[Martinus]

Originally posted by ZylonBane
(the one where the Centauri bombard Narnia using mass drivers).

[color=66ff00]Narnia?!? Aslan's going to be pissed!!


BTW Shrike nautical miles isn't a international unit; it's an imperial unit which means we crazy europeans might never have heard of it.

*oh I love you metric system*
[/color]

[Shrike]

Originally posted by Maeglamor
[color=66ff00]BTW Shrike nautical miles isn't a international unit; it's an imperial unit which means we crazy europeans might never have heard of it.

*oh I love you metric system*[/color]

Knots and Nautical Miles are standard for warship speeds and ranges, not just for US ships.  Unless you're a naval nut you might not know that, but it's the way it is.

[ZylonBane]

Originally posted by Maeglamor
nautical miles isn't a international unit; it's an imperial unit which means we crazy europeans might never have heard of it.

Yes, you're so right. We Americans invented an imperial unit.  Think a little more before you type next time, eh, green-boy?

Originally posted by Kazashi
Tunguska. The object that exploded in the air was not a heavy metal asteroid, it was either a carbonaceous asteroid or a comet. In either case, it only measured 100m across, and is composed of loosely compressed matter. Nevertheless, the resulting explosion would've wiped out a major city.

And of all the tens of thousands of meteors Earth has encountered in the last few hundred years, how many Tunguskas have we had? One. I think we can safely relegate that yield to the far end of the bell-shaped curve.

[Bishop Gantry]

*rubbs hands* BOLOS here we come *rubbs hands*

US can make lasers small enough to fit in a 747 (erm did i say small)  capable of shooting down missiles... it wasent to succesful the ranges was poor... atmospheres a tard yah

[neo_hermes]

I wonder why no one has ever tried using lasers in space.

[Martinus]

Originally posted by Shrike
Knots and Nautical Miles are standard for warship speeds and ranges, not just for US ships.  Unless you're a naval nut you might not know that, but it's the way it is.

[color=66ff00]Definetly not a naval nut, I always was more impressed by stuff that flew than stuff that floated as a kid. I did like Stingray though but I don't know if it was ever aired in the US/Canada. BTW is there any difference between miles and nautical miles? [/color]

[Shrike]

Yeah.  A nautical mile is a hair short of 2 km, and a normal mile is, of course, roughly 1.6 km.

[Stryke 9]

Originally posted by Cannikin
Bah, people dream too much.

A VERY basic scientific principle: You can only get energy out of something what was put into it in the first place!

Yes.

If you want a 10 megaton explosion from a, say, 10 ton shell fired from orbit, gravity sure isn't gonna provide that kind of energy . You want that bigass "meteor impact", you're gonna have to provide the 10 megatons worth of energy in the first place. So you basically have to take a 10 megaton nuke, detonate it, somehow channel all that energy into propelling the shell

No. Ever seen a sattelite hit the atmosphere? Ever seen a meteorite? Those things move damn fast, and only some metorites are moving anything close to at a dangerous speed before they encounter gravity's pull. Think about it- you're talking about a force strong enough to keep the moon from going off on its own momentum- something capable of exerting an incredible force to constantly move several trillion tons of solid rock. You think it wouldn't have a strong effect on something at ten tons moving straight towards it?

There's a difference between knowing physical laws, and understanding how physics works.

as well as preventing the imminent EMP that would spread across the world on the planet's magnetic field and the light that would instantly burn any exposed skin below and blind anyone looking that way...)

From a ten-megaton nuke? The atmosphere absorbs many times that much energy from the sun every day. And ten megatons ain't exactly powerful for a nuclear weapon, anyway. I believe the USSR developed a 100-plus megaton bomb towards the end. And tested it. And the world failed to suddenly end. So there.

These futuristic weapons people keep imagining are vastly inefficient and fairly useless. Not only do they use up an amount of energy impossible to realistically achieve, they fail an enormous amount of the time. Just take a look at the old Star Wars project. The dumb laser failed about 40 times before it hit it's target even once. And the plane mounted laser took a freakin Boeing 707 commercial jet to fly. One of the people on the project joked that it would do more damage by dropping the sucker on the enemy than shooting with it (which was probably true).

