the current rate of extinction is faster than any of the 5 previous mass extinctions. the most recent mass extinction (not counting the current one) resulted in the loss of 95% of all life on earth.

 because the earth's rotation is gradually slowing down, a day back when dinosaurs were still alive was just 23 hours long.

10 billion years from now, when our sun is no longer capable of sustained nuclear fusion, it will swell to 250 times its current size and explode. leaving behind a cloud of gas and dust. our own planet will burn up long before then.

the moon is so far from the earth that you could easily fit all of the other planets in our solar system between them, with plenty of elbow room left over.

due to the gravity well caused by earth's mass, time in our planet's core is roughly 2.5 years behind the surface.

the largest hydroelectric project to date, china's 3 gorges dam, has actually slowed the earth's rotation by 0.06 microseconds.

the fact that the earth is a globe was common knowledge 200 years before columbus set sail. all you have to do is watch a ship sail over the horizon to figure it out. washington irving made up the flat earth nonsense in his biography of columbus to make the story more interesting.

the center of the earth is not molten. it's a 700 mile across ball of very solid nickel and iron.

because there's no atmosphere in space, there's also no sound (sorry, star wars and guardians of the galaxy fans - all explosions are silent).

also, because mars has a thinner atmosphere than we do, with a different chemical makeup, sounds are higher-pitched there.

our planet doesn't get closer to the sun in summer - it's just that the northern hemisphere tilts in that direction during part of the year, and the southern hemisphere does the same during the other part of the year. it's not proximity - it's all about the tilt.

2500 years ago, eratosthenes figured out that the world was round, and even calculated its circumference with 99% accuracy.

every day, about 100 tons of space dust lands on earth.

it takes 492 seconds for that ray of sunlight to reach earth.

the earth's north and south magnetic poles have flipped roughly 20 times in the past 5 million years, making north south and vice versa.

only 1% of all the water on earth that we can easily get to is drinkable. because of this, many companies are trying to buy the rights to it.

the north magnetic pole used to be over canada, and is slowly making its way toward russia.

one earth day is 24 hours, right? wrong. the actual amount of time that it takes the earth to rotate is 23 hours, 56 minutes, and 4.1 seconds.