Our Moon is Actually More Fascinating Than You May Have Imagined

Our Moon: More Fascinating Than You May Have Imagined
The moon may not be as mysterious as deep space - after all, we've already been there. But it is amazing in its own right, and definitely worth some deep thought and gazing time. Without it, we probably wouldn't exist - we owe it our very lives.
As a species, we take our moon for granted. It's the most familiar thing in the night sky, and we hardly even notice it most of the time. This is new - for most of human history, the moon has dictated the pace of our lives - the calendar month is based on the moon cycle, planting and harvest were timed by the phases of the moon, and menstruation was even called 'moonblood'.

Modern life, though, leaves little room for our poor moon. Sure, we may appreciate it briefly when it's low and dramatic during a harvest moon, or we may wish for it when camping in the darkness of the new moon. But compared to the fantastical offerings of deep space, our moon looks kind of boring by comparison. I mean, come on, we've already been there. But really, it's a fascinating piece of rock, from its formation to its effect on Earth - without it, we couldn't live here.
It's Not Made of Cheese
You never really thought the moon was made of anything but rock, but did you know how it formed? A long, long time ago, when the Earth was a very young planet and the solar system was a volatile place, there was a planet the size of Mars. It had no particular path in life, and found itself crossing Earth's orbit - the two planets collided in what was surely the most dramatic entrance in the history of our planet, sending loads of debris flying into space.

As time went by, Earth continued on her orbit around the sun and the debris continued to orbit the Earth. Eventually, the debris clumped together and coalesced into the rocky satellite we now know as the moon. The weird part? The stuff that made up the moon came from the debris sprayed off the Earth - the Earth completely absorbed the Mars-sized planet. Yes, the moon is made of Earth.
Full moon close up
We Got Seasons
The impact between the Mars-sized planet and the Earth was tremendous enough to knock the Earth crooked. That's why there's a difference between magnetic north and true north - our planet is tilted about 24 degrees off the vertical. That tilt is what makes part of the globe hotter and part of the globe colder depending upon the point in the rotation around the sun - in other words, seasons. Had that impact never happened, our climate wouldn't vary throughout the year. This may seem fine on a nice spring day, but imagine how it would have limited the rise of Homo sapiens - limited seasons means limited food supply - imagine how much more difficult it would have been for our ancestors to establish a foothold.

Sadly, the moon doesn't really have seasons. It is nearly vertical on its axis, providing the area around its north pole with eternal light. This doesn't mean it's beach weather though - winter temperatures in parts of the moon's north pole are the lowest ever recorded by a spacecraft - 27K, or colder than the surface of Pluto.
Water Loves the Moon
The moon affects the tides - you learned that in school. But have you ever pictured it on a macro scale? See, the moon has a minor gravitational pull - just enough to create a slight rise in huge bodies of water on Earth. As the moon orbits us, that slight rise - picture a big bubble of water in the ocean - follows it along. When the moon rises over the shore of a land mass, the bubble follows it and you get high tide. The shore on the other end of body of water, the one from which the moon is receding, has low tide at the same time because the bubble has been pulled away. So yeah, water follows the moon. This only works on very large water systems though, so don't stare at your water glass all night trying to catch it moving.
It's Actually Pretty Big
Our moon is actually the fourth largest in the solar system relative to the size of the planet. It could almost be considered a planet itself - it's bigger than Pluto, but then again, Pluto was demoted. And millions of years ago it was closer to the Earth, and therefore looked much bigger in the prehistoric night sky.

The moon has a core, mantle and crust just like the Earth, and topography includes mountains, craters and basins. We've even found water ice there. It looks almost like it's lit from within, but it's actually only about as reflective as coal - the lunar soil has a very particular quality that makes it reflect high levels of light directly back at the sun. This is why the moon can look dim and orange when it's low on the horizon during a harvest moon - it's reflecting light at the sun, not at us. But as everyone rotates as the night goes by, the moon rises in the sky and becomes smaller and brighter as we move into its path of light.
Full moon
The moon is gorgeous and quite miraculous when you think about it - sit and stare at it tonight, and think about how if it weren't for a catastrophic collision, we might not be here.