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Which is Bigger, the Sun or the Earth? Check it Yourself!
Once you’ve convinced yourself the Earth’s a spinning sphere of diameter about 8000 miles (13000 km), and you’ve estimated the Moon’s size and distance (diameter about 1/4 Earth’s, and distance about...
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Who Orbits Who, and Where? Check it Yourself
So far the arguments given in recent posts give us a clear idea of how the Earth-Moon system works: Earth’s a spinning sphere of diameter about 8000 miles (13000 km), and the size of the Moon and its...
View ArticleFrom Kepler’s Law to Newton’s Gravity, Yourself — Part 2
Sometimes, when you’re doing physics, you have to make a wild guess, do a little calculating, and see how things turn out. In a recent post, you were able to see how Kepler’s law for the planets’...
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The Artemis Rocket Launch and Particle Physics
A post for general readers: The recent launch of NASA’s new moon mission, Artemis 1, is mostly intended to demonstrate that NASA’s incredibly expensive new rocket system will actually work and be safe...
View ArticleIn Brief: Unfortunate News from the Moon
Sadly, the LunaH-MAP mini-satellite (or “CubeSat”) that I wrote about a couple of days ago, describing how it would use particle physics to map out the water-ice in lunar soil, has had a serious...
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Mars Meets the Moon
A break from all these wormholes and strings; let’s take a moment to look at the sky. In the US, sadly, most of the country will be under cloud, but for those who aren’t, you have a spectacle tonight,...
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Beyond the Book (and What the Greeks Knew About the Earth)
Since the upcoming book is basically done, it’s time for me to launch the next phase of the project — the supplementary material, which will be placed here, on this website. Any science book has to...
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What Ocean Tides Teach Us About the Sun and Moon
The Moon has a four-week cycle; it is full every four weeks (actually every 29.5 days). But ocean tides exhibit a two-week cycle; they are large one week and then smaller the next. Specifically, as in...
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