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Ask Slashdot: How Could We Actually Detect an Alien Invasion From Outer Space?
First time accepted submitter defiant.challenged writes As I was watching another sci-fi blockbuster about aliens wanting to harvest the life stock population on earth for their energy since we are such a robust species, I was wondering how likely and easy/difficult it would be currently to actually detect an outer space invasion (fleet). I am a firm believer that if we would be invaded, we would not stand a chance and would probably not even hit a single ship when it comes to fighting them. The aliens in the movie had the capability to space-jump right into our solar system and even very close to earth. My question is how good are we at the moment in detecting an alien ship/fleet that jumps into our solar system. Do we have radio dishes around the globe such that we can detect objects in space in all longitude and latitude degrees? I know we have dishes pointing to the skies but how far can they reach? Do we have blindspots perhaps on the poles? I also wonder if our current means, ie radio signals, are relatively easy to be compromised with our current stealth technology? To formulate it in more sci-fi terms, how large is our outer space detection grid, and what kind of time window can they give us?
Email Elon, see what he thinks.
Any race advanced enough to travel here to invade will have capabilities way beyond anything we could hope to combat or detect. I would imagine the first sign you would have would be if you were one of the lucky ones to see half the world wiped out a few seconds before you yourself were removed from this mortal realm.
Do you expect any other answer than "we would be fucked"?
When it is completely unclear what to expect, no predictions can be made. Hence the question is utterly stupid.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
Frankly, any aliens able to travel here from another world are so far ahead of us, it wouldn't make any difference if we detected them or not.
However, you asked the question... so...
Our space detection system is largely aimed at Earth. For example, to warn of us of ICBM launches the first system put into space was called MIDAS between 1960 and 1966.
http://en.wikipedia.org/wiki/M...
The GPS satellites have nuclear detonation detectors, which doesn't do any good, but it another example of how our systems are aimed at Earth.
All the stuff pointed out into space, like the Hubble Space Telescope, are designed to see VERY far away and aren't looking for ships. Given the small likely size of any ships compared to planets and moons, we aren't likely to be able to see them even if we're looking for them, until they are on top of us.
After all, we still don't have a telescope that can see the moon landing sights. Pictures taken from sats in lunar orbit have gotten some pictures, but they aren't as good as you'd expect.
http://en.wikipedia.org/wiki/T...
This is the best image I could find of Apollo 11's landing site, and this was after the LRO was moved into a lower orbit:
http://featured-sites.lroc.asu...
Yea, you can tell what it is, because you know what you're looking at, but if you didn't even know where to look? You could stare at the moon for a month with such a camera and see nothing.
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TL;DR - We likely would have no notice whatsoever of aliens until they entered orbit of Earth, and even then, it is just as likely to be a random person with a telescope who spots them as anyone from the government.
Unless of course they can be seen with the naked eye, if their ships are big enough and they are in low orbit, that is possible.
you could probably notice it after they "jumped" in.
depending on how close anyhow, how big, how much radiation/light they were emitting and all that jazz.
not that you could do shit about them if they were prepared though of course. but if they thought humans were good livestock and worth the effort of harvesting AND were capable of interstellar jumpmagic technology, you would have to ask just how fcking shitty farmers are they?
world was created 5 seconds before this post as it is.
Just a few years ago I would have implicated Sony, but Samsung's recent moves tell us that it is they who will violate confidentially.
Time is what keeps everything from happening all at once.
Your detection window is probably close to 0. Any sufficiently advanced belligerant civilization capable of what you mention will probably use a relativistic kinetic weapon to wipe out Earth rather than going through all the trouble of an invasion. And why would they? IT's not that the Earth has some unique resource nonexistant anywhere else in the Universe.... So they're much safer just exterminating us.
Life is pretty rare in the Universe and as far as we know Earth is the only planet with it in a pretty large radius.
So any invasion will be completely uninterested in the resources we consider valuable and it will avoid using weapons that destroys valuable biomatter.
You don't stop a lobster from pinching you by smashing it with a sledgehammer, you put rubber bands around its claws. I'd expect something like focused energy weapons to knock out anything resembling weapons so that the biomatter can be harvested peacefully.
I thought Iain M Banks had a rather cute description of an alien fleet arriving in Consider Phleabas
1. the first "ships" arriving at high speed go straight past and drop drones to scan and gather intelligence. If we're smart enough we might detect that. Although, reasonably large asteroids zip past us all the time and we only notice them at the last minute. if you were a war faring civilisation then using asteroids or dressing up your "ships" to look like asteroids would probably be a good move.
2. Once intelligence has been received and analysed, the main "fleet" then power up to decelerate, from an Earth position would look like lots of blue "stars" of light in the night sky getting gradually brighter for a few days/weeks/months (delete as applicable).
3. err
4. alien profit
If they have the technology to get here, then they have the technology to approach such that celestial bodies obscure them. Also, if they have the technology then be glad that they're invading when they should simply destroy the entire solar system instead. Hope they see fit to let our species survive. It's that simple.
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The usual example given to illustrate an Outside Context Problem was imagining you were a tribe on a largish, fertile island; you'd tamed the land, invented the wheel or writing or whatever, the neighbors were cooperative or enslaved but at any rate peaceful and you were busy raising temples to yourself with all the excess productive capacity you had, you were in a position of near-absolute power and control which your hallowed ancestors could hardly have dreamed of and the whole situation was just running along nicely like a canoe on wet grass... when suddenly this bristling lump of iron appears sailless and trailing steam in the bay and these guys carrying long funny-looking sticks come ashore and announce you've just been discovered, you're all subjects of the Emperor now, he's keen on presents called tax and these bright-eyed holy men would like a word with your priests.
