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Tsunami Warning From Space? 351

Peter bayley writes "Tell me I'm crazy or tell me someone has already done it — but wouldn't a satellite equipped with a laser be a great way to warn people of tsunamis? I was pondering how to warn people in remote coastal areas once evidence of a seismic incident has been received by the monitoring stations that have now been set up following the large Boxing Day tsunami. The idea is to illuminate the areas that are likely to be at risk with a bright (but not dangerous) light. People would be told to head to higher ground if such a light appears in the sky. Put the satellite in a geosynchronous orbit. Make it tunable so that different colors can convey different meanings. You would be able to warn anyone, anywhere they can see the sky. The laser could be directed to illuminate only those areas at risk, skipping unnecessary areas to save power. Power could be varied so that it is visible day and night and through cloud (raise the power where the satellite detects cloud cover). I emailed some people at NOAA about it but they said it would stand on too many toes by circumventing local emergency service organizations in the various countries. I replied that countries could easily opt out, in which case the laser would be turned off for those countries — but received no further reply. Anyway, I thought the massed minds of Slashdot would relish the chance to demolish my idea."
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Tsunami Warning From Space?

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  • Satellite? (Score:3, Funny)

    by dov_0 ( 1438253 ) on Monday April 05, 2010 @05:14AM (#31731406)
    Better a shark with a fricken laser - they're right where the action is!!!
    • Opt out? (Score:3, Interesting)

      This should be opt-in, not opt-out. As cool as the idea is, someone messing with your emergency services by lighting emergency signals from space on your country just isn't cool. The countries should sign that they agree to have such emergency warnings issued above their territory. And maybe should otherwise participate in the system. Such deals are much better done with opt in, not opt out.

      Also, who runs the system? It should be multinational, otherwise someone might decide to run false warnings during a w

      • Re:Opt out? (Score:4, Funny)

        by Cryacin ( 657549 ) on Monday April 05, 2010 @05:59AM (#31731628)
        What about rogue pringles cans with tv aerials sticking out of them?!? How about a pair of sneakers tied together and thrown over a power line? OMG P0n13$!!!

        I'd say that right about now you should check your tinfoil hat dude.
      • Re:Opt out? (Score:4, Insightful)

        by irtza ( 893217 ) on Monday April 05, 2010 @06:56AM (#31731894) Homepage

        Could you imagine a nation whose citizens are not informed about this? They will develop new fears. "Billy, don't look at the sky you might go blind". and then after Billy goes blind from looking at the laser beam, the island gets hit with a tsunami at which point they will accuse Billy of being a prophet of doom.

        Well, in conclusion, I think opt-in with formal education about not looking in a particular direction in the sky would be a good thing.

        • Re: (Score:3, Insightful)

          by Bakkster ( 1529253 )

          Formal education would remove some of the need for tsunami warnings in themselves. For example, the American tourists who saw the water recede sharply before the Indian Ocean tsunami (an obvious warning sign), and took that time to explore the newly uncovered beach rather than getting to higher ground. Then we can just skip the laser satellite, and focus on education and audible warning systems (which do not depend on people looking the right direction)

      • Re:Opt out? (Score:5, Insightful)

        by tibit ( 1762298 ) on Monday April 05, 2010 @09:25AM (#31732898)

        I guess there's some misconception about what such a "light" would look like.

        Everyone seems to react like this was going to be a streetlight type of a thing. You'd need a rather big nuclear powerplant to get that sort of power density on the ground. Assume we want 1W/m^2 on the ground, and a "square" area 5,000km on the side. That's 2.5E10 m^2, so you'd 25GW of optical power output for your illumination. How anyone sees that much power being generated in orbit using current technology -- I don't know. Even getting a 1MW generator in the orbit would be a big feat. You can't exactly put a chiller tower up there. Dissipating all the waste heat would be a huge fucking problem, no kidding.

        For what's achievable with current technology, we're talking about a faint star that say can be red, green or blue. So beam forming to a point where "a country could opt-in" etc. is a fantasy at this point. How hard is it *not* to look up?

  • I don't think so (Score:2, Interesting)

    by tsa ( 15680 )

    I'm not an expert on tsunamis but I understood that tsunamis start as very low waves that roll over the face of the ocean for many many miles before reching land. Only where the sea gets less deep they turn into the ferocious waves that destroy everything. So even if you could see them then with a satellite you would still be warned late.

