Disadvantages of In-Office Whitening. 1  In-office bleaching is more expensive than take-home alternatives. 2  Its cost, on average, is $650, compared to $400 for take-home trays and under $100 for over-the-counter bleaching trays or whitening strips.
Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions.
A planetary ring is simply a ring of cosmic dust and space junk orbiting around the planet. Jupiter, Saturn, Uranus and Neptune all contain rings because the gravity is so strong that when a moon or something has gotten too close the planet simply ripped it apart and the remains orbit in an endless circle around the planet.