Astronomers announced last week that they had discovered a black hole spitting energy across 23 million light-years of intergalactic space. Two jets, shooting in opposite directions, compose the biggest lightning bolt ever seen in the sky — about 140 times as long as our own Milky Way galaxy is wide, and more than 10 times the distance from Earth to Andromeda, the nearest large spiral galaxy.
Follow-up observations with optical telescopes traced the eruption to a galaxy 7.5 billion light-years away that existed when the universe was less than half its current age of 14 billion years. At the heart of that galaxy was a black hole spewing energy equivalent to the output of more than a trillion stars.
The discoverers called this system Porphyrion, after a Greek giant. You can read about this just about anywhere.
I want to write about because for me it ties into the so-called Fermi Paradox. This line of thinking supposedly got started when physicist Enrico Fermi asked, "Where is everybody?" That is, where are all the alien civilizations.
One way to think about the problem is the Drake Equation, which looks like this:
The terms represent the rate of star formation, the fraction of stars that have planets, the fraction of planets where life is possible, the fraction of those planets where life appears, the likelihood that life becomes intelligent, the fraction of civilizations that develop technology we could see from light years away, and the duration of the average such civilization.
I don't see why the obvious rarity of spacefaring civilizations is any kind of paradox; if you simply assume that any one of the middle terms is one in a hundred trillion, the "paradox" disappears.
And one reason I think those terms could be very small is the titanic violence of the universe. The discoverers of Porphyrion think its power is so great that is is rerranging matter across a supercluster of galaxies, and therefore that the uneven distribution of matter is the universe might be partly due to such phenomena. Imagine what would happen to any civilization that got in the way of such a blast.
These enormous jet systems may be the most striking examples of galactic violence we know of, but lesser violence is everywhere: colliding galaxies, giant black holes, colliding planets, exploding stars. The more I ponder what the galaxy is like, the more I think we are riding a stupendous lucky streak. We got lucky when one of our sun's rocky planets ended up in a zone where water is liquid much of the time, making it possible for life to get going. Life has tenaciously hung on every since, but it has been nearly wiped out several times (or at least complex multi-cellular life has). We have had mega-extinction after mega-extinction, caused by asteroid impacts, volcanism, a planetary ice age, and who knows what else.
And having dodged all of them, we may one day be finished off by another space rock or, if we last long enough, by the expansion of our aging sun.
Our world is a miracle of astonishing improbability, and we should cherish the chance we have been given to thrive.
4 comments:
I don't see why the obvious rarity of spacefaring civilizations is any kind of paradox; if you simply assume that any one of the middle terms is one in a hundred trillion, the "paradox" disappears.
I know some people will balk at the idea of "one in a hundred trillion" as sounding like far too small of a chance, but if you examine the number of stars in the universe it suddenly doesn't seem that small.
As far as we can tell, there are 200 billion trillion stars out there.
If we cancel out the trillions on both sides of the comparison, it gets a little easier to wrap your head around. Frame it as needing one of those middle terms to be "one in a hundred" in a universe that contains "200 billion stars", and suddenly it sounds much more reasonable. In fact, that way it almost sounds TOO LIKELY, given our observations, and the temptation is to assume the chance is even lower.
Sure, but what the paradox is asking us isn't that simple. Make any of those numbers zero, and that's that. No intelligent life at all. Yet intelligent life clearly exists.
So, shunt back a bit, to the 'the fraction of planets where life appears' factor and ask the question again. Evidently, not zero. But on a sample size of one, the Earth, you can't extrapolate anything at all. One data point isn't proof of anything either way, it's just an observation.
Where things get interesting is if we discover some sort of life inside the Solar System. Even microbial life. From a sample of eight planets, a quarter host life. While that doesn't prove life is 'common', in certainly disproves that life is 'unique'.
That's where the Fermi Paradox gets hard to process. Should we discover life elsewhere in the Solar System, we can't just assume some of those factors towards the right-hand size of the equation are so vanishingly small that they approximate so closely to zero that human life is unique.
We don't have anything like the scientific data to imagine what those numbers might be, of course. But that's the fun!
@Neale Monks - I agree that even a little more data would make the calculations much more meaningful. There doesn't seem to be any life on Mars, so we are moving our search to the moons of Jupiter and Saturn. So far the molecular analysis of the water gassing from those hasn't seemed very promising to me, but missions like the Europa will fill in the picture. If there is no other life in our solar system, that would be interesting, although not proof on anything.
The thing is, so far as we can tell, there's nothing remotely intelligent anywhere even remotely within reach of us. It might turn out that there's intelligent life somewhere out there, but if it's on the other side of the Milky Way galaxy then it might as well not even exist in practical terms.
And that's just within our own galaxy. There are estimated to be 200 billion to 1 trillion observable galaxies. And we're never reaching ANY of them.
The closest known is Ursa Major III, and it's 33,000 light-years away. Even if we started receiving radio transmission from some intelligent life forms in that galaxy, they'd be 33,000 years out of date by the time they arrived. And any responses we might think to send would be take their own 33,000 years to arrive. You simply can't communicate when a single message and response takes 12 times the length of all written human history playing out.
At best, we could treat such transmissions as a sort of astro-archaeology mystery, trying to interpret ancient radio artifacts to glean some kind of limited understanding of them, without having the context necessary to really properly figure it out.
And that's the closest galaxy to us! Everything else is further away - usually, much, much further! The average distance between galaxies is 1 million light years! We are never, ever, EVER interacting with life that far away. It would require the faster-than-light travel or communications, which all of physics tells us is not remotely possible, but is just a convenient and necessary sci-fi trope for storytelling.
Post a Comment