UCSB Science Line
 Can you use the gravity of a planet, to accelerate past the speed of light? Question Date: 2019-04-01 Answer 1: In theory, you can use Newton's law of Gravitation to predict the required conditions for a planet to orbit at the speed of light. A rough approximation of this gives us that the velocity is given by v= G M/r, where r is the orbital radius and M is the mass of the body that the planet is orbiting around. If we want this velocity to be the speed of light, we can set v = c and solve for the required radius, which gives us r = G M/c2. To get an idea for how small this radius is, for the mass of our sun, the planet would have to be orbiting just around 1.5 km away from the center of the sun. So, this scenario is not possible of an orbiting planet moving at the speed of light, is not possible. However, an example of something similar happening is that light orbits around a black hole at the speed of light. Thanks! Answer 2: No. Here's a good source - Scientific American - for news about neutrinos that travel faster than light in a special container. As far as I can tell, the results are still correct. Sep 22, 2011 - "An Italian experiment has unveiled evidence that fundamental particles known as neutrinos can travel faster than light. Other researchers are ..." Answer 3: No, the gravity of a planet is not strong enough to accelerate past the speed of light. The only class of object whose gravity is strong enough to accelerate an object past than the speed of light are black holes, and that only happens inside of the event horizon - which means that whatever does go faster than light inside of a black hole will not come back out. Click Here to return to the search form.