Yes. Lasers are inefficient now. Which by no means means they will be in the future. You know how bad the first cannons were? Or the first missiles? Hell, the first rifles, the arquebuses, were so inaccurate, so slow-loading, and so dangerous to the user it's a wonder they weren't abandoned for crossbows. Right now, you'd be lucky if a laser heated up your cup noodles for you, or if a significant amount of the beam was still there at about 400 yards. That doesn't mean anything at all.

[Shrike]

Originally posted by StrykeIX
From a ten-megaton nuke? The atmosphere absorbs many times that much energy from the sun every day. And ten megatons ain't exactly powerful for a nuclear weapon, anyway. I believe the USSR developed a 100-plus megaton bomb towards the end. And tested it. And the world failed to suddenly end. So there.

Relative to what?  The largest nuclear weapon in the US arsenal is a 9 MT device.  Nukes that big really are of surprisingly limited use.  You're far better off to scatter 100-500 kT nukes instead of using one big one.

And the biggest bomb detonated was the Novaya Zemlya bomb, at 56 MT.  The Russians said they could make it at 100 MT..... doesn't mean they ever did, and they certainly never detonated one.

[Anaz]

Originally posted by StrykeIX
Yes. Lasers are inefficient now. Which by no means means they will be in the future. You know how bad the first cannons were? Or the first missiles? Hell, the first rifles, the arquebuses, were so inaccurate, so slow-loading, and so dangerous to the user it's a wonder they weren't abandoned for crossbows. Right now, you'd be lucky if a laser heated up your cup noodles for you, or if a significant amount of the beam was still there at about 400 yards. That doesn't mean anything at all.

The reason that arquebus were used instead of crossbows is that crossbows were made illegal by the church...

And that is your random trivia of the day

[Stryke 9]

Shrike: You sure? I thought Tsar Bomba was up there. Ah well- at any rate, far less than necessary to do that scale of damage.


Analazon: Longbows, then. I don't know.

[Shrike]

Originally posted by StrykeIX
Shrike: You sure? I thought Tsar Bomba was up there. Ah well- at any rate, far less than necessary to do that scale of damage.

The Tsar Bomba is another name for the Novaya Zemlya bomb.  *shrugs*

[Deepblue]

Actually my brothers physics class built a railgun that fired metal bricks. only problem was the brick has a chance of fusing to the conducting rods.

[Stryke 9]

Hmm... friction do that? I dunno, I think you can put a protective tubing in it between the shot and the electromagnets, if you don't mind a slight loss in power...


Pretty cool, though. I was wondering if it was actually for some reason impossible to do at home, and that was why everybody didn't have one.

By the way, do you know how they did it? Last I read you need some way to delay the charge between the coils, so they don't just power up in array at the speed of light and move the projectile only a little before losing pull on it, and my limited versing in electronics stops before there.

[Nobilis Draco]

no the electrical current has a tendancy to weld the projectile to the rails.

Rail guns don't use electromagnets they run the current through the projectile. massdrivers use electromagnets.

you can build them at home it's just expensive, big, and not all that powerful.

[Cannikin]

Originally posted by StrykeIX
Think about it- you're talking about a force strong enough to keep the moon from going off on its own momentum- something capable of exerting an incredible force to constantly move several trillion tons of solid rock. You think it wouldn't have a strong effect on something at ten tons moving straight towards it?

There's a difference between knowing physical laws, and understanding how physics works.

Yes, I've thought about it and um, the amount of force exerted on an object depends on the mass of the objects does it not? For some reason I figured that this formula: F = G*(m1*m2)/r² explained why you don't need countless trillions of newtons of force to jump off the ground...

I calculated how much energy could be produced by dropping a 10 ton object from 100km altitude, assuming it survives completely intact and completely ignores ALL air friction, it would hit the ground with a force of a puny 9.8 billion joules. This equates to approximately a 2.33 ton (0.00233kt) explosion. And if it has been fired from space at a very high speed, obviously it's going to travel through the atmosphere at very high speeds and reduce the amount of time it can accelerate. I also calculated that if you could fire it at 50km/s (which is absolutely insane) the impact would yield 12.596 trillion joules which is approximately 3kt... And my final calculation to achieve about 10Mt from that same 10 ton shell you'd have to achieve a speed that's almost 1% the speed of light!