Banks goes on to note that most civilisations tend to encounter an Outside Context Problem only once, at the point where that particular civilisation ends or is subsumed into the more powerful one. (Incidentally this is also the title of a series of eBooks by Christopher Nuttall which are satisfyingly geeky.)
Of course, there are plenty of fictional examples of invasion, I guess ranging from the barely-competent aliens in Niven & Pournelle's "Footfall" (who were easily detected) and the almost-Gods of Arthur C Clarke's "Childhood's End" who basically just turned up without warning. It's too varied a field to come up with an idea of how we could detect them.
Never email donotemail@WeAreSpammers.com
http://xkcd.com/1377/
...but I had to sign an NDA.
I once had two ducks. I wondered what I looked like to my ducks. I decided that I look like a duck. All the extra powers that make me more than a duck - speech, thinking, telphones, etc. - are beyond the duck's imagination. To a duck, I look like a duck.
Then I wondered what an alian would look like to me, a human. I decided that an alien would look just like another human. So I began to wonder what advanced characteristics I couild watch out for. Successful businessman, good luck, healthy long life, mysterious origin, that sort of thing.
I found one. At the time he was my boss. He pretends to be Chinese, but hey, what westerner really knows what Chinese people look like?
They have landed already; and they are friendly. I was friendly to my ducks, and that Chinese family is friendly to me.
I have no idea what you are talking about, but it sounds professional.
Life is pretty rare in the Universe
Source?
I'd be shocked if we didn't find life in the oceans of Jupiter's moons, if we ever bothered to go there.
We have found life on Earth in places once thought impossible to support it.
I suspect the Universe is full of life, we can't can't see it from here and some of it we wouldn't be looking for until we ran over it.
You don't stop a lobster from pinching you by smashing it with a sledgehammer, you put rubber bands around its claws. I'd expect something like focused energy weapons to knock out anything resembling weapons so that the biomatter can be harvested peacefully.
Why use weapons? Why not just put the population to sleep? A modern tazer is a police officer's tool to subdue someone without shooting them, but it is crude in practice. Advance that idea 100 years and I imagine we'll have something closer to the stun rods from Demolition Man, just touch someone and they are put nicely to sleep. Advance it further and you could probably hit a whole city with a "go to sleep ray".
Weapons are crude instruments.
Heh, you're assuming they'd attack in space ships as if they'd escaped from some 1950s B-Movie. If they've travelled this far to 'attack' us (Whatever that might mean in this context) their technology would be so far in advance of our own we wouldn't even know we were being threatened. Hell. We might have fought and lost that battle already and you'd never know.
I had a dream, bright and carefree, but now there's doubt and gravity
Sorry, but this question is fully based on speculation. How can one even expect an serious answer on this one?
Point is: to ask the question, you need to speculate on what an alien invasion would be. You even need to speculate further to provide an answer. What's that worth? What do you learn out of it? How do I know if I can detect and observe something if I have no Idea what it is?
I could tell you, for example, that we will definitely be able to see the aliens come because of the huge gamma flash their flying saucers produce when they drop from hyperspace nearby Saturn. Our detection change is 100%. Or is it? My answer here is worth nothing, because I have to speculate to what an alien invasion would be. I could sit down with scientist, military analysis et politicians for week and make nice action plans based on what-ifs, but it would all be a waste. Why? Because we simply don't know anything about this topic.
A more serious question would be the same, but replacing "alien invasion" by "potentially hazardous asterioids". Now you can start an interesting discussion because you know what asteroids are and which one can be classified as hazardous. You know what you can observe and what you can't. Knowing the detection limits and methods, you can start to discuss about blind spot and detection probability. Going further you can even talk about mitigation, worst case scenarios and post-impact solutions. On this one I'd gladly sit down with other experts.
Why would you want to harvest biomatter? Personally, I would be more worried about them liking the location of the planet relative to the sun. The biomatter just complicates things, it has stuff like diseases and bacteria, why would you want it? An invasion would also be illogical in my mind, wouldn't it be far cheaper to for example, install a large mirror, either between earth and the sun, reflecting all the sunlight away from earth to cool us down and kill all the microbes, or alternatively, somewhat off to a side to cook earth to kill all the pesky biomatter infecting 'their' planet. Then once all biomatter is killed off, land and install your own eco-system.
Beta?
Well, an invasion would not normally happen out of the blue. It would normally be preceded by scouting parties, etc, to determine the strength and/or weaknesses of the adversary. So I guess the first step in detecting a possible invasion would be to detect the scouting party. Anyway, according to Fermi's Paradox, I think we should have been invaded long ago, that is, if there are any aliens out there to invade.
We actually have quite many detectors pointing in every direction and these are for detecting different kinds of interesting stuff. Gamma rays, radio, gravity waves, neutrinos, asteroids, and so forth. There are satellites and ground based detectors to make sure that there is essentially no blind spot, not even behind the Moon or the Sun, and the detectors are very very sensitive. These are all automatic and will report anomalies quite fast. Most of these are even linked to other detectors that would try to capture events in another medium. For instance, when we detect a gamma day burst, we want to detect it in optical and gravity as soon as possible. We also have an army of amateur astronomers with very good telescopes (with wide fields of view) trying to hunt asteroids, comets, and by all means.. aliens too (we've found none yet, in case you were wondering). So, in an event of an alien fleet would suddenly appear in our solar system, I'd guess that such an agent would register as an anomaly in all kinds of different detectors, and turn pretty much the world's eyes towards it within hours. Astronomers are very keen of detecting new and strange phenomena. I think the alien technology would be pretty advanced to cloak it from detection in such different mediums as broad spectrum electro magnetic (gamma, optical and radio), neutrino and gravity. I think such technology would have to be so utterly alien that we probably would detect an innovation, even in progress.. we might already be invaded and exploited. And what would be the point of fending off such innovation, if we wouldn't even take notice of it?
