Quote:
Originally Posted by softness
I am pretty amazed that we look outside ourselves for someone to blame for the death of nature...when birds die in hundreds and fall from the sky, we think the alians have done it.
its not them
why would someone travel all the way here to kill birds? Its not like THEY are bemused with video games and needed new targets so they flew to earth.
Its us. We are of this earth. We are living together on this earth and somehow, biospherically, the birds died of something....
is it the end of the world?
well, for the birds it is...
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Well, for the DEAD birds it is. Birds have seen worse than this. Keep in mind that birds are the last living descendants of the dinosaurs. That means that birds have been around FAR longer than we poor chimpanzees. As far as aliens, it's not aliens. I'm reasonably confident about this. The reason is really straightforward.
Interstellar travel may be possible but it would be prohibitively expensive for ANY civilization. Let's take a look at the history of manned spaceflight as a comparative. How far have we gone? The moon. Less than a million miles away. In fact, not even half a million miles from Earth. Everyplace else we have explored we have not sent humans, we've sent robots. Let's take about the three big problems with ANY explanation for events on Earth being because of aliens. The problems are non-trivial and they are as follows:
1) Distances between stars
2) The speed of light
3) Number of stars & planets total vs. number of stars & planets with life
So we'll take this one at a time:
The *nearest* star is 4 light years away. The nearest star with planets is 10 light years away. If you could build a ship that could accelerate to the speed of light (and you can't*) it would take you four years to get to the nearest star and 10 years to get to the nearest one with planets. Since you can't build a ship that can travel the speed of light (I'll explain why in a bit) it may take considerably longer than that to get from the next nearest extrasolar planet to here. There are no planets in the solar system that can sustain complex life--at least none we are aware. The two innermost planets are way to hot (Mercury and Venus). Mars has no liquid on its surface, has a very thin atmosphere and is WAY too cold (thus no liquid). The outer gas giants (Jupiter, Neptune and Uranus) don't have surfaces. The only other object that might have life (and it would be very simple life at that) is one of Jupiter's moons, Europa. There's a giant ice sheet that may have liquid water underneath. But that's it. I'm not arguing there is no other life in the Universe other than here. We don't know that and since it happened on *one* relatively ordinary planet orbiting a very common star, it's reasonable to think that it happened more than once. Intelligence is SUCH a good adaptation that I'm willing to go so far as to say that intelligent life may be spread throughout the Universe. But whether that life can contact another intelligent species becomes vanishingly improbable.
The reason why you can't accelerate to the speed of light is that as you approach C the energy required to go any faster approaches infinity. Since you can't create infinite energy you can't accelerate anything with mass can't go the speed of light (light gets away with it by having no mass--photons are massless particles). Even if you could, for instance, wrap a bubble of space-time around a starship (which, technically, you should be able to do) and then accelerate that bubble of space-time to the speed of light (which is legal) you would still deal with the problem of time dilation. If you took off this minute in a spaceship capable of light speed and spent one year at light speed returning to Earth a year later (by the clocks on the spaceship) you would find that a *hundred* years had passed on Earth!
Lastly, there's the number of stars w/ planets vs number of stars with *inhabited* planets problem. To understand the nature of the problem of someone finding us, let's do a little thought experiment. Imagine that you are in a lifeboat in the middle of the Pacific ocean. You suspect that somewhere *else* in the Pacific ocean there is someone else in a lifeboat. You both have flashlights one of you is using a red-filter and the other is using no filter at all. You are both shining your lights around. Now, you are looking for a flashlight using no filter and the other person is looking for a flashlight using a red filter. So even IF you could see one another's light in the awesome vastness of the Pacific, you might not recognize it as being a signal from someone else in a lifeboat. To make things even more challenging, when the Sun comes up both of your lights are washed out by the brightness of our local star. This is the challenge facing us finding intelligent life on some other planet and the same problem they have finding us. The filters represent frequencies of light we might be transmitting on (they might be using microwave while we're looking for radio waves, for example). The Pacific ocean represents the vastness of space. The Sun represents ALL the other sources of electromagnetic emissions in the Universe (remember that what we call 'light' is just a special case of EM radiation---from gamma rays at one end to radio waves at the other, it's all just electromagnetism). So any alien species looking for us or us looking for them is searching for a flashlight, in broad daylight, while you're in the Northern Pacific and the person you're trying to find is in the Southern Pacific.
So, to sum up. The alien explanation--before we get to motivations for why they would travel all that distance to go bird hunting--runs aground on the shoals of the physical world. In order to chalk it up to aliens, we have to assume that aliens would have some reason to visit this planet (up until about 120 years ago there was no reason for ANY extrasolar civilization to even suspect that there was intelligent life on this planet--the first sign we were here was the first radio broadcast. Anything else that one could detect (atmospheric composition, say) would be better explained by natural forces. We also have to assume that in the last 100 years or so this species decided that old radio shows made us curious enough for them to come find us. We then have to assume that they could make a spaceship capable of traveling a substantial fraction of the speed of light. We then have to assume that they came here themselves instead of sending robots. Then we have to assume that they decided, for no good reason, to kill thousands of birds in random locations.
OR we could go with a more parsimonious explanation. Birds use the Earth's magnetic field to navigate. The magnetic field is just part of the electromagnetic spectrum. The Earth's magnetic field is moving at about 40 miles a year. You know what else puts out an electromagnetic field? Look outside your window. See a power line? That's putting out a field. As is every cell phone tower. The most likely explanation (given that a lot of the birds had blunt force trauma) is that they flew too close to a strong EMF source and got confused. Keep in mind that not only can the Earth's magnetic field tell you *where* you are (if you have the right wetware and software in your head) it can tell you how far above the Earth you are since the Earth's magnetic field decreases the farther away you are from the center of the Earth. But if you are being thrown off by a strong EMF in your vicinity and that EMF source is, say, 100 feet *above* the ground suddenly 'ground' may appear to be 100 feet higher than it is. All that needs to happen for this to get really bad, really fast, is for there to be a tower on a tall hill. The birds, thinking that they are only at, say, 800 feet climb to be above the Earth and suddenly they are at, say, 5000 feet. It's a LOT colder two miles up than it is at ground level. That, alone, could explain it.
LONG before we have to get to aliens as an explanation or even, for that matter, assign cosmic meaning to it there are very natural explanations available and none of them involve us facing extinction or the end of the world.
Cheers
Aj