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

"a telescope nearly as big as Earth"

[Anonymous Coward]

That's nothing. They needed a computer nearly the size of Jupiter to process the data.

Re:"a telescope nearly as big as Earth"

[opus]

The VLBA was aimed at one of the few radio-wave emitting stars in Orion, which was viewed twice in a single a year. The almost 200-million-mile width of Earth's orbit around the sun allowed the VLBA to serve as one eye, then again as the other eye six months later.

Wouldn't that be a telescope 200-million-miles wide, using the same poetic license that led them to say they used a telescope as big as the earth.

Re:"a telescope nearly as big as Earth"

[mstahl]

Maybe we'll get a better answer than "42" this time then!

Re:"a telescope nearly as big as Earth"

[Anonymous Coward]

Saying that the telescope was "nearly as big as Earth" is dead wrong. The effective aperture of the telescope, for this purpose, is twice the radius of the orbit of Earth around the sun, or almost 200 million miles. Gotta love those science reporters...

Re:"a telescope nearly as big as Earth"

[Nimey]

How many Ping-Pong balls & how many Libraries of Congress, please.

Re:"a telescope nearly as big as Earth"

[Propaganda13]

The answer was fine (I still like the base 13 idea even if Douglas didn't), but the Ultimate Question Of Life, the Universe, and Everything could be a little more Ultimate.

Re:"a telescope nearly as big as Earth"

[SnoopJeDi]

Not to mention if you consider that the awful comparison seems to suggest Gravitational Lensing.

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:"a telescope nearly as big as Earth"

[nschubach]

Pfft.. they measure things here in America on Football fields, Empire State Buildings and Statues of Liberty.

Re:"a telescope nearly as big as Earth"

[Gigaflynn]

43?

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

[syrinje]

I wonder what they mounted it on! And yes, I did not RTFA - this is /., you insensitive clod

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

[jnik]

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

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

[ribman]

Well that's very clever sonny, but it's telescopes all the way down.

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

[fellip_nectar]

/usr/local ?

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

[RogerWilco]

We've been doing radio-interferometry already quite a bit longer, I work at the WSRT, which became operational in 1970.
http://www.astron.nl/p/WSRT2.htm

From http://www.aoc.nrao.edu/~cwalker/talks/aaas_2001/tsld007.htm, it looks like VLBI is already 40 years old.
        * 1967 First VLBI
                    o Jan: U. Florida - 1 kHz on Jupiter bursts
                    o Apr: Canadian group 448 MHz, 1 MHz bw
                    o May: NRAO-Cornell 610 MHz, 360 kHz bw
                    o June: MIT-NRAO-Cornell OH masers

        * 1968 Jan. First multi-station observations
                    o Already global - includes Onsala, Sweden

        * 1969 Oct. First US/USSR observations

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

[jnik]

Um, I was replying to a comment on having to "start" doing space VLBI and specifically linked the WP topic on space VLBI. I've done the NRAO "boot camp" and published work from VLA data; I'm aware of the history of radio interferometry.

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

[daeley]

Stupid machine. Oh, wait a minute -- this isn't the Interferometer, it's the Telescope Exaggerator!

Mm-hi.

Re:question:

[The_Mystic_For_Real]

Or maybe the nebula is just moving 20% closer every six months!

Fortunately it will get caught in Xeno's paradox.

Re:question:

[Mahjub Sa'aden]

Very good question. I can only reply by pointing to the scalar polarisation effect negating the red/blue doppler shift you mention. Couple that with Newtonian dynamics in question, and you have a very good correction mechanism along the theta axis. Not to mention that the wibble-wobble isn't nearly as unstable as once thought.

Wow, I'm full of shit.

Re:question:

[siddesu]

the sun travels around the galactic center at about 20km/s. even assuming than sun and orion nebula travel away from each other at this speed, for 6 months they'd have moved away at about 6 billion km. this is about 0.00068 light years. since the distance is estimated at 1250+ l.y. give or take 50-60, the error due to the relative movement of the two objects seems accounted for.

Three Dimensional Object

[ks*nut]

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!

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:Three Dimensional Object

[nschubach]

But if you have two points of Earth in it's rotation and one point of star you should be able to triangulate the distance. So tracking one star should be enough to give you a guess. I assume they picked multiple stars to get an average for all bodies in question. I actually would have been interested to run the photos (or radio information as is the case) and the progression information from about every month for the six month rotation through a program to compare stars movement and form an average on more than a couple stars.

Actually, is anyone recording star positions and comparing them on a regular basis? I don't mean single bodies like this, but having Hubble and/or other telescopes capture images at increments and store the point information. What would be interesting to me would be to build up a sort of 3D image of the visible solar system around us using that data.

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.

summary

[evwah]

how the summary should have gone: /summary
the orion nebula is ___ light years away /end summary

end of story :P

Re:summary

[Tuoqui]

But then there would be no room for any 'in soviet russia' jokes or similar.

Expanding Universe...

[CODiNE]

Let's just wait a little longer and we won't have to reprint all those textbooks.

Re:Expanding Universe...

