One of the most apparently obvious properties of the world we live in is that it has three spatial dimensions (obvious to you because you can move left or right, walk forward or backward, or jump up and down). But one of the most fascinating non-obvious properties that the world might exhibit is that it may have additional (“extra”) dimensions of space that you and I are unable to perceive, either directly through our senses, or indirectly through the many machines that we humans have built, up to the year 2011. This possibility has been considered for at least 90 years, in various forms, and it is alive and well for physicists working at the Large Hadron Collider, and beyond.
This is a very big subject and requires a lot of sub-articles, so I’ll be building this section for quite a while. Of course there are many other articles and books on this subject, including tomes for the public by my famous colleagues Brian Greene and Lisa Randall, but I hope I’ll transcend redundancy here by providing some complementary insights.
Here’s an article (with sub-articles that give examples) on how to think about extra dimensions. We may as well get that straight before trying to describe how extra dimensions might show up at the Large Hadron Collider!
Next, an article (with sub-articles that explain more details) describing some of the signs of extra dimensions that we might look for in experiments.