Simplify the following text for a Grade 11 native English-speaking person.
Original: The long wavelength limit is the size of the universe itself , while it is thought that the short wavelength limit is in the vicinity of the Planck length , although in principle the spectrum is infinite and continuous .
Simplified: The short wavelength limit is likely to be the Planck length , and the long wavelength limit is the size of the universe itself , though in principle the spectrum is infinite .