Harshaw

Can someone explain this definition to me?

Main Entry: par·sec
Pronunciation: 'pär-"sek
Function: noun
Etymology: parallax + second
: a unit of measure for interstellar space equal to the distance to an object having a parallax of one second or to 3.26 light-years

I know it should probably be easy, but I'm just not catching it?

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stingc

Hold a finger in front of yourself, and look at it with one eye and then the other. It will appear to move. That is parallax.

Similarly, stars appear to move when looked at from one end of the earth's orbit versus half a year later on the other side of the sun. There's more of a motion the closer the star is.

One parsec is the distance to a star that will move one arcsecond on the sky (1/3600 degree) over the earth's orbit.

stevie667

failing that, watch star trek.

didn't know about the parralax thing though, learn something new everyday.

asaris

And, as the definition also notes, that distance happens to be equal to 3.26 light-years.

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"Die Deutschen meinen, daß die Kraft sich in Härte und Grausamkeit offenbaren müsse, sie unterwerfen sich dann gerne und mit Bewunderung:[...]. Daß es Kraft giebt in der Milde und Stille, das glauben sie nicht leicht."

"The Germans believe that power must reveal itself in hardness and cruelty and then submit themselves gladly and with admiration[...]. They do not believe readily that there is power in meekness and calm."

-- Friedrich Nietzsche

Dilbert1234567

wow i learn new things everyday

COOL

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"Love is not finding the perfect person, but learning to see an imperfect person perfectly." -Sam Keen

SixEdxMia

Damn,Go stingc,I had an idea but no way to explain it whatsoever.
Tfp totally helps me to learn new things all of the time.
Meow.

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jwoody

My favourite resource for space related knowledge is the Starchild website.

The Starchild explanation of a light year for kids (but still too long to cut & paste):-

http://starchild.gsfc.nasa.gov/docs/...uestion19.html

Munku

Parallax effect. Man something from astronomy coming into use!