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Light years are relative

2023-06-12

I was today years old when I learned that "light years" is actually relative to time on Earth 🤯

E.g. if you're traveling at 99.99% the speed of light to a star that's 4 light years away, it would take you just 3 weeks.

But to your loved ones on Earth, those 3 weeks = 4 years. pic.twitter.com/aMxNqdLswK

— Steven Tey (@steventey) June 11, 2023

See also this article about time in Harper's Magazine. I feel like the more I learn about time the less I know.

Aside: I feel like there is an awesome pop culture book to be written about relativity and quantum mechanics that makes it accessible for people like me; or maybe it exists and I haven't found it yet?

About time

2023-05-11

A beautiful essay about the nature of time by Tom Vanderbilt. My favorite excerpt:

"For now, such clocks can at least confirm the old physics. “If you were to lift this clock up a centimeter of elevation,” Hume told me, “you would be able to discern a difference in the ticking rate.” The reason is Einstein’s theory of relativity: Time differs depending on where you are experiencing it. When standing upright, your head exists at a slightly different timescale than your feet. But with this accuracy comes a sobering reality. “There are not just two times,” notes the physicist Carlo Rovelli in The Order of Time. “Times are legion: a different one for every point in space.” What we think of the present, he writes, “does not extend throughout the universe.” Rather, “it is like a bubble around us.” The “well-defined now,” as he calls it, “is an illusion.”"

Found via The Browser.

The most common noun in the English language…

2022-12-23