The only reason why meteors do so much damage is because of their huge masses. If a rock 100m in radius had only the density of water (which obviously it is far denser than) it would have a mass of 4188790 tons.

Please know what you're talking about before criticizing other people.

From a ten-megaton nuke? The atmosphere absorbs many times that much energy from the sun every day. And ten megatons ain't exactly powerful for a nuclear weapon, anyway. I believe the USSR developed a 100-plus megaton bomb towards the end. And tested it. And the world failed to suddenly end. So there.

Erm, what you fail to realize is that the LOCATION of the nuke has a tremendous effect on what it does. Tsar Bomba (which I think translated to "King Bomb" or something to that effect) was an air drop and therefore very close to the ground so it did not have the adverse effect of EMP. Ever heard of the Teak and Orange missile tests? Each was slightly less than a measely 2 megatons in yield, and detonated at approximately 50 miles up. The resulting EMP (which travels very far and quickly because it can directly interact with the earth's magnetic field) fried several sattelites and caused electronic disturbances across a lot of the Pacific extending as far as Hawaii and New Zealand (and caused an artificial aurora borealis). On the ground, the EMP is blocked by molecules in the air long before it reaches the magentic field which is why it doesn't do as much.

Oh and the light intensity of nukes is FAR beyond that of the Sun. In the brief instant of detonation in can achieve a luminosity 10^16 (no I didn't pull that number out of thin air. See section 5.3.1.1 on this site: http://nuketesting.enviroweb.org/hew/Nwfaq/Nfaq5.html ) times that of the sun's surface which leads to the infamous "flash burns" where the light can deal third degree burns (or worse) to skin exposed to it dozens of miles away.

EDIT: Note, when I say ton, I mean metric tons, 1000kg, which is approximately equal to 2200lb or 1.1 short ton (US).

[Kazashi]

Originally posted by ZylonBane
And of all the tens of thousands of meteors Earth has encountered in the last few hundred years, how many Tunguskas have we had? One. I think we can safely relegate that yield to the far end of the bell-shaped curve.

The relevance being......?

Firstly, a correction. There have been two known events in the past century alone, the second happening in 1947 but on a smaller scale. However the occurence of such events happening naturally on Earth doesn't indicate the numbers of such objects existing. There are hundreds of thousands of such sized objects in this solar system alone. If anyone wanted to bomb a planet they wouldn't have to look very far. If they could bomb a planet in that manner, they wouldn't have trouble dragging big rocks from hundreds of millions of km away.

[Stryke 9]

ND: Ah. Didn't know there was a difference. Mass drivers are the cool ones, then, 'cos I understand the principles behind them.

Cannikin: Why would you drop something from 100K? High-altitude sattelites start at 600. The moon is at 384,500 and still heavily influenced by gravity. Say 100,000 km- a decent distance, we've got some scientific sattelites out there, and since the military makes billions more than the average scientific venture, well within its reach. Anything dropped from space in order to be used as a weapon would most certainly be launched from far enough to let it achieve terminal velocity in the atmosphere- after all, once you're up there, it's relatively cheap in fuel to go the little extra way in the weaker outer gravity, particularly since the whole point of the theoretical flight would be to do some damage back home, so you might as well DO it.

And you wouldn't be able to reach 1% the speed of light, anyway- at that rate most anything would burn up in atmosphere (meaning you'd have, for a high guess, one ton left by impact). Not exactly dissapointing, anyway, since you'd still take out most cities wholesale with the energy release we're talking- and since we're talking about a directed energy, with most of the force going straight into the ground instead of in a more or less radial burst a la nukes, it's probably a good thing you can only get a megaton or so. It's nice to still have a planet left when you've beaten your enemies, particularly when you can't just move to another one.

Please know what you're talking about before you act snooty about it.



I'll leave you to the nuke thing, since I don't care to go look around for info about it, and nuclear weapons history isn't really my forte (a bit boring, since I can't go make one to get a little... uh... hands-on education. )