  • Cheaper solution (Score:5, Insightful)

    by mhajicek ( 1582795 ) on Monday April 05, 2010 @05:19AM (#31731418)
    Wouldn't it be cheaper to hand out emergency radios that wait in a low power standby mode until a certain signal is received?
    • Re: (Score:3, Informative)

      by will_die ( 586523 )
      And easy in training people in what to do or what a laser from space would look like.
      Just going with the old Communist fixed frequency radios or similar to the ones the US dropped during Korea or Vietnam would be cheaper and provide more and better information.
    • Re:Cheaper solution (Score:5, Interesting)

      by ipquickly ( 1562169 ) on Monday April 05, 2010 @06:08AM (#31731682) Homepage

      Just give them cell-phones that can do that instead.
      Make each cell phone have an emergency receiver.

      The phone is more likely to be close to the person.
      It has a greater chance of being charged.
      People will not ignore it.

      And the best part is that cellphones are spreading even in poorer countries.
      Implementation costs would be minimal, just make sure every cellphone receives an emergency band.

      (and being waterproof with a solar charger on the back would be nice too)

      • Re:Cheaper solution (Score:5, Informative)

        by the_womble ( 580291 ) on Monday April 05, 2010 @07:02AM (#31731924) Homepage Journal

        Living in one of the countries affected by the Boxing Day Asian Tsunnami, the problem was not lack of a way to reach people, but the lack of a mechanism to pass the message along. IN particular the people who had the warning, said they did not know how to contact the governments of some countries (which shows a worrying lack of resourcefulness, but that is another subject).

        As you say, mobile phone penetration is easily high enough to work, but you will need to guard against hoax calls. A designated number of warnings would have to be well publicised.

        Radio will work, but you hardly need to distribute them specially: just ask all radio and TV broadcasters to broadcast an emergency message. It may not work that well late in the night. For times like that vehicles with big speakers on them driving through towns with loud warnings should work well.

        The laser idea is stupid: there are all kinds of lights in the sky to confuse people: I remember a huge number of people seeing "UFOs" in London in 1990 or 91 because someone said there was one on a popular radio station, so people started looking up and seeing all kinds of things they normally never noticed.

        • Of course the laser idea is stupid! How is the shark going to swim in space? I'm pretty sure they need water to breathe, too!

      • Re: (Score:2, Interesting)

        by Anonymous Coward

        I reviewed a prototype for a mobile phone four days ago that would be perfect for this.

        With mobile devices still pretty big and requiring something to stow them in, this company is trying to fill a niche market with a mobile device that's completely voice driven and pretty small as far as phones go. You don't actually stuff it in a purse or pocket, but rather pin it on your shirt like military insignia. They are offering integration with the audio system in your house for advanced features that require a co

      • Yes, the cell phone based solutions are much better.

        The dedicated satellite solutions will never happen. They're way too expensive, high technical risk, have a single point of failure, and are politically more tenuous (primarily, who will pay the billions for it?). The use of a high powered flashlight would also REALLY be hard to pass through (not to mention the size of it makes it impractical even if the international political entities could get behind it).

        A much more feasible solution is bouys connecte

      • by CODiNE ( 27417 )

        Even cheaper than that, using existing cell phones and a "broadcast" message from the towers. No need to make new hardware for that.

        Heck you could just send a mass SMS to everyone along the coast.

      • Re: (Score:2, Informative)

        by itoledo ( 210137 )

        Here in Chile, everyone rushed to call their relatives when the earthquake came. The three main provides of GSM telephony collapsed, because of the huge number of people calling, oversaturating all the base stations. Also, the lights went off, and most towers shut down. Almost no one could place a call, and certainly not at the epicenter.

        So I think that sat phones are a better idea for tsunami warnings.

        • Re: (Score:3, Informative)

          by DiegoBravo ( 324012 )

          Exactly the same happened in Perú in our last big earthquake (2008). The epicenter was about 200 km south of the capital (Lima), but nobody in all the region could make a call after several hours (afterward there was a government investiagtion to the carriers, pure blah, blah..) Cell phones are useless at least in standard commercial installations or configurations.

