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Tsunami Warning From Space?

kdawson posted more than 4 years ago | from the that's-no-star dept.

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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Satellite? (3, Funny)

dov_0 (1438253) | more than 4 years ago | (#31731406)

Better a shark with a fricken laser - they're right where the action is!!!

Opt out? (2, Interesting)

impaledsunset (1337701) | more than 4 years ago | (#31731458)

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.

Re:Opt out? (3, Funny)

Cryacin (657549) | more than 4 years ago | (#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.

Arr! (-1, Troll)

Anonymous Coward | more than 4 years ago | (#31731704)

Suck me cock.

Re:Opt out? (3, Insightful)

irtza (893217) | more than 4 years ago | (#31731894)

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.

I don't think so (2, Interesting)

tsa (15680) | more than 4 years ago | (#31731410)

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.

Re:I don't think so (1)

jaxxa (1580613) | more than 4 years ago | (#31731444)

I think that the idea is to use the satellite as a Warning after an earthquake has been detected by seismic sensors, as they do now. Not actually finding a Tsunami. But yes I think you are right in that they could not be used to detect the wave.

Re:I don't think so (3, Funny)

tsa (15680) | more than 4 years ago | (#31731508)

You're right, I only read the first sentence of the question before replying, so my reply was totally off topic. That will probably cost me some karma.

Re:I don't think so (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#31731872)

Would the sattelite run linux ? I think it would have to be open source. Definitely open source.

Re:I don't think so (2, Insightful)

DJRumpy (1345787) | more than 4 years ago | (#31731974)

Wouldn't it be a little cheaper, and a bit more sure way to communicate with the locals if they just issued sat phones to the local government?

Re:I don't think so (1, Insightful)

Anonymous Coward | more than 4 years ago | (#31731512)

I was thinking the exact same thing.

But isn't the other problem that this warning could be easily be overseen? Like when people sleep or when there is a really sunny/cloudy day?

Just some seismic sensors in the sea with some kind of network connection and sirens on the other end should do just fine.

Wave height (0)

Anonymous Coward | more than 4 years ago | (#31731414)

I was under the impression tsunami waves are not that high until they pile up at shallow depths, out at sea a ship can pass right over one without noticing.

I could be wrong though.

PS: I'd use radar instead of a laser, the former goes through clouds.

Re:Wave height (0)

Anonymous Coward | more than 4 years ago | (#31731424)

RTFS. Not detection. Notification.

Re:Wave height (0)

Anonymous Coward | more than 4 years ago | (#31731678)

They have satellite radar altimetry: [] []

For early warning they use undersea pressure sensors: []

Cheaper solution (5, Insightful)

mhajicek (1582795) | more than 4 years ago | (#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:Cheaper solution (2, Informative)

will_die (586523) | more than 4 years ago | (#31731540)

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 (4, Interesting)

ipquickly (1562169) | more than 4 years ago | (#31731682)

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 (5, Informative)

the_womble (580291) | more than 4 years ago | (#31731924)

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.

Cheaper solution! (1)

Mirar (264502) | more than 4 years ago | (#31731962)

Why not just have a GSM/3g/4g signal that can be transmitted from the base stations? Either SMS or make all cell phones in the cell wake up and loudly tell the message.

Re:Cheaper solution (2, Interesting)

Anonymous Coward | more than 4 years ago | (#31732004)

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 computer. If your in the house you simple call up the system by saying a keyword (default is "Computer", which I think is too common a word, but hey, I'm no Vulcan). If you're not in the house you simply touch the phone on your chest and call up people by name.

I think this would be perfect since you would be wearing it the whole time. And somehow when I wear it I feel.... complete.

Terrible idea, of course, which is why we don't (5, Informative)

Anonymous Coward | more than 4 years ago | (#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:Terrible idea, of course, which is why we don't (2, Informative)

burisch_research (1095299) | more than 4 years ago | (#31731442)


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

Re:Terrible idea, of course, which is why we don't (2, Interesting)

pspahn (1175617) | more than 4 years ago | (#31731680)

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:Terrible idea, of course, which is why we don't (3, Insightful)

burisch_research (1095299) | more than 4 years ago | (#31731836)

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.

Re:Terrible idea, of course, which is why we don't (1, Funny)

Anonymous Coward | more than 4 years ago | (#31731452)

So a medium-size nuclear reactor in the sky.