[CODiNE]

How I wish you hadn't replied AC.

Next Apolcalyptic Movie

[mrbluze]

"Impacted" Plot: In the year 2050 the Earth almost crashes into the Orion Nebula, only to be rescued from destruction by two nerdy radio astronomers from Parkes Observatory in the middle of nowhere in Australia, who, whilst trying to find a cure for constipation from eating too much McDongles(TM) Impact McBurglettes, find that by injecting massive amounts of First Fleet Enema into the Nebula they can cut a path through the Nebula. The romantic part of the movie is where the local district nurse shows up and a tense love triangle is set up between herself and the astronomers.. etc..etc

Re:question:

[servognome]

but if the Orion Nebula is undergoing rapid beta expansion, the measurements would be invalid. I don't know of any way to correct for this phenomenon...

Release it and figure it out in Service Pack 1.

Closer than we thought...

[LordP]

Measured incorrectly, or has the Orion Nebula just been sneaking closing over the last 25 years?

Re:Closer than we thought...

[jamesh]

Hmmm... 10 to 20 percent closer in 25 years... (gets out calculator)... that means that it will be here in 125 to 250 years!!!

I for one welcome our invading Orion Nebula overlords.

Re:Closer than we thought...

[davburns]

Bower and his colleagues came up with a distance of 1,270 light-years, give or take 76 light-years. That compares with the previous estimate of 1,565 light-years, give or take 266.

There's still overlap in the uncertainties of the measurements. So it wasn't incorrectly measured, just measured with a 17% error margin. The only ones who are incorrect are the people who quote the estimate without including the uncertainty.

Re:Closer than we thought...

[Mushdot]

Maybe it's like that scene in The Holy Grail, where the Knight is running toward the castle and not getting any closer.

Then all of a sudden, 'ahaaaa!' he appears at the gate and stabs the guards.

Re:Closer than we thought...

[Shadowlore]

you may a point, but I'm not entirely sure.

Telescope warning

[autophile]

Warning: Objects in telescope are closer than they appear.

--Rob

Re:question:

[Anonymous Coward]

How could they not have realized that we've actually travelled in "Hypertime" and all their measurements from 25 years are all vaild ?
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/10/10/scitime110.xml

That's easy...

[SteveFoerster]

...four elephants standing on the back of a turtle.

Re:question:

[Anonymous Coward]

You just don't get it! All they're doing now is using Excel 2007 to calculate the distance. No wonder they're seeing this anomaly!

Translation

[Anonymous Coward]

>One of the most famous and scrutinized heavenly objects is 10 to 20 percent closer than we thought

In other words, Natalie Portman moved from Boston to New York.

Re:question:

[budgenator]

FTA they measure the paralax six months apart, comparing to know pulsars to get the results; so while a layman I don't think doppler enters into the observations.

Re:question:

[christurkel]

If we reverse the tachyon field and reorient the warp field along a negative subspace axis, your still full of shit.

Re:question:

[Mahjub Sa'aden]

Apparently that manoeuvre also eliminates apostrophes. Who knew.

Stellar parallax?

[langelgjm]

Correct me if I'm wrong, but isn't this basically measuring stellar parallax, but instead of using visible light and optical telescopes against a background of stars, they are using radio waves and radio telescopes against a background of quasars?

Re:Stellar parallax?

[glavenoid]

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

Objects in mirror are closer than they appear!

[kcbanner]

It *was* nearly the size of Earth after all!

Lens-shaped?

[NonCow]

Isn't the galaxy *lens*-shaped ... ;)
Humour Disclaimer - yes, no medium change, therefore a refractive index ratio of 1 ... unless you count stars as being "like atoms" in that they are *relatively* small "solid" object with large spaces in between them, suspended in a "space". Then therefore we *do* have a medium change and a ratio of refractive indices: light passes from an area of space populated by N stars / lightyear^3 to an area of space with M stars / lightyear^3 where N << M, and the N populated area is lens shaped, therefore visual distortion!
[cough]ull$hit! :)
ANonCow
---
Sir Bedevere: ...and that, my liege, is how we know the Earth to be banana shaped.
King Arthur: This new learning amazes me, Sir Bedevere. Explain again how sheep's bladders may be employed to prevent earthquakes.

MOD PARENT UP

[glavenoid]

Sheesh.. Doesn't anyone here understand the Messier catalogue?? If 42 has ever had a more apropos moment in recent /. convo, I'll eat my M104 with salsa...

Re:MOD PARENT UP

[mstahl]

No one gets it :(

Re:question:

[Belacgod]

In Soviet Russia, shit fills you!

Wait...In Soviet Russia, you fill shit!

Ahh hell, I for one welcome our Orionian overlords a bit sooner.

Oh My GOD!

[grumling]

It's coming right at us!

Looks like I picked the wrong week to stop sniffing glue...

-Steve McCroskey

Re:question:

[SEWilco]

Or maybe the nebula is just moving 20% closer every six months!

