Our moon is one of the few constants that we can depend on. It’s up there in the sky every night and we have books, poetry, and songs that are devoted to singing its praises.
However, the moon is more than just a beautiful sphere in the sky, because without the moon, we may never have existed.
There are a number of theories about how the moon came about, but the one that most scientists agree on is the collision theory.
It’s believed that early on in the Earth’s development, a large planet-size object, around the size of Mars, hit the Earth.
The collision created a huge amount of debris that was now orbiting a smaller sized Earth. The debris eventually came together and formed our moon.
Our moon is tidally-locked to the Earth. This means that it only shows one side facing the Earth at all times and we never see the other side.
It’s thought that this was caused due to the gravitational effects of the Earth on the moon, slowing its rotation combined with the moon’s axis.
Being tidally-locked seems to be common because there are a lot of moons circling around other planets that behave in the same way.
Our moon is always up in the sky but it doesn’t always “look” the same to us. These are called moon phases and they happen when the sun throws light on only part of the moon due to Earth blocking the rays.
The phases run from a sliver of a crescent moon all the way to a full moon when the moon is opposite of the sun.
Astronauts are always doing experiments in space. One of the coolest experiments happened in 1971 when Stuart Roosa, an Apollo astronaut, took a bunch of tree seeds to moon with him.
The purpose was to see if being in space would change or harm the seeds. Once he returned to Earth the seeds were planted all over the U.S. and are known as “moon trees.”
It turns out that almost all of them are doing fine.We have spent our entire live assuming that we have only one moon, however, this may not be entirely true.
There is a good possibility that Earth has a second satellite. In 1999, scientists located a 3 mi/5 km asteroid, named Cruithne that is orbiting the Earth in a huge horseshoe-shaped orbit.
It’s believed that it takes around 770 years for it to complete its orbit and it will hang around the Earth for around 5,000 years.
Our Earth has a lot of environmental and tectonic activity that covers over many of the asteroid and meteor hits that have occurred.
Our atmosphere also protects us from these collisions making many burn up before they have a chance to do any damage.
This is not the case with the moon. When we look at the moon’s surface we see the results of millions of years of damage in the craters that the hits have created.
Viewing the moon’s surface gives us a good idea what happened to our own Earth.
Since the moon isn’t tectonically active and doesn’t have an atmosphere, scientists assumed that it was a dead satellite.
However, this idea was changed when astronauts took seismometers with them to the moon.
When they set them up they found that the moon has “moonquakes” that occur several miles below its surface.
These moonquakes are believed to be caused by the Earth’s gravitational pull. Astronauts also found small surface fractures that allows inner gas to escape.
It’s believed that the moon has a small hot or partially molten core much like the one on Earth but a lot tinier.