Ask Slashdot: How Could We Actually Detect an Alien Invasion From Outer Space? 576
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?
maybe we should (Score:5, Funny)
Email Elon, see what he thinks.
Sweet F A (Score:4, Interesting)
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.
Re:Sweet F A (Score:5, Interesting)
Re:Sweet F A (Score:5, Insightful)
While that is a nice hopeful story, and while I suppose ANYTHING is possible...
It isn't very probable...
Besides, even if they were at our level of technology, if they have starships, then they have nuclear weapons. They don't have to invade, they can simple drop rocks or nukes on us to accomplish the same thing, and there wouldn't be anything we could do about it...
Unless of course, someone had a Mac laptop and was a cable repair man! :)
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But a space-jumping fleet of invading space aliens is? Did you even read the summary?
Re:Sweet F A (Score:5, Insightful)
But a space-jumping fleet of invading space aliens is? Did you even read the summary?
Actually, it is very probable indeed... just not HERE!
Space is big, really big, unbelievably big... Odds are, somewhere out there, "space-jumping fleet of invading space aliens" DOES exist. Odds of them being ANYWHERE NEAR HERE? Almost zero.
Two separate points. :D
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The second point is not really relevant, given that the thought experiment is about our ability to detect something that was invading us. If they are invading us, then they have found us.
So you now have to explain 2 discrepancies in technology. 1) They are sufficiently advanced to have found us. 2) They are sufficiently advanced to get to us.
The more you add to the list of things they would have to have in order to invade us, the less and less likely they are missing the things required to eliminate us unde
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Math...
The number of planets, number of galaxies, and the size of the universe... if it doesn't exist, then there is something wrong with basic probability theory...
There are simply too many chances for it to exist for it not to. It just isn't likely to exist anywhere near us.
Re:Sweet F A (Score:5, Insightful)
If physics doesn't allow for it, it doesn't allow for it anywhere. It doesn't matter how large the Universe happens to be.
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So in your mind we know all there is to know about this?
There is no room for further advancement?
Guess we better tell all the physics researchers they're no longer needed.
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You speak as if you live in a reality where there can be an objective third party point of view, and where physics has some kind of existence outside human imagination. How 19th century quaint.
The Copenhagen interpretation is the best we've got since the upsets by Heisenberg et al.. To whit: physics is our best imaginary model of what the Universe might be like. That's not only as good as it gets, by the very nature of things that's as good as it can ever get. There is no objective reality. It is all in yo
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Re:Sweet F A (Score:5, Interesting)
if something isn't forbidden by the laws of physics ...
FTL travel, or even FTL communication, is forbidden by the laws of physics. Light speed limitations lead to boring science fiction, so FTL travel is common in sci-fi, where starships travel at the speed of plot. But there is no evidence that it will ever be possible in reality, and plenty of evidence that it will not.
The real alien threat is not a giant fleet of starships coming out of hyperspace, but a small probe filled with nanobots.
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FTL travel, or even FTL communication, is forbidden by the laws of physics.
It's not strictly forbidden. However, FTL communication is equivalent to time travel in special relativity. This means that it breaks causality. Since we haven't observed any breaks in causality, and special relativity is an extremely well tested theory, we assume that FTL communication can not exist.
Re:Sweet F A (Score:5, Interesting)
Actually travelling faster than light isn't really forbidden. What's impossible is accelerating to or past light speed. (Your mass will increase infinitely as you accelerate requiring an infinite amount of fuel.) However, you could theoretically start faster than light. The equations lead to an imaginary number which leads to some debate as to what that means. Interestingly, if you were going faster than light, you'd encounter the same effects (divided by the square root of -1) slowing down to light speed that we encounter speeding up to light speed. However, you could reduce those effects by travelling even faster.
We haven't detected anything travelling faster than light, but that could just be a limitation of our detection capabilities rather than a limitation of the Universe.
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Parent post presents a reasonable argument. But the argument depends on an unstated assumption that cannot be verified and is most likely not true. The assumption being that our observational skills are so highly developed that we would recognize a break in causality if we saw it.
On every scale from the dark matter/energy that makes galaxies the way they are to the mysteries of quantum foam, there are a multitude of indications that we really are not very good observers. For if we were, there would be a lo
Re:Sweet F A (Score:5, Insightful)
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Entangled photons do not transmit information. Assume two states, A and B, such that a pair of entangled photons, when measured, will have one in state A and one in state B.
Any modification to the state of one photon breaks the entanglement. The Earth observer can find that his photon is in state A, and therefore knows that the Pluto photon must be state B, but that doesn't pass information, since the Pluto observer knows only that its photon is in state B.