          Interestingly, the DSL services remained operative (at least in the capital) and it was the only way to communicate with peers.

    • by Dan541 ( 1032000 )

      low power standby mode until a certain signal is received?

      In other words switched on.

    • Re: (Score:3, Funny)

      by Thelasko ( 1196535 )

      Wouldn't it be cheaper to hand out emergency radios that wait in a low power standby mode until a certain signal is received?

      Not to mention more effective. The people who were affected by the Boxing Day Tsunami didn't know what it meant when the ocean suddenly receded. How will they know what a blinking light from space means?

      With a radio, you greatly reduce the chances of the message being misinterpreted. I fear this satellite may become worshiped by some isolated people as the great God of the sea.

  • by Anonymous Coward on Monday April 05, 2010 @05:20AM (#31731422)

    No, because the amount of energy, in the form of light, would be immense. You're talking at least 10 watts per square meter, much more during the daytime. Tsunamis can affect hundreds of miles of coastline.

    By my impromptu math, you'd need at least a gigawatt of power to light up that kind of area. So a medium-size nuclear reactor in the sky.

    How about, instead, we just use these devices that transmit sound and vision via lower-frequency light, aka radio and television? Cheap transistor radios are much, MUCH cheaper than launching a reactor into the sky.

    • Re: (Score:2, Informative)


      This idea will never fly. Ten out of ten for style, but minus several million for good thinking.

      • Re: (Score:2, Interesting)

        by pspahn ( 1175617 )
        Does the laser have to be in the sky? Is ground-basing and bouncing it around okay? A laser cage would probably also help in asteroid defense someday.
        • Re: (Score:3, Insightful)

          You'd still need enormously powerful lasers, and sufficient power generation on the ground. We're talking about space-based weapon class power here, and honestly politicians would be far more excited about the offensive capabilities of such a system than 'merely' saving civilian lives.

          A slightly more realistic approach would be to use massive space-based tinted mirrors to reflect sunlight toward the ground. You'd still need truly enormous mirrors for this to work at all -- $$$$$$$. It's not gonna fly.

        • by A nonymous Coward ( 7548 ) on Monday April 05, 2010 @08:22AM (#31732254)

          How you gonna get enough power to make daytime *brighter*?

          Was the idea to cook people and see who notices?

          How about bad stormy weather which the (visible light) laser can't penetrate?

          You going to have geostationary satellites so far away as to multiply the power required and the tremendous power losses?

          Or were you going to have low level satellites, and need thousands to make sure every inch of ground was within a few seconds of any satellite coming into position?

          How about topography blocking line of sight?

          There are so many FAILs all over this idea.

          It's a comic book idea, should never have gotten past the hangover stage.

    • Re: (Score:3, Interesting)

      by fractoid ( 1076465 )
      How about instead of assuming that we need to simultaneously light up hundreds of square miles of land, we assume that we only need to make the land 'blink'? Using your figure of 10 watts per square meter, and assume a 0.1 second flash every 3 seconds. That would require 1/30th the power, and it would only be necessary to transmit the warning for maybe 15 minutes at a time. A 10kWh battery pack should do the trick, and can trickle-charge from solar panels between tsunamis. In fact, the figures are even bett
      • by xous ( 1009057 )
        I'm pretty sure someone is screwing up the math. Aren't you forgetting all the crap in the atmosphere that's going to diffuse the light?
    • Re: (Score:2, Funny)

      by pspahn ( 1175617 )
      You'll have my laser, Chris, and you'll have it by mid-May.
    • by Zumbs ( 1241138 ) on Monday April 05, 2010 @06:01AM (#31731642) Homepage

      you'd need at least a gigawatt of power to light up that kind of area.

      You are sure it is not 1.21 GigaWatts? If we just could find a way to pump a lighthing bolt into space, we would be able to go back to the ... no, wait, wrong movie ...

    • by r00t ( 33219 ) on Monday April 05, 2010 @06:44AM (#31731858) Journal

      Look, we just need a bright flash of light. It doesn't have to be a laser.

      Put up a large number of satellites, much like GPS or Iridium. Each one holds a 30 megaton nuke. When an area is affected by a tsunami, we set off all the nukes that would be visible above the horizon.

