0
Usenet Posted 23 years ago
Usage
Novel word: jet-year
From the NY Times:
A Measurement Whose Time Has Come
By AMIR D. ACZEL
Published: September 9, 2003
With all eyes on Mars, this may be the right time to demystify distances used in astronomy.
Astronomers have several different measures of distance in space, and all of these are puzzling to the general public and even confuse some scientists.
The distance to the Sun is defined as one astronomical unit, or A.U. It is about 90 million miles. The distance to Mars right now, although it is moving away from Earth again, is about 34 million miles, which is 0.4 of an astronomical unit.
This is fine, and the average distances to the other planets are all several A.U.'s (5 for Jupiter, 9 for Saturn, 39 for Pluto).
But when we go to the nearest star, astronomers suddenly switch the unit of distance on us. Distances to the stars are measured in light-years. One light-year is the distance light travels in one year, about six trillion miles.
Most people do not have an intuition about the light-year. At 186,000 miles per second, a ray of light will go around the world a little more than seven times in one second. But to expand to the distance light travels in a year, one would have to multiply this number by 60 seconds in a minute, 60 minutes in an hour, 24 hours a day, and 365 days a year.
The nearest star, Alpha Centauri, is 4.2 light-years away, about 25 trillion miles. Go farther, and astronomers change the unit of measurement again. Now they talk about a parsec (about 3.26 light-years) and the megaparsec, which is a million times greater, or
3.26 million light-years.
No wonder few people have a good feel for astronomical distances.
I suggest a new unit of measurement, which I call a jet-year. A jet-year is just what it sounds like: the distance a jet travels in one year, flying nonstop.
People who have flown on airplanes have a very good intuition for what a jet-year is. At roughly 600 miles an hour, a jet travels 5 1/4 million miles a year. Now, the distance to Mars these days is about six jet-years.
A pilot or air crew member who has worked for 14 or 15 years has already traveled the distance to Mars. A crew member who has served for 40 years and is about to retire has traveled the distance to the Sun, which is about 17 jet-years.
Now, the same intuitive unit of measurement can work for the stars as well.
Alpha Centauri, our nearest neighbor, is 4.7 million jet-years away. This measurement gives us good intuition about the distance to the nearest star: if you flew in an airplane nonstop for a little under five million years, you would get to the nearest star.
Sirius is about 9.5 million jet-years away, and the center of our galaxy is about 30 billion jet-years away.
To go to the nearest neighbor to our Milky Way galaxy, the Great Galaxy at Andromeda, which is 2.2 million light-years away, would take about 2.5 trillion jet-years. The Moon, however, is a mere two weeks away by jet, or 0.04 jet-years.
So next time you look up at that beautiful red dot in the evening sky, think of it as being as close as six years on your favorite airline.
Charles Riggs
Email address: chriggs>at>eircom>dot>net
A Measurement Whose Time Has Come
By AMIR D. ACZEL
Published: September 9, 2003
With all eyes on Mars, this may be the right time to demystify distances used in astronomy.
Astronomers have several different measures of distance in space, and all of these are puzzling to the general public and even confuse some scientists.
The distance to the Sun is defined as one astronomical unit, or A.U. It is about 90 million miles. The distance to Mars right now, although it is moving away from Earth again, is about 34 million miles, which is 0.4 of an astronomical unit.
This is fine, and the average distances to the other planets are all several A.U.'s (5 for Jupiter, 9 for Saturn, 39 for Pluto).
But when we go to the nearest star, astronomers suddenly switch the unit of distance on us. Distances to the stars are measured in light-years. One light-year is the distance light travels in one year, about six trillion miles.
Most people do not have an intuition about the light-year. At 186,000 miles per second, a ray of light will go around the world a little more than seven times in one second. But to expand to the distance light travels in a year, one would have to multiply this number by 60 seconds in a minute, 60 minutes in an hour, 24 hours a day, and 365 days a year.