- Henrik
- when the Shadows descend -
http://neo.jpl.nasa.gov/neo.html/
This is not the sig you're looking for.
Assuming they don't use some sort of anti radar/optical material/scifi cloaking... they should be detectable if we have a full radar/optical map of the whole solar system. This is more a problem of computation then anything. You get a series of cameras and radar receivers and they all take regular scans of the whole solar system. Anything "ship" sized should be logged and fed into a model of the solar system. Anything that deviates from one scan to the next was either influenced by something the model did not account for or is operating under its own power.
I've decided to stop wasting my time responding to AC trolls/sockpuppets... so if you want a response from me... login.
My thoughts exactly. The environments we've physically checked so far are:
Earth: High degree of confidence that there is life here.
Moon: A couple spots on the surface, moderate degree of confidence that there is no life there. Surface in general, low degree of confidence, based only on comparing the few places we've checked with how the geology looks from orbit, with no data from many types of terrain. Elsewhere: no degree of confidence.
Mars: Same.
Elsewhere in the solar system: no degree of confidence (no other probes to other bodies have returned samples or returned data that would allow us to have any sort of confidence in determining whether life was present or not)
Elsewhere in the universe: no degree of confidence.
Many people gladly make assumptions about where life would or wouldn't be, but that's of course highly anthropocentric. "We need water, a solid rocky surface, a low radiation environment, temperatures in the 273-330 kelvin range, and these building blocks..." - you have no idea what you actually need, you have a sample size of "1". That's why people obsess over, say, Europa, despite us having absolutely zero evidence that there's any sort of life there. Heck, the best direct evidence currently on hand for life outside of Earth is probably Titan's "acetylene / ethane, hydrogen, and methane problem" (acetylene and ethane seem to be highly deficient at the surface compared to what should be there; there's some evidence that hydrogen may be disappearing at the surface; and Titan's methane persistence over geological times has long baffled; before the data on acetylene, ethane, and hydrogen was even known, it had been theorized that any life on Titan would most likely metabolize acetylene and ethane with hydrogen into methane). Plus, we know that there's extensive organic chemistry making all kinds of complex CHN "building blocks" in the upper atmosphere. But any life on Titan would have to be utterly different than LAWKI to survive the radically different environment.
We gotta go to a crappy town where I'm a hero.
As other poster pointed out : no because our detection system are mostly directed toward earth, and the few toward space cover not even a single % of sky at any time. But the reason why it is so is trivially simple : the energy requirement, and the distance make it an extremely improbable event, and why would we spend money for that ?
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
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To me the best argument against an invasion is this (not mine, of course): with all the incredible technology they would have, they would find what they need in millions best places in the galaxy. Why should they chose one little planet among billions ones, and just the rare one that's hosting life? Unless they are sadist and enjoy killing living beings, of course, but that would be a too much expensive hobby even for them, I guess...
We have problems spotting and tracking 1km-long rocks in space beyond the Earth's orbit. We literally get taken by surprise by large rocks and their orbits all the time, whizzing around our solar system without us knowing they're there.
We're also not looking for those kinds of things, as such. A ship of some description able to sense us from afar and come into the system probably wouldn't jump in at the third planet out by default. They'd probably jump in off-axis, far away, and we'd be hard pushed to spot anything of space ship size (http://io9.com/nasa-spots-a-po...
That wasn't spotted for ages, discovered only in 2013, when it was only 10 times the moon's distance away (nearly a Mars distance). It was spotted only by something looking for near-earth objects and only because it looked like its natural trajectory may bring it close to Earth in the next 100 or so years. It's 650 metres long, orbits every three years and could weigh tens or hundreds of thousands of tons.
We can't see this kind of stuff. The angles and chances are just too small and anything that settles into a natural orbit is basically indistinguishable from a rock. It wouldn't take much for something to jump in just outside the outer planets and settle, say, a Saturn distance away, probably off-axis (hiding in-axis may well give shadows etc. that give it away and we likely look at the planets and other things in our axis more than elsewhere) and we'd never spot it. Never. If we did, we'd think it was a rock.
From there, a basic telescope (or a pair of binoculars) would be able to light us up like a Christmas tree, show us to be particularly interesting, and a simple radio antenna would be able to prove that their was life on here, while at the same time being basically invisible to us without even trying.
Any civilisation with a 1km intra-system space-ship capability likely has much better tech than a $200 telescope and a satellite dish connected to a radio scanner, They'd know we were here, and be able to observe us for centuries, long before we ever would know they were there - and we'd probably NOT know they were anything other than a rock.
The distances are too immense, the angles involved far too tiny once you get out past the moon, and there's just too much stuff moving about if you have a sensitive instrument. Hell, we don't even reliably know what everything in EARTH ORBIT is, let alone trying to go out to even a Moon-distance or Mars-distance or Neptune-distance.
