by Akim Reinhardt

We’re circling the Sun at a rate of between 18.20–18.83 miles per second. It is not a fixed speed because Earth travels on an ellipsis, and moves a hair faster when it’s closer to the Sun than it does when further away. It averages out to about 67,000 miles per hour over the course of the year. At that speed, a full revolution is 365 days, 5 hours, 48 minutes, and 46 seconds in the making. At least for now.

Each year, Earth’s voyage around the Sun takes just a little bit longer, to the tune of roughly 3 nanometers per second. It’s minuscule, but adds up over time. Since the solar system’s inception 4.571 billion years ago, Earth is moving 22 mph slower.

The main reason is that Earth is drifting ever so slightly away from the Sun, stretching out the orbital path, and lengthening the duration of a revolution.

We’re not fleeing the Sun so much as it’s pushing us away. As the Sun’s hydrogen core transmogrifies into helium through the process of nuclear fusion, the Sun loses somewhere in the neighborhood of 4 million tons of mass every second. Since that process began billions of years ago, the Sun has lost mass equivalent to 1 Saturn, or approximately 95 Earths if you prefer to think about it in homier terms. The Sun also suffers particle loss through Solar Wind, and that has resulted in its shrinking by another 30 Earths or so. Solar flares and coronal mass ejections also steal away mass. In all, the Sun is ~10²⁷ kg lighter than it was at the birth of our Solar System. Here’s what 10²⁷ looks like written out in digits:

1,000,000,000,000,000,000,000,000,000

Since a ton equals two-thousand, feel free to add another three zeroes and flip that one to a two. Then again, a gram ain’t much, so maybe just leave it as is, stare at it a bit, and try to feel the full weight of it. Read more »