As two massive objects pass near each other, gravitational forces induce dramatic physical changes -- decompressing, melting, stripping material away and even annihilating the smaller object.

As two massive objects pass near each other, gravitational forces induce dramatic physical changes—decompressing, melting, stripping material away, and even annihilating the smaller object. You can do a lot of physics and chemistry on objects in the solar system without even touching them.

However completely people might fulfil themselves in other spheres, if they don’t possess this understanding between their hands and material objects, they can never have more than an incomplete understanding of the world.

We all teach students a massive body of material to get some sort of mastery of it, pass a judgement, and defend it.

Things changed with the discovery of neutron stars and black holes - objects with gravitational fields so intense that dramatic space and time-warping effects occur.

There are other families of particles out there that can form massive compact objects.