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Lasers Could Hide Us From Evil Aliens (washingtonpost.com)
An anonymous reader quotes a report from Washington Post: Most of the time when we talk about silly scientific papers related to alien life, we're talking about crazy ideas for how to find aliens. But a new study in the Monthly Notices of the Royal Astronomical Society proposes a way of hiding from aliens. Humans are so fickle. A lot of our search for Earth-like planets (and, by extension, for life as we know it) hinges on transiting planets. These are planets that pass in front of their host star in such a way that the transit is visible from our perspective. The movement of the planet in front of the host star makes the light from that star dim or flicker, and we can use that to determine all sorts of things about distant worlds -- including how suitable they may be for life. Professor David Kipping and graduate student Alex Teachey, both of Columbia University, determined how much laser light it would take to mask the dimming caused by our planet transiting the sun, or cloak the atmospheric signatures associated with biological activity, [such as oxygen, which is achievable with a peak laser power of just 160 kW per transit].
From the report: "According to their math, it would take 10 continuous hours of shining a 30 MW laser once a year to eliminate the transit signal in visible light. Actually replicating every wavelength of light emitted by the sun would take about 250 MW of power."
Use lasers to cut the aliens planet in half. Shoot first, ask questions later. Send space archeologists to figure out if they were naughty or nice. Better safe than sorry.
Yes, this might work, as long as you know exactly where the aliens are observing your transit from. If you didn't know their location then they could be anywhere in the sky and the transit would be at different times, so you wouldn't know just when to hide the transit or where to point the highly directional laser beam. I take this as another admission that we know about the aliens and this time we know where they are watching from. However, they likely have already visited us (or we wouldn't know about them) and so they know we are here and are not going to be fooled by our laser trick.
I'm an American. I love this country and the freedoms that we used to have.
There is never no direction from which the earth is not currently transiting the sun. April Fool.
I don't know if any space faring alien society would necessarily be evil. Consider that for a species to survive long enough on a planet to develop the science to get into space it has to not cause its own destruction first. It's certainly possible that in order to make space travel more possible we'll develop the kinds of technology that make far deadlier weapons than we already have. Any species that is overly xenophobic or uncooperative would probably wipe itself out before developing the kinds of technology needed to cross the vast distances of space, assuming that it's even possible.
If aliens with that kind of capability did find earth, they'd probably leave us the hell alone simply because we haven't evolved enough as a species to avoid destroying ourselves with the kind of advanced technology that any alien species that could reach our planet would have developed. They might study us, much like we do with insects or animals, but even that assumes that doing so provides them with knowledge they don't already have which is again a pretty big assumption.
Just think what a 10'000 years head-start would give to a civilisation!
Human civilization started with agriculture ~10,000 years ago. Today we have Facebook. Hmm... Maybe another 10,000 years will improve things.
What the hell kind of alien goes out of his way to visit a planet where the most technologically advanced species still kill each other over tribal god-images and petrochemicals?
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
Am i missing something, or would those ten hours only cloak us from one vantage point? How are they deciding which single point in the sky we need to cloak against?
Human civilization started with agriculture ~10,000 years ago. Today we have Farmville. Hmm... Maybe another 10,000 years will improve things.
FTFY.
At the worst, Nova Express would simply have to explain that he meant "in all directions away from the sun at all times". Maybe he assumed readers would pick up on that limitation on their own.
I think the more important limitation not mentioned here is the time scale.
If we want to hide the fact there is oxygen production on our planet, the lasers would have had to be turned on over 3 billion years ago.
To hide the planets existence in general, the lasers needed turned on over 4 billion years ago.
Sorry to say but this paper was published just a tad too late to be useful for anything related to its stated purpose.
Yes, I've heard two criticisms that really resonate: (1) a planet simply blinking out of existence is worth further scrutiny, and (2) the laser light would not be warm-body radiation, but at best some kind of combination of coherent light sources, which would be quite interesting and worth investigation.
I'm not worried about faster-than-light travel, or for that matter interstellar warfare. But if I were worried about alien invasion, I would assume that anyone who could get here in a reasonable amount of time could also wipe us out of existence. I think if you gave us a starship even earth technology could wipe out life on a defenseless planet.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.