Why hasn't anybody done this yet?

Re:Terrible idea, of course, which is why we don't (1)

WORMSS (1431561) | more than 4 years ago | (#31731636)

You are not allowed to have nuclear devices in space by international law.
Its why we don't already have them on ISS.

Re:Terrible idea, of course, which is why we don't (1)

dattaway (3088) | more than 4 years ago | (#31731734)

Don't many satellites have isotope powered batteries?

Re:Terrible idea, of course, which is why we don't (3, Insightful)

EdZ (755139) | more than 4 years ago | (#31731832)

A nuclear battery is not a nuclear reactor. And nuclear reactors are not prohibited: they're just deemed to risky to launch (and need to be parked in a long term high orbit, or risk raining down reactor bit that don't burn up), and generally are too large and heavy to be cost effective. It's nuclear weapons that are prohibited in space.

Re:Terrible idea, of course, which is why we don't (3, Informative)

HungryHobo (1314109) | more than 4 years ago | (#31731822)

The testing of nuclear weapons in space is banned.
Nuclear reactors are fine.

The reason we don't see them on the ISS is the people who too terrified of anything with the word nuclear attached to think rationally.

Re:Terrible idea, of course, which is why we don't (1)

HungryHobo (1314109) | more than 4 years ago | (#31731930)

*also for the ISS a full scale nuclear reactor would be utterly OTT.
Some kind of RTG makes much more sense for small scale stuff like that.

Re:Terrible idea, of course, which is why we don't (2, Informative)

r00t (33219) | more than 4 years ago | (#31731870)


The USSR launched plenty of full-blown reactors, and RTGs are still popular.

You're not supposed to park ground-attack devices (like ICBMs) in space. Of course, if you imagine that Russia hasn't done that for decades, you're pretty gullible.

Re:Terrible idea, of course, which is why we don't (1)

xous (1009057) | more than 4 years ago | (#31731886)

The Russian's have several nuclear devices in space: []

Re:Terrible idea, of course, which is why we don't (1)

bigsteve@dstc (140392) | more than 4 years ago | (#31732012)

I think that the treaty in question bans Nuclear WEAPONS in space. Both the US and USSR have launched satellites, etc that have used nuclear power sources.

Re:Terrible idea, of course, which is why we don't (1)

Leperous (773048) | more than 4 years ago | (#31731460)

Right, and if we could launch a powerful enough laser into space, I think some people (i.e. the Chinese, Russians, in fact anyone in the world) would be very unhappy about the potential for this thing to be turned into a weapon. I'm trying to remember what program/website has a satirical idea about using such a device to shoot the homeless.

Re:Terrible idea, of course, which is why we don't (1)

j35ter (895427) | more than 4 years ago | (#31731506)

Actually, they would happily send their own high power laser "Tsunami Warning Systems" into orbit, aimed at Washington...a friendly gesture towards their U.S. friends ... to warn them of a possible tsunami, of course!

Re:Terrible idea, of course, which is why we don't (2, Interesting)

fractoid (1076465) | more than 4 years ago | (#31731576)

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 better because the tsunami would hit different pieces of coastline at different times.

Re:Terrible idea, of course, which is why we don't (1)

xous (1009057) | more than 4 years ago | (#31731902)

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:Terrible idea, of course, which is why we don't (2, Funny)

pspahn (1175617) | more than 4 years ago | (#31731616)

You'll have my laser, Chris, and you'll have it by mid-May.

Re:Terrible idea, of course, which is why we don't (4, Funny)

Zumbs (1241138) | more than 4 years ago | (#31731642)

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 ...

Re:Terrible idea, of course, which is why we don't (1)

WORMSS (1431561) | more than 4 years ago | (#31731688)

If we could also slow the satellite down to 88 miles then maybe the Tsunami would never happen.

Re:Terrible idea, of course, which is why we don't (0)

Anonymous Coward | more than 4 years ago | (#31731960)

i was going to mod this up but i couldn't find +1 nerdy in the dropdown

Re:Terrible idea, of course, which is why we don't (0)

Anonymous Coward | more than 4 years ago | (#31731698)

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.

someone please tag this "1.21 jiggawatts"

easier way to get the power (5, Funny)

r00t (33219) | more than 4 years ago | (#31731858)

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.

