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.
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.
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.