Last year I did a “Wonder Project” on Time Dilation. In this kind of project we have to ask ourselves a meaningful question (in the field of science), research about it, and make a blog post with all of our findings. This year we are doing a “Wonder Project” again, but it has to be space oriented.

**My inquiry question for “Wonder Project 2.0” is:**

*What is “String Theory” and how does it explain our universe?*

## The Main Idea: Strings and a Theory of Everything

String theory is a theory that describes all forces and particles with one entity, the string. To do this, it tries to bring together elements of quantum physics and Einstein’s theory of relativity. It is basically a theory that tries to explain everything beyond our standard model of physics (beyond atoms, and subatomic particles).

## How it’s Supposed to Work

String theory theorizes that everything in the universe is made up of tiny vibrating strings having a Planck length of about 10^-35 meters. They vibrate in different ways to make up all of the atomic and subatomic particles.

These strings could be open, form loops, merge with other strings, or divide into sub-strings. Like waves or particles from quantum mechanics, which string theory extends from, the strings aren’t made of any substance. If the theory is correct, these fundamental strings just * are.* They are like a kind of force. To make this theory work mathematically, there has to be eleven dimensions. Three spacial dimensions (up/down, left/right, and forward/backward), time, and seven more dimensions that are hidden from human senses because of their subatomic size, or because we are stuck in the four known dimensions and the others extend off from them.

## How String Theory was Created

Unlike Einstein’s Theory of Relativity, String theory was created by many theoretical physicists over a long period of time. When it was first proposed, the strings were either closed or open, and there was no concept of an extra 7 dimensions. String theory lost traction in the world of science because of difficulties with the mathematics, but in the early 1980s there were two new mathematical discoveries that got it back on track. The first one was by using ten dimensions. The second one was by using something called the E(8) × E(8) symmetry model. By combining both of these concepts it repaired the mathematical difficulties string theory couldn’t previously overcome. Later, physicists Michael Green and John Schwarz, found that string theory could explain known particles, their behavior, and solve the point particle problem, and in 1995, another discovery showed that string theory could be combined with another theory called Supergravity, which used eleven dimensions instead of ten. Eventually it got to the point where the string theory we know today is actually now called Super String theory.

## A Problem with Quantum Physics

In quantum physics, there has long been an issue with point particles. A point particle mathematically defined is a point, but, with a diameter of zero. At least a point that has a diameter that approaches zero. With all of the mathematics we have today forces on particles are related to the distance between particles; forces like magnetism and gravity. If something is infinitely small, then the radius, also being infinitely small causes the mathematics to grow the forces to infinite levels. So, point particles cause a paradox. The problem with Quantum Physics is you have these point particles that are infinitely small colliding with each other that should produce mathematically infinitely large forces but in reality, they don’t. This doesn’t make sense to the physicists, but in String theory, this problem doesn’t occur.

## Conclusion

To conclude, string theory is a theory that attempts to explain all forces and all matter in the universe using very small, vibrating strings and an extra seven dimensions, sadly, we cannot observe either. As of now, there has been no physical evidence or proof that string theory is actually correct; the only proof we have is the elegantly complex mathematics that works it out. The main critics of string theory today, criticize the theory on the basis that it cannot be experimentally tested or proven.

Many researchers are wondering if they are going down an infinite rabbit hole; ”String theorists propose a seemingly endless amount of mathematical constructions that have no known relationship to observation,” Sabine Hossenfelder, a physicist at the Frankfurt Institute for Advanced Studies in Germany said. But, I think that eventually, they will be able to make an experiment that proves or disproves this theory.

Here is a video that explains string theory in a simplified way:

## Bibliography

Mann, Adam. “What Is String Theory?” LiveScience, Purch, 20 Mar. 2019, www.livescience.com/65033-what-is-string-theory.html. Accessed 24 May 2019.

Gilman, Larry. “String theory.” The Gale Encyclopedia of Science, edited by K. Lee Lerner and Brenda Wilmoth Lerner, 5th ed., Gale, 2014. Science In Context, http://link.galegroup.com/apps/doc/CV2644032154/SCIC?u=43sbo&sid=SCIC&xid=8a365a32. Accessed 23 May 2019.

“The Basic Elements of String Theory.” Dummies, www.dummies.com/education/science/physics/the-basic-elements-of-string-theory/. Accessed 24 May 2019.

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