Nuclear Explosion [weapon] in Space - result?

[Bullgrit]

Everyone seen "Armageddon"? They drill down into the asteroid, and plant the bomb deep.

Whoa! You're using the Armageddon movie as a example for a real scientific concept? Don't they take away your scientist credentials for something like that?

When you start using The Core, I think they shoot you.

Bullgrit

 

[Nifft]

One note on the thought of diverting an asteroid with nukes...if it isn't an iron asteroid (many are rock or dust), you risk shattering it, which doesn't help a bit.

If you have a 1,000,000 ton single impactor or 1000 1000-ton impactors, the energy and thus destructive power is still the same.

Are you sure about that?

Many small waves are rather different from one big tsunami... and that's assuming the little ones still retain enough mass to even make it to the surface, as opposed to burning up in the atmosphere.

Cheers, -- N

 

[Mouseferatu]

This got me thinking. If a nuclear weapon were detonated in space, (way out in space -- not in the upper atmosphere), what would be the result?

You would free Zod, Ursa, and Non from the Phantom Zone.

 

[Umbran]

Whoa! You're using the Armageddon movie as a example for a real scientific concept? Don't they take away your scientist credentials for something like that?

It all depends on whether it passes peer review. I either get shipped off to a weather observatory in Alaska, or they give me a Nobel Prize

One note on the thought of diverting an asteroid with nukes...if it isn't an iron asteroid (many are rock or dust), you risk shattering it, which doesn't help a bit.

If you have a 1,000,000 ton single impactor or 1000 1000-ton impactors, the energy and thus destructive power is still the same.

Destructive power is not simply and directly related to total energy. Exactly how that total energy is delivered matters a great deal. Don't believe me? How about we do an experiment. Let's haul out a grad student. I'll toss a large number of ping-pong balls at him...

*pokpokpokpokpokpokpokpokpokpokpokpokpokpokpokpokpokpokpokpok*

See? No damage.

Now, I'll give him a single punch to the gut, with the same total energy...

*whoomph!* Ugggh! Thud!

See? Now the poor grad student is doubled over in pain, possibly with a ruptured spleen.

The larger the impactor, the deeper it drives into the Earth, and the more debris it kicks back out. The relationship is not linear - two half-sized impacts are not the same as one whole impact. If you reduce the asteroid to dust, we may only notice the "impacts" as pretty sunsets for a while. In between dust and whole, there are many, many different scenarios, some are better or worse for us, depending on specifics.

 

[LightPhoenix]

Are you sure about that?

Many small waves are rather different from one big tsunami... and that's assuming the little ones still retain enough mass to even make it to the surface, as opposed to burning up in the atmosphere.

A lot of it also depends on the shape, velocity, and composition of the a meteor. What causes an explosion (such as the Tunguska blast) is compression of the atmosphere in front of the meteor. This in turn causes extreme heat (PV=nRT, where PV rises), rather than friction.

If a long elliptical meteor came into the atmosphere roughly parallel with the atmospheric plane (ie, long side first), it would most likely break up. However, if it came in perpendicular (ie, end first), there's a lot less surface area being compressed, and may be more likely to actually impact before bursting.

Similarly, since different compositions will have greater or lesser resistance to heat, they will fragment differently.

Velocity also plays a role; the faster a meteor is travelling, the more dramatic the compression will be. This is because velocity (not acceleration) affects the force placed upon the atmosphere through fluid dynamic equations. Additionally, the angle of impact matters as well.

A rough back of the napkin calculation: most meteors are stony, with a density of roughly 3.5 g/cm^3. Given a mass of 1000 tons = about 900 million grams, and substituting those in for volume to find the radius of a sphere... you get a sphere of with a radius of 395 cm, or roughly 8 meters in diameter. That's still large enough to cause some pretty serious damage. If you explode the meteor and say even 1% enter Earth and explode in air versus on the ground you're still looking at roughly 10 square miles of destruction total, based on impact craters of similar size.

Not to worry though, because it's highly unlikely a meteor of significant size will strike Earth.

 

[MarkB]

Are you sure about that?

Many small waves are rather different from one big tsunami... and that's assuming the little ones still retain enough mass to even make it to the surface, as opposed to burning up in the atmosphere.

Cheers, -- N

Also, once you shatter it, the fragments will each have differing velocities to the original rock. Do it at a great enough distance and most of them will drift far enough off that course to miss Earth entirely.

 

[Mustrum_Ridcully]

I feel we need a thread that discusses how impulse, force, energy and power interact for purposes of "damage" - what is it that causes deformations vs. what causes penetration, for example. If Umbran needs to use some grad students for tests, that's okay with me.

 

[Plane Sailing]

Not to worry though, because it's highly unlikely a meteor of significant size will strike Earth.

Not to be picky, but technically it isn't the meteors we are worried about, but the asteroids and other larger stuff, right?

On the Definition of the Term Meteoroid



The other question is just how unlikely is 'highly unlikely'? We know that there have been many large and small catastrophe-sized impacts over the lifetime of the earth. Although the probability is low, many scientists think that we are currently 'overdue' a strike (to use the colloquial term), and just because an event is unlikely in our lifetime doesn't make it impossible. Hence the effort in some quarters to look for potential killer asteroids, or to improve our ability to look for them.

Cheers

 

[Umbran]

Not to worry though, because it's highly unlikely a meteor of significant size will strike Earth.

I'm dealing with the last first. This is incorrect. It is nearly certain that an object of significant size will strike the Earth... eventually. It is unlikely to happen in our lifetimes.

However unlikely it is, however, it is still a concern. Risk is a combination of probability and potential loss. From a major impact the human race stands to lose everything, so while the probability is low, the risk is not negligible.

If a long elliptical meteor came into the atmosphere roughly parallel with the atmospheric plane (ie, long side first), it would most likely break up. However, if it came in perpendicular (ie, end first), there's a lot less surface area being compressed, and may be more likely to actually impact before bursting.

Generally speaking, meteors don't have attitude control. They don't come in with one orientation and hold it - they tumble. The greater determiner is the angle of approach with respect to the Earth's surface. They can come in anything from perpendicular (heading straight towards the center of the planet), to a shallow angle (almost glancing off the surface)

It also depends on what you call "long" - long or short only matters for smaller objects. The largest estimated impact in recent history was the Tunguska event you mentioned - but best guesses are that this object was only tens of meters across. Such an object has a destructive capacity on the order of one of our nuclear bombs (the Tunguska blast had a yield of probably 10 to 15 megatons of TNT). It could destroy a major metropolitan area on a direct or near hit.

But tens of meters is not large - it is on the order of a house or apartment building. There are plenty of rocks out there that are on the order of hills to mountains (hundreds to thousands of meters across). Once you get to this size, the shape and angle of approach are not much of an issue.

 

[TanisFrey]

You don't get much thrust unless the boil-off is focused, like a rocket engine. In general, surface detonations are a poor, poor way to change the momentum of large objects.

Everyone seen "Armageddon"? They drill down into the asteroid, and plant the bomb deep. That is to contain the explosion, and make sure most of the energy gets deposited directly into the fragments of asteroid, making them fly off in various directions.

Bad science from the movie Armageddon wont get you a lot of support, the movie from the same year Deep Impact would be a better reference.

However, when I said close denationalize think within a few miles. Only one side gets the radiation (manly in the form of neutrinos) and boils off the surface layer on one side. This causes a small amount of thrust in the opposite direction. If you aim right and early enough, you can get the asteroid to sift its orbit to miss the earth.

Where did I get this idea you may ask? A program on the science cable station where they asked astrophysicists for their best ideas to deal with an potential asteroid strike.