As an object gets arbitrarily close to c, its kinetic energy approaches infinity. The gravitational binding energy of earth is about 2.5 x 10^32 joules, which is finite. So you could actually do it with any size of object that’s traveling sufficiently close to c.
Thus, Holeo manuever wouldn't work, but only because if it was attempted it would release such an immense amount of energy multiple systems would be destroyed
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u/TimeKepeer 20h ago
It takes surprisingly little, in terms of sci-fi, to destroy a planet.
If a civilization can send ships flying at light speed or at nearly light speed, it is fair to assume they can also send projectiles at such speeds.
A very small projectile traveling at such high speeds would be enough to destroy our planet. I believe a baseball sized one would suffice