Let's take an analogy that's not too horribl
Re:Sweet F A (Score:5, Informative)
http://en.wikipedia.org/wiki/Action_at_a_distance could be used as to communicate.
No it can't. Although entangled particles can interact, you cannot use the channel to communicate. Any "message" sent looks like random noise. It is only when you compare it after-the-fact that you can see the FTL influence.
It is like you have two perfect random number generators, and you can switch from one RNG to the other, and have the change happen instantly light years away. But on the other end, they just see a continuous stream of random numbers. If you can latter look at the stream of numbers, you can see that the switch happened at faster than light speed, but no useful information was communicated.
Re:Sweet F A (Score:5, Informative)
1. Measure the entangled property, say, the spin, on Earth.
2. Be like: Wow, on Pluto that must've given <opposite property>.
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You'll have to start by first finding some fundamental physics which allows superluminal travel. Sorry, but Star Trek physics doesn't count.
Re:Sweet F A (Score:5, Funny)
By the same logic, there's also a room of moneys with typewriters somewhere turning out all the great books
Thanks to the Internet, we now know that's not true.
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The probability is much greater that, before that roomful of monkeys turns out its first Shakespeare play, it will produce parseable statements in Perl. At that point, anything can happen.
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Keyboard mashing can produce word patterns. If someone is mashing a keyboard and accidentally mashes "t" and "h", there is no magical force in the universe which quickly checks an English dictionary and stops the masher from mashing any button which would create a word ("the", for example). That's the thing about infinity - it makes the massively unlikely infinitely more likely. As long as something is not impossible, if attempted an infinite number of times, it is possible that it will happen.
But the universe isn't infinite. Infinity is a mathematical concept, not a description of reality.
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Your monkeys are deficient in randomness.
Of course truly random monkeys would contain many random mutations many of which are not going to be viable, which means that room no matter that it is infinitely big, is going to be full of the stench of dead, decaying monkey flesh. The whole damn metaphor stinks.
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I understood that, what I am saying is that the chance is not infinitesimal, it is 100% improbable because keyboard mashing *is not random* it is the product of hitting the keyboard in a particular manner that looks random and may be 99.9999999999999999999999999999% similar to random, but that is no-where near close enough. It is not random because a monkey is not a random number generator it will follow certain rules in order to mash and none of the finite number of patterns those rules will equate to anything substantial.
But if you start with the premise that the keyboard mashing is perfectly random then yes, infinite monkeys will write books.
You seem to be assuming that these are real monkeys. They aren't, any more than Schrodinger's cat was real.
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Well if they're not real then they can't write books can they.
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given either enough time or distance anything not specifically prohibited by the laws of physics is happening somewhere.
if the universe were something like 10^10^100 light years across then there would be an exact duplicate of "you" somewhere in it. because there are only so many configurations and quantum states that a specific volume of space can take.
granted we don't believe our universe is that large, only i think about 10^26 light years., but given a universe that is large enough then some seemingly u
Re:Sweet F A (Score:5, Insightful)
It's a cute concept, but the simple fact is, if you have some simple technology for gravity control that can take a primitive society whizzing around the cosmos, then that primitive society wouldn't be using flintlocks for battle. Because if you control gravity to the point that you can hop some primitive ship in and out of gravity wells and move at relativistic speeds then you're controlling *vast* amounts of energy to do so. And there's no way such a species is going to only make use of this vast amount of energy in their spaceships but not their weapons - even if they're only kinetic impactors.
Re:Sweet F A (Score:5, Insightful)
Just because the hypothetical aliens are ahead of us in some respects (e.g. the ability to practically travel across interstellar distances) it does not necessarily follow that they would be ahead of us in all others.
Uh, yes, it absolutely does. If they have mastered interstellar travel, then then there is no way that they will be behind us in any other aspect.
On the positive side, this also probably means that they'd have nothing to gain by coming here or killing us off.
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Necessity is the mother of invention, the saying goes.
But even more accurately:
-Innovation is a result of necessity of some form or other.
-Continued use of innovation is also a result of continued necessity.