Reactor/Laser on Ground, MIRROR in sky (0, Redundant)

wisebabo (638845) | more than 4 years ago | (#31731946)

I was going to post something to the effect that I agree with the parent post (energy requirements would be obscene) but there *might* be a way around this.

Put a not too big (optical experts please weigh in) lightweight mirror in geosync orbit. Aim a very very powerful visible light laser at it and Voila! Instant early warning system!

Of course you'd be making the energy requirements even more obscene but it should still be a lot cheaper than lifting a giga-watt (tera-watt?) class reactor and laser into high orbit. Since you're not trying to use this for missile defense, the pointing requirements should be a lot less. Maybe even a giant sphere like Echo-star 1 could be used or a giant disco ball! ;)

In any case I don't think you'll get much more than a bright point of light in the sky (hopefully visible in daylight), but that might be enough. If the mirror is large enough and the beam tight enough you might not lose too much energy so it might be conceivably possibly practical. If you modulate the beam you could even send a message ("go to higher ground" or "earthquake, stay outdoors"). Too bad morse code isn't being used anymore.

Of course, if you had a couple of well placed reflectors in orbit, you could make it so that people would only need to "follow" the beacon (from the appropriate reflector) to safety. Sort of like the light of Bethlehem huh?

How much energy ? (0)

Anonymous Coward | more than 4 years ago | (#31731426)

So you basically want to be able to illuminate half the planet from your satellite. Have you any idea how much energy this would take ? A hint: The sun is quite big.

Re:How much energy ? (1)

fractoid (1076465) | more than 4 years ago | (#31731470)

If half the planet is at risk from a single tsunami, we've got bigger problems than just 'how do we power this satellite?'.

Re:How much energy ? (1)

nunojsilva (1019800) | more than 4 years ago | (#31731510)

On one hand, as it may save lives, we shouldn't worry that much about the cost, but, on the other hand, if it just drains all the energy from the planet, that's another (big) problem to solve...

So, before deploying such a system, ideas on a less expensive way to power it, and discussions on that, are really important.

Re:How much energy ? (1)

fractoid (1076465) | more than 4 years ago | (#31731604)

True, but my point was that it wouldn't drain much power at all, unless the scale of the disaster is so huge that warning won't help anyway. With a few simple modifications (chiefly, the assumption that instead of constant illumination, it's better to make the light blink) the power requirements are easy to fulfill with a solar panel and a modest sized battery pack - say, one smaller than that used by the GM Volt.

Re:How much energy ? (1)

Klintus Fang (988910) | more than 4 years ago | (#31731730)

you seriously think that the battery used to power an electric car has enough energy to illuminate 100s of miles of coastline from orbit? I don't think you have a clear sense of how much energy it takes to get a beam of light to travel such a large distance.

And even if you had a satellite with enough energy, what is your warning system going to do when it is cloudy in the area where the tsunami is going to hit?

and even if you solved that problem too somehow, what if the people you are warning are asleep because it is night time? how are they going to see your warning system? what if they are awake but inside a building?

vastly more effective would be the systems that are already in place: a siren so loud that it is essentially impossible for people not to hear it unless they are deaf.

Re:How much energy ? (1)

digitalchinky (650880) | more than 4 years ago | (#31731816)

Although I don't really think it's a good idea given how much of my life I spend indoors, who is actually saying the satellite needs to illuminate 100's of miles of coastline all at once? Wouldn't it be more logical to pan the laser back and forward along the danger areas?

You don't need a huge amount of energy for a pencil beam to be visible, particularly at night, though obviously in the day time it'd require 11 on the dial.

So... it's a super hi-tech siren? (5, Insightful)

chefmayhem (1357519) | more than 4 years ago | (#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.

Re:So... it's a super hi-tech siren? (1)

the_womble (580291) | more than 4 years ago | (#31731934)

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.

Re:So... it's a super hi-tech siren? (1)

RobVB (1566105) | more than 4 years ago | (#31731992)

3) It does not work well with sharks.

Crazy (1)

mseeger (40923) | more than 4 years ago | (#31731466)

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

Re:Crazy (1)

Kittoa (218844) | more than 4 years ago | (#31731516)

A 200MW laser would probably violate the Outer Space weapons ban in some way.

Re:Crazy (1)

PiSkyHi (1049584) | more than 4 years ago | (#31731528)

Lasers can move around you know.