      Tsunamis are rare enough that we can normally launch a replacement system fast enough, assuming we don't put spares in different orbits. Have replacements ready to launch.

      • by number11 ( 129686 ) on Monday April 05, 2010 @07:54AM (#31732114)

        Look, we just need a bright flash of light. It doesn't have to be a laser.

        Put up a large number of satellites, much like GPS or Iridium. Each one holds a 30 megaton nuke. When an area is affected by a tsunami, we set off all the nukes that would be visible above the horizon.

        Take out their power grid, their radios and computers, their cell phones, and their vehicles with the EMP. And, of course, the power grids of everybody else who can see those satellites above the horizon. Then while they're going "WTF???" hit 'em with the tsunami.

        • Not to mention you'd also destroy pretty much every non-military (ie very seriously rad-hardened) satellite which didn't have the Earth between it and the nuclear device.

          So, a large area of Earth based elecronics destroyed, and even if you've managed to avoid that, no communications or Earth observation satellites to aid in recovery.

          (...and yes, most satellites are built with rad-hard components, but they're not designed to withstand an EMP, which requires substantially more shielding).

        • by Alsee ( 515537 ) on Monday April 05, 2010 @09:13AM (#31732748) Homepage

          Dear Iran,
          This is a test of the Emergency Tsunami Warning System. Had this been an actual emergency these EMP pulses would have been followed by a tsunami. This concludes this test of the Emergency Tsunami Warning System.


    • My impromptu came up with a similar number.

      The sun is awful bright, so the laser would have to be (awful bright + some) * the area covered. :)

      The more practical answer is to have warning sirens in populated areas, so they would know to go to higher ground quick. Sirens are an awful lot cheaper than a network of specialized satellites, and hoping people noticing that the ground is lit up by a funny light *and* hoping people don't look up and blind themselves befo

    • At 10W / m^2 it would light up the sand! You don't need anywhere near that amount just to see a "light in the sky". You can see stars, they don't put out 10W/m^s.

      That said, your basic ground-based siren is the way to go.

  • by chefmayhem ( 1357519 ) on Monday April 05, 2010 @05:26AM (#31731464)
    They used to use warning sirens for that sort of thing. Far more low tech, but quite cheap, and a single siren can be heard for quite a distance. Just put them near the shore. Now, it's not nearly as cool as the satellite, but it would work if people are indoors and not looking out the window.
    • There are two problems with that solution:

      1) Its already been done (at least in Sri Lanka), so there is no point suggesting it
      2) Its too low tech and non-geeky, and does not user lasers.

  • Already tried to produce a laser capable of illuminating an area of several hundred square miles in broad daylight? Even if such a laser would already be feasible, the power supply would require a nuclear reactor.

    if you need just 1W per square meter (very low for a visible light), 100 square miles (a tsunami danger zone would probably be bigger) would require >200MW.

    I think we are currently 2-5 magnitudes away from feasability.

    CU, Martin

  • Laser Power... (Score:5, Insightful)

    by GrpA ( 691294 ) on Monday April 05, 2010 @05:28AM (#31731472)

    Getting a laser from a sattelite to one place on earth so it could be seen would require a LOT of power, even at night. Illuminating an entire part of the earth would take more power than you could imagine...

    Even measuring the ocean's height with a satellite would be challenging.

    However, I think you've uncovered the real problem. It's not warning people that's the issue ( you could easily broadcast radio and pick it up with a small receiver ) it's that there's no desire to create such a system.

    Usually, the authorities would prefer to be the only ones to know. Then they can make the decisions... Do they tell people in all areas? How do they handle the evacuations? etc.

    Your heart is in the right place, but your idea itself presents a lot of problems... If you really want to help, then spend a few years teaching yourself world politics. Speak to experts in the field of emergency services and become one yourself. Don't wait for others to pick up your idea, make it work yourself and become an expert. Most experts are simply people who were driven for one reason or another to keep on learning about a particular field.

    As a suggestion? The easiest way to address tsunami's might be without sattelites and high-tech... Perhaps just keep an eye on the situation by following the websites that publish that kind of information, then set up your own website to co-ordinate redistribution of it - Then people who are worried about it, such as yourself, can subscribe - perhaps you could even use SMS to notify them?

