# What Is String Theory?

Space.com | 7/11/2019 | Charlie Wood
Level 3
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String theory represents a major dream of theoretical physicists — a description of all forces and matter in one mathematical picture. But after countless papers, conferences and dry-erase markers, the breathtaking breakthrough many once hoped for seems further away than ever.

Nevertheless, even without signs of flashy progress, the resulting insight has left a deep imprint on both physics and math. Like it or not (and some physicists certainly don't) string theory is here to stay.

#### Theory - Everything - Candidate - Theory - Aims

As a so-called "Theory of Everything" candidate, string theory aims to address various theoretical conundrums; the most fundamental of which is how gravity works for tiny objects like electrons and photons. General relativity describes gravity as a reaction of large objects, like planets, to curved regions of space, but theoretical physicists think gravity should ultimately behave more like magnetism — fridge magnets stick because their particles are swapping photons with fridge particles. Of the four forces in nature, only gravity lacks this description from the perspective of small particles. Theorists can predict what a gravity particle should look like, but when they try to calculate what happens when two "gravitons" smash together, they get an infinite amount of energy packed into a small space — a sure sign that the math is missing something.

One possible solution, which theorists borrowed from nuclear physicists in the 1970s, is to get rid of the problematic, point-like graviton particles. Strings, and only strings, can collide and rebound cleanly without implying physically impossible infinities.

#### Object - Thing - Infinities - Calculations - Marika

"A one-dimensional object — that's the thing that really tames the infinities that come up in the calculations," said Marika Taylor, a theoretical physicist at the University of Southampton in England.

String theory turns the page on the standard description of the universe by replacing all matter and force particles with just one element: Tiny vibrating...