|April 20th, 2017 at 6:22:43 AM permalink|
Member since: Oct 24, 2012
A lens is merely an object that bends light, thus focusing it if properly shaped. Many materials can do this, but glass is the easiest to work with and to shape with high precision.
Energy can bend light, too. But it takes a lot of energy. Gravity bends light, for example, and gravitational lenses are a well-known astronomical phenomenon. But as yet, the only way to create gravity is to gather lots of mass in a small space. You could conceivably use a black hole or a neutron star as a lens, but three's no known way of handling such things.
Mass and energy are equivalent, though. Therefore a great deal of energy concentrated in one small place would generate gravity and bend light. But you need a really large amount of energy to obtain a small amount of mass-equivalent gravity. Since you get energy from material masses, the math doesn't work out.
Mass isn't all. Space matters. A black hole is a tad less massive than the star that collapsed into it, but has all that mass concentrated in a literal point. You could conceivably cram lots of energy into a space the size of a big atomic nucleus, say.
Now guess what can keep massive amounts of energy in a small space? Gravity.
If Trump where half as smart as he thinks he is, he'd be twice as smart as he really is.