Three Dozen New Galaxies Are Found in Nearby Space

NY Times ^ | December 22, 2004 | DENNIS OVERBYE

[neverdem]

Fourteen billion years after the Big Bang started it all, there is still life in the old cosmos.

Astronomers announced yesterday that they had discovered three dozen baby galaxies in what passes for nearby space in the universe - two billion to four billion light-years distant. The galaxies, which are blossoming with new stars at a prodigious rate, resemble the infant Milky Way 10 billion years ago, the astronomers said.

Studying these new galaxies could give cosmologists new insights into the processes by which galaxies and stars first formed out of clouds of primordial gas and dust at the beginning of time.

"It's like looking out your window and seeing a dinosaur walk by," said Dr. Tim Heckman of Johns Hopkins University, who led a team using a NASA satellite, the Galaxy Evolution Explorer, or Galex, to pinpoint the newborns. Dr. Heckman spoke in Pasadena, Calif., at a news conference at the Jet Propulsion Laboratory, which manages the satellite. A paper describing the results has been submitted to The Astrophysical Journal.

The babies were a pleasant surprise.

Like the parents of a woman of a certain age who long ago gave up hope of grandchildren, astronomers had given up hope that the universe was still producing galaxies that could grow up to be the size of the Milky Way. The heyday of making stars, the active ingredients of galaxies, was five billion to eight billion years ago. Perhaps only dwarf galaxies were being born today.

"We didn't know if there were any newborns still around or if this phase of cosmic creation is over," Dr. Heckman explained.

The baby galaxies appear as bluish blobs of light about 10,000 light-years across in images sent back by the Galex satellite, which was launched in 2003 on a 29-month mission to survey the sky for ultraviolet emissions.

Ultraviolet light, which has a shorter wavelength than visible light, is produced by the hottest, most massive stars, like those of the Pleiades cluster, which shines in the sky above Orion these frigid crystalline nights. Because such stars do not last very long, they are also among the youngest stars in the sky.

As a result, young galaxies stand out in ultraviolet light, said Dr. Chris Martin of the Jet Propulsion Laboratory, the principal investigator for the Galex project. "Ultraviolet traces star formation," Dr. Martin said.

The hitch for astronomers hoping to study the recent evolution of stars and galaxies is that the atmosphere blocks ultraviolet rays from reaching Earth. So ultraviolet astronomy can be pursued only in space, with instruments like the Hubble Space Telescope and Galex.

Galex is designed to spot the ultraviolet glows of young stars and galaxies and thus help fill in the history of star formation and cosmic evolution over the last 10 billion years. It has a specially designed 20-inch-diameter telescope with a field of view four times as big as a full moon.

The new babies are only the first results of the project, and the astronomers said they expected to find more, although not many.

While they are not nearly the size of mature galaxies like the Milky Way, which is about 100,000 light-years across and has about 200 billion stars, the newborn galaxies outshine them in ultraviolet by a factor of 100 or so, which means they are producing stars "at a prodigious rate," in the words of Dr. Martin.

Dr. Alice Shapley, a theorist at the University of California, described them as "stragglers" of the great wave of galaxy formation that peaked when the universe was half its present age.

It is important, Dr. Shapley said, to try to find out what is finally causing these galaxies to form now. Are they accreting fresh star material from outside, for example? Indeed, she said, astronomers still do not know for sure whether these are really new galaxies, or whether perhaps they are old galaxies, hiding old stars inside them, that are undergoing a new burst of star formation.

These would be ideal objects to study with the Hubble Space Telescope, she added.

What will happen to these newborns is another mystery, Dr. Heckman said.

The infant Milky Way coalesced out of the murk 10 billion years ago, when the universe was more crowded and baby galaxies could bang into one another, merge and grow. "It's less clear what will happen in the future," Dr Heckman said.

The universe is now a more diffuse place, and the baby galaxies may have been born into loneliness. If so, they will never grow up.

[Einigkeit_Recht_Freiheit]

Ok Baraonda, I appoint you king of Galaxy KM3421. Enjoy.

