Signore Galilei

If you were to add up the mass of all the atoms in the Earth, you’d get a number 3 trillion tons more than the Earth’s actual mass. We didn’t have to count all the atoms down to the Earth’s core to figure this out. It’s a consequence of the laws of physics. Let’s start…

Let me tell you the story of saints Barlaam and Josaphat of India. A king named Abenner, who persecutes Christians, hears from his court astrologers that his son will attain great power and rule over India. But one astrologer predicts that the prince will instead become a great holy man – a Christian. Alarmed, Abenner…

Last week, we talked about how moons in the outer solar system can see total eclipses as good as the ones we see on Earth. To recap, if you’re standing on one big round moon of a planet like Jupiter or Saturn, you can watch another big round moon just barely block out the Sun,…

This past week, there was a total solar eclipse, visible from a path stretching along far northern Russia, Greenland, Iceland, and Spain.  Like many of this year’s eclipse chasers, I was clouded out – though I did have a lovely couple minutes of darkness on an Icelandic fjord. I’m already planning for the next time…

Today is August 4th, 2026. Today is the original setting of Ray Bradbury’s short story “There Will Come Soft Rains” from The Martian Chronicles.1 Bradbury himself once described this story as best representing the essence of his work,2 and I know of no story more appropriate for today. It’s also only about 2,000 words, if…

You might already know that atoms are mostly empty space. Physical size behaves a bit weirdly at the atomic scale, but essentially the radius of an atom’s nucleus is tens of thousands of times smaller than the radius of an electron’s orbital. That’s the same ratio as a single grain of sand1 to a football…

We all learned in science class that water freezes at 0 °C or 32 °F at atmospheric pressure. But what water, exactly? Even after you distill out all the dissolved salts and minerals to get pure H2O, not all H2O is created equal – and for the most precise temperature measurements, the differences really matter. Here’s…

Let’s consider a person you don’t know. Maybe they live in the Republic of the Congo. Let’s say they’re near a city – not the country’s biggest city, but maybe its 5th biggest city. I don’t know that city’s name, but I could probably look it up. And they’re not in the city center, but…

Last week, we looked at some other things besides the USA that are turning 250 in 2026.  As promised, here are a few more: The Dominguez-Escalante expedition Atanasio Dominguez and Silvestre Vélez de Escalante were two priests from New Spain, who set out on July 29th 1776 to find an overland route from Santa Fe…

This year, we celebrated the 250th anniversary of the Declaration of Independence, the final text of which was ratified by the Second Continental Congress on July 4th, 1776.  The year 1776 has become synonymous with the United States of America, but there were in fact other things that happened that year, some of which also…