Destroy a World: Methods & Energy Requirements

[FtlIsAwesome]

Ok, I'm wondering about various methods of destroying a terrestrial planet or moon.

I can catagorize them into the following:
1. Scorching. Damage the surface significantly.
2. Splitting/shattering. Break the world into multiple pieces.

Possible methods would be multitudes of nuclear warheads, antimatter asteroid impact(s), fusion engine propelled kinetic weapons, antimatter propelled kinetic weapons, or a combination of these.

How much energy/firepower is required to destroy a world? At what point is it pulverized and there's no purpose in shattering it?

Something to take into account is that different worlds have differing radii, masses, composition, etc.


Also, is there a purpose to destroying a jovian planet (I don't think so), and how could this be accomplished?

 

[Calimero]

You can try with STBH - Small Tactical Black Hole. Although they are hard to find legally, there are some Russian versions on the black market. Be careful, once out of package it will evaporate very quickly!

 

[qraal]

Ok, I'm wondering about various methods of destroying a terrestrial planet or moon.

I can catagorize them into the following:
1. Scorching. Damage the surface significantly.
2. Splitting/shattering. Break the world into multiple pieces.

Possible methods would be multitudes of nuclear warheads, antimatter asteroid impact(s), fusion engine propelled kinetic weapons, antimatter propelled kinetic weapons, or a combination of these.

How much energy/firepower is required to destroy a world? At what point is it pulverized and there's no purpose in shattering it?

Something to take into account is that different worlds have differing radii, masses, composition, etc.


Also, is there a purpose to destroying a jovian planet (I don't think so), and how could this be accomplished?

To totally smash a planet requires enough energy to unbind it gravitationally. For a sphere of uniform density the equation is straight-forward, and for most reasonable planetary interiors the energy is a small multiple of that. The equation is 0.6*G*M^2/R where G is the gravitational constant, M the object's mass and R the radius. Since Earth masses ~6E+24 kg, you can see the amount of energy is very, very large. In normal circumstances the energy required can only be delivered by very high speed and very large masses. For example unbinding the Earth would require smashing the Moon into it at about 80 km/s.

For smaller objects the unbinding energy is lower than the internal cohesive forces, thus proportionally more energy is required. Thus blowing up small asteroids takes more energy input than the initial equation implies. Most rocks are held together by contact forces, which are weaker than chemical bonds, but substantially stronger than their self-gravity. Below about 200 km diameter one needs to shatter the rock as well as unbind it.

As for gas-giants... the energy needed is immense - BUT there is one caveat. Concentrated deuterium in a planet can provide the energy. Above about ~1/150 concentration, then a continuous fusion detonation can be set off in the stuff, conceivably blowing off the outer layers of the planet. While not a total disruption, the sudden loss of the over-pressure could be enough for the remaining core to unbind itself via rebound. Maybe. I'd have to grind through the maths to check.

 

[FtlIsAwesome]

As for gas-giants... the energy needed is immense - BUT there is one caveat. Concentrated deuterium in a planet can provide the energy. Above about ~1/150 concentration, then a continuous fusion detonation can be set off in the stuff, conceivably blowing off the outer layers of the planet. While not a total disruption, the sudden loss of the over-pressure could be enough for the remaining core to unbind itself via rebound. Maybe. I'd have to grind through the maths to check.

So the bombs set off a chain reaction in the gas giant? Cool.

I see that it probably would be more practical to scorch a planet than break it apart.



Some examples:
Death star
Covenant fleets in Halo "glass" the surfaces of planets

 

[MathematicalPhysicist]

You sound like a man with a mission.

May the force be with you!

 

[qraal]

So the bombs set off a chain reaction in the gas giant? Cool.

I see that it probably would be more practical to scorch a planet than break it apart.



Some examples:
Death star
Covenant fleets in Halo "glass" the surfaces of planets

The enriched deuterium layer may not exist - it's dependent on stratification and some kind of concentration process. Intriguingly Uranus has some kind of stratification blocking heat-flow from its interior...

 

[FtlIsAwesome]

My guess is that around 100,000-200,000 nuclear weapons might cover the surface of a terrestrial world, but this depends on the yield and the surface area of the world, and can also be affected by crust and atmosphere composition.
Some other weapons would be antimatter explosives and kinetic weapons. Kinetic weapons can be dropped from orbit and have no fallout or radiation.