Re:Crazy (0)

Anonymous Coward | more than 4 years ago | (#31731676)

Exactly. The parent might want to consider replacing street lamps too. Those things cost a lot and use a lot of power. (For example, more than 100kWh per night and road kilometer in Belgium, which illuminates its highways.)

Re:Crazy (0)

Anonymous Coward | more than 4 years ago | (#31731686)

Even if such a laser would already be feasible, the power supply would require a nuclear reactor.

Well, there is a big nuclear reactor at the center of the solar system. But if you're going to go that route you might as well just use a really big mirror that can be rotated into position (e.g. have some big gyroscopes on your satellite).

Laser Power... (4, Insightful)

GrpA (691294) | more than 4 years ago | (#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:Laser Power... (0)

Anonymous Coward | more than 4 years ago | (#31731596)

Actually one of the big problems is that a seismic sensor is quite expensive (the must be very precise) and you need quite a few of them, because the earthquake that create those tsunami waves can be really far away.

I worked on a project with a different approach where you use crappy sensors but then a lot of them. This is for earthquake (early) warning. But last fall one of the leading scientists for tsunami warning meet us at a talk and wanted our project to be extended for tsunamis too. (This hasn't happen jet because of funding)
See: brief project description []

Re:Laser Power... (2, Insightful)

gandhi_2 (1108023) | more than 4 years ago | (#31731920)

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.

Problems (2, Interesting)

jaxxa (1580613) | more than 4 years ago | (#31731488)

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.

Nice idea ... needs work (0)

Anonymous Coward | more than 4 years ago | (#31731498)

Mainly you need to figure out how to make other people some money with this. As soon as you can show the government how they can get more tax money or how they can line their pockets, they will be beating down your doors to get this up and running.

Plastic shopping bags (-1, Offtopic)

MrKaos (858439) | more than 4 years ago | (#31731502)

50 years after the world stops using plastic shopping bags, this idea will become feasible.

Clouds? (1)

DeadRat4life (1638391) | more than 4 years ago | (#31731504)

Planes? what if its night and everyone is asleep? Perhaps putting alarm systems in these areas that are run off solar power and get warnings via radio or satellite (the regular kind, not laser) would be better.

Genius... (1)

Ecuador (740021) | more than 4 years ago | (#31731514)

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...

square km (1)

Ecuador (740021) | more than 4 years ago | (#31731530)

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.

Re:Genius... (1)

karuna (187401) | more than 4 years ago | (#31731602)

Is it really required to illuminate the area? Maybe it would work better as short pulses of strobing light with the interval of about 1 sec. Would such flickering be easily noticeable during bright daylight?

It seems that audible sirens would work better for tsunami warnings in either case but the idea is so cool that it would a shame to let waste it. Could it be used for more local emergencies gas leaks or big fires? Let say, if there is a big crash on the highway that blocks the traffic for several hours all drivers in the vicinity could be warned to seek detour or at least turn on the radio to listen for emergency warnings.

Unmanned Warning System (1)

Kitkoan (1719118) | more than 4 years ago | (#31731544)

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 knowledge something bad is happening. A tsunami would literally 'wash' away the evidence. And looting might not be the only thing that could happen. People act crazy when mass danger is about to happen. The idea is a good one, but not everyone will use good ideas in positive ways.

Re:Unmanned Warning System (4, Insightful)

Igmuth (146229) | more than 4 years ago | (#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.

Re:Unmanned Warning System (1)

jargon82 (996613) | more than 4 years ago | (#31731986)

Wash away the evidence? Yeah, so they are stealing stuff that is about to be destroyed... Worry about the looting AFTER the event.

Coupla problems (0)

Anonymous Coward | more than 4 years ago | (#31731550)

Energy: If you wanted to illuminate a single city with the equivalent of, say, a 15W lightbulb every 100 square meters (possible to detect during the day if you were REALLY looking for it, maybe), your satellite would have to output a TON of energy. For example, the city I'm in right now is only about 25 square miles, and it would take 10 Megawatts to light it all up even very dimly. You're proposing to light up way more than that. Unless you're going to ship a few dozen power plants into space, that's impossible for any period of time.

Being bad for peoples' eyes: *Oh noes my eyes.*

People wouldn't know what it meant: Unless you spent lots of money - money that could be better spent - telling them.

Illuminating areas from space (0)

Anonymous Coward | more than 4 years ago | (#31731556)

A ballpark calculation.

