Scientists use this notation as an easy way to write really large, or really small numbers. A number like 10^{8} represents 10 multiplied by itself 8 times, which is a 1 with 8 zeroes after it: 100,000,000.
A number like 10^{-21} represents 0.1 multiplied by itself 21 times, which is a 1 with 21 zeroes in front of it (including the one before the decimal point): 0.000000000000000000001.
This is frequently a much more efficient way to write numbers. For example, 3.765x10^{17} is much easier to write and think about than 376,500,000,000,000,000.
The SXS project is a collaborative research effort involving multiple institutions. Our goal is the simulation of black holes and other extreme spacetimes to gain a better understanding of Relativity, and the physics of exotic objects in the distant cosmos.
The SXS project is supported by Canada Research Chairs, CFI, CIfAR, Compute Canada, Max Planck Society, NASA, NSERC, the NSF, Ontario MEDI, the Sherman Fairchild Foundation, and XSEDE.