Messier 101 from NASA's Hubble Space Telescope

galaxies

Surprise! Galaxies Still Evolving in Present Universe

19 Oct , 2012 by

A giant spiral of gas dust and stars, Messier 101 spans 170,000 light-years and contains more than a trillion stars. Astronomers have uncovered a surprising trend in galaxy evolution where galaxies like M101 and the Milky Way Galaxy continued to develop into settled disk galaxies long after previously thought. Credit: NASA/ESA Hubble

Graceful in their turnings, spiral galaxies were thought to have reached their current state billions of years ago. A study of hundreds of galaxies, however, upsets that notion revealing that spiral galaxies, like the Andromeda Galaxy and our own Milky Way, have continued to change.

“Astronomers thought disk galaxies in the nearby universe had settled into their present form by about 8 billion years ago, with little additional development since,” said Susan Kassin, an astronomer at NASA’s Goddard Space Flight Center in Greenbelt, Md., and the study’s lead researcher in a press release. “The trend we’ve observed instead shows the opposite, that galaxies were steadily changing over this time period.”

A study of 544 star-forming galaxies observed by the Earth-based Keck and Hubble Space Telescope shows that disk galaxies like our Milky Way Galaxy unexpectedly reached their current state long after much of the universe’s star formation had ceased. Credit: NASA’s Goddard Space Flight Center

Astronomers used the twin 10-meter earth-bound W.M. Keck Observatory atop Hawaii’s Mauna Kea volcano and NASA’s Hubble Space Telescope to study 544 star-forming galaxies. Farther back in time, galaxies tend to be very different, say astronomers, with random and disorganized motions. Nearer to the present, star-forming galaxies look like well-ordered disk-shaped systems. Rotation in these galaxies trumps other internal, random motions. These galaxies are gradually settling into well-behaved disks with the most massive galaxies always showing higher organization.

This plot shows the fractions of settled disk galaxies in four time spans, each about 3 billion years long. There is a steady shift toward higher percentages of settled galaxies closer to the present time. At any given time, the most massive galaxies are the most settled. More distant and less massive galaxies on average exhibit more disorganized internal motions, with gas moving in multiple directions, and slower rotation speeds. Credit: NASA’s Goddard Space Flight Center

The sampling of galaxies studied, from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey, ranged between 2 billion and 8 billion light-years from Earth with masses between 0.3 percent to 100 percent that of our own Milky Way Galaxy. Researchers looked at all galaxies in this time range with emission lines bright enough to determine internal motions. Researchers focused on emission lines characteristically emitted by gas within the galaxy. The emission lines not only tell scientists about the elements that make up the galaxies but also red shifting of emission lines contains information on the internal motions and distance.

“Previous studies removed galaxies that did not look like the well-ordered rotating disks now common in the universe today,” said co-author Benjamin Weiner, an astronomer at the University of Arizona in Tucson. “By neglecting them, these studies examined only those rare galaxies in the distant universe that are well-behaved and concluded that galaxies didn’t change.”

In the past 8 billion years, mergers between galaxies, both large and small, has decreased. So has the overall rate of star formation and associated disruptions due to supernovae explosions. Both factors may play a role in the newly found trend, say scientists.

The Milky Way Galaxy may have gone through the same chaotic growing and changing as the galaxies in the DEEP2 sample before settling into its present state at just about the same time the Sun and Earth were forming, say team scientists. By observing the pattern, astronomers can now adjust computer simulations of galaxy evolution until they replicate the observations. Then the hunt will be on to determine the physical processes responsible for the trend.

This cosmological simulation follows the development of a single disk galaxy throughout the life of the Universe; about 13.5 billion years. Red colors show old stars, young stars show as white and bright blue while the distribution of gas shows as a pale blue. The computer-generated view spans about 300,000 light-years. The simulation, running on the Pleiades supercomputer at NASA’s Ames Research Center in Moffett Field, California, took about 1 million CPU hours to complete. Credit: F. Governato and T. Quinn (Univ. of Washington), A. Brooks (Univ. of Wisconsin, Madison), and J. Wadsley (McMaster Univ.).

A paper detailing the findings will be published in the October 20, 2012 The Astrophysical Journal.