According to Wikipedia, about 700-1000 watts per square meter reach the surface of the Earth at noon for most populated latitudes.
I don' know how much power a satellite would need to put out to make a visible difference, but let's be optimistic and assume 10% of that for strongly colored light, so about 70 watts.
Let's assume you want to light up the coast of California, without any of the islands for simplicity's sake - this is about 1300 kilometers. Let's light up a strip with a width of about 500 Meters (in practice the danger zone can probably be several kilometers, depending on tsunami size and topography of the area).
This is 650 square kilometers, or 650 million square meters; so we end up with 45500 MW (or 45.5 GW) of power. A typical nuclear generating station has an output of 800 MW (0.8 GW), so good luck generating that much power on a sattelite sustained for several hours, and good luck having an optical system that can distribute it without evaporating...

Jews for Nerds! (-1, Troll)

Anonymous Coward | more than 4 years ago | (#31731568)

Jews, also known as kikes, hebes, hymies, yids, gold niggers, oven magnets, hook noses, sheenies, swindlers, criminals, "firewood", and Arabs in denial are a subhuman species of reptilian extra-terrestrials and adherents to one of the world's oldest major religions, called "Judaism", otherwise known as "The Worship of Money" or "Eating Arab Babies".

Judaism was the world's first master race theory. The Jew religion teaches that Jews are the Chosen People of God and that there is a sacred mystical quality to Jew DNA. In olden times, Jew prophets would, under the command of YHWH, frequently lead the Jews on genocidal rampages against neighboring populations, and even today Jew leaders often cite Jewish religious ideals to justify their ongoing genocide of sandniggers. Judaism ironically found its mirror-image inversion in the anti-Jew Aryan racialism of the Nazis.

Despite only being 0.22% of the world's population, Jews control 99% of the world's money. Not only do the Jews control the world, but also the media, the banks, the space program, and LiveJournal's porn communities and Gay communities. All Jews possess the following features: an extremely large nose, fake boobs, curly hair that reeks of faggotry, one of those gay hats, a love of coke, a law practice, a roll of money, a small cock, or shitty taste in dental hygiene.

Jews invented both Communism and Capitalism. Karl Marx, of course, was a Jew, which was why he understood money so well, and in fact he was converted to Communism by another Jew, Moses Hess, the actual founder of Zionism, who ghost-wrote Marx's The German Ideology. Capitalism was created when Christian Europeans threw away their morals and decided to embrace Jewish practices like usury (see: John Calvin). Jews were the first group to create a sophisticated banking system, which they used to fund the Crusades in order to pit Christians and Muslims (both adhering to religions derived from and controlled by Jews) against each other to kill as many people as possible in a macabre human sacrifice to YHWH.

The Jew banking system was based on fraud and lies, so when it inevitably collapsed, the Jews just pwned as many people as possible by unleashing the Black Plague on them. Later, Jews economically controlled medieval Venice (the first modern maritime trade empire), and then crypto-Jewish merchants economically controlled the Spanish Empire, including the slave trade. Openly Jewish bankers orchestrated the Dutch Empire and founded Jew Amsterdam (later Jew York). Later the Dutch Jews moved to London because they thought it would be a better base for a global empire, and actually brought a Dutch nobleman, William III, with them, who they installed in a coup d'état (more like Jew d'état, amirite?) as new King of the British Empire. For hundreds of years, Jewish bankers controlled global trade through their bases in Jew York City and London. European colonialism was, through its history, essentially a plot whereby Jews could gain control of gold and diamond mines in poor countries and increase their stranglehold over the global economy.

Jews also enjoy slicing up baby penises for fun, some even enjoy sucking them. See below.

Jews also created Jew search engine Google, so now they can find all Jew information on Internets.

Some suggest that we should use Jews instead of dogs to sniff out large amounts of concealed cash or anything else worth smuggling at airports due to their sensitive Jew noses. Obviously, this is a horrible idea, because the pay is bad, and the dirty Kikes would probably form a union and demand moar money, thus increasing the burden on taxpayers everywhere.

Dumbest. Idea. Ever. (4, Funny)

Anonymous Coward | more than 4 years ago | (#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?

Kewl (1)

Fuzzums (250400) | more than 4 years ago | (#31731574)

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.