[Einigkeit_Recht_Freiheit]

First answer is yes if we can, we will.

There will be 2 different types of planetary explorers

The first will be economic. Once governments pave the way for colonies and the necessary technology begins to fall within the range of corporations, they will proceed to exploit the resources of other planets for profit. It is a natural step.

The other will be religious zealots unable to live probably in the United States as a result of the manner in whichthe country changes as the population grows.

Much like the Pilgrims they will put their fate in the hands of God in search of a promised land.

My guess is that this will happen on several occassions with some failures and some successes. They will then proceed to build societies as flawed as the ones from which they came.

[alnitak]

Wikipedia Entry

Milky Way

From Wikipedia, the free encyclopedia.

This article is about the galaxy called the Milky Way. For the candy bar of the same name, see Milky Way (candy).

The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Galaxia (gala, galactos means "milk")) is a hazy band of white light across the celestial sphere, formed by stars within the disc of its namesake galaxy. It is also simply known as the Galaxy as our Solar System is a part of it. The Milky Way appears brightest in the direction of Sagittarius, where the galactic center lies. Relative to the celestial equator, the Milky Way passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux. This reflects the fact that the Earth's equatorial plane is highly inclined to the galactic plane, as is the Sun's equator and the ecliptic (the plane in which the Earth and the other significant planets orbit the Sun). The galactic pole lies at right ascension 12 h 51,42 m, declination 27° 7,8' (epoch 2000.0; this is a conventional value adopted by the IAU in 1959). The fact that the Milky Way divides our night sky into two roughly equal hemispheres reflects the fact that the solar system lies close to the galactic plane.

The approximate shape of the Milky Way Galaxy and the position within it of our solar system.

Contents

1 Structure

2 The galactic neighborhood

3 Mythology

4 References

4.1 External links

[edit]

Structure

The Milky Way galaxy is a large spiral galaxy of Hubble type SBbc (loosely wound barred spiral) with a total mass of about 10¹² solar masses (M_☉), comprising 200-400 billion stars (see [3]). The galactic disk has a diameter of about 100,000 light-years (see 1 E20 m for a list of comparable distances). The distance from the Sun to the galactic center is about 27,700 light-years.

The stars in the Galaxy's disk rotate around the Galaxy's center, which is suspected to harbour a supermassive black hole. Sagittarius A* is agreed to be the most plausible candidate for the location of this supermassive black hole. It takes the solar system about 226 million years to complete one orbit, and so has completed about 25 orbits during its lifetime. The orbital speed is 217 km/s, i.e. 1 light-year in ca. 1400 years, and 1 AU in 8 days. The orbital speed of stars in the Milky Way does not depend much on the distance to the center: it is always between 200 and 250 km/s [1] (http://zebu.uoregon.edu/~imamura/123/lecture-2/mass.html). Hence the orbital period is approximatedly proportional to the distance from the star to the Galaxy's center (without the power 1.5 which applies in the case of a central mass). The disk has a bulge at the center.

There are believed to be four major spiral arms and at least two smaller ones which all start at the Galaxy's center. These are named as follows, counting outwards from the centre along a radius through our solar system:

• Norma Arm, or 3 kpc Arm
• Scutum-Crux Arm, or Centaurus Arm
• Sagittarius Arm, or Sagittarius-Carina Arm
• Orion Arm, or Local Arm - labeled "0"; a minor spiral arm. The Earth's solar system may be found close to the inner rim of the Local Arm, in the Local Bubble, 8.0 ± 0.5 kpc from the galactic center.
• Perseus Arm
• Cygnus Arm, or Outer Arm

The distance between the local arm and the next arm out, the Perseus arm, is about 6,500 light-years (see [2]). Each spiral arm describes a logarithmic spiral (as do the arms of all spiral galaxies) with pitch approximately 12 degrees (see [1]).

The disk is surrounded by a spheroid halo of old stars and globular clusters. While the disk contains gas and dust obscuring the view in some wavelengths, the halo does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but not in the halo. Open clusters also occur primarily in the disk.

