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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.
I like how all these types of articles always assume aliens have the same primitive tech as ours.
Just think what a 10'000 years head-start would give to a civilisation! It's ridiculous to assume they'd be fooled by us.
This thing sounds like some guy trying to get grant money from the DoD or something.
We don't even know aliens even exist, let alone the need to hide from them.
Waste of money.
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.
The problem is that while this may be necessary over a single day from a single identified star, there are more than 2 stars in the universe (citation needed). And we are talking about shining directed light on the opposite side of our planet near continuously at a variety of angles, exponentially increasing the power requirements to effectively hide. This also assumes casting more light directionally wouldn't also cause greater attention due to the whole 3 dimensional nature of this problem.
Thirty four characters live here.
Given the vastness of the galaxy, it seems inevitable that the earth is transitioning the sun from some distant viewpoint on the galactic plane essentially all the time. Are we supposed to continuously fire lasers (which would probably screw up our own astronomy) in all directions at all times?
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I'm going to guess that it's 10 hours a year if we know where to point the laser.
If we don't know where to point the laser, it's not going to do us any good.
Likewise, if we find two ore more inhabited planets, it would be 10 hours PER planet.
They are called demons. Read about them in an old book once.
This means that in theory, aliens could hide this way from us. That furthermore makes it so that our detection methods might not be detecting much at all... If we hid ourselves and they hid from us... we would never know of each others' existence- but then, if we don't know of someone to hide from, why are we hiding? paradox?
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.
Do pay attention, newly owned editors.
I'm all for it! Trump 2016!
And our planet always casts a shadow. More interesting would be to calculate the orbit for a laser system to always stay on the far side of earth with respect to the sun. On the plus side, that satellite wouldn't need solar panels.
Given the vastness of the galaxy, it seems inevitable that the earth is transitioning the sun from some distant viewpoint on the galactic plane essentially all the time. Are we supposed to continuously fire lasers (which would probably screw up our own astronomy) in all directions at all times?
Alpha Centauri is about 4 light years from us, so if we actually started doing this they would get 4 transits and then none.
Stars further out would have even more transit information, and there's no way we can retroactively take back that information.
If the transit information suddenly stopped, wouldn't this attract more alien attention than just keeping our heads down and hoping no one notices us?
Pointless. Sufficiently advanced aliens would be able to see us via the wobble of the star our planet(s) cause.
In many countries firing lasers in any format of away from the surface of earth would require co-ordination with the national aviation administration agency. Clearly flying aircraft through the beam of a 30MW visible light laser would be a lot worse than having a laserpointer aimed at them by kids. I heard this all day on April 1st on NPR and the BBC. Although the BBC news site dates it March31st I doubt the story is anything more than an April Fool joke by the original authors.
We'll just ignore the whole beaming of radio signals into space, and the fact our planet has already been transiting the sun for millions of years thing as well.
Seeing as we have been doing our damnedest to make ourselves known ever since we discovered wireless technology, just how will these lasers help ?
If you're afraid of the space aliens, maybe Donald Trump can build a big wall in orbit for you.
So the evil aliens are scanning space. They notice a planet around an insignificant star about halfway along the Orion arm of the Milky Way. It gets filed for eventual exploitation. Then at some point it disappears. Now it's INTERESTING. That's bad.
"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. "
For a single known direction. It will not mask it for all directions, but only a tiny 2-3 degree slice of the entire 360 dransit
Do not look at laser with remaining good eye.
Unless you know exactly where the aliens are in the sky, you would have to broadcast in all directions. That would take more energy than we can make, to say the least.
"Transparent" is a shit show that trades on every stereotype going. A man in drag is NOT a transsexual.
That's the thing about hiding. Once you know it is useful, it is too late to do it. That's why some animals often try to stay hidden, and if they're not hidden and wish they were, they don't hide, they freeze.
So, with that power consumption the government has to choose between the age of exaflop machines and a frigging laser to hide us from speculated hostiles from our imaginations?
This is something to keep in mind as we observe planets around the closest stars. Despite what our instruments tell us, advanced civilizations may have already found us and implemented cloaks to hide.
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
That "...250 MW of power." would be for each planet we want to hide from. We might need a a lot of lasers and we have no idea where to point them.
Aliens we need to fear probably can detect us with something more sophisticated than the transit method.
Greed is the root of all evil.
So, if we spot a star where the transit method shows no planet but the doppler shift method does show a planet, we will know that not only is there intellgent life there, but that they have somethng to hide.
RJG.
