The twin paradox What if we replace the Earth with a neutron star or a black hole Which will be younger

The twin paradox is a thought experiment in special relativity that involves two twins, one of whom travels at high speed for a period of time and then returns to Earth. The twin who travels at high speed will experience time dilation, meaning that they will age more slowly than the twin who stays on Earth. This means that when the traveling twin returns to Earth, they will be younger than the twin who stayed on Earth.

If we replace the Earth with a neutron star or a black hole, the situation is more complicated. Neutron stars and black holes are extremely massive objects with very strong gravitational fields. This means that time is also affected by gravity, and there is a phenomenon known as gravitational time dilation.

In the case of a neutron star or a black hole, the gravitational time dilation would be much stronger than the time dilation due to the high speed of the traveling twin. This means that both twins would experience time dilation, but the twin who stays on the neutron star or black hole would experience more time dilation due to the stronger gravitational field.

Therefore, the twin who stays on the neutron star or black hole would age more slowly than the traveling twin, and would be younger when the traveling twin returns.