Hacker News Reader

Not really, the answer you are referring to is for completely stopping the moon by delivering enough energy to cancel out its current kinetic energy, of the entire moon!

We don't need to stop the moon to change its orbit. With careful and deliberate adjustments via bombing and letting Earth gravity do its job, we could alter its orbit by adding to its force vector instead of trying to negate it.

View on HN

Applying millions of nuclear bombs to either slow down or speed up the Moon by the same amount will change its orbit by a similar magnitude in terms of the sheer change in energy.

The energy required to achieve a specific Δv is the same whether you are accelerating or decelerating. This is because energy change associated with velocity (ΔE) in a conservative system is dependent on the square of the velocity change (Δv^2), regardless of direction.

Potential energy is twice the kinetic energy in a stable orbit. Changing the orbit by epsilon/r would require roughly U*epsilon/r energy. Which means that a tsar bomb would only move the moon distance to earth by 10^-10

Reply on news.ycombinator.com