The Challenge of Relativistic Spaceflight
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The Challenge of Relativistic Spaceflight
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Re: The Challenge of Relativistic Spaceflight
#2I think he may have meant 1/12th rather than 1/2th of the speed of light, but I must say I'm very tempted now to start calling one half a "tooth" instead.
Re: The Challenge of Relativistic Spaceflight
#3I think he may have meant 1/12th rather than 1/2th of the speed of light, but I must say I'm very tempted now to start calling one half a "tooth" instead.
Maybe not "tooth", but why do we use the phrases "a third" and "a fourth" for fractions, but not "a second" for half?
Re: The Challenge of Relativistic Spaceflight
#4I think he may have meant 1/12th rather than 1/2th of the speed of light, but I must say I'm very tempted now to start calling one half a "tooth" instead.
[deleted]
Re: The Challenge of Relativistic Spaceflight
#5I think he may have meant 1/12th rather than 1/2th of the speed of light, but I must say I'm very tempted now to start calling one half a "tooth" instead.
Maybe not "tooth", but why do we use the phrases "a third" and "a fourth" for fractions, but not "a second" for half?
Perhaps because of the potential confusion with "a second" being used to mean "another" i.e. 2X rather than 1/2X.
e.g. I could eat a second pizza
Do I mean another pizza or half a pizza?
[OK it should be phrased as "a second of a pizza" - but that is rather close to "a second pizza"]
Re: The Challenge of Relativistic Spaceflight
#6Earlier quoted context omitted.
Maybe not "tooth", but why do we use the phrases "a third" and "a fourth" for fractions, but not "a second" for half?
Perhaps because of the potential confusion with "a second" being used to mean "another" i.e. 2X rather than 1/2X. e.g. I could eat a second pizza Do I mean another pizza or half a pizza? [OK it should be phrased as "a second of a pizza" - but that is rather close to "a second pizza"]
You can say "a third of a pizza" and not be confused though, so there's no difference in saying "a second of a pizza" if that were indeed an accepted use of the word.
Re: The Challenge of Relativistic Spaceflight
#7I think he may have meant 1/12th rather than 1/2th of the speed of light, but I must say I'm very tempted now to start calling one half a "tooth" instead.
No, he meant 1/2 the speed of light. The speed of light is 299,792,458 m/s, so about 300,000 kilometers per second. Half that is the speed he mentioned.
Re: The Challenge of Relativistic Spaceflight
#8Earlier quoted context omitted.
Maybe not "tooth", but why do we use the phrases "a third" and "a fourth" for fractions, but not "a second" for half?
Perhaps because of the potential confusion with "a second" being used to mean "another" i.e. 2X rather than 1/2X. e.g. I could eat a second pizza Do I mean another pizza or half a pizza? [OK it should be phrased as "a second of a pizza" - but that is rather close to "a second pizza"]
Not that I have a better answer, I believe the phrase "a third of a pizza" is just as confusing.
Re: The Challenge of Relativistic Spaceflight
#9I think he may have meant 1/12th rather than 1/2th of the speed of light, but I must say I'm very tempted now to start calling one half a "tooth" instead.
Maybe not "tooth", but why do we use the phrases "a third" and "a fourth" for fractions, but not "a second" for half?
Because we should be saying "one third", "one fourth", etc., but it's a little bit faster to say "a third".
Re: The Challenge of Relativistic Spaceflight
#10Earlier quoted context omitted.
Perhaps because of the potential confusion with "a second" being used to mean "another" i.e. 2X rather than 1/2X. e.g. I could eat a second pizza Do I mean another pizza or half a pizza? [OK it should be phrased as "a second of a pizza" - but that is rather close to "a second pizza"]
Not that I have a better answer, I believe the phrase "a third of a pizza" is just as confusing.
You are, of course, quite correct.
I should make a mental note to comment on HN while actually focusing on something else..... :-)