Jeanway 0 Posted April 20, 2004 I believe it's the distance light travels in one year. Right nik? WHEW! Share this post Link to post Share on other sites
nik 0 Posted April 20, 2004 Very close. The distance light travels in a year is a light year. Question: If light travels 2.99*10^8 m in one second, how far does it go in a year? A parsec is 3.26 light years. How do we get this? Parsec is a term invented by the astronomers. It's an abbreviation for "parallax of one second of arc" or something like that. We can measure distances by looking at an object when the earth is on one side of the sun, then when the earth is on the other, and then then see what the angle is between measurements. It turns out that an object one parsec away will result in a differenc in angle of one arcsecond, or 1/60 or 1/60 or a degree. Try this: go to one side of your yard, face the street, and look at your mailbox. Note how you have to "angle" your head to see the mailbox (assuming your mailbox is on the street like mine). Walk to the other side of your yard, still facing the street, and look at your mailbox. You have to look at a different angle. That's how parsec works. Interesting Note: The known universe it about 20 billion light years in radius. Pretty big, huh? Make sense? Share this post Link to post Share on other sites
Jeanway 0 Posted April 20, 2004 (edited) I disagree, nik, I think it's immeasurable. That's just my opinion. The distance light travels in one year, yes, a Parsec is X 3 :huh: Edited April 20, 2004 by Jeanway Share this post Link to post Share on other sites
nik 0 Posted April 20, 2004 I disagree, nik, I think it's immeasurable. That's just my opinion. The distance light travels in one year, yes, a Parsec is X 3 :huh: OH! THE UNIVERSE! I thought you were talking about a parsec being immeasurable. Well.... you might be right.... Share this post Link to post Share on other sites
trekzone 0 Posted April 21, 2004 nik, thats great thanx..... Share this post Link to post Share on other sites
nik 0 Posted April 22, 2004 nik, thats great thanx..... Of course! ::bows low:: Share this post Link to post Share on other sites
WEAREBORG4102 0 Posted April 22, 2004 I disagree, nik, I think it's immeasurable. That's just my opinion. The distance light travels in one year, yes, a Parsec is X 3 :) well that's not true according to some models of the universe... according to the Big Bang theory, the universe will stop expanding and will finally start contracting causing Big Crunch.... Share this post Link to post Share on other sites
nik 0 Posted April 23, 2004 I disagree, nik, I think it's immeasurable. That's just my opinion. The distance light travels in one year, yes, a Parsec is X 3 B) well that's not true according to some models of the universe... according to the Big Bang theory, the universe will stop expanding and will finally start contracting causing Big Crunch.... I just heard a pretty good talk a few days ago arguing that the universe will not only continue to expand, but accelerate (omega>1 for you cosmologists, or rather, non-zero lambda). I was always skeptical, but now, I don't dismiss the idea anyway. Share this post Link to post Share on other sites
Jeanway 0 Posted April 25, 2004 Just watched ' The Wrath of Kahn" saw it before but it was a while ago, 'Genisis' looked like a mini-'Big Bang', no? :blink: Share this post Link to post Share on other sites
Doc Niel 0 Posted May 4, 2004 See my post on book Parsecs is covered and nik is correct in what it stands for and how it is used. I believe the folmula is in there also. If you give me a day I'll find it....... Share this post Link to post Share on other sites
