Cosmic Coffee with the Moon

We are so used to see the Moon that we sometimes forget that our Earth’s steady companion is fascinating. 🌝

But, is this actually true that he is OUR companion? Actually, the Sun is trying to pull it away from Earth with a gravitational attraction on the Moon around twice than that of Earth. Luckily, the Moon takes it slow: it would need a high enough escape velocity to escape the Earth. But he indeed is very slowly moving further away from us due to tidal friction, currently around 3.82 cm per year.

And here is another fun fact: You probably know that the Moon always shows us the same side. Can we know then how the far side looks? Yes, we can! One of the techniques used is so called laser altrimetry where pulsed laser light is send to the Moon. By measuring the differences in the return times from the reflected pulses, a 3D map of the Moon can be reconstructed.

Enjoy the lunar eclipse today!