User blog comment:PlantyThePottedPlant/Random Topic Blogging II: Electric Blogaloo/@comment-4123215-20120325160441/@comment-2077777-20120325173028

The two most smallest things in the history of everything are Quantum foam(the fabric in Einstein's space-time theory) and Strings in the string theory. Both are about 0.00000000000000000000000000000000001 m (10-35 m) and anything smaller makes physically no sence to exist. The estimated size of our universe is 93,000,000,000 light years big. :)