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The Andromeda Nebula seems to be three times bigger than we thought it was.
It's diameter seems to be some 220.000 lightyears.
The Andromeda Nebula is part of the Milky Way and the closest Nebula to our own. Of which our Sun is not really an important star.
It lies some 2.000.000.000 lightyears from us.
Technically it is a galaxy not a nebula, although nebulosity is included within it, but "faint clouds" of stars/gas were refered to as "nebula" by Messier and others before the discovery of what they really were.
Some other info:
The Andromeda Galaxy, M31
The Andromeda galaxy, M31, is the nearest major galaxy to our own Milky Way galaxy. It is about twice the size of the Milky Way (old estimates = now we can include the 3,000 or so stars that used to be thought of a just part of M31's "halo" which is what scientists have used recently to revise the galaxy's size to triple what it was before), lies 2.5 million light years away, and is the most distant object that can be seen with the unaided eye. To find the Andromeda galaxy, first locate the Great Square of Pegasus using a sky map and then star-hop over to M31.
To the eye and in binoculars the Andromeda galaxy looks like a small, elongated "faint cloud." A modest telescope will show only the central portion of the galaxy as a featureless luminous glow. A very large telescope and good viewing conditions are required to see a hint of the underlying structure. However, even a small telescope will show that M31 is accompanied by two much smaller galaxies M32 and M110.
In the early part of the 20th century M31 was at the center of one of the most important discoveries in modern science. Early observers were not aware of the true nature of M31 and believed it to be a nearby gaseous nebula made up entirely of glowing gas. As a result, for many years M31 was known as the Great Andromeda Nebula (nebula is the Latin word for cloud). The development of long-exposure astronomical photography revealed the spiral structure of M31 and lead to the discovery of many more "spiral nebulae." The dynamic motion suggested by the shape of these objects lead some astronomers to believe that M31 was a solar system in the making. However, spectroscopic measurements revealed the Andromeda "nebula" was not a gaseous nebula at all but was in fact made up of a multitude of individual stars.
In 1923, Edwin Hubble found several Cepheid variable stars in photographic images of M31 taken with the 100-inch Mt. Wilson telescope. A Cepheid variable is a type of star that changes in brightness in a way that is directly related to the star's true brightness. By comparing the true brightness of these stars with their apparent brightness as seen from Earth, astronomers can calculate the distance of Cepheid stars. The Cepheids discovered in M31 enabled Hubble to establish that the "nebula" was not a nearby object but a galaxy far beyond the edges of the Milky Way.
Edwin Hubble went on to discover that the sky is full of galaxies all moving away from one another, thus revealing that the Universe is expanding.
Below an image showing the location of the galaxy.
Glittering stars. Distorted galaxies. A cluster of more than 100,000 stars. The celestial objects in this six-panel photograph are just a sampling of the more than 300,000 stars and the thousands of distant galaxies seen in the image of a small region of the Andromeda galaxy's halo, a spherical cloud of stars around the galaxy. The image was taken with the Advanced Camera for Surveys aboard NASA's Hubble Space Telescope.
This photograph shows some of the interesting details found in that image. The stars in these panels are located in Andromeda's halo. The galaxies seen in five of the panels represent some of the background galaxies located far beyond Andromeda. A few of them appear distorted, such as the curved red streak of material seen at top row, center. Their distorted shapes suggest that they collided with other galaxies. The white spherical object [bottom row, right] is a collection of more than 100,000 stars called a globular cluster, located in Andromeda's halo. Andromeda is located 2.5 million light-years from Earth.
Andromeda is approaching our galaxy at a rate of 670,000 miles per hour. Five billion years from now it may even collide with our Milky Way galaxy.
The members of the M31 halo science team are: T.M. Brown, H.C. Ferguson, E. Smith (STScI); R.A. Kimble, A.V. Sweigart (NASA/GSFC); A. Renzini (ESO); R.M. Rich (UCLA); and D.A. VandenBerg (U. of Victoria)
Sheesh Raven, you could host a whole other forum "astronomy" [confused] . You posted like mad! Anyways, thanks for the info. I knew of the Andromeda Nebula, but I thought erik was talking about a seperate nebula in the Milky Way.
By the way, have you ever tried downloading raw Hubble data; you get HUGE images, 3 seperate ones that is. You get the green, red, and blue channels, then you colorize them to get a colour image. It's quite fun actually. You have to get the FITS PS plugin before you can open the images, but I found it was worth it.
Never knew you liked astronomy, Raven. The only astronomical info I know I get from watching Star Trek episodes. 3[ 8[
[righton] I haven tried downloading any of the Hubble pics in raw format (haven't got the plugin you mentioned), thanks for the info too, but that does sound like something that would be fun. So many of the images they show the public of, things like Mars, even deep space shots, they have color adjusted for their own purposes...so people don't always get pics that would represent what the eye really sees if they could be there in person.
Glad you enjoyed the info and pics! Yeah, I've got several large telescopes and do some astrophotography -- I've given some advice about telescopes/use for photography over on the Talk Graphics forums, (my location now in cloudy/rainy Oregon, though, doesn't allow for any where near as much of that as I used to be able to do while in Calif. and had much better weather conditions). It's been a lifelong interest. 3[
Good info indeed. I often visit Hubble's site to download the photographs.
About nebula and galaxy: it is an understandable "error" of mine as in my mother tongue we speak of the Andromeda Nebula. Which, in turn, goes back to the old days, when people could see Andromeda as a nebulous, blurry blotch in the starry sky. Galaxy is based on Greek, and means something like milky way. We never use the word galaxy here, and Milky Way is reserved for "our" group of stars.
It's the same kind of unscientific babbling as someone saying that the Sun comes up in the East.
(it does not come up at all: Earth falls straight into it, but space is curved in such a way that it turns around it. And that "East" is also very variable between Winter and Sommer Solstice).
Anyways: these distances show how fragile we are, how small in the vastness of the Cosmos. How unimportant if you will.
Yet, when I drop something on my toe, the pain I feel is real.
The vastness of the cosmos is certainly mindboggling, vastly interesting. Within that thought we are indeed on a very small piece of real estate here.
At times, when I've had the pleasure to be under a dark country sky shining full of stars, I'd sometimes just lie on the grass looking up and find myself, mentally, just drifting up into it like I could float away into that deep vastness to other places... 8D
Are we alone in the cosmos (and which one are we in if there's others \:] )? We haven't scientific evidence yet that there's life (at least as we tend to think of as "living") elsewhere beyond Earth...but it's certainly not out of the question imo. ( Just in our "neighborhood" I personally think there's been, or even is now some form of life on Mars. I think the moons Europa (of Jupiter) and Titan (of Saturn)have possibilities too in spite of the extreme conditions). I would find it hard to imagine that there wasn't any other life in the cosmos -- but that's just my own notions/feelings about it. *If* we are alone, as some believe, then planet Earth is special beyond measure....but even if we aren't alone this place is very special and precious, as is all on and in it, no matter how small, to all of us here. B7
Andromeda and we 
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