And how many people... (1)

warGod3 (198094) | more than 4 years ago | (#31731578)

...get killed when that thing fires off and people forget about a "Tsunami Warning System" and think that they are either 1) under attack from little green men from outer space OR 2) that the gods are angry with them?

This reminds me of something that we hear about (0)

Anonymous Coward | more than 4 years ago | (#31731624)

the military spending tons of money on only to realize how fucking stupid it is. I bet we have already spent billions developing this, and the teabaggers bitch about free healthcare, fucking twats.

Please... stop... (4, Insightful)

mad flyer (589291) | more than 4 years ago | (#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...

Here's the condensed Slashdot answer. (1)

Jimbookis (517778) | more than 4 years ago | (#31731670)

You stupid twat!

How the system will work (1)

drmofe (523606) | more than 4 years ago | (#31731684)

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!

What a lame-brained idea (0)

Anonymous Coward | more than 4 years ago | (#31731724)

This is the kind of pseudo-scientific mumbo-jumbo that comes from a populace with no math or science education. A geo-synchronous orbit is 24,000 miles above the earth. It can see half the globe, but a beam coming from such a platform would reach the earth through an oblique path cutting through hundreds of miles of atmosphere - like the sun at sunset. This would erode the intensity of any beam tremendously. Even without atmospheric attenuation, the tsunami covers thousands of miles of coastlines. You would need a signal strength of about 100 lumens per foot to be visible in the daytime. That is going to require about 10,000 watts of power per thousand feet or about 50,000 watts per mile. Say 5,000 miles to cover the impact area of the wave - you need a power budget of about 250 megawatts BEFORE accounting for atmospheric attentuation. You're talking a power plant on the order of the anti-matter engines of the Starship Enterprise. Not to mention a laser a couple of orders of magnitude more powerful than anything ever attempted before. This reminds me of the gubernatorial candidate in the Maryland elections who suggested that the earth's garbage problem could be solved by vaporizing the garbage with lasers. Complete drivel.

Satellite Base laser Show (0)

Anonymous Coward | more than 4 years ago | (#31731740)

OMG...First LHC and now Satellite Based laser show...need to leave this planet for good.

Mobile (0)

Anonymous Coward | more than 4 years ago | (#31731754)

Build in a protocol in all mobile devices that can be used in an emergency to broadcast a warning. Done.

Danger vs. Visibility (1)

ralfmuschall (1782380) | more than 4 years ago | (#31731764)

IMHO, this cannot work. Sunlight comes with approx. 1kW/m^2, the human eye detect changes in brightness if they exceed 30%, i.e. we'd need 300W/m^2 to be visible at daytime. OTOH, looking directly at the sun is harmful even with the sun having a diameter of 0.5 degrees. A light source with a third of the sun's brightness, but point-like would probably burn a hole right through the retina before the blink reflex can kick in.
Even the discussed 10W/m^2 (absolutely invisible unless one looks directly at the right point in the sky) would be dangerous (the eye's resolution is one angular minute, i.e. light from a point source would cover 1/900 of the sun's image's area, giving a retina burning power density of 9 suns).

Short wording: you can't see it unless it makes you blind.

Re:Danger vs. Visibility (1)

ralfmuschall (1782380) | more than 4 years ago | (#31731856)

A purely unrealistic idea came after submitting: Instead of illuminating the whole area, illuminate a mm-sized milliwatt-powered spot every meter. Such a spot is visible on the ground even in daylight (laser pointers to exactly that). Unfortunately, the laws of optics get in the way: To get meter-resolution on the ground, we need meter-sized optics in orbit (that's what spy satellites do (to get resolutions in the decimeter range, they fly very low and crash down all the time due to aerobraking)). For mm-resolution, we'd need kilometer-sized satellites.

You're a little late to the party... (1)

EmagGeek (574360) | more than 4 years ago | (#31731778)

April Fools was a few days ago...

Mwah - Hah Hah Hah (1)

mac1235 (962716) | more than 4 years ago | (#31731780)

Sounds great! Yes do it! No, I have no intention of focusing a laser that can be visible from tens of thousands of square kilometres onto a single city. None at all. Why do you ask dear?

Clouds (1)

imsabbel (611519) | more than 4 years ago | (#31731806)

Oops. Did i just break the stupid concept in another way?

Astronomers will love you (1)

nospam007 (722110) | more than 4 years ago | (#31731834)

Especially the idea of a continuous light.

