Pluto. Since being declassified as a planet, Pluto's technical name is "134340".

It Becomes Dense. Warm air pushes cold air down, creating an inversion.

Rabbit. In Australia, rabbits are considered a serious pest that is responsible for widespread erosion.

Stratosphere. The stratosphere is the second layer of the Earth's atmosphere.

1.5 Volts. The D sized battery can supply power for a longer time than C, AA or AAA cells at equal current levels.

186. The North Pole has six months of uninterrupted darkness every year.