Home Remedies for Whiter Teeth. Some people still prefer the age-old home remedy of baking soda and a toothbrush to gently whiten teeth at home. Also, some foods such as celery, apples, pears, and carrots trigger lots of saliva, which helps wash away food debris on your teeth.
Roche limit. n. The smallest distance at which a natural satellite can orbit a celestial body without being torn apart by the larger body's gravitational force. The distance depends on the densities of the two bodies and the orbit of the satellite.
The limit for long wavelengths 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.