Suppose they have a physiology similar to hydra or certain jellyfish, where they have the capability to regenerate completely, or in the case of hydra, actual re-order their cells back into a recognizable organism after being blended into a soup. Such a species could easily have a reduced or non-existent
Re:Sweet F A (Score:5, Interesting)
The invasion starts in a forest near a small polish village, and the aliens transform into local people they just saw passing by, thus totally hiding their alien presence. But then they meet a drunkard, who bears a grudge against one of the people they have turned into anyway. Their biogenic attack weapons (a swarm of insect-like stitching and poisoning robots) turn back because they can't get through the ethylalcohol cloud surrounding the prospective victim, and the drunkard gets agitated because they aliens don't really react when he yells at them. Their weapon detecting device doesn't warn about the knag lying wayside, and the drunkard takes it and hits them on the head, while they still try to get their translation device to decipher the messages he was mumbling at them - thus killing the aliens and fighting off the alien invasion.
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I like the novel approach that "Footfall" took: the aliens aren't very smart - their technology came from a predecessor species on their planet that had driven itself extinct. Everything they could do with technology came from ancient documents. So they came in with a tremendous technology advantage, but also an evolutionary disadvantage.
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Except, if they are that advanced they likely wouldn't even bother. We would be far more likely to not even see it as an invasion, hell they wouldn't even see it as an invasion.....no more than we see it as an invasion when we bleach the toilet.
If anything we are far more likely to have them giving us their version of the smallpox infested blankets.
When they post on Slashdot... (Score:3)
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.
Re:Sweet F A (Score:5, Interesting)
it's highly unlikely that space travel can be accomplished without huge amounts of EM radiation.
Why? Why is it unlikely? We have really no idea how to travel faster than light, like so many things, I suspect it is something we haven't even thought of... like how silly airplanes looked, until they actually flew and pretty fast they didn't look anything like the silly 19th century attempts to fly.
What was missing was power, lots of power, in a lightweight package.
Even once we had airplanes, you have only a lifetime from 1903 to 1969, yet people in 1903 couldn't have dreamed of what the Saturn V would look like or how it would work.
It is not rational to assume that unknown technology means godlike abilities.
Nonsense, sure it does...
I am quite sure that if you went back 500 years and took modern technology with you, it would look quite "godlike" to those people.
If we can detect exoplanets, what makes you think that we wouldn't be able to detect alien ships?
For one thing, the planets are in one place, stay in one place (well, in orbit) for a long time, they aren't trying to avoid detection, and they are really big. They also have an effect on something even bigger that is its own light source, a star.
Starships fit none of those parameters. Even more, we aren't even looking for starships and if we were, we don't know what to look for. We DO know what to look for when it comes to stars and planets.
Re:Sweet F A (Score:5, Insightful)
The better analogy would be near-earth objects. Even still, they stay in (sort of) fixed orbits, generally close to the orbital plane of the planets, and don't try to avoid detection. Yet we're nonetheless pretty terrible at detecting "ship-sized" NEOs. If by "ship-sized" one means "aircraft carrier-sized", odds are better than not that it wouldn't be spotted until it was within the orbit of the moon. If we're talking "space shuttle sized", it probably wouldn't be spotted until it got near LEO.
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That is a good point, and near-earth objects such as asteroids and comets aren't actually trying to avoid being detected.
Could WWII RADAR detect a modern Stealth Bomber?
Why do we think anything we have could detect a starship that has its "stealth systems" on? (whatever they might be)
Re:Sweet F A (Score:5, Insightful)
people in 1903 couldn't have dreamed of what the Saturn V would look like or how it would work.
Funny that you chose 1903 as your date, since that was the year Tsiolkovsky published The Exploration of Cosmic Space by Means of Reaction Devices, wherein among other things were mentioned that escape velocity could be achieved with a multistage rocket fueled by liquid oxygen and liquid hydrogen.
So yes, at least one person in 1903 not only could have dreamt, but did dream and explicitly state how rockets like the Saturn V would look and work.
Re:Sweet F A (Score:5, Funny)
"I am quite sure that if you went back 500 years and took modern technology with you, it would look quite "godlike" to those people."
Don't behead me until your sailors have seen this! A little box, which I carry around with me everywhere, that knows its own position to within mere feet! All I do is press this button, tap right here, and --
Oh, wait --
Re:Sweet F A (Score:4, Insightful)
Even once we had airplanes, you have only a lifetime from 1903 to 1969, yet people in 1903 couldn't have dreamed of what the Saturn V would look like or how it would work.
In 1969 there were people still alive who were born in 1860.
Even one who was born in 1858.
Granted only a couple were in the US (and the recorded 1858 individual was in the UK).