    Big ideas are easy to implement and opt-in is the best system.


    • Re: (Score:3, Insightful)

      by gandhi_2 ( 1108023 )

      if the laser was intense enough to be visible on the ground in the day, how intense would it be at 40,000 feet? would we be frying pilots eyeballs?

      disregarding the impossibility of generating that much energy in space. and the lack of Pink Floyd to go with the laser light show.

    • by thewiz ( 24994 ) *

      Getting a laser from a sattelite to one place on earth so it could be seen would require a LOT of power, even at night. Illuminating an entire part of the earth would take more power than you could imagine...

      Watched Star Wars a few too many times?

      Of course, the Death Star would get everyones attention.

  • Problems (Score:2, Interesting)

    by jaxxa ( 1580613 )
    I don't think that this is a practical solution. Lasers are very focused and don't spread out like normal lights, if they were to spread out the power requirements would be huge. Also It would be walking a very fine line between delivering enough light to be noticed and too little to cause eye damage to people looking up. Lastly You would have to check the wording on the agreements banning weapons in space, even though it is not the intention this could be viewed as one. While this is an interesting idea I
  • A warning system that requires GW of power (we are talking about making light visible over several km, right?) and people have to be looking at it (and having an unobstructed view to the sky)...
    I suspect the power requirement would only be sort of manageable during night time, but that is when people sleep and a laser would not go far in waking them. Now, if it was SHARKS with lasers...

    • The superscript "2" that was next to km was "eaten" by the slashdot comment engine, I was talking about the surface to be covered, although the distance is also a factor of the power requirement.

  • My concern is with something like this is not everyone will see the warning light as a reason to leave. It would get many people out, but not all. Some would stay just for the sake of looting and something like this would only help. Telling people they need to leave with a big group behind you when your telling is one thing. Doing it alone (or unmanned) is worse. Think of all the looting that happened during the Hurricane Katrina. Now think about what people will due when they are left alone and have knowle
    • by Igmuth ( 146229 ) on Monday April 05, 2010 @06:01AM (#31731640)

      Wait a damn second here. You are against warning people about tsunamis because some might use it as a chance for looting? Personally, if there is a giant wall of watery death heading my way, I'd like to know about it. If some moron decides to stay behind to grab my stuff, I'll the aforementioned wall of watery death deal with him, wash away all evidence, including the moron himself.

    • Wash away the evidence? Yeah, so they are stealing stuff that is about to be destroyed... Worry about the looting AFTER the event.
  • by Anonymous Coward on Monday April 05, 2010 @05:47AM (#31731570)

    Why not just get Superman to fly backwards around the world really fast thereby (somehow) turning back time? He could then fly under the country in danger and lift it up until the tsunami passed safely underneath.

    Seriously - why is this crap get on the front page?

  • Connect them satellites to Google Maps and draw arrows on the streets in the safe directions.
    Zap everybody that isn't listening.

    While we're at it. If there is no water, there is no wave.
    Use the lasers to evaporate the wave part of the sea before it hits the shore.

  • by mad flyer ( 589291 ) on Monday April 05, 2010 @06:07AM (#31731664)

    Yeah, now brainfarts... directly on slashdot... the only thing more stupid than anything following "Hey y'all watch this" are usually exposee introduced by a falsely humble "crazy idea" which in 90% of the case is totally retarded and in the 10% remaining already more common than water but the bragging genius was to dull to understand how it worked in the first place.

    Seriously, keep this for april first or Digg...

  • I envisage this system as working something like in Wall-E when he follows the red light from the approaching spaceship. That would be cool - a little guide light showing you which way to run in an emergency. Or you could like shine it on some landmark that was a set height above the estmated wave and say "Try and get to this!". Or like a laser sight, shine it on someone running really fast in the right direction and say "Try and keep up". Man, look at those little ants scurry!
  • Oops. Did i just break the stupid concept in another way?

    • yes - this is just your classical theoretical discussion

      please leave real world realities out of it
  • Especially the idea of a continuous light.

  • There is no practical way to generate enough light to alert people on the ground of an approaching disaster. At best they would see a bright light if they looked in the right direction.


