Andromeda galaxy larger than thought-astronomers

Reuters on Yahoo ^ | 5/30/05 | Reuters

[NormsRevenge]

WASHINGTON (Reuters) - The Andromeda galaxy just got bigger -- three times bigger, astronomers said on Monday.

The galaxy is not actually expanding. But new measurements suggest that the nearest galaxy to our own Milky Way is three times broader than astronomers had thought.

They now believe a thin sprinkling of stars once thought to be a halo is in fact part of Andromeda's main disk.

That makes the spiral galaxy, so close to Earth that it appeared as a fuzzy blob to the ancients, more than 220,000 light-years across -- triple the previous estimate of 70,000 to 80,000 light-years.

It appears that the outer fringes of the disk were made when smaller galaxies slammed together, they told a meeting of the American Astronomical Society in Minneapolis.

The structure is too bumpy to have been formed otherwise, said Rodrigo Ibata of the Observatoire Astronomique de Strasbourg in France.

"This giant disk discovery will be very hard to reconcile with computer simulations of forming galaxies. You just don't get giant rotating disks from the accretion of small galaxy fragments," Ibata said in a statement.

Ibata, Scott Chapman of the California Institute of Technology and colleagues in Britain and Australia worked together using observations from the Keck II telescope in Hawaii.

They studied the motions of about 3,000 stars thought to be a mere halo and not an actual part of the galaxy's disk.

But they are in fact sited in the plane of the Andromeda disk itself and move at a velocity that suggests they are in orbit around the center of the galaxy, Ibata's team said.

Andromeda is 2 million light-years from Earth. A light-year is the distance light travels in a year -- about 6 trillion miles.

[DManA]

I read somewhere that Andromeda is the most distant object that can be seen with the naked eye.

[org.whodat]

Just who or what ARE these "thought-astronomers" and how large are they?

Very good question, one would think that anyone with a little education could grasp the meaning of infinity.

[Tax Government]

With all due respect to science and its actual progress, cosmology is little more than today's secular religion. Nothing can be said about the universe with any certainty; the big silly joke of our era is the seriousness with people talk about the big bang and such stuff.

Everyone secretly knows that when they go to sleep at night, the entire physical unvierse evaporates in the literal blink of an eye.

[Dont_Tread_On_Me_888]

The Andromeda Galaxy is the largest "spiral galaxy" to our own Milky Way. However, it is NOT the nearest galaxy to our own, as you pointed out.

The MSM is made up of a bunch of morons that write articles for the masses of morons and they fail to be specific.

[Imperialist]

Andromeda is approaching us here, in the Mily Way. One day the two galaxies may collide. Maybe it is approaching faster than we thought?

[restornu]

Now that is what I needed a galaxies list when I was trying to think of a user name.....

[Talking_Mouse]

How about a picture of Tyr for the ladies?

[JohnnyZ]

Will this do? ;)

[DoctorMichael]

The telescopes in the Hawaian Islands are always interesting to visit if you happen to vacation there. You start out in tropical heat and humidity at sea level in a tank top and shorts and get out of the rent-a-car at 10-12,000 feet after only a half hour of driving, not dressed properly for the sudden plunge in temperature! Great, crystalline views!

[ForGod'sSake]

Could someone, anyone explain to this simpleton: If the universe is supposedly still expanding from an infinitely small, infinitely dense point outward from the original big bang, how anything could be colliding with anything?

Thanks in advance ;^)

FGS

[JohnnyZ]

If the universe is supposedly still expanding from an infinitely small, infinitely dense point outward from the original big bang, how anything could be colliding with anything?

Every once in a while the kids act up real bad and Dad has to turn the Galaxy around and head home.

[ForGod'sSake]

;^)

[King Prout]

ping

[King Prout]

oh, the fundamental problem with the bigbangtheory...

I'd like a GOOD explanation for that, too.

y'd think, based on the BBT, that the universe would be a microns-thick skim of uniformly distributed matter moving outward in perfect radial symmetry from a very hugoungous core of hard vacuum... which does not fit the observable scene even slightly.

[ForGod'sSake]

oh, the fundamental problem with the bigbangtheory...

I wasn't aware of that, but just applying some basic horse sense to it leaves me scratching my head.

y'd think, based on the BBT, that the universe would be a microns-thick skim of uniformly distributed matter moving outward in perfect radial symmetry from a very hugoungous core of hard vacuum... which does not fit the observable scene even slightly.

What you said(I think). If we don't hear something from someone in our local knowledge base, I may be forced to go snooping around for some answers myself. Tough sleddin' for an ol' salesman.

FGS

[Arthalion]

What does the new size of Andromeda do to the collision of Andromeda and the Milky Way

The additional mass may change the closing velocity slightly, but other than altering the impact date by a few million years it shouldn't have a major impact.

[Arthalion]

When Andromeda and the Milky Way collide, when will those of us still around start to feel something?

Our descendants probably won't "feel" a thing since galaxies are mostly empty space and the collision is really just a combination of the gravity wells.

Best case scenario: The constellations shift in the sky as gravity scrambles the orbits of the stars, and other than having to remake our star charts every century or so, humanity is untouched.

Less good but more likely scenario: The sun and Earth are ejected from the galaxy and live out their existence in a material filament in intergalactic space. Except for the sky getting a lot darker at night, humanity is also likely to ride this one out without feeling anything.

Equally likely but far worse possibility: The colliding gravity wells cause the dust lanes in both galaxies to compress and begin a period of new star formation. The resulting gamma ray bursts would likely sterilize our planet. On the upside, it would be instant and we wouldn't feel anything. On the downside, we'd all be dead.

Very unlikely but even worse possibility: Our sun could be at just the right spot when they collide that it gets sucked into either our own galaxies or the Andromeda galaxies core. Why is this one worse than gamma ray extinction? Because it would take centuries to fall into either one, and we'd see it coming. We'd know we were doomed and would have no escape.

[Arthalion]

Simple: Gravity.

The distribution of energy (and therefore matter) wasn't even during the big bang, resulting in a universe filled with "filaments" of matter. Our galaxy is part of a cluster called the Local Group, which is itself a part of an even larger group of 100 or so clusters called the Virgo Supercluster.

Basically put, everything in the Virgo Supercluster was blown in roughly the same direction at about the same velocity by the big bang...we're all going in the same direction (there ARE other superclusters going in other directions). Now, all of our galaxies, clusters, and superclusters have gravity wells and are attracted to each other. If they're close enough, like the Milky Way and Andromeda are, that attraction can alter their courses enough to cause a collision. Andromeda and MW ARE going in the same direction but, thanks to gravity, our paths will cross in a few billion years.

[Talking_Mouse]

Very unlikely but even worse possibility: Our sun could be at just the right spot when they collide that it gets sucked into either our own galaxies or the Andromeda galaxies core. Why is this one worse than gamma ray extinction? Because it would take centuries to fall into either one, and we'd see it coming. We'd know we were doomed and would have no escape.

Only upside to this is we would have absolutely beautiful night sky -- and probably day sky, too.

All of these scenarios presuppose that the human race is still on earth during these events. Somehow, in the intervening billions of years, I think we will have abandoned earth for other more resource rich planets or we will have destroyed ourselves (war, over population, mutating plague, whatever) and some other life form will be dominate then.

Personally, I go for the former choose, I'd like to think of my descendants living thought so much of the galaxy that the destruction of one star system will not impact the population density of the human race.

[Einigkeit_Recht_Freiheit]

Andromeda is a cool name

It's Greek. Go rent "Clash of the Titans" and you will learn who she was (at least mythically).