The nearest star, Alpha Centauri, is 4.2 light-years away, about 25 trillion miles. Go farther, and astronomers change the unit of measurement again. Now they talk about a parsec (about 3.26 light-years) and the megaparsec, which is a million times greater, or
3.26 million light-years.
No wonder few people have a good feel for astronomical distances.
I suggest a new unit of measurement, which I call a jet-year. A jet-year is just what it sounds like: the distance a jet travels in one year, flying nonstop.
People who have flown on airplanes have a very good intuition for what a jet-year is. At roughly 600 miles an hour, a jet travels 5 1/4 million miles a year. Now, the distance to Mars these days is about six jet-years.
A pilot or air crew member who has worked for 14 or 15 years has already traveled the distance to Mars. A crew member who has served for 40 years and is about to retire has traveled the distance to the Sun, which is about 17 jet-years.
Now, the same intuitive unit of measurement can work for the stars as well.
Alpha Centauri, our nearest neighbor, is 4.7 million jet-years away. This measurement gives us good intuition about the distance to the nearest star: if you flew in an airplane nonstop for a little under five million years, you would get to the nearest star.
Sirius is about 9.5 million jet-years away, and the center of our galaxy is about 30 billion jet-years away.
To go to the nearest neighbor to our Milky Way galaxy, the Great Galaxy at Andromeda, which is 2.2 million light-years away, would take about 2.5 trillion jet-years. The Moon, however, is a mere two weeks away by jet, or 0.04 jet-years.
So next time you look up at that beautiful red dot in the evening sky, think of it as being as close as six years on your favorite airline.
Charles Riggs
Email address: chriggs>at>eircom>dot>net
Top answer
[nq:1]From the NY Times: A Measurement Whose Time Has Come By AMIR D. ACZEL Published: September 9, 2003 With all ... [/nq] I am not extensively informed on astronomy and I agree that, to me as a layman, the many different ways of measuring the distances are confusing.
- [nq:1]From the NY Times: A Measurement Whose Time Has Come By AMIR D.
- ACZEL Published: September 9, 2003 With all ...
- [/nq] I am not extensively informed on astronomy and I agree that, to me as a layman, the many different ways of measuring the distances are confusing.
- But I imagine that professionals in the area have their reasons for the different ways of expressing the distances.
- Beyond that, although the speed of passenger jets has remained constant for a couple of decades, large changes are possible and probable in the near future.
Get the Weekly English Kit 📬
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
40 Answers
0
[nq:1]From the NY Times: A Measurement Whose Time Has Come By AMIR D. ACZEL Published: September 9, 2003 With all ... red dot in the evening sky, think of it as being as close as six years on your favorite airline.[/nq]
I am not extensively informed on astronomy and I agree that, to me as a layman, the many different ways of measuring the distances are confusing. But I imagine that professiona
I am not extensively informed on astronomy and I agree that, to me as a layman, the many different ways of measuring the distances are confusing. But I imagine that professiona
00
[nq:1]From the NY Times: A Measurement Whose Time Has Come By AMIR D. ACZEL Published: September 9, 2003[/nq]
(Deleted text of NYT article stolen by the "Buddhist")
Is it part of Buddhism to steal copyrighted articles, instead of as civilized non-Buddhists do just posting the URL?
Buddha sucks. So do his wacky faux-followers.
Reinhold (Rey) Aman, Ph.D.
"Ex-jailbi
(Deleted text of NYT article stolen by the "Buddhist")
Is it part of Buddhism to steal copyrighted articles, instead of as civilized non-Buddhists do just posting the URL?
Buddha sucks. So do his wacky faux-followers.
Reinhold (Rey) Aman, Ph.D.
"Ex-jailbi
00
} From the NY Times:
}
} A Measurement Whose Time Has Come
} By AMIR D. ACZEL
}
} Published: September 9, 2003
(The bulk of a presumably copyrighted article snipped.)