X-ray image of Milky Way taken by Chandra X-ray Observatory

[edit]

The galactic neighborhood

The Milky Way, the Andromeda Galaxy and the Triangulum Galaxy are the major members of the Local Group, a group of some 35 closely bound galaxies; The Local Group is part of the Virgo Supercluster.

The Milky Way is orbited by a number of dwarf galaxies in the Local Group. The largest of these is the Large Magellanic Cloud with a diameter of 20,000 light years. The smallest, Carina Dwarf, Draco Dwarf, and Leo II are only 500 light years in diameter. The other dwarfs orbiting our galaxy are the Small Magellanic Cloud; Canis Major Dwarf, the closest; Sagittarius Dwarf Elliptical Galaxy, previously thought to be the closest; Ursa Minor Dwarf; Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I.

[edit]

Mythology

There are numerous legends in many traditions around the world regarding the creation of the Milky Way. In particular, there are two similar ancient Greek stories, that explain the etymology of the name Galaxias (Γαλαξίας) and its association with milk (γάλα). One legend describes the Milky Way as a smear of milk, created when the baby Hercules suckled from the goddess Hera. When Hera realized that the suckling infant was not her own but the illegitimate son of Zeus and another woman, she pushed it away and the spurting milk became the Milky Way.

Another story tells that the milk came from the goddess Rhea, the wife of Cronus, and the suckling infant was Zeus himself. Cronus swallowed his children to ensure his position as head of the Pantheon and sky god, and so Rhea conceived a plan to save her newborn son Zeus: She wrapped a stone in infant's clothes and gave it to Cronus to swallow. Cronus asked her to nurse the child once more before he swallowed it, and the milk that spurted when she pressed her nipple against the rock eventually became the Milky Way.

[edit]

References

1. J. P. Valleé: "The Milky Way's Spiral Arms traced by Magnetic Fields, Dust, Gas and Stars", The Astrophysical Journal, volume 454 (1995), pp.: 119-124, 1995. Available online through NASA's Astrophysics Data System http://adswww.harvard.edu
2. Press release Canadian Galactic Plane Survey, http://www.ras.ucalgary.ca/CGPS/press/aas00/pr/pr_14012000/pr_14012000map1.html
3. Sandage, A. & Fouts, G. 1987, AJ, 97, 74

[edit]

External links

1. The Milky Way Galaxy (http://www.seds.org/messier/more/mw.html), SEDS Messier pages
2. Milky Way spiral gets an extra arm (http://www.newscientist.com/news/news.jsp?id=ns99994959) New Scientist.com

Retrieved from "http://en.wikipedia.org/wiki/Milky_Way"

Categories: Milky Way Galaxy | Barred spiral galaxies | List of galaxies

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• This page was last modified 17:22, 23 Dec 2004.
• All text is available under the terms of the GNU Free Documentation License (see Copyrights for details).
  
• About Wikipedia
• Disclaimers

[insider_uk]

Three Dozen New Galaxies Are Found

Don't tell Mrs Insider. She'll want them all for herself!!!

[Larry Lucido]

I'm trying to remember where I left my Ford Galaxy.

[G.Mason]

Thank you.

From my home to yours, Merry Christmas and a happy and healthy New Year.

[R. Scott]

Distance is relative. Compared to the far reaches, that is close.

[R. Scott]

So what's at the edge of the farthest/oldest galaxy?

If the Universe is closed, we are there.

[R. Scott]

Yes, all the time. It's just hard to publish a scientific paper consisting entirely of "Wow!"

I’ve had conversations with people from the nearby CEBAF (Jefferson Lab). I have seen the look of amazement on many a face.

[Riley]

The post was a gag. It's a line from a movie.

[crude77]

Is there the edge of the page out there?

But whats beyond the edge of the page, or on the next page, or outside the box? These questions are so far beyond my comprehension it drives me nuts. (OK, its not a drive, its a short put).

[R. Scott]

Sorry about that – I’m a bit “movie deprived”...does that put be into a special protected class?

[edwin hubble]

All the best for a peaceful Christmas, RA

Thanks for the Christmas wishes.

PS
The Geminids were a surprise hit here. All over the sky.

