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 nebula is a nebula that is made up of gas and plasma. They are made by certain types of stars when they die. They are named this because they look like planets through small optical telescopes.his is what causes a planetary nebula to look like it does. Planetary nebulae are very special objects because they can help make more stars. When a star dies, the metals that were in the core of the star are sent to other places in the universe.