But it is so freaking cool, that in their lifetime humanity saw:
-the first transcontinental railroad and mass adoption of trains globally (1863)
-the American Civil War, and other wars around the world
-the height of the Age of Sail, and then its end
-the rise of the steamship
-the rise of the automobile
-the rise of the airplane
-the shrinking of the world, and the end of the blank spaces on the map
-the rise of nuclear energy
-the rise of the League of Nations, and then the United Nations and the first real attempts at global diplomacy in place of war (and a reduction in large scale conflict; albeit with a shift to the Cold War)
-the emergence of computers
-and finally yes, the Saturn V rocket, and a man landing on the moon
That is so FREAKING COOL, all that happened in those persons' lifetimes.
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Assuming that I took more than just myself, I don't think burning on a large stake would be a risk, we have automatic weapons. :)
That being said, your example proves my point, it would look like magic to those people who have no frame of reference.
We like to think we're smart today, but the reality is, we can't conceive of what 500 years from now will look like. We can guess, but we are likely to not just be wrong, but REALLY BADLY WRONG.
We may not even keep our bodies in 500 years, preferring to replace t
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Relativistic kinetic weapons aside, it's highly unlikely that space travel can be accomplished without huge amounts of EM radiation.
so let me get this straight. You think you have enough knowledge of technology we can't even fathom how it could operate to know how we would be able to detect it and yet you call me the idiot?
Just nope (Score:2, Informative)
Do you expect any other answer than "we would be fucked"?
The question is utterly stupid... (Score:2)
When it is completely unclear what to expect, no predictions can be made. Hence the question is utterly stupid.
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The question isn't stupid, just asking it focuses attention on the fact that there are likely aliens out there.
Perhaps we should stop fighting each other on this planet and develop a real space transportation system?
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Stack Exchange now has a sub-site for questions like this:
http://worldbuilding.stackexch... [stackexchange.com]
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When it is completely unclear what to expect, no predictions can be made. Hence the question is utterly stupid.
Of course there's millions of possibilities of how alien life could reach earth and it may be something completely different than a Goa'uld ship. But if we look only at his core question, it's not that hard to answer. His starter question was "how good are we at the moment in detecting an alien ship/fleet that jumps into our solar system". What can our space observation gear or closer-to-ground systems such as air traffic control do to detect an alien vehicle?
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That question is actually even more stupid. It starts with "jumps": As far as we know, that is physically impossible. Hence if such a fleet actually "jumps" into the system, it is so far beyond even our understanding of the fundamentals of Physics, that it is as good as magic. Adding a perfect cloak and gravity-distortion shielding to make them undetectable would be mere trivialities on top of that.
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I don't think the question is stupid. Dismissing it out of hand seems more so.
1. Asking questions such as this, where we have limited information, often spawns interesting approaches to solving them
2. Any method for detecting 'unwanted visitors' may also be effective in detecting unintelligent (but still unwanted) visitors like significant lumps of fast moving rock which if unencumbered may cause an extinction event
3. It is an opportunity to involve people across national, political, tribal and ethnic di
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Would it matter? (Score:5, Informative)
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... [wikipedia.org]
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... [wikipedia.org]
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... [asu.edu]
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.
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Imagine the US Military of today decided to invade Europe of Napoleon's era.
Would their "old" technology do them a lick of good when a thousand M1 tanks rolled across the field at them? What about when Predator drones are flying overhead launching missiles at their supply depots behind the lines?
Perhaps their bow and arrows will be effective against the modern artillery and mortars of modern warfare?
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Instead perhaps we are "closer" to the aliens, so lets move forward to World War I, it is 1916, armies in
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> Would their "old" technology do them a lick of good when a thousand M1 tanks rolled across the field at them? What about when Predator drones are flying overhead launching missiles at their supply depots behind the lines?
Just like the US military in Iraq, right? Or the British, Russian, and now US armies in Afghanistan for the last 150 years? Or both Napoleon and Hitler invading Moscow? While a thousand armored vehicles would flatten any native standing army any interstellar military force has _incredi
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Economics.
Good archery takes more training, more equipment, and the equipment is much more fragile. A javelin can last for thousands of training uses, sit in a closet or in an armory for decades, and still work perfectly. A bow is much more difficult to make and maintain, much more fragile, and the ammunition is much less durable for training.
how close to earth? (Score:2)
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?
just read other sci-fi authors (Score:2)
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
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You can't. (Score:2)
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They still have to match orbital velocity on the same ecliptic, even at 0.1c they would show up from a long ways away. There's no "stealth" in space, plain and simple. Spaceships produce too much everything, heat, radiation, gas etc.
Orbital insertion would be pretty obvious as well, even at the L1 behind the moon we would notice them coming in.
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They still have to match orbital velocity on the same ecliptic, even at 0.1c they would show up from a long ways away. There's no "stealth" in space, plain and simple. Spaceships produce too much everything, heat, radiation, gas etc.