Not enough power (1)

MichaelSmith (789609) | more than 4 years ago | (#31731838)

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 disaster in advance and give people a warning of sorts.

But these days mobile phones are all over the place and can be used to warn people. If you want to predict the part of the tsunami then something which can get the Doppler shift from water a metre or so under the surface would be invaluable. Maybe a long wave radar, in orbit and pointing down.

guys, it's kdawson... (0)

Anonymous Coward | more than 4 years ago | (#31731848)

no surprise then :(

Email Ad Agencies - They May Be Intrigued. (1)

Ron Bennett (14590) | more than 4 years ago | (#31731850)

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 not what the article poster is suggesting, would be a better use of orbiting lasers - detection of small rise in sea-level over a large area would, presumably, be a phenomena easily spotted from space.


Radar not laser (1)

orbitalia (470425) | more than 4 years ago | (#31731862)

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. []

Back of the envelope (0)

Anonymous Coward | more than 4 years ago | (#31731864)

Let's get some rough estimate of the order of magnitude involved.
The sensitivity of the human eye (from quick and dirty Googling) is cited around 1.5..2.9 mW/m^2.
To cover an area of say 100Kmx100Km, and to *just reach this threshold*, you'd have to output
(10^5)^2 mW == 10^7 W == 10 gigawatt of power.

The power of the sun hitting us is around 1KW per square meter. Of that, not much falls in the visible spectrum, but still it will be a couple of orders of magnitude greater that the above.

Of course you'd just need very short pulses and all that -- but still you are moving at the limit of what seems feasible.

I'd say radios (or adapted mobile phones or whatever) seem to offer a better price/performance ratio.

(Captcha was "tradeoff" -- how appropriate. Is Slashdot becoming sentient?)

and.. (0)

Anonymous Coward | more than 4 years ago | (#31731880)

if you can put such a laser on a satellite, make me a smaller version, my sharks are waiting.

Power requirements (0)

Anonymous Coward | more than 4 years ago | (#31731914)

Have you ever considered how much power you would need for that? You have to illuminate large areas for a considerable time at power levels not too much below that of the sun (about 1kW/m^2). TV sattelites (with outputs in the 100W range) don't need that much power since you have large receiver dishes and very, very sensitive receivers, finely tuned to a very small frequency band, so extremely small power levels are sufficient to detect the signal. But with light you have just the eye (small iris diameter and not tuned to a single frequency), and all that with the high background level of the sun light. Thus such a sattelite would need many, many orders of magnitude more power then your typical TV sattelite. Just to illuminate a single square kilometer with a power density of just 1W/m^2 you would need a MW-laser - and that's probably nothing the eye would be able to notice. And while on a dark, moonless night the power requirements would be much lower, how many people would be watching at 3AM?

My tags for this story (2, Insightful)

cheesethegreat (132893) | more than 4 years ago | (#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

Almost as crazy as... (1)

EpsCylonB (307640) | more than 4 years ago | (#31732022)

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.

Tsunami Warning System (1)

Vhaldera (1269312) | more than 4 years ago | (#31732024)

I don't think its such a bad idea. I have to ask, would people really assume they are "under attack from little green men from outer space"? or "the gods are angry with them"? It's not first thing that would come to mind when I think of seeing the local area light up with bright light. That seems very 1950s, and extremely unreasonable.

Having the local area brighten suddenly, I would look around and then look up to search for the reason behind the sudden increase in luminance. what may be the reason for it before making assumptions like that. Measuring a tsunami is certainly feasible, even with low wavelengths, a tsunami is still a tsunami a excessively large mass of moving water in a series of waves. Instead of interfering with local emergency systems, a tsunami warning system as this could be used to complement local emergency systems by serving as primary warning.

Using different colours for the warning system would be pointless because until each you advertised each of the specific meanings to literally everyone, it would waste time for people to try to figure out what it meant. The biggest problem is powering such a system. (Perhaps you should get N.A.S.A.'s ideas for that part?)

On a point made by GrpA, if a person stopped to check a website to figure out if their area is about to be hit by a tsunami and one were on its way, then by the time they got outside, they'd be as good as dead.

"Do not go to look for a tsunami - if you are close enough to see one, you are too close to escape it unless above its level." (Wiseman, J (2004). SAS Survival Guide)

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