Recent content by Jonathan Scott

I just saw that physicist Kenneth Nordtvedt died on October 9th, according to his Wikipedia entry: https://en.wikipedia.org/wiki/Kenneth_Nordtvedt He had a fluent grasp of relativistic gravity theories, and is particularly known for using the Lunar Laser Ranging to check the equivalence...

In the late 1980s, working for a university, I wrote some terminal graphics routines for the IBM PC which among other things drew arcs without needing multiplication or division, and I was told I couldn't include them in the terminal program I was selling because the algorithms had been...

My primary concern is that PF users should try to comply with any license conditions, so 1 is much less important and 2 is not a valid excuse. Obviously the original fault lay with the Facebook poster, but as this was obviously XKCD and I was aware of the license (as I have used other excellent...

The terms of use for the XKCD website mean you should provide a link or give credit. That's XKCD 2848, "Breaker Box", https://xkcd.com/2848/

The triple-decker bus is the "Knight Bus" from the Harry Potter movies; there is one which can be viewed at the Warner Bros Studio Harry Potter tour, where we took our children some years ago: https://beingkinetic.com/2024/06/29/harry-potter-behind-the-scenes-the-knight-bus/ It doesn't look as...

According to Spacenews: My non-expert guess would be that some temperature parameter was exceeded as a result of the longer burn needed for the heavier XL version.

I always wondered how they managed "synchronous orbit above the south pole of the planet".

Thanks very much - that's much better than anything I found so far. But it's a lot to digest to get the value of a simple constant! Their model for the method of acceleration seems very contrived, being a charge distribution inside the shell. I know that constant linear acceleration in free...

Linear frame dragging is the effect predicted by General Relativity that if a gravitational source is accelerated, this produces a small gravitational induction effect on other objects which tends to accelerate them in the direction of the source acceleration. The induced acceleration is a...

The bus is turning towards the left of the picture, which will take it in a loop round the station. The "Look Right" bit is one-way from the right.

I'm somewhat distracted from the mindblowing concept of a Braille gearstick by the weird arrangement of the gears, assuming I'm reading them correctly: 465 R123

I don't know if this applies elsewhere, but in the UK it is common for a trade vehicle to display a notice saying something like "No tools left in this vehicle overnight" or "Nothing of value left in this vehicle overnight" to discourage any attempts to break into the unattended vehicle. This...

This is a consequence of RFC 2324, dated April 1 1998: https://datatracker.ietf.org/doc/html/rfc2324 418 I'm a teapot Any attempt to brew coffee with a teapot should result in the error code "418 I'm a teapot". The resulting entity body MAY be short and stout. The more serious-minded...

I ran into this problem recently and found this thread. I was going to say that next week was last week, but I guess one could argue that it's never next week. Hoping for a fix soon!

I mean that if you have an equilateral triangle inside a circle inside a triangle, the larger triangle is four times the area of the smaller one, and that is clear from the ratios if you rewrite ##\frac{\sqrt{3}\pi}{9}## as ##\frac{\pi}{3\sqrt{3}}## for consistency with the other ratio. The...