Source: NASA

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By  -      
John Williams is owner of TerraZoom, a Colorado-based web development shop specializing in web mapping and online image zooms. He also writes the award-winning blog, StarryCritters, an interactive site devoted to looking at images from NASA's Great Observatories and other sources in a different way. A long-time science writer and space enthusiast, he created award-winning Hubble Star Cards. Use coupon code UNIVERSE to Hold the Universe in your hands. Follow John on Twitter @terrazoom.



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John Widule
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October 20, 2012 1:26 AM

Galaxies, like all things, were created and perfectly ordered.

IVAN3MAN_AT_LARGE
Member
IVAN3MAN_AT_LARGE
October 20, 2012 2:07 AM

… by the Flying Spaghetti Monster!

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
October 20, 2012 12:21 PM
That sounds like a creationist speaking, but I will give you the benefit of doubt. But as a creationist the comment’s analysis of the presented research says precisely the opposite of what the article describes that everyone can see in nature, to wiz: – No structures (here the structure formation central part, galaxies) is created but evolves over time. – Nothing was or will be perfectly ordered. The asymptote for heavy galaxies in the 2nd image is quite reasonably never approaching 100 %, because individual galaxies will never conform to absolute absence of disorganized inner motion. Random chance will always let us see some disorganized ones. This is of course what we see in the present epoch of… Read more »
bugzzz
Member
bugzzz
October 20, 2012 5:22 PM
Your post is as interesting as usual T. I don’t find an evolving universe and a belief in a higher intelligence (or god, if you like) to be in conflict. There is a contradiction at the heart of creation. Which is true – a universe that birthed itself from nothing, or an intelligence that always existed and designed it? Either answer is absurd, which amuses me. Life is absurd, as would be the absence of life. That the universe behaves like a quantum computer suggests many possibilities as to the nature of “god” or whether god is in fact the machine on which the universe runs. It is endlessly fascinating to ponder. For now, lacking proof, it comes… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
October 21, 2012 11:46 AM
Hm, well, my comment was a bit cryptic due to my hurriedness. But thanks! – From a secular viewpoint, religious freedom including the freedom to criticize it, it is easy to see the basic conflict between the two phenomena as they appear to society. Science is in the business to replace belief with facts, and religion is in the business to replace facts with belief. You may criticize the claim of “replacement”, but we see this and it is a solid observation. (Say, science replaces the belief in a creator with chemical evolution and cosmology, conversely some religions claim there is a “soul” golem driving our minds so replaces what is observed with what is not). The conflict… Read more »
bugzzz
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bugzzz
October 22, 2012 3:15 AM
The thing is though that I’ve been witness to magic in the physical world for 15 years. I’ve detailed some of my experiences here before. What I’m currently pondering is how I might eventually demonstrate or re-create what I’ve experienced in a way that can be measured and observed. This is difficult because it doesn’t really “work that way.” If I showed you something magical, and you observed it with your own eyes in my presence, do you think you would have to rethink your position? The reason I ask is because that is what happened to me. I was an atheist/agnostic and then I had direct physical experiences with the inexplicable. Spirits if you like. Of some… Read more »
IVAN3MAN_AT_LARGE
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IVAN3MAN_AT_LARGE
October 22, 2012 5:02 AM

Your experience(s) is just anecdotal evidence.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
October 22, 2012 6:32 AM
That is no “thing” we need to be concerned with here though, since it is anecdote. It could be anything, except actual facts of course because then we wouldn’t have anecdote but observation. So to answer your question: no. This is why Randi have a reward for showing the world anything magical, under controlled conditions, with mutually agreed on observations, and with experts on illusions and tricks. And it hasn’t happened, despite ~ 10 billion people having by now a few decades (2?) to do so. I admire that in Randi. Instead of accepting people routinely waving around anecdote as if it meant anything at all, except our ability to invent them, he took the societal power out… Read more »
bugzzz
Member
bugzzz
October 22, 2012 9:37 AM

You both display disappointing rigidity of thinking. I had actually expected more. Some day soon I may figure out how to show you and the world something undeniable. I am already close. I hope you will not come to regret the limitations you have imposed on yourselves in a universe that is all quantum possibilities.

IVAN3MAN_AT_LARGE
Member
IVAN3MAN_AT_LARGE
October 22, 2012 3:44 PM

Yeah, good luck with that!

bugzzz
Member
bugzzz
October 22, 2012 5:18 PM

oh, i love a challenge. my entire life has been spent turfing naysayers. i’m adding you to my list for the future. don’t worry, you will hear from me in time.