Don't be silly. It says 20% closer since 25 years ago. So it will be here in 100 years, as in 25 years it's traveled one-fifth of the way, so it only has four more fifths to travel.
Dibs on the Trapezium.

Re:question:

[barakn]

What a load of crap. The study didn't use doppler shift to measure the distance, it used parallax. Beta expansion is a made-up term (in terms of astronomy), and the "counter planar" rotation is also imaginary. But the biggest clue was that Anonymous Coward was supplying the information.

Wow!

[sunspot42]

The Galactica is closer to Earth than we thought!

Combine the measurements for increased accuracy

[SirBruce]

The old measurement was 1,565 +/- 266 LY.

Bower's new measurement is 1,270 +/- 76 LY.

Assuming both error bars are correct, then by combining the two measurements we get between 1,299 LY and 1,346 LY.

Reid's new measurement is 1,350 +/- 23 LY.

So combining again, we can conclude the Orion Nebula is between 1,327 and 1,346 LY away, or 1,336.5 LY +/- 9.5 LY.

Re:Combine the measurements for increased accuracy

[moosesocks]

You can't combine statistics like that.

We have no idea of the accuracy of either measurement (specifically because we don't actually know how far away it is).

What we do know is that the new measurement is more precise. It's probably also safe to assume that the new one's at least slightly more accurate.

The troubling bit is that the median of the new measurement is considerably lower than the original, and lies outside of the error bars of the original estimate. This suggests that there's a good chance that one of the estimates is fundamentally flawed.

Re:Combine the measurements for increased accuracy

[AaronParsons]

That's not how you combine numbers with error bars. First, you do weighted average based on how small the error bars are: 1/(1/266+1/76+1/23) * (1565/266 + 1270/76 + 1350/23) = 1346 LY And then to find the error, you take the square root of the sum of the squares of all the errors in the final number that are introduced by the errors in the initial numbers: sqrt(1/(1/266+1/76+1/23) * ( (266/266)^2 + (76/76)^2 + (23/23)^2 ) = +- 7 light years.

Re:Combine the measurements for increased accuracy

[cdpage]

Based on the Potential Old Measurement and Bowers measurement, 1565 + 266 = 1299 1270 + 76 = 1346 Rieds new new is 1350 +/- 23 seems like they were not far off in the first place.

Re:Combine the measurements for increased accuracy

[HarvardAce]

Based on the Potential Old Measurement and Bowers measurement, 1565 + 266 = 1299 Are you a programmer for Excel 2007?

Re:Combine the measurements for increased accuracy

[cdpage]

I must be working for M$... still have yet to see a paycheck though. 1,831

Re:Combine the measurements for increased accuracy

[strikethree]

"So combining again, we can conclude the Orion Nebula is between 1,327 and 1,346 LY away, or 1,336.5 LY +/- 9.5 LY."

Since your numbers are not scientific, you should just round to 1337 LY. :P

strike

Why is this insightful ?

[aepervius]

At best it should be only funny.

Orion nebula distance : 1500 light years. 10% of this : 150 light years. IF you suppose that it is getting closer by that distance, then it means roughly 5+ light years for every years for 25 years. Nothing goes at a speed of 5+ light years per year. At best all physical stuff can only goes at near c (1 light year per year ;)...) with photon going at exactly c in vacuum. And we would remark the relativistic effect, at those speed with such an enormous mass... (is that even possible?)

So no, we are pretty sure the orion nebula has not been sneaking closer (sic) behind our back for such distance difference.

nah, not true

[someone1234]

This won't save your ass when the distance is only 1mm :)

Re:question:

[DeadChobi]

Not if we take the limit as the number of lengths approaches infinity. Screw you, Xeno! I know calculus!

Re:question:

[WeeLad]

I think I've heard this before, but it rhymed just a bit more

"Just remember that you're standing on a planet that's evolving
And revolving at nine hundred miles an hour,
That's orbiting at nineteen miles a second, so it's reckoned,
A sun that is the source of all our power...."

Re:question:

[DeadChobi]

I'd think Beta expansion refers to a term in one of the Lorentz transformations for Special Relativity. Still, I don't know what the hell he's talking about so you're probably right.

Re:You thieving bastard!

[Bastard of Subhumani]

You think that's bad - it was the combination to my luggage!

Re:question:

[ImprovGuy]

Probably a typo, but the Sun has a circular orbit velocity of ~220 km/s, not 20.

http://adsabs.harvard.edu/abs/1986MNRAS.221.1023K

I'm writing my astrophysics thesis right now, so I have all kinds of literature references at my fingertips! Anyone want to know how to calculate the cross section of a neutralino and a sulphur atom? Hey, where did everyone go?

SP

[tonyreadsnews]

NED: Oh, no it's coming right for us. Jimbo: Quick Ned, the rocket launcher.

Re:question:

[siddesu]

typo in my ole physics book. that makes the max distance 0.068 l.y., still well within the margin of error even accounting for the large beta expansion and the wobbling due to galactic core protuberances.

Re:question:

[rebelcan]

Screw you, Xeno! I know calculus!

I'm tempted to use that as my new sig, but where would I put my current one?