This Is A Light-Nanosecond!

less than 1m read

·Nov 10, 2024

I trimmed my beard yesterday, so I'm feeling a bit like a baby today. But look at the trimmings! Specifically this one that is 2.4 fortnits worth of beard growth. How do I know? Well, because of this tool I made. This about 5 years ago to free people from the tyranny of standard units. It measures in weird units like beard fortnits, the typical length of beard grows every 2 weeks.

It's also got light pico seconds, how far light travels in a trillionth of a second. If you didn't get one 5 years ago but you're subscribed much later this year, three boxes from now you'll get one in a special Legacy box we're making. The entire ruler is exactly one light nond long. This is how far light travels in a vacuum in 1 nond.

Everything I see from this distance, I'm seeing as it was a billionth of a second ago. It's a reminder that you live in the past because light has a finite speed. You do not see things as they are; you see the universe only as it was. Also, you're going nowhere if you fall asleep tonight in the same bed you woke up in this morning. Your average velocity for the day will be zero.

Dividing 3-digit numbers by 2 digit-numbers | Grade 5 (TX TEKS) | Khan Academy

Are You Lightest In The Morning?

View All

Does Earth Have a Twin? These People Want to Find Out | Short Film Showcase

[Music] Curiosity and exploration are simply part of our DNA. What’s at the top of that mountain? What’s around that ridge? What’s in that forest? What’s across that body of water? This quest to explore things that we think might be beyond our reach or mi…

YC Founders Made These Fundraising Mistakes

If you look at why the Google founders are the Google founders and still have all this control over their company, you can look all the way back in time to the moment of the earliest fundraisers. They were not desperate for cash and load leveraged. Hey, …

Cells - Course Trailer

Hello. Now, when you look at me right now, you probably think that it’s me, Sal, talking to you. But really, what is talking to you is a society of over 30 trillion cells that have somehow collectively convinced itself that it is Sal. What we’re going t…

Proof: Parallel lines divide triangle sides proportionally | Similarity | Geometry | Khan Academy

We’re asked to prove that if a line is parallel to one side of a triangle, then it divides the other two sides proportionately. So pause this video and see if you can do that, and you might want to leverage this diagram. Alright, so let’s work through th…

Worked examples: interpreting definite integrals in context | AP Calculus AB | Khan Academy

Julia’s revenue is r of t thousand dollars per month, where t is the month of the year. Julia had made three thousand dollars in the first month of the year. What does three plus the definite integral from one to five of r of t dt equals 19 mean? We have …

Worked example: forming a slope field | AP Calculus AB | Khan Academy

In drawing the slope field for the differential equation, the derivative of y with respect to x is equal to y minus 2x. I would place short line segments at select points on the xy-plane. At the point (-1, 1), I would draw a short segment of slope blank.…

This Is A Light-Nanosecond!

More Articles