} A pilot or air crew member who has worked for 14 or 15 years has } already traveled the distance to Mars. A crew member who has served } for 40 years and is about to retire has traveled the distance
}
} A Measurement Whose Time Has Come
} By AMIR D. ACZEL
}
} Published: September 9, 2003
(The bulk of a presumably copyrighted article snipped.)
} A pilot or air crew member who has worked for 14 or 15 years has } already traveled the distance to Mars. A crew member who has served } for 40 years and is about to retire has traveled the distance
00
the center of our
[nq:1]galaxy is about 30 billion jet-years away.[/nq]
...which earns enough FF points to get you 13,000,000,000,000 Round-The-World tickets. Not bad.
[nq:1]galaxy is about 30 billion jet-years away.[/nq]
...which earns enough FF points to get you 13,000,000,000,000 Round-The-World tickets. Not bad.
00
[nq:1]the center of our[/nq]
[nq:2]galaxy is about 30 billion jet-years away.[/nq]
[nq:1]...which earns enough FF points to get you 13,000,000,000,000 Round-The-World tickets. Not bad.[/nq]
Oops. I've just realised that in order to take advantage of all those free trips, you would also have to return from the centre of the galaxy. So you'd actually earn twice as many points and would t
[nq:2]galaxy is about 30 billion jet-years away.[/nq]
[nq:1]...which earns enough FF points to get you 13,000,000,000,000 Round-The-World tickets. Not bad.[/nq]
Oops. I've just realised that in order to take advantage of all those free trips, you would also have to return from the centre of the galaxy. So you'd actually earn twice as many points and would t
00
[nq:1]Oops. I've just realised that in order to take advantage of all those free trips, you would also have to ... for 26,000,000,000,000 RTW trips. You'd probably have to share them around your family if you wanted to use them up.[/nq]
Read the fine print, though: you'd probably have to use them all on a single day-trip to a limited selection of particularly crummy destina
00
[nq:1]The nearest star, Alpha Centauri, is 4.2 light-years away, about 25 trillion miles. Go farther, and astronomers change the unit of measurement again. Now they talk about a parsec (about 3.26 light-years) and the megaparsec, which is a million times greater, or 3.26 million light-years.[/nq]
Don't forget the attoparsec.
Gary G. Taylor * Rialto, CA
gary at donavan dot org / ht
Don't forget the attoparsec.
Gary G. Taylor * Rialto, CA
gary at donavan dot org / ht
00
[nq:1]This is fine, and the average distances to the other planets are all several A.U.'s (5 for Jupiter, 9 for Saturn, 39 for Pluto).[/nq]
The average distance to Mercury and Venus is pretty close to 1 AU.
David
The average distance to Mercury and Venus is pretty close to 1 AU.
David
00
[nq:2]This is fine, and the average distances to the other planets are all several A.U.'s (5 for Jupiter, 9 for Saturn, 39 for Pluto).[/nq]
[nq:1]The average distance to Mercury and Venus is pretty close to 1 AU.[/nq]
The average distance to any planet (except Earth) is about 1 AU. Assuming that all the orbits are circular(1), the average position of each planet coincides with the center o
[nq:1]The average distance to Mercury and Venus is pretty close to 1 AU.[/nq]
The average distance to any planet (except Earth) is about 1 AU. Assuming that all the orbits are circular(1), the average position of each planet coincides with the center o
00
[nq:1]The average distance to any planet (except Earth) is about 1 AU. Assuming that all the orbits are ... of the sun. And the average distance from Earth to the center of the sun is 1 AU, by definition.[/nq]
By this argument, it would seem that the average distance between the Earth and the moon (or between the Earth and me, come to think of it) is 1 AU. I think that there may be a flaw in t
By this argument, it would seem that the average distance between the Earth and the moon (or between the Earth and me, come to think of it) is 1 AU. I think that there may be a flaw in t
0
Related Questions