for our own very young civilisation. Some scientists believe that at least some of earth's large extinctions were triggered by the solar system's eccentric orbit out of the plane of the galactic disc every 62 million years.

While the universe is clearly a hostile place without the help of alien intelligences, we should consider that our dominant vision of wise, long-lived, peaceful elder races may be a bit uninformed--if not naive. We may be surrounded by evidence of scores of intelligent civilisations, and not know it--as in this online story by David Brin. Sometimes, ignorance is bliss.

So, although our noisy existence in this corner of an unexceptional galaxy would seem to have gone undetected by outsiders--so far--that may actually be a good thing, for all we know. It might simply be better for us, as a baby civilisation, to just watch and learn for a while. Explore our local neighborhood, send out robotic probes, extend our observational range as far out and back as we can. What we discover cannot help but surprise us.

At the same time, we should look into placing some of our eggs into other, well padded baskets.

Hat tip Advanced Nano.

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“During times of universal deceit, telling the truth becomes a revolutionary act” _George Orwell

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