Orion Nebula Gets New Milepost Marker, Now Closer

twilight30 writes "Discovery News is reporting that 'One of the most famous and scrutinized heavenly objects is 10 to 20 percent closer than we thought, say two teams of radio astronomers who have made some of the most precise cosmic distance measurements ever, with a telescope nearly as big as Earth. The Orion Nebula is the closest major stellar nursery to Earth, so it has been heavily studied to learn about the lives of stars. Its distance from Earth, however, has long been a matter of uncertainty, with an estimate made about 25 years ago in need of revision.'"

Comments

Re:..with a telescope _AS BIG AS the EARTH" ?

[Anonymous Coward]

It's an interferometer. It's not one telescope the size of earth but many smaller telescopes each collecting samples along a line with a length of about the diameter of Earth. The samples can be processed to give a picture with the resolution of a telescope the diameter of Earth (but it still only captures a small amount of em waves).

Re:You thieving bastard!

[Mahjub Sa'aden]

Well, frankly, I just made a bunch of stuff up.

Unlike String Theory, a rigorously testable... oh wait.

Re:Three Dimensional Object

[CaptainPatent]

Aren't they measuring the distance to stars within a three-dimensional object? I would guess that they could pick two stars that appear close together along our line of sight and come up with wildly different distances. Now perhaps if they measured the distance to one of the Trapezium stars (a very bright formation thought to lie at the "heart" of the nebula) they could come up with some meaningful measurement of distance. Just thought of something else. Let's find a really large repository for data and create a three-dimensional map of the nebula. Don't try to shove this single star data down my throat! It is true that the nebula is three dimensional, but it is nowhere near 1/10th the distance from earth to the orion nebula. The margin of error associated with the "front" of the nebula with the "back" or "center" of the nebula is a fraction of a fraction of a percent. (and I purposely used relative terms to demonstrate where error can lie)

Additionally, they did not use line of sight. They were using radio telescopes making them able to "see" the star at the center of the nebula without necessarily having a true line-of-sight.

Re:..with a telescope _AS BIG AS the EARTH" ?

[jnik]

Actually, we've been doing it for a decade.

Re:"a telescope nearly as big as Earth"

[glavenoid]

Wrong again. The 2 points, ~200 million miles apart were used as points in a measure of parallax. The virtual aperture of the VLBA scope is ~5000 miles diameter, which isn't *quite* "nearly as big as earth". Still a pretty big aperture, even though it's not a complete circular area, the resolution provided is apparently sufficient to measure the stellar (nebular?) parallax wrt M42.

What I find more interesting in this article is the close relationship alluded to between the trapezium and the nebula...

Re:Stellar parallax?

[glavenoid]

Yep. That's exactly what it is. Not exactly revolutionary, but interesting nonetheless...