Basically, we would never know. The only way to get to the point we would know would be to colonise enough of the solar systems to provide mapping and triangulation of the entire space in-between, And even then, you probably could still hide if you were at all careful.
How did the American Indians detect the Europeans?
I suggest we *not* do that...
Also how did the Poles detect the Mongols?
Let's *not* do that, either...
just write a virus on your apple powerbook and upload it to their mothership
problem solved
neil degrasse tyson understands:
http://www.goodreads.com/quote...
We conquer the Independence Day aliens by having a Macintosh laptop computer upload a software virus to the mothership (which happens to be one-fifth the mass of the Moon), thus disarming its protective force field. I don’t know about you, but back in 1996 I had trouble just uploading files to other computers within my own department, especially when the operating systems were different. There is only one solution: the entire defense system for the alien mothership must have been powered by the same release of Apple Computer’s system software as the laptop computer that delivered the virus.
duh! easy as pie
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
They will come here slower or faster than the speed of light? If they come faster, no matter what technology we have to detect them, they will be here before the light of their travel. And if they are using something like the alcubierre drive, life on the entire solar system may be wiped on arrival anyway, with no defense possible.
And if they are coming slower than the speed of light, taking decades or centuries of their timeframe, they probably won't be an invasion or destruction force. Is just too much investment of time and resources for what you may get cheaper elsewhere. What makes us unique is our culture, and that would not survive an invasion.
If there are using a form of space-time distortion to travel, then we wouldn't detect them at all. The best we can hope for is to see the distortions as they appear in orbit above us.
Don't you watch the X-Files?
Politics is Treachery, Religion is Brainwashing
Go see Randall, he's a specialist on this kind of subject. https://what-if.xkcd.com/
The problem is really resources.
The gap between us and the Moon means we used vast portions of the available resources that have been here for milions of years to get to that point. And we've never gone back because to do so again would be just too expensive in those terms, even with advances in technology.
Now extend that to extended life on the Moon, stripping that bare and moving to Mars, stripping that bare to move to the other planets, etc. By the time you're heading out of the solar system, you've got such few resources that you have to use most of them to stay alive and keep moving. Even assuming some form of nuclear fusion "alchemy" (where we could form any material from hydrogen, and convert anything at all to energy) - getting intact to the next star is a huge feat. And you better hope there's resources there to plunder enough to reach the next, and so on.
You need seriously advanced technology, you need to continue to work for tens of thousands of years, just to survive to the point where you could strip enough planets of their base resources to contain the technology to sustain you to the next star. This is why Dyson-spheres were in such vogue - the only way to get that amount of sheer energy is to capture and live off of entire stars, to get enough energy to get to the next.
You need lots of huge breakthroughs, like fusion, then you need to shrink them to practical sizes, like spaceships, then you need to keep them running forever, which requires an awful lot of infrastructure to keep supplying all those advanced materials, then you need to be able to strip anything you come across of any useful resource, forever, and maintain it all, and then head somewhere practical that will be useful to you and not just "another M-class planet".
Fermi's Paradox is really right here. Anybody who could do all that would have no interest in us, our technology, our resources, or anything at all really... and that's one of the reasons that we wouldn't see them.
Once you hit a certain point of exponential growth and advancement, you'll never bother with planets and the things that live on them again.
An alien invasion could be detected by satellite control radar for earth orbit. However, if they use stealth technology. We would only be able to see them after landing. If they try to infiltrate us by replacing one by one with remote controlled automatons, then we would see that only on a personal level (at least in the West, because we normally do not care about our neighbors that much).
However, it is totally stupid to think that any alien able to travel to the stars requires our planet.
WTF does that even mean? It is useless speculating about what is unknown or is fiction.
That said, if they were arriving through more conventional means, we would simply see them: some mode of optical detection such as star occultation, sunlight glints, drive flares, and eventually just flat out seeing them via telescope (assuming we were looking).
Also we could hear them: energy discharge from drives, EM transmissions... assuming they communicate as we do.
So far as I know there are no deep space facing military radars - I once worked at the Maui Space Surveillance Site in Hawaii: basically the place is an Air Force observatory with awesome optical trackers and some laser tracking facilities. No massive radars pointing at Alpha Centauri.
Maybe we would get lucking with some ballistic missile early warning radars... but they would be fairly close in at that point.
I am very small, utmostly microscopic.
We do not. We have detectors for big honking stellar explosions. If a bunch of objects 200m across were as close as the lunar orbit, if we knew exactly where to look, it is unlikely we could really distinguish them from rocks.
They might even be rocks. A 200m rock makes a very effective Kenetic Kill round. A 200m chunk of ice is probably going to be even harder to see, but still rates in the tens of MT range.
What was the movie?
Always remember, if a species figured out interstellar flight, then they are centuries ahead of us in technology. It would be the equivalent of monkeys with rocks against stealth bombers. Except.... the monkeys do have a weapon that would decimate nearly anything any alien race could come up with. It's a horrible weapon, and would probably leave the planet useless..
Dig deep holes, put a nuclear bomb at the bottom of the hole, and cap it off with the biggest heaviest single piece steel plug we can find. Basically we are making a Nuclear canon and using the earth as a gun. When you detonate the bomb, the steel plug will be thrown with so much energy that it will destroy nearly anything on it's way through it. And yes if you did things right you could take out giant indestructable ships in orbit with this, you just have to wait for the ship to go overhead.
http://en.wikipedia.org/wiki/O...
Do not look at laser with remaining good eye.