We have pilots complaining about the dangers of .5 watt laser pointers, and we're talking about firing up a 30 megawatt laser? What happens if we accidentally blind Gort? I don't want to have to answer to the galactic equivalent of the FBI. Hell, that might be considered an act of war. Or at least the equivalent to a rabid dog attack. And it never turns out well for the dog, does it?
If there's an alien civilization out there that: 1) can detect us, 2) wants to fuck with us, and 3) has the means to travel here in a reasonable time (hundreds of light years) -- then I think we have way bigger problems than trying to fool them with lasers -- assuming we even know which planet it is...
Well we could set up a bunch of really big mirrors to redirect all of the sunlight that would normally hit the earth around the earth, thus masking our transit shadow and making the earth invisible to any outside observers. This would totally cloak us and make us safe from future invading aliens. The only side effect I can think of is that it would be darker and colder here on earth.
As most posters note, there is never a direction from which the earth isn't transiting the sun. Therefore, a single location on the surface of earth for a laser other than perhaps either pole is not a practical implementation anyway since it will be on the sun facing side of earth about half the day. It will not be able to mask the transit taking place while it is on the daytime side of earth. You couldn't fire 30MW visible light lasers into the sky from earth without the massive objection of at least aviation. The "visible" light from the sun isn't a flat spectrum anyway, any laser system that didn't replicate the spectrum of the solar radiation (visible and invisible) wouldn't be a mask to anyone capable of observing the transit in the first place. Then, so what! There's nothing special about the earth transit of the sun that says to any aliens "here be a food or war source". Each of the other planets in the solar system is also at any instant in transit of the same sun when observed from some direction. You might be able to say because of the spectrum filtering what the atmosphere of a transiting planet is made of but which scientists assume there's anything special about an atmosphere of nitrogen with a bit of oxygen to aliens? Which scientists assume that all aliens are of a similar composition to humans (by saying that masking ourselves from aliens at all only requires masking the solar transit of earth within the solar system while there is continual RF energy from earth radio stations anyway). Any aliens capable of coming over from their planet to the solar system for a fight/feed (i.e. the definition of what we want to mask ourselves from) are, given our current capabilities of carrying out war in space, just as likely to hook (insert your choice of solar system planet) to a tow hook and take it back to their own home as a source of raw materials leaving us bewildered at a vanishing planet while they laugh at the ease of the exercise. Nope, it was a decent and entertaining April Fool joke by Kipping and Teachey from Columbia University but no more.
Think along the lines of a society with technological advances thousands or millions of years beyond ours. Do you think that they might notice that the coherency of light emitted by our star increases by about the same amount that a planet might dim the start during transit? A very high percentage of stars have planets. This method of "hiding" would only out us as technologically capable of making lasers.
Nothing more easy than distinguishing coherent light with one single frequency (that is what we call a laser) from "normal sunlight".
You could as well just place a sticker on the sun: planet 3 is inhabited, 7 billion intelligent meat bags and a few billion big animals ripe to cull.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
You can replace the transit shadow with 10 hrs of 30 MW laser light. But that assumes you know where the aliens are so you know when to start and stop the laser. But if you don't know where the aliens are, you have to assume that someone is always watching. So that would be 876 times as much energy in order to run the laser continuously.
"He took a duck in the face at 250 knots." -- William Gibson, Pattern Recognition
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?
Good luck getting the fricken' sharks to do our bidding.
They'd probably enjoy aliens destroying humanity.
OK, they'd miss the lawyers and the politicians. But other than that?
It does not compute. kW is power. But then they need 30 or 250 MW to get those 160 kW. Maybe its 160 kWh or kWs?
Also, we don't know where the observer is. This means "transient" is pretty much continuous, the shadow that earth is casting. That needs continuous output.
The story falls down when you consider the ridiculous assumption it is founded on, that we can use our technology to defeat more advanced technology that we can't even imagine. So are these guys idiots or do they think we are? I say they are idiots because as far as deliberately concocted tall stories goes that is a very lame effort.
Minor assumption here, we have to know where the aliens are. Lasers are kind of directional and you also need to know when the Earth will transit in front of the sun relative to their perspective. If we knew so much about the aliens it's likely they would also know about us. Still, I trust to the vast interstellar distances to keep us "safe". FTL travel belongs in sci fi.
Seven puppies were harmed during the making of this post.
This will be how it works, like in the new Stars Wars movie, see.
We’ll shoot a Big Red Laser out at those dastardly aliens and it will travel many lights years in seconds, see. While Gurrgelon and his pals are eye-balling our beautiful little planet with ill-intent, the laser will suddenly arrive, see. “OW MY EYE!” Gurrgelon will scream, now missing an eye. His good buddy Spazticon will exclaim: “Dudz you have 12 more, stop whining!”
