You're right that we have precise ways to say this, but people like seeing bigger numbers rather than smaller ones, and most people aren't "precise" about anything.

Consider something that weighs half as much. It's 50% lighter ... 0.5 times lighter.

It's a relative metric, not an absolute one. And since they're using the word "lighter" (i.e. less massive) it means that they're talking about the reciprocal of mass.

I.e. 1/5 the mass = 5 times "lighter"

If something is 50% the mass of something else, you could say the the heavier one is twice as heavy as the light one. Which means that the light one is two times "lighter" than the heavy one.

But I agree with your sentiment, relative comparisons of reciprocals is confusing at the best of times.

Keep in mind that you cannot copyright ideas. You copyright the specific implementation of those ideas. So simply mentioning Zaphod Beeblebrox doesn't trigger anything to do with copyright, but if you had a word for word introduction of Zaphod Beeblebrox copied straight from Hitchhiker's Guide that would be a problem.

Then after that you can normally have "de minimus" use, where you can use a small portion (think quotes, short phrases etc). As long as your work can't be used as a replacement for the original then you are normally in the clear (legally speaking, as far as copyright goes).

But none of this goes into trademark law, but that's a whole other thing and are generally easier to avoid too (e.g. don't use the word "coke" to sell your drink).

TL;DR: As long as the AI doesnt spit out a verbatim copy of the original, and then if you copied it verbatim from the AI, then you'd be in trouble.

I am not a lawyer, just a dude interested in copyright law.

This is the second time I've seen Kagi referenced with their summariser. It looks super useful, and the fact their summary references their points is just spectacular.

My only concern is around running out of searches with their basic plan.

The ground noise is expected to be around 60 dB(A), about 1/1000 as loud as current supersonic aircraft. This is achieved by using a long, narrow airframe and canards to keep the shock waves from coalescing.[4] It should create a 75 Perceived Level decibel (PLdB) thump on ground, as loud as closing a car door, compared with 105-110 PLdB for the Concorde.[5] Wikipedia

Cool. A car door closing is far more acceptable than thinking you're being bombed. But yeah, the nose on it is really long. Considering that this experimental craft can only carry a pilot, any kind of passenger craft using the same technique would have to be absolutely enormous.