View Deneb, one of the most distant stars
2 comments Print Me Email to FriendTonight is Sunday, May 10 2009
The star Deneb – visible now by mid-evening – is one of the most distant of the bright stars. When you gaze at this star, you are gazing across a distance of 1,500 light-years away, according to the Observer’s Handbook. Meanwhile, Wikipedia places Deneb’s distance at 3,200 light-years.
Why the difference? It might relate in part to the way that science itself is done. Science is not a body of facts. It’s a process. Different astronomers or teams of astronomers occasionally try to improve on published distance estimates to the stars, and their various estimates are then published and passed along.
The distance to Deneb is estimated by stellar parallax, whose basic principle you can demonstrate to yourself by holding a finger in front of your nose and gazing at it with one eye closed, then the other eye closed. When you do this, you see your finger appear to jump from side to side with respect to background objects. If you hold your finger farther from your nose, it’ll appear to jump a smaller distance.
As Earth orbits the sun, astronomers can measure the locations of stars against the starry background, first from one side of Earth’s orbit and then – six months later – from the opposite side. The shift of stars due to parallax is exceedingly subtle, however, and subject to errors, which you can read about on Wikipedia’s parallax page.
I read that Deneb was too far away to determine it’s distance by paralax, so they have to do it by stellar type vs brightness, but Deneb is a variable star, thereby producing the mixed results.
okay, so im new to this site, and im fascinated by all the stuff i just learned in 5 minutes. and this comment is out of place but i couldnt see how to post it on the last page. so about dark matter and that the theory of space conastantly expanding. when it expands, where does it expand into, like is there a boundary line to where space stops? and that, that line keeps growing? like for example: think of space as a city, and the city limits is where space stops right? and the limits keep expanding due to dark matter, so what if something steps out of the line, where does it go? when the city limits grow, it grows on land, space grows on….nothing?
Please answer, many thanks.