Energy released in an Earth/Anti-Earth Collision

[fenderzilla]

So I was thinking, what if you crashed the earth into a body of antimatter of the same mass? I know they would be repelled by antigravity, and i know the initial explosion would push the outer parts of the planets away, but I'm just focusing on the energy released here. I tried some calculations, and i'd like you guys to look and see if they're not totally wrong (which they very well could be - there's a lot of zeros).

1 gram = 90000000000000 joules aka 90 terajoules

mass of the earth = 5.972 * 1024 kg aka 5972000000000000000000000000 grams

5972000000000000000000000000 * 2 = 11944000000000000000000000000

11944000000000000000000000000 * 1,074,960,000,000,000,000,000,000,000,000 terajoules or 1,074,960,000,000,000,000,000,000,000,000,000,000,000,000 joules

Colliding the earth into an antimatter body of equal size would create One quattuordecillion, seventy-four tredicillion, nine hundred sixty duodecillion joules, or one decillion, seventy-four nonillion, nine hundred sixty octillion terajoules. This is about a tenth as powerful as the average supernova.

how does that sound?

[rodion]

I know they would be repelled by antigravity

but wait, that's not true. there's no good experimental or theoretical reason to suggest that gravity would affect antimatter any differently than matter. probably they would interact gravitationally in exactly the same way as any two earth-sized lumps of matter would.

otherwise though, your calculations seem to be correct. the only flaw in the practical application is that you're assuming that every single gram of both bodies would be consumed in the interaction, which is highly unlikely as a large fraction of the mass would probably be propelled away at very high velocity by the ensuing cataclysm and thus not converted directly into energy, but i'm not in a position to say exactly how much would survive.

[Frozen_Heart]

I know they would be repelled by antigravity

There are a few theories that antimatter has opposite gravity. (I'm not convinced on that one though)

Even if that were the case the earths gravity and the anti-earths anti gravity would cancel out so they wouldn't repel or attract.

[peadar1987]

They would presumably hit each other at escape velocity, and I would bet that most of the mass would actually be carried away by the ensuing explosion. Each kilogram that annihilates (500g matter, 500g antimatter), releases enough energy to carry 14.9 billion kg to escape velocity (someone feel free to correct my maths on that one!). Of course, not all of that will actually go in the right direction, but you'd probably get well under 1% of the total mass reacting before both planets were shattered into trillions of pieces flying away from each other at speed.

[sndrtj]

So I was thinking, what if you crashed the earth into a body of antimatter of the same mass? I know they would be repelled by antigravity, and i know the initial explosion would push the outer parts of the planets away, but I'm just focusing on the energy released here. I tried some calculations, and i'd like you guys to look and see if they're not totally wrong (which they very well could be - there's a lot of zeros).

1 gram = 90000000000000 joules aka 90 terajoules

mass of the earth = 5.972 * 1024 kg aka 5972000000000000000000000000 grams

5972000000000000000000000000 * 2 = 11944000000000000000000000000

11944000000000000000000000000 * 1,074,960,000,000,000,000,000,000,000,000 terajoules or 1,074,960,000,000,000,000,000,000,000,000,000,000,000,000 joules

Colliding the earth into an antimatter body of equal size would create One quattuordecillion, seventy-four tredicillion, nine hundred sixty duodecillion joules, or one decillion, seventy-four nonillion, nine hundred sixty octillion terajoules. This is about a tenth as powerful as the average supernova.

how does that sound?

First of all: there is no such thing as antigravity! Antimatter (probably) attracts matter just like matter attracts matter.

As for energy released: E=mc^2, assuming all matter and antimatter is totally consumed.

Thus: E=(2*Earth_mass)*c^2 = 1.19E25 * 229792458^2 = 6.28E41 J, which is about one-thousandths of the power of a Type 1a supernova explosion.

[fenderzilla]

i know the initial explosion would push the outer parts of the planets away, but I'm just focusing on the energy released here.

remember when i said that? yeah.

[ZetaX]

Even if that were the case the earths gravity and the anti-earths anti gravity would cancel out so they wouldn't repel or attract.

That's just nonsensical. If matter attracts antimatter, then antimatter attracts matter; that's just Newton's law. Same for "repells". There is no "matter repells antimatter, but antimatter attracts matter". It may be (but very unlikely) that they neither attract nor repell each other, but then that's not because of what you say.

[meve12]

otherwise though, your calculations seem to be correct. the only flaw in the practical application is that you're assuming that every single gram of both bodies would be consumed in the interaction, which is highly unlikely as a large fraction of the mass would probably be propelled away at very high velocity by the ensuing cataclysm and thus not converted directly into energy, but i'm not in a position to say exactly how much would survive.

So instead of a star destroying explosion, you get a world shattering one that sprays antimatter and chunks of Earth in every direction?

[Tommygun]

So instead of a star destroying explosion, you get a world shattering one that sprays antimatter and chunks of Earth in every direction?

Sounds like a solar system wide Kessler syndrome with antimatter.