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.
Planetary science is the study of the assemblage of planets, moons, dwarf planets, comets, asteroids, and other bodies orbiting the Sun, as well as extrasolar planets. The Solar System has been relatively well-studied, initially through telescopes and then later by spacecraft.