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All the assumes that an invader would be perhaps biological and probably macroscopic. Assuming for the moment no faster than light travel and no magical energy sources. This means that travelling between stars will take a long time and need lots of energy. So mass and biological lifespans are a huge factor, the smaller the mass and the longer the passenger lives, the faster it can be pushed with less energy, relativistically speaking...
Today in the near earth environment we can track things larger than a baseball travelling at orbital velocities with existing NORAD space tracking. But anything smaller or faster or further away, forget it. Therefore I wonder if we would even know should the invader consisted of a cloud of nano-machines released from a micro-probe that had travelled here at near light speed.
Once the invader was here, floating down from the stratosphere scanning for useful biological machines with large enough brains we would not even be aware. Save perhaps for a spectacular sunset or two. The first sign that we had been invaded would be perhaps a sudden breakout or global cooperation and perhaps the appearance of apparently physic abilities and heightened regenerative abilities in infected subjects. It would only be much-much later that any remaining uninfected individuals would see the real purpose, when a new international space plan is put into place to send AI nano-machines as avatars for ourselves to the nearest stars.
This question is so loaded it's pointless. You may as well as "when did the aliens stop beating their wives?" You have to assume, axiomatically, that they would have any reason to invade, but that's absurd. It's even self contradictory. The nature of the challenge put forward is that aliens have mad advanced technology... so what would they invade for? It's like a person from affluent western society giving up their life and flying to the other side of the world, to a desert island, to beat up a native, take their shack.. just because they have a tree that grows fruit you like. IT MAKES NO SENSE. In fact that makes even more sense than alien invasion because aliens will have evolved in a completely different eco-system an wouldn't consider our's very inviting. This is just another zombie apocalypse escapist fantasy distracting people from real looming apocalypses that are too boring to worry about.
Life is rare??? really? based on what?
Direct observation.
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Nice try advanced scout party. You slipped through but I doubt the armada will fair as well.
They always ask to see our leader.
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Sanity is the trademark of a weak mind. -- Mark Harrold
Life is pretty rare in the Universe Source? I'd be shocked if we didn't find life in the oceans of Jupiter's moons, if we ever bothered to go there.
Direct observation. Anything other than evidence based science is just you daydreaming. Besides, even if life was found elsewhere in this solar system that wouldn't be enough to change the general premise that life is pretty rare in the Universe. When all is said and done, as of 2015, life has only been observed on one planet, in one system, in one galaxy in the entirety of the Universe. You can't even point to evidence of past civilizations. But I guess it's only been 14 billion years give or take. Give them some time. They'll show. In all honesty though, if life was as common as you assert then shouldn't we see colonies and ships by now? It'd only take 1 civilization to decide to colonize our galaxy. Mathematically, they could have done it in 50 million years without FTL travel. So where are they?
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Don't worry - the aliens are waiting for us to finish the process of nuclear disarmament - then it will be safe to proceed with their invasion.
There is no God, and Dirac is his prophet.
A civilization advanced enough to get here from another star would have better control of matter than we do. Coming here would be pointless; all we have to offer is just more carbon, oxygen and iron -- who cares? Cheaper to harvest atoms and energy more local to them and organize them beneficially.
Large, easily detectable mirrors? Perhaps they're just quietly filling our atmosphere with CO2.
I wasn't really referring to the detection thingy. I have no clue what we can or cannot detect. Mirrors would be in the invasion scenario. Considering that if they wanna invade us, there is no need to be subtle, just efficient. After all, we can discuss for ages what their advantage would be technologically, but there is one advantage which is undeniable if they are hovering over us in big-ass ships, and that is that gravity is on their side. If they can destroy us without even setting foot on the planet or ever entering our atmosphere, our near complete inability to send anything into space would doom us from the start.
According to Snowden, the NSA has AIDS (Alien Invasion Detection System). The exact particulars are classified but the amount of data collected should serve to warn us in plenty of time to mount a defense. No worries.
Any technology that enables aliens to visit us would be so advanced that we could never combat it at all. But the good news is that any such advanced beings would also have no need for us or anything we possess. Concepts like wealth would probably not exist in such a race and ideas like eating may also have been reduced to some sort of technology that disallowed ingesting what we call food. The technology possessed by such beings is beyond our imagination. To us a comparison might be that God dropped in on us and had a real craving for a quarter pounder with cheese and some of those skinny french fries.
They'd send a couple of capsules the size of a nickle into our atmosphere from outside the ort cloud. They'd either be laced with a virus to kill us all, antimater or some other yet-to-be-discovered nastiness and it'd be all over in seconds. We'd have no idea if they didn't want us to have one.
That being said, if the craft was travelling at light speed you could not see it. The light emitted from the front surface at near the speed of light would be so highly blue shifted that it would be above or in the gamaray zone, but not a particularly powerful source nor a single burst that would then trigger sensors like SWIFT, or Fermi, but might be visible to HESS if they do comparative imaging over time to detect moving gammaray objects *across* its field of view. If its coming right at us probably not.
Due to the laws of physics I can still sleep well at night.
We likely wouldn't even realize we were under attack until it was far too late to do anything.
You're pretty sharp for an immature Pak Protector.
Il n'y a pas de Planet B.
If we reject the OPs "jumping in" and assume the statement is from a person who's watched too much sci-fi, what would we see as the alien fleet arrives?
Well, the first question is, what methods do we know of right now that could work for the alien's engines?
