A portal (aka a wormhole) is a theoretical topological feature of spacetime that would be, fundamentally, a shortcut connecting two separate points in spacetime. They are consistent with the general theory of relativity but whether wormholes actually exist remains to be seen.

What is physics? Physics is the branch of science that deals with the structure of matter and how the fundamental constituents of the universe interact. It studies objects ranging from the very small using quantum mechanics to the entire universe using general relativity.

Historically, physics emerged from the scientific revolution of the 17th century, grew rapidly in the 19th century, then was transformed by a series of discoveries in the 20th century. Physics today may be divided loosely into classical physics and modern physics.

Physics is a challenging subject ─ it's a combination of math and science that can be difficult even for the best of us. But despite its challenging nature, with a few basic tips and a little practice there's no reason you can't succeed.