Also something the attackers might want to consider is if they want to be able to salvage infrastructure/technology/raw materials.

Since the defenders will be attempting to stop the bombs by shooting them or blocking them the attackers will need extra. And the defenders will fire on the attackers' delivery craft.

There is also the route of only partially scorching the world and forcing the inhabitants to surrender. Depends on if the attackers want to conquer or exterminate.

 

[IsometricPion]

Are you guys aware of this site?: http://qntm.org/destroy#sec3
It is devoted to Earth destruction monitoring and innovation.

 

[JaredJames]

Are you guys aware of this site?
It is devoted to Earth destruction monitoring and innovation.

It also lists the number of times Earth has been destroyed as 1.

Not to mention the fact it calls Earth a ball of iron.

 

[IsometricPion]

It also lists the number of times Earth has been destroyed as 1.

Not to mention the fact it calls Earth a ball of iron.

I admit, it is not an entirely serious website. However, the math generally works (he shows at least part of his work http://qntm.org/data" at the time.

 

[Nabeshin]

My guess is that around 100,000-200,000 nuclear weapons might cover the surface of a terrestrial world, but this depends on the yield and the surface area of the world

Just for a back of the envelope calculation, I get ~65,000 nuclear weapons to plaster the entire Earth's land surface (I figured the large radius of destruction shown here http://upload.wikimedia.org/wikipedia/commons/8/8c/Abombdamage1945.svg multiplied by five).

 

[Chronos]

So ... why was Jupiter not destroyed by the Levi comet impact? How many megatons was that? According to lunar impact theory Earth collided with a body nearly the size of Mars - how did Earth survive that event?

 

[FtlIsAwesome]

(I figured the large radius of destruction shown here http://upload.wikimedia.org/wikipedia/commons/8/8c/Abombdamage1945.svg multiplied by five).

Here are some images of Tsar Bomba's destructive radius.
http://en.wikipedia.org/wiki/File:Comparative_nuclear_fireball_sizes.svg
http://upload.wikimedia.org/wikipedia/commons/1/1c/Tsar_Bomba_Paris.png (its in french!)
It has a radius of 35 km for its "destruction totale".
So my bomb is bigger than your bomb (light damage 5.6*5=28 km vs total destruction 35 km). Now consider that the attackers probably have gigaton-scale warheads or larger...

So ... why was Jupiter not destroyed by the Levi comet impact? How many megatons was that?

Fragment G is estimated to have released 6 teratons of energy, making an impact mark twice the radius of Earth. I believe the other fragments created similar, smaller, impact marks.
http://upload.wikimedia.org/wikipedia/commons/5/5d/Jupiter_showing_SL9_impact_sites.jpg

Are you guys aware of this site?: http://qntm.org/destroy#sec3
It is devoted to Earth destruction monitoring and innovation.

lol
A bunch of possible methods for the second option I listed in the first post. It also has a list of planetkillers appearing in fiction.

 

[jhae2.718]

You really want to blow up a planet, don't you?

 

[FtlIsAwesome]

You really want to blow up a planet, don't you?

Yep. Its fun.

It might even be an entertainment option for our megapowerful descendants.
"Blow Up Mercury Today! Entry Fee is at the low low low price of 50,000,000,000,000 credits! That's low!"



Question: How much can we goof off outside GD? I don't want to derail myself here...

 

[qraal]

So ... why was Jupiter not destroyed by the Levi comet impact? How many megatons was that?

Jupiter is largely convective. Thus no enriched stratum? More importantly the impactor's energy was much too diffuse. A fusion reaction trigger has to focus an intense amount of energy onto a fusion fuel, else it just won't start a detonation wave.

According to lunar impact theory Earth collided with a body nearly the size of Mars - how did Earth survive that event?

Theia, the Moon-making impactor, struck at just above escape velocity, but massed about ~0.1 Earth masses. Thus the total energy to unbind Earth would've been about ~10 times more than what Theia could supply.

 

[Chronos]

An impact at just above escape velocity would better be characterized as a merger.