Orbital insertion would be pretty obvious as well, even at the L1 behind the moon we would notice them coming in.
We would? You mean like we notice all those asteroids flying by that we get a few days notice of, or sometimes get notice of AFTER they have passed us?
What makes you think there is no stealth in space? Anyone who can come up with a FTL drive likely can come up with stealth in space.
How does it work? I haven't a clue, but I don't know how FTL works either, just like someone from 400 years ago couldn't tell you how a modern turbofan engine works.
Re:You can't. (Score:5, Insightful)
In fact, to suggest an old theory that says stealth of any kind is impossible not only imagines a theory that doesn't exist, but it violates the very principles of empiricism, thereby undermining the entirety of Physics with every other science to follow.
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be glad that they're invading when they should simply destroy the entire solar system instead
If these aliens were intent on destroying us, they'd simply drop something large, fast and nasty into the sun and cause some sort of X-Ray eruption. Since there is a massive nuclear reactor so close, it would be silly not to leverage that to your goals. No need for ships or an invading force.
So we can assume that if aliens did arrive here, our destruction would not be their goal. They might, for example, just be neighbours popping over to ask politely if we'd mind turning down our electromagnetic emissio
Outside Context Problem (Score:5, Interesting)
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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 [chrishanger.net] 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.
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Of course, which is why our Sci-Fi shows are fun, but at the end of the day, silly...
Take Star Trek... 400 years from now, I highly doubt we'll be walking around talking to the ship, we'll be interfaced directly with it and with each other...
But that doesn't make sense to your average person today and it doesn't make for great television, so they show "future versions of today", rather than the complete change that would really happen.
Go back 400 years, what were most people doing? Heck, most people could
mandatory (Score:2)
Human (Score:5, Interesting)
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.
Re:Human (Score:5, Funny)
And if that Chinese family serves you Peking Duck what would you then conclude?
Re:Human (Score:5, Interesting)
The best example individual that fits, is Elon Musk. The guy is ridiculously successful, but that is merely a means to his alien ends, which seem to be: to go back to his home planet. He needs processing power, so he funds high tech development, then sells it when it's sufficiently advanced so he can focus on developping the battery tech that he will also need later on, etc. Repeat the cycle until he gets the effective rocket / spaceship / dimensional portal tech required to get back home.
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Attack? (Score:2)
This speculative question really can't be answered (Score:2)
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 fly
We'd probably detect an invading fleet quite early (Score:3)
Ask NEO (Score:2)
http://neo.jpl.nasa.gov/neo.html/ [nasa.gov]
Assuming they're not stealthed... (Score:2)
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 n
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It would be an infeasibly difficult and expensive project to cover all of the Earth's surface alone in radar / optical scans in near-enough time to spot anything moving oddly no matter what it was or where it moved, and then isolate that from the background noise of trees moving and things rolling down hills.
To then extend that by several DOZEN orders of magnitude to cover the entire solar system? Sorry, it's really sci-fi at the moment. If we could populate a few of the outer planets and triangulate, may
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First off, who says it needs to be on the earth at all?
Second off, you just need enough resolution that something in the solar system takes up a single pixel. It doesn't need any detail. Just enough to pick up motion.
Third off, I am aware it is a huge undertaking. However, ideally you could give it multiple purposes. the reason it is considered too expensive is largely because the threat is not credible. The trick would be to give the system enough other uses that justified the system indifferent to alien i
Answer : no until they are in our face (Score:2)
Why should they invade earth? (Score:3)
Sigh (Score:5, Informative)
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? (Score:3)
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...
don't worry about it (Score:2)
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... [goodreads.com]
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
Speed matters (Score:2)
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
How do you know it has not already happened? (Score:2)
Simple answer (Score:2)
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.
"Jumps into our system"???? (Score:2)
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 mi
Today In: (Score:3)
I'm not doing your homework (Score:4, Funny)
Nice try advanced scout party. You slipped through but I doubt the armada will fair as well.
Calvin said it best (Score:3, Funny)
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If Sony knows, then North Korea will be the first to know!
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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 ide
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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. Gi
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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 o
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To be invaded, you have to have something worthwhile. Colonisable planets wouldn't be hard to find for a civilisation capable of inter-system travel. We don't have anything particularly rare or in unusual abundance in terms of useful minerals. We are boring in and of ourselves and contact would be pretty pointless for anything working at that level.
And the more we find out, the more "usual" we become - there are now orders of magnitude more stars believed to have Earth-like planets than before. There's
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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 go