Slashdot Mirror
Tsunami Warning From Space?
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."
Better a shark with a fricken laser - they're right where the action is!!!
sudo mount --milk --sugar
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.
-- Cheers!
Wouldn't it be cheaper to hand out emergency radios that wait in a low power standby mode until a certain signal is received?
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.
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 war, or to otherwise hurt an enemy nation through it. Also, how long before someone launches an amateur satellite that makes fake warnings as a prank? The last one is not a big deal, but also worth spending a second thinking about.
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.
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.
GrpA
Enjoy science fiction? "Turing Evolved" - AI, Mecha, Androids and rail-gun battles. What more could you want?
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 don't think it is very practical and there could be better solutions.
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?
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.
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...
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.
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
"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"
Who said this thing had to illuminate the entire damn planet in one go? Jeez, ever heard of raster scanning people?
Ok, as the post above stated above, it takes ~10 watts / m^2 to illuminate. Raster scanning does not fix the problem. if you only have a signal in a given place for say 1/1000th of the time, then the signal needs to be 1000 times stronger to be noticed by the naked eye. You have to remember that we are not talking about a transmission to dedicated hardware. The end result is that your power level required is the same no matter how fancy you get with your scanning system. Unless you are proposing that we attempt to shoot just the people with the laser, and skip everywhere else to save power, but I humbly suggest that this is impracticable...
So, it has to warn people in at-risk sections of coastline. That alone cuts the area to be illuminated by orders of magnitude. Then, it doesn't need to illuminate all of these areas simultaneously and permanently - it could sweep them repeatedly. Imagine that the laser was spread out along a line, say 20Km wide, and that then scanned the affected coastlines. So the people underneath might only see a bright flash lasting for say, 10th of a second every ten seconds. Brief, but maybe enough - better than nothing if you're out of range of a siren.
Say for the sake of argument that this was just 1 square mile of coastline. That is around 2.5 Million square meters, so again for just one square mile of coastline you need 25 Megawatts. This is roughly the power consumption of a small town. Good luck with that.
The whole idea is thoroughly unworkable, not necessarily because we cant build the tech, but because the cost would be prohibitive, and there are far cheaper and more effective solutions. The process you have witnessed here, is one I have seen countless times in engineering:
Step1: Clueless moron (usually management), says hay, lets build x to solve problem y.
Step: Engineer looks at solution x, and cringes at the raw stupidity of it, then looks at problem y, and realizes that there is a far cheaper solution, possibly even already in place.
Step 3: if this is government, the moron pushes ahead with solution x anyway because it is politically valuable, even though it has no practical value.
This whole thread has been an exercise in those who understand good engineering trying to pass some knowledge to those who are quite clearly ignorant and should stop trying to solve engineering problems with frikkin lasers
-=Geoskd
I wish I had a good sig, but all the good ones are copyrighted
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.
Infuriate left and right
I actually think people aren't afraid of the word nuclear. It's nucular that scares them. Mostly because they don't know nuclear is a real word and think nucular means big bad bomb go boom.
how is detecting a tsunami from space better than our current method? 1. seismometers detect earthquake, computers & scientists quickly determine possibility of tsunami generation and issue a warning. 2. buoys in the ocean and pressure sensors on the ocean floor detect passing tsunami energy wave, allowing warnings to be updated. This system works well in about 90% of cases where it's installed; it still isn't fully operational in the Indian Ocean(the Pacific system worked very well after the Chile quake in February), but should be soon. The only major gap that leaves is the places where time from wave generation to impact is only a few minutes -- that is, a city like Padang, Indonesia, or Seattle, which sit just a few miles from a huge fault. What do we do then? A satellite might be useful, but only if it can detect the formation and size of a tsunami and issue a warning *instantly*. Fortunately, those cities have a natural warning system in place: the earthquake itself. They're so close to the fault that inhabitants will certainly feel any tsunami-generating quake. So, spending tens (hundreds?) of millions of dollars on a satellite or satellites to monitor tsunamis probably isn't the best course when you can educated people about how to get out of harm's way for a tiny fraction of the cost.