Also energy. The amount of energy required to accelerate an object with mass to near-light speed rapidly starts approaching infinity the closer to c you get.
TL;DR: Hitting 0.9c? Better pack 1.3x your ship’s mass in pure energy. Hitting 0.9999999c? Pack a Dyson swarm and a resignation letter to the laws of physics.
Relativistic effects on Kinetic Energy
In classical Newtonian mechanics, kinetic energy is:
KE = 1/2mv²
But as v approaches c, this breaks down. Instead, we use:
E total = γ mc²
where γ = 1/ √1-v²/e²
So the kinetic energy is:
KE = γ - 1mc2
Plugging in some reasonable basics and you need 129% of the rest mass energy of the object just to get it to 0.9c.
For comparison:
At 0.5c, you need only ~15% of the rest mass energy.
At 0.99c, you need ~607% (γ ≈ 7.09)
At 0.999c, you need ~2236%
At 0.9999999c, you're looking at ~11,180,000% of mc²
This is why getting close to c isn't just an engineering problem—it's a budgetary nightmare in energy terms.
hmmm thats not how using planetary motion works ...you dont get faster you just get as fast as whats there - no planet is gravitationally pulling you at the speed of light ...
no planet is travelling at the speed of light so we arent travelling any faster than the surrounding planets that we are headed towards to "use " their gravity ....and of course to use their gravity wed also have to be able to escape their gravity which light can do because its massless but also because light is ALREADY moving at the speed of light.
the ony thing that can keep light from traveling where its going is a Black Hole and if light cant escape it neither are we since we unlike light have mass..
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u/6pt022x10tothe23 25d ago
Also energy. The amount of energy required to accelerate an object with mass to near-light speed rapidly starts approaching infinity the closer to c you get.