What if there was no moon? In this episode, we find out that there's a lot of fascinating lunar science that goes into answering that question. Miquel Sureda is a Spanish astrophysicist and science communicator who helped us figure it out. Check out his Spanish language blog, Gaia Ciencia.
And before we get to the science, one more thing: We collaborated with fellow Kids Listen podcast What If World to tell a much less science-based story about what would happen if there was no moon! It's silly and hilarious. Listen here.
Now, back to science!
HOW THE MOON WAS MADE
Scientists are still trying to figure out how the moon was formed. They have a number of theories, or hypotheses, about it. The most popular theory is called The Giant Impact Theory. Here's a short summary from Space.com:
Earth formed about 4.5 billion years ago, and scientists think the moon came into being shortly afterward. The prevailing explanation for the moon's origin, known as the Giant Impact Hypothesis, is that it resulted from two protoplanets (or embryonic worlds) that slammed together — the Earth as it was forming, and a Mars-size object called Theia. A lot of debris went on to form the moon.
Scientists developed this theory by analyzing 900 pounds of moon rocks collected by astronauts on the surface of the moon. Phil Plait, at Bad Astronomy, explains the support for this theory:
It explains why the Moon has some chemicals similar to Earth—it used to be part of the Earth—but also why it has a lower overall density. The Earth was old enough at the time that heavier elements had started to sink to the center of our planet, leaving lighter stuff floating at the surface. The grazing impact skimmed off this lighter stuff, and that’s what formed the Moon.
But other scientists are still coming up with their own ideas for how the moon was made. One recent paper suggests that the Moon "actually formed inside a giant, donut-shaped cloud of molten rock." It says that the Moon is actually older than the Earth!
Any way you slice it, the Moon's formation was pretty darn cool.
THE MIRROR ON THE MOON
The mirrors left on the moon by Apollo 11 astronauts Neil Armstrong and Buzz Aldrin have a fancy name: The lunar laser retroflector array. It's a two foot wide panel made up of 100 mirrors that point at Earth. They tell us how far the Moon is from Earth - and how fast it's moving away from us.
Read NASA's article on how the lunar laser retroflector array works.
WHAT IF THERE WAS NO MOON?
We've learned that scientists believe there was a time before the Moon came into existence. They also believe that in the future, the Moon will have less of an influence on Earth. So this is not just a hypothetical question!
In our episode, Miquel broke down three major changes:
1. Smaller tides
2. A shorter day
3. Crazy seasons and climate
To learn more, check out these videos!