[Riley]

But whats beyond the edge of the page, or on the next page, or outside the box? These questions are so far beyond my comprehension it drives me nuts.

Billions of unmatched socks and car keys.

Actually, I sympathise. I wonder about stuff like this, too. If the representation of an expanding universe is true that likens it to dots on the surface of an expanding balloon, what does one find when one travels away from the center, beyond the 'surface' of the balloon? Blank space?

[starfish923]

If the Universe is closed, we are there.

Deep....

[starfish923]

You have no imagination. The thought of man landing on the moon could not have been conceived 2000 years ago because people did not really know what the moon was.
How do you know that in 2000 more years travelling to the other side of the galaxy might not be as easy and routine as a transatlantic flight?
There is more under heaven and earth than is dreamt of in your philosophy starfish923.

Lol.

I've been a trekkie since the 60's, have read enough scifi to satisfy even the most ardent dreamer and DO actually have a good imagination.
However, I have enough common sense to know that the periodic chart precludes "dilithium crystals" or any unknown substance in the universe. The periodic chart is it. All that is in the universe is made up of what's on our "humble" little periodic chart. THAT is the chemical part of the physics of our reality.
With that comes the inevitable limitations of fuel. This may burst your bubble, but it doesn't mine.
In another 2000 years the other side of the galaxy will be even farther away than it is now. That's another fact that inevitably closes off even more avenues of travel.
Our lifespans are very short, but so what? We can achieve here on earth. We don't have to go far away to achieve.
We coulc make our bodies last a long, long time. We could, perhaps, have quasi-bionic bodies. If we can put our minds to sleep, we can travel. We don't know the lifespan of our minds. The human mind MAY have a lifespan.

Exploring our own mind offers, imho, the most profound possibility of exploration. Lol. Wookies, Klingons and other aliens, notwithstanding, earth is where our unity, law and freedom really are. Going out there isn't going to change that.

You underestimate me, yourself and all humanity if you exclude the mystery and majesty of exploring our own brain.

Merry Christmas!

[starfish923]

Is there the edge of the page out there?
But whats beyond the edge of the page, or on the next page, or outside the box? These questions are so far beyond my comprehension it drives me nuts. (OK, its not a drive, its a short put).

These questions drive me nuts, too. I always like to throw them out to athiests. They can't comprehend a God, but they can't answer these questions...and the only answer has to be a God.

Philosophers have been asking the SAME questions since there have been sapient beings. The question won't be answered but it IS a topic which scifi OFTEN asks.
Talk about imagination. THAT question, the GOD QUESTION, is always a source of unending exploration.

[winodog]

Do all the stars we see with the naked eye belong to our galaxy? The Milky Way.

[starfish923]

But whats beyond the edge of the page, or on the next page, or outside the box? These questions are so far beyond my comprehension it drives me nuts.

Billions of unmatched socks and car keys.

Actually, I sympathise. I wonder about stuff like this, too. If the representation of an expanding universe is true that likens it to dots on the surface of an expanding balloon, what does one find when one travels away from the center, beyond the 'surface' of the balloon? Blank space?

Lol. Karl Sagan voice: BILLions and BILLions of....unmatched socks and car keys.

The answer to the "blank space" question is one that can be explored by scifi for the next BILLions and BILLions of years.

It MIGHT be unending. Hmmm. It might reverse on itself, physically or timewise. Time IS a substance, I think, or an element or a dimension. The answer to that, o "unity, law and freedom," is in our own brain. I am sure of that.

Now to unlock our little brains...now THAT is the hardest exploration of all.

[R. Scott]

The night sky in such a place is simply amazing, and totally awe inspiring. And the 'milky way' (the area of the sky looking into the massive amount of stars which make up our galaxy, is readily apparent.

One of the joys I experienced when at sea was the night sky. The stars weren’t mere points of light – they were multicolored jewels spread thickly on a black velvet cloth.
Betelgeuse was not just a bright star in the constellation Orion, it was a massive bright varicolored jewel - changing from red to yellow to blue, blazing forth as a heavenly beacon.