What happened to Phobos, Mars inner satellite?
Phobos’s mass is 1.08 e 16 kg. It orbits 9,378 km from Mars every 10 hours. The force holding Phobos to Mars is 5.262 e 15 newtons. The Earth would not be able to capture Phobos from Mars until it was around 28,598 km from the Earth. I see two possibilities here. (1) Phobos was always far enough away from the Earth that the Earth couldn’t and didn’t capture it. (2) As Mars approached the Earth Phobos was captured by the Earth when it was around 28,598 km from the Earth’s center. At that distance it would take Phobos 13.369 hours to orbit the Earth. Phobos made four trips around the Earth while Mars made around 2 and 1/4 trips. At that point Mars recaptured Phobos and Deimos and having reached escape velocity Mars proceeded on orbiting the Sun once again. In a couple paragraphs, you’ll see the formula you can use to compute the orbital period. How far was Mars from the Earth and how fast did Mars orbit the Earth-Mars barycenter? Using Kepler’s 3rd law, scientists tell us a satellite wou
