How Much Energy Would It Take to Destroy a Planet?

Blowing up a planet is a staple of science fiction, but how much energy would it really take? Physics gives a clear answer, and the numbers are staggering.

Destroying vs. damaging

Wiping out life on a planet is relatively “easy” — a large asteroid can do it. Truly destroying a planet means breaking it into pieces and scattering them so far apart that gravity can never pull them back together. The energy needed for that is called the gravitational binding energy.

For a ball of uniform density, it is:

U = 3GM² / 5R

where G is the gravitational constant, M the planet’s mass and R its radius. Because mass is squared, bigger planets get dramatically harder to destroy.

Energy needed for each planet

These are uniform-density estimates. Real planets are denser in the middle, which makes the true values somewhat higher — especially for the gas giants with their compact cores.

Putting Earth’s number in perspective

Earth’s binding energy of roughly 2 × 10³² joules is hard to imagine, so here are some comparisons:

• The Sun: our star radiates about 3.8 × 10²⁶ watts. Destroying Earth would take about a week of the Sun’s total output — not just the sliver that reaches us, but everything it emits in every direction.
• Nuclear weapons: the Tsar Bomba, the largest bomb ever detonated, released about 2 × 10¹⁷ joules. You would need around a million billion of them.
• The dinosaur-killing asteroid: the Chicxulub impact released somewhere around 10²³–10²⁴ joules — devastating for life, but hundreds of millions of times too weak to break the planet.

Why Mars is so much easier than Venus

Mars has about one-tenth of Earth’s mass, and since binding energy scales with mass squared divided by radius, it ends up needing around 45 times less energy than Earth. Venus is almost Earth’s twin in size, so it is nearly as tough.

Could anything natural destroy a planet?

Yes, but only on cosmic scales. A collision with a body of similar size can partly disrupt a planet, and a planet that wanders too close to its star or a giant neighbour can be torn apart by tides. When a star like the Sun dies, it swells into a red giant that may swallow the inner planets. To see what happens when planets hit each other, read what would happen if two planets collided.

Try it (without the physics bill)

In Planet Smash you get a black hole, a supernova, lasers, meteor showers and whole planets to throw — no 10³² joules required. Start with Mercury if you want an easy win, then work your way up to Jupiter.