There are :
1. Nuclear salt water or nuclear pulse (orion drive)
2. Fission Fragment
3. Fusion
4. Black holes
5. Antimatter annihilation
6. Some kind of sci fi method to just release the rest mass as energy in ordinary matter without the antimatter needed.
Number 1 is some variant on a fission bomb propelling the ship. A couple percent of the speed of light, tops. Number 2 and 3 have the problem of pathetically low thrust although high isp. Black holes depends upon assumptions about a black hole that makes them movable (they have to be electrically chargeable) and constructible (you need solar system sized mass drivers to accelerate metal rods to slam into each other at a sliver below the speed of light to form the black hole). But, they are a near perfect form of engine - you feed the black hole a particle beam of ordinary matter, collected by ramscoop, and you get back gamma rays that your enormous ship reflects like a parabolic dish. Antimatter annihilation is similar to black holes except it requires you to carry all your antimatter with you, and it's immensely difficult to avoid blowing up the ship.
Anyways, all these methods have a common factor. All of them will release a flare of gamma rays as the alien fleet decelerates. The alien fleet probably would not even use their engines except to maintain speed and slow down - they'd probably use a stream of mass accelerated pellets launched by mass drivers in their starting system to reach their cruising speed.
Also, all these methods have the problem that they provide pathetically low acceleration. 0.1 g (1 m/s^2) at best, a tiny fraction of that at worst. Realistically, the alien fleet will be decelerating for about 10 years to centuries. We'd be able to see the gamma ray flare from this for many years if a gamma ray telescope is pointed the right way.
As for vulnerability - they'd be immensely vulnerable upon arrival. Not to the technology we have now, but technology we could probably develop relatively rapidly. The alien ships would not have high acceleration engines able to avoid incoming fire or outmaneuver attackers because that kind of engine is too inefficient for interstellar travel. Their ship is unlikely to have anything on it more than a payload of factories and data, because the mass for weapons or engines is too much.
Their plan would almost certainly have to involve decelerating to rest near an object with some mass in our solar system, preferably one close enough to the star so that solar energy is available. One of the various comets or asteroids would do fine. They'd eat the rocks, turning it into more equipment, and essentially regrowing all their technology and infrastructure from the actual starship seed payload.
This is when you jump them. You need an orion drive space battlewagon to show up before the aliens eat enough rocks to build something to fight with.
Ask the Indians how it went for them.
You would be able to tell because the background music would get more dramatic whenever you looked into the night sky.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
Obviously if there were an invasion fleet looming around our planet, it would first be detected by some misanthropic kid with a telescope. That would be the easy part. Then the kid would have to convince his alcoholic, ex-Air Force father of the impending invasion. Then the father would have to swallow his pride and contact his old partner (the one who was promoted after turning in the father for doing something that was technically wrong, but was undeniably the honorable thing to do in the situation), who now just-so-happens to head a clandestine wing of the military specialized in dealing with alien invaders. Obviously.
We almost certainly wouldn't see the alien ships until they were in orbit, particularly if they approached from one of the solar polls rather than in the ecliptic plane (the geometric plane that contains the planets and asteroids).
We can get radar observations from objects as far away as Saturn, *but we have to already know they're there* to observe them with radar astronomy, and they have to be quite large -- 100s of km across. Even as far away as the moon an object would have to be a km across to be caught on radar. So we don't send radar signals willy-nilly into space unless we know the object is already there. The way we detect near-Earth objects like asteroids is optically, looking for "stars" that move across photos taken in succession. But this might not detect the approaching fleet at all, even if it were approaching along the ecliptic; and if it did it's likely that we wouldn't notice for days. The system isn't designed to detect fast spacecraft maneuvering toward Earth; it's designed to detect rocks more or less traveling along with us that wander into our gravity well.
Of course all this depends on your assumptions about the ships. If the ships were as big as the Moon, we'd notice them from a few AU away. If they emitted exhaust plumes that were bright as Jupiter, we might even see them with our naked eyes well before they reached orbit. But if they're only a few km across and not fantastically bright, chances are we wouldn't notice them until they showed up on our orbital debris tracking system. Even then we wouldn't necessarily notice right away. The system isn't a real-time early-warning system. We'd probably still be chasing down the "glitch" in our systems when the first aliens landed.
Now I wanted to answer your question, because it raises and almighty rant in me that I just have to get out: is it too much to ask that writers of "science fiction" have a *little* science knowledge and a more-than-room-temperature IQ? For Pete's sake the energy in life forms (at least Earth ones) is solar radiation converted into chemical bonds. The notion that a spacefaring species would have to transport those chemical bonds across insterstellar distances for its *energy* needs is preposterous. The notion that this would net them any usable energy is nearly as preposterous. Would you send a log into orbit to fire a boiler?
It's not just second string popular sci-fi that has this problem. Both the J.J. Abrams Star Trek movies show a complete lack of thinking about the geometry of space. In the last movie the Enterprise is chased across interstellar space only to be stopped 240,000 km from Earth, and they're *right by the Moon*. Yes, 240,000 km is roughly the radius of the Moon's orbit, but the chance you approached from some random direction and happened to end up right by the moon is minuscule, even if you're at the right distance. And then when they lose power they *instantly* fall *straight down* into the Earth's atmosphere.
Yeah, I understand it's the storytelling that counts, but it matters if the scenario is just plain stupid.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Erich von Däniken, is that you?
Il n'y a pas de Planet B.
Obviously.
A better question would be how we could detect the activities of extraterrestrials who have been visiting Earth routinely for a very long time, and whether it's even in our interest to do so.
Nope it's too late - they are already here having strategically taken over Comcasts call center in a bid to drive us off the planet.
