# Could planets explode in space?

Could a planet like the Earth or any other explode or be destroyed and did we see a planet explosion with Hubble?

• What makes you think it can? – user1569 May 30 '18 at 8:36

Of course if you supply enough energy, you could destroy a planet. If it's applied efficiently enough then the energy you need is basically the gravitational binding energy of the planet. For the Earth that is about $2\times 10^{32} J$ (source) which is perhaps better though of as the energy equivalent of about 2 million million tons of mass. So if you could supply a million million tons of antimatter (roughly a 1km diameter asteroid) and get it into the centre of the Earth so that it could annihilate with the matter there, that would do it and you'd be left with a (hot, radioactive) asteroid belt where the Earth used to be. (see Greg Bear's "The Forge of God" for a fictionalised account of this. Alternatively, that is twelve days of the Sun's total output if you could somehow focus it on the Earth.

• What I don't understand here with this antimatter scenario, is why do you think the released energy would convert directly into directed kinetic energy of the surrounding planet? I think you're making a hypothetical argument that it actually would, but that's not so to say "hard scifi". – AtmosphericPrisonEscape May 30 '18 at 12:08
• It doesn't have to be directed. Heat will do it, the planet just "boils away into space". You do need to get the antimatter down to the centre of the planet so you don't lose too much energy as radiation, or directed KE of smaller pieces. – Steve Linton May 30 '18 at 12:55
• If you heat the planet above the boiling temperature of Olivine, sure. Still, just putting it there is not an efficient mechanism of delivery. We're about science here. – AtmosphericPrisonEscape May 30 '18 at 16:26
• No honestly. If you put that much energy in then all the matter is moving at more than escape velocity, whether randomly due to heat, or purposefully. Either way or escapes – Steve Linton May 30 '18 at 17:37

We never saw a planet explosion with Hubble.

To make something explode it has to produce a lot of energy in a very short time. Gravitational collapse and thermonuclear fusion in degenerate matter are two possible ways of producing enough energy to produce a supernova.

These mechanisms can not cause a planet to explode. Planets are solid and supported by their own matter, so can't collapse, and they don't contain large amounts of hot degenerate matter, so don't have any kind of fusion.

Planets don't produce much of their own energy, and there is no mechanism known that could cause a planet to explode.

The closest you may get is planetary collisions, such as that which likely formed the moon. But these have never been directly observed.

• Roche limit: en.wikipedia.org/wiki/Roche_limit Ganymede and Titan are bigger than Mercury, but there's no obvious way to lower their orbits. – Wayfaring Stranger May 30 '18 at 14:54
• But planet disintegration has probably been "seen". – Rob Jeffries Nov 9 '19 at 18:09