Particle Physics, Exploring the Very Smallest and Largest Scales of Reality

The scale of reality goes from the smallest to the largest things we know. Particle physics explores the very smallest scales of reality and reaches its limit according to current modern physics at the Planck length which is equal to 1.616255 ×10−35 m.

At the opposite end of the scale is the size of the known observable universe at 93 billion light years across. The whole universe may be very much bigger than the observable universe and may even be infinite in size.