Owing to the vast distances between planets likely to have intelligent life, machines are likely the only alien things you'll ever see. Owing to the energy expense of traveling vast distances, they will likely be very tiny machines, like nanobots from science fiction. Due to the speed of light and hence radio communications, the machines won't be able to be in contact with their makers, at least without significant transmission delays; therefore, the machines will likely possess advanced intelligence on their own.
Having said all that, we could very easily have been invaded many times over by intelligent nanobots from space. They would have been completely undetectable until maybe a few decades ago and perhaps are clever enough to continue to escape detection. Our planet is highly unexplored. We've only cataloged a tiny percentage of life. We've barely glimpsed into the deep oceans. We're also quite ignorant about the underground, as we're drilling for oil right now and have no clue what might even cause an earthquake (so we're ignorant about not just tiny things, but features gigantic enough (possibly miles in diameter) to produce earthquakes).
In fact, the very cells in our bodies could be invaded by aliens disguised inside bacteria or viruses. How many of these bacteria and viruses have we even looked at under a microscope? We have trillions of these organisms. Imagine the power of one million compute nodes that could hide in less than 1% of our cells. And right under our noses is just one possibility among many.
Maybe the world is like the Matrix, except the robots are tiny instead of massive with a little bit of Scientology thrown in, where our bodies have an alien presence inside of them (but not the part about stealing people's money).
Agreed that we are not going to be getting a personal visit from alien life forms anytime soon.
That does not mean that SETI is a waste of time however. Earthlings have been making radio broadcasts for close to 100 years. The nearest stars to Earth (apart from the sun) are only 4-5 light years away. It's also possible that intelligent life in other parts of the universe could be millions of years ahead of homo sapiens in terms of technology. Planning for a visit from aliens is a waste of time. Trying to pick up some signals emanating from elsewhere in the universe is not.
Any race advanced enough to travel here to invade will have capabilities way beyond anything we could hope to combat or detect. I would imagine the first sign you would have would be if you were one of the lucky ones to see half the world wiped out a few seconds before you yourself were removed from this mortal realm.
Well, I think when they start posting on slashdot asking about the possibility of detection, that's a pretty good first sign.
Direct observation.
Wow, you've had direct observation of more than one planet in the "life belt" of a star?
I don't think direct observation means what you think it does. We have a sample size of 1, it is useless for figuring out anything.
All we can go off of is the fact that we keep finding life here on Earth in places we didn't think we'd find it.
So what we consider to be "life supporting environments" keeps changing, even in just the past 10 years.
It'd only take 1 civilization to decide to colonize our galaxy. Mathematically, they could have done it in 50 million years without FTL travel. So where are they?
You are looking at it from the viewpoint of your own life and civilization, neither of which are very long lived.
If they show up in 5,000 years, that would be "soon" from their point of view, but "forever" from ours.
You have a very human centric view of the situation, and that isn't unusual, but it does mean you can't see the forest for the trees until you remove your own human biases from the study.
Chances are they will treat us as a holiday destination, or a research station. Chances are they wont be that interested in the earth, you people are so planetist
The only areas we have detailed direct observation say that life is abundant.
Some alien scouts have recently landed on earth. Right now, the alien scounts are investigating the best way to invade earth. They have found 'humans', and learned that humans use something called 'internet' to ask for information.
The aliens were detected when they submitted a question to slashdot to investigate if their invasion would be detected.
Same reason I cringe at Star Trek battle scenes. I I was Picard (or Worf) I would just beam a big blob of plasma straight onto the enemy bridge. Or beam their warp core out. Or just beam them all straight off their ship into a holding cell. Or to the inside of a star. OR beam the enemy warp core containment into space. Why even launch a photon torpedo? Just beam it there ASAP. I could go on and on on on.
If enemy shields is a problem just beam the photon torpedoes en masse to a point 1 second before impact on their shilds. They can't evade and you can saturate the shield with missiles until it collapses. And then go beaming away.
A transporter beam a la Star Trek is pretty much the ultimate weapon.
Breaking Bad has a classic piece of dialogue between Badger and Skinny Pete about this.
http://www.cinemablend.com/tel...
The dangers of excessive individualism are nothing compared to the oppressiveness of excessive collectivism
It took NASA about 20 years to find 90% of NEO asteroids bigger than 1KM in diameter. and most of those more than 100M... so if The Aliens have been stalking earth for the last decade trying to match orbit, and have a ship more than 1KM in diameter, then there's a 50% chance that we've mistaken them for an asteroid.
Sometimes boldness is in fashion. Sometimes only the brave will be bold.
Easy. They will not have valid credit cards.
... Will destroy themselves centuries before they can come and kill us.
Unless there is technology that we can only dream of today, like warp propulsion, our current physics can't provide us even with the means to power a warp drive.
Even with the most advanced conceivable nuclear ion propulsion, coming with anything over a few dozen tons from the closest solar system is essentially inconceivable.
If mankind decided to put together a large enough spaceship to send men to the nearest goldilock planet on another solar system would require all of earth to pool together massive resources, like decades worth of current space budget of all of earth's planets combined.
So while it highly likely there are many planets with intelligent life in the milky way, that civilization would first have to fully unite itself before they could dream about launching a spaceship able to just visit earth. In fact should their intents be military, its far more likely they would land on Mars, and use Martian resources to increase their popullation and manufacturing resources before trying to attack us.
Its all about understanding DeltaV, Specific Impulse and other utterly inconvenient scientific facts that make sending humans to other solar systems impossible today (hence the same challenges for the inverse trip). The rest is just Sci Fi.