    Solar sails in orbit could be used to illuminate the surface of the Earth and I have seen proposals to use them to illuminate disaster areas where infrastructure has been destroyed. The idea was to give people light to work by until the sun comes up but I suppose you could illuminate the location of an anticipated disaste

  • The article poster may get a better reception emailing advertising agencies - using orbiting lasers to beam down advertising to millions.

    From a technical standpoint, as another poster on here already mentioned, the power consumption could be greatly reduced by illuminating only sections of area at a time instead of all at once in a strobe like fashion.

    Or a more practical way, which is likely already feasible now, is to illuminate the sky instead of the ground.

    As far as detecting tsunamis from space, while n

  • Typically a better solution is to use radar or infrared, laser tends to have problems penetrating cloud cover and the like. Space based radar altimeters are nothing new, and yes you could theoretically set up a tsunami warning system in space. Radar technology has come a long way in terms of power and range. I work in the radar altimeter industry so maybe I am biased. []

  • by cheesethegreat ( 132893 ) on Monday April 05, 2010 @07:02AM (#31731922)

    This is obviously absurd, as pointed out by plenty of the above posters. What I'm more concerned about, is why this got posted to the Slashdot front page. We have the Digital Economy Bill about to be passed without debate in the UK, various stories on the LHC's full power experiments, all sorts of lunacy in the US with patents, and we get a "hey guys, what about this idea" from a random slashdotter.

    If this were coming from a noted astronomer, a major figure in disaster relief, or GWB, then it would be Slashdot-worthy. But seriously, what value did this Ask Slashdot add?

    Also, the previous story on the sun-chandelier was such a non-story as to be shocking.

    I've now started tagging stories: ohnoitskdawson

  • Wow this story is almost as crazy as my idea to build a giant water tower in the ocean to lower sea levels, see [] for more details.

    In all seriousness the poster seems to be interested in using the laser to communicate, is that such a big problem ?. The world is a much smaller place than it used be, I suspect that simply activating the laser would take some time, possibly calling the local officials would be almost as effective.

  • The idea that you can outshine the sun with a man made satellite is so absurd, you have to question the intelligence of the person asking this question. At night it would be easier, but still require an insane amount of power and be totally useless when there are clouds.

    At first I thought the question might be about measuring the oceans for tsunami waves, but this kid wants to put up some kind of disco lights.

    You already need binoculars to see the ISS and then you can only spot it if the light reflects of

    • You already need binoculars to see the ISS and then you can only spot it if the light reflects of it in the right way.

      Patently false. Every overhead pass of the ISS results in a very bright, fast-moving display. In fact, the ISS is one of the brightest objects in the night sky. Most passes are magnitude -3.4 (very bright) to -3.0 (bright) - recall that stellar magnitudes are brighter the smaller the number, and are logarithmic []. For reference, the brightest star is Sirius [] at magnitude -1.46. Venus is as brig []

  • Good old fashioned air raid sirens would be much cheaper and a hell of a lot more effective at getting the information to the people most likely to be in harm's way during a tsunami. The people who are most likely to be affected are the poor and uneducated, or tourists. The poor and uneducated are not likely to know what the "different colors in the sky" mean, no matter how hard you try to educate them. Tourists won't understand either unless they're from a place where such things are also a likelihood.

  • This. is the voice. of the Mysterons...

  • Sounds like a space-age version of the weather lights on top of the old Hancock building in Boston:

    Steady blue, clear view.
    Flashing blue, clouds due.
    Steady red, rain ahead.
    Flashing red, snow instead.

    (During baseball season, flashing red means the Boston Red Sox game has been called off on account of weather.) []

  • "And when the unblinking star starts to blink.. Beware o evildoers... And when the star starts blinking red, Knoweth that thy doom is at hand Saints and sinners alike For the sea will come And seek you out of your lowly abode"
  • "Thousands killed from partly cloudy skies"
  • Or at least keep them to yourself.

  • No that how they set them off and it's a good way to be able to have a under cover way of ......

  • You'd need a frakkin powerful laser to punch through clouds from geosynchronous orbit (about 36,000 km above the Earth).
    What if it's a sunny day? How bright would the laser need to be to be noticeable in bright tropical sunlight?

You are in a maze of little twisting passages, all different.