They will then all agree, with heavy angst, that they will boycott ‘the Laser Planet’ and never go to that terrible place with the dreadful eye-gouging laser because those mean, dreadful, mean, beings will rob them of their “safe space” and they might actually feel, you know, like, uncomfortable, seeing words and things and stuff they don’t like. They will all have a good cry together and light a space-candle, see.
And those poor, poor Aliens will be spared from coming to the most horrible place in the multi-verse. See.
Depending on where the observer is located, aren't we always transiting the sun from somebody's point of view?
Really? 100 comments in and not one reference to 1970s sitcom Mork and Mindy?
At least one of the plot lines revolved around Ork being such a cowardly place that they'd hide the entire planet from other aliens.
Looks like someone is turning old sitcoms into grant applications.
Learning HOW to think is more important than learning WHAT to think.
ignorant Americans in the other thread - Oh wait they go oh look at tat pretty lights and walk , into the beam. Never mind, carry on!
Now to find out ways of detecting if some planet is using a similar device to hide itself. And we'll have found life. Intelligent, paranoid, life. Perhaps that's why SETI comes still empty-handed, perhaps only the paranoid survive.
Rome taught me patience and assiduous application to detail. Virtues which temper the boldness of great, general views.
That's assuming the aliens are so primitive that they haven't developed the instant anywhere machine yet.
We will be searching for alien life by looking for the telltale signs of shining 250MW lasers outwards to try and hide themselves...
What if we are the evil aliens?
Unless the lasers are shark mounted, what's the point?
Earth is always transiting the sun from some point of view. So the laser would need to be continually running.
[Explicit denoting intelligence challenged person redacted]
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.
Even if they haven't visited, if they have their own data showing worlds transiting stars in fifty systems, and suddenly one of the worlds disappears...
The thing about aliens They are alien. It’s unknowable.
The aliens could be totally hive minded with only a tiny portion of creatures controlling everything else. No individuality. No personal greed. No personal ambition. Only serving the “hive”.
Such a species would be hyper aggressive towards any perceived threat. If they happened on Earth, what would they see? They would see a species that is very aggressive internally and hyper aggressive towards anything perceived as different from the norm. A species on the verge of developing the technology to leave the planet. Who already has the technology to destroy an entire world.
Most likely such a species would lay waste to Earth by dropping rocks on it.
The thing about this technique, it only works once you've spotted the aliens and if they're worth being concerned about their spotting us, it's already too late.
Since the laws of physics are the same thus the laws of economics will be the same they will be Libertarians since that is the only long term viable society.
Thus they will respect the None aggression principle and property rights and we will be fine.
Interstellar warfare is unlikely to be feasible, full stop. What resource, if it existed outside this solar system, would be economically viable to go fetch? What would be worth the additional cost of warfare?
There is nothing suggesting FTL travel is reconcilable with the laws of physics, and it is certainly not reconcilable with causality. Also, if FTL exists, then aliens can travel into our past, which would probably make the whole concept of warfare moot.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
Seriously the spectral properties of the laser light will be an unmistakable sign of life and civilization. Do these people actually think?
You're just ignoring what I said, and repeating what I responded to without even considering what I said. Why even say nothing? Do better.
You give no reason to believe what you say is true. Animals in nature who hide, often do not try to hide once seen. They only do that if they have a safe place nearby to run to, which we wouldn't have in that scenario. Why would we be able to see aliens with better tech than us before they see us, and then hide? That seems pretty silly. If you're against hiding, be against it for rational reasons, not illogical ones. If we're going to even try to hide, it would have be started before any contact.
I suppose it never occurred to them that aliens would want to investigate the star with a mysteriously missing planet that is out of sequence?
Tracy Johnson
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BT
Evil aliens are always stopped by the insignificant intelligence of the residents of this backwater planet.
Humans are so stupid they can't even figure out how to live with each other in peace.
We deserve what we get.
So what you're saying is that we went from creating food, to sharing pictures about it...
Probably the one with the one true god...
I for one welcome the teachings of Xel'Nor* the Great!
Yeah, but what if we mask as a silicon-based planet and end up getting invaded by silicon-reavers? That'd be not good.
"According to their math, it would take 10 continuous hours of shining a 30 MW laser once a year
I'm confused. From someone's (something's) perspective, isn't earth always transiting the Sun? Wouldn't you need to blast lasers in an infinite number of directions continuously?
Add THAT to the Drake equation! The factor of potential alien life that is actively hiding from US! Can you blame them?!
Self-importance and self-indulgence is the root of ALL evil.