SteveZodiac
Member
SteveZodiac
October 21, 2012 8:01 AM

and potatoes are created perfectly formed by the supermarket. I have seen them with my own eyes and I refute all talk of seed and fields.

magnus.nyborg
Guest
magnus.nyborg
October 21, 2012 10:16 AM

Just like the banana.

wavettore
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wavettore
October 20, 2012 2:43 AM
New and old Science A new and Progressive Science shows how Wavevolution, or the transformation from waves to atoms, is the connecting link that closes the circle of science to open new horizons never seen before. The bureaucracy of traditional science prevents the recognition of any event unless certain criteria are first met. The problem of this science is buried deep right in the compilation of these “laws” or criteria introduced by a few scientists in the name of all science and from their erroneous understanding of the relation between Space and Time. This antiquated system of rules also results in misleading theories. For example, the Space is not “curved”. In Einstein’s paradigm, a stone that falls on… Read more »
IVAN3MAN_AT_LARGE
Member
IVAN3MAN_AT_LARGE
October 20, 2012 2:45 AM

Here’s the link to the relevant paper: The Epoch of Disk Settling: z~1 to Now.

Steve Nerlich
Guest
October 20, 2012 11:36 AM

Surely it’s all about density waves. It must take a while for mean forces to become established – but when they do, you get the characteristic spiral galaxies that we see frequently and nearby in the contemporary universe,

Lawrence B. Crowell
Member
Lawrence B. Crowell
October 21, 2012 1:06 PM
The evolution of galaxies by this accreting process of smaller structures appears to have some sort of attractor basin. A basin of attraction is a set of final states that in the case of an attractor point means there is only one final state. For complex systems, or systems that have a driving potential or force along with an attenuating system that dissipates energy the basin of attraction can define a set of orbits. The spiral galaxy appears to reflect this basin of attraction. We are all familiar with Newton’s law of gravity. For two masses M and m at a distance d apart their mutual attractive force of gravitation has magnitude F = GMm/d^2, for G the… Read more »
Mike
Guest
October 21, 2012 10:43 PM

It is like the Universe is really alive.

bugzzz
Member
bugzzz
October 22, 2012 3:18 AM

Some believe the universe is filled with intelligence. I’m among them.

SJStar
Guest
SJStar
October 22, 2012 6:37 AM

That ain’t science and not how it works. Science isn’t “best guess.”

shadowmajestic
Member
shadowmajestic
October 24, 2012 5:06 PM

If you do not believe, you will never figure out wether your beliefs are true or not.Science can be done in 2 ways… by accident and by believing.

Prism2Spectrum
Guest
Prism2Spectrum
October 23, 2012 1:16 PM
“Both religion and natural science require a belief in God for their activities, to the former He is the starting point, and to the latter the goal of every thought process. To the former He is the foundation, to the latter, the crown of the edifice of every generalized world view.” — Max Planck, German theoretical physicist who originated quantum theory, which won him the Nobel Prize in Physics in 1918 “Lecture, ‘Religion and Natural Science’ (1937) In Max Planck and Frank Gaynor (trans.), Scientific Autobiography and Other Papers (1949), 184.” ______________________________________________________________ ~ Could it just be, the basic foundation of all knowledge, from which all Scientific constructs can be firmly based, and built-up, lies in one Book… Read more »
katesisco
Member
katesisco
October 23, 2012 10:36 PM
Great science. I have this idea that if the galaxies are moving toward a ‘standardized form’ then they can hardly be this ‘starless dark’ noted here: p://idealab.talkingpointsmemo.com/2012/07/dark-starless-galaxies-observed-for-the-first-time.php This article at idealab.talkingpointsmeno.com says the ‘starless dark’ is working toward becoming spirals. I wonder if that is just the opposite; that spirals form globular clusters when new and almost immediately degrade and lose their magnetic field and blow out energy through the galactic equator to the rim where new blue stars form. This off gases tremendous amounts and the gas eventually envelops the entire galaxy. The outside of the gas shell cools and Viola! you have a ‘starless dark.’ The timeline would then be: tight spirals form globular clusters axially,… Read more »
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