Maybe the next Einstein will revolutionize Physics like the last one and unleash practical, compact, lightweight fusion to power and solve warp drive physics to use that power.
Take Ion thrusters. In order to be very efficient, it pushes individual little molecules at very high speeds, typically using electricity from solar panels.
Very high ISP, but tiny thrust. That good old solar energy problem, low energy density.
If we could increase ion thrust energy by a factor of a thousand, we would need monster energy sources to generate that kind of power, but if those are too heavy, the whole advantage of reducing the fuel used is wasted by the heavier energy source. So far there has been no viable electricity source that was light enough to replace solar cells to power an ion drive efficiently (for interplanetary level missions).
Plus the most efficient propellants are heavy noble gasses, like Xenon and Krypton, both very hard to come by (one predictable source for them would be nuclear reactors, but solid fuel reactors make harvesting those complicated, can't drain the gasses in realtime).
Some one will suggest plutonium 238 type nuclear thermal generators, but those only last one century, their power drops precipitously due to half life effect. It has to be a nuclear fusion / fission power source whose fuel can be stowed aboard and be good to use 10000 years later.
Oh, and the ship must be big enough we must send families that will live and die aboard the ship. Those landing on the other side will be dozens to hundreds of generations later.
HFT (High-Frequency Trading) technology applied to detection and defense: discuss amongst yourselves.
Scientists and Philosophers at SETI believe that an alien race sufficiently advanced to visit our solar system would have evolved beyond biological life, becoming cyborg or truly artificial life. It's a logical progression from computing to AI to re-engineering their own life forms, and we are likely headed that way if we survive. I blogged about it, as evidence for my own assertion that Web 3.0 will involve a direct neural connection to the internet, a first step in melding human and artificial intelligence. Philosopher Susan Schneider has proposed that any alien race we are likely to counter are probably BISAs: Biologically-Inspired Superintelligent Agents. One reason SETI has not produced results is because we have been looking for biological life and consciousness. And what would any sane and advanced alien civilization want with our messy biological self-destructive race, and our ruined planet, anyway? I think they stay the hell away from us, like we have Ebola. I have also considered that UFOs may be time travelers, perhaps from our own future?
Since we are just beginning to appreciate the tenacity of life itself, currently we only have ourselves to look upon for some precedent regarding intelligent extraterrestrial life. At this point in developed countries' cultures much of the expenditure is on military spending. We have not progressed past our warlike tendencies. It has been suggested that, were an alien race to make themselves known to us, that they would have transcended their cultural tendency towards war expenditures and spent more time on exploration to the extent that would allow them intergalactic travel. In the ability to see other planets, Kepler, despite being hobbled by its pointing wheels, has already given four or more years of planetary data and new discoveries of planets within the habitable zone are always being found. Recently the question of what we consider to be habitable has even been revised. For closer objects, I think we could be doing better; not necessarily for flying saucers but to safeguard our planet against things such as Chelyabinsk or worse. Asteroid 2014 BA14 was discovered by an independent group in Spain by using equipment by a grant from the Planetary Society so this was no large government funding this project. The asteroid is 250 feet (45 meters) in diameter so that should give you an indication of what a small but dedicated team of researchers can accomplish. The problem with spotting near Earth objects, be they ETs or asteroids, is where they are in the sky and their composition. Looking towards the sun is not very successful and if the object is dark, space is dark as well, compounding the problem of seeing it, therefore infrared is a good way of spotting it. Mathematically, its very possible and plausible that there is life on other planets. How much is intelligent remains to be seen.
I think there is such a time that the radio signals emanating from our planet will become indistinguishable from the Cosmic Microwave Background radiation. Radio signals travel forth in a wave, spreading out, which means that there will be more square units that the signals must illuminate. So at twice the distance from the source, the signal will only one one fourth as strong and at ten times the distance, it will only be one hundredth as great. So at a few light years from Earth, the television and radio signals will become indistinguishable from the CMB. However, this is only because our radio and television waves were not intended for transmission to outer space. If someone were to build a purpose built transmitter here or on another planet, and depending on the initial strength of that transmitter, that extends the signal out to another hundred light years or so.
With things like a parasite that can change behavior, I'd say we've already been invaded and no, we haven't noticed it. (Toxoplasmosis is one example.)
Lemme guess, it didn't work because no birds. But they still would have killed for the accurate clock and camera. Show them your sextant app, and they'll show you their sex tent "app".
The issue at hand would be to detect an invasion fleet jumping in directly to our solar system. That's be an event probably releasing extreme amounts of energy. Considering it would be a fleet, I assumed it to be ships considerably larger than 200 m across, and more than a few. The reference was sci-fi movies so I gathered Star Destroyers or Independence day, Goa'uld or V motherships, i.e. kilometers across, and perhaps hundreds of them. Just the warping in millions of tons of matter into the solar system would release a gravity wave that'd be detectable. These ships will radiate enormous amounts of IR just by being lit buy the sun, not considering spill heating from the internal environment. Their propulsion would generate exotic energies, and/or release chemicals that would radiate in turn (and be harder to cloak). And if they were to communicate by something in the EM-band, that would also be detectable too, even if they were to use very focused beams, since there'd be scattering in the interplanetary dust leaving trails (like a cloud chamber, or comet trails). and the list goes on.
- Henrik
- when the Shadows descend -
FTL is impossible, per Einstein. So yes, we know that it has to use the physics in this universe.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.