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APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 5:06 am
by APOD Robot
One Million Galaxies
Explanation: Are the nearest galaxies distributed randomly? A plot of over one million of the brightest "extended sources" detected by the
Two Micron All Sky Survey (2MASS) shows that they are not. The vast majority of these
infrared extended sources are
galaxies. Visible
above is an incredible tapestry of structure that
provides limits on how the
universe formed and
evolved. Many
galaxies are
gravitationally bound together to form
clusters, which themselves are loosely bound into
superclusters, which in turn are sometimes seen to align over even
larger scale structures. In contrast, very bright stars inside our own
Milky Way Galaxy cause the vertical blue sash.
[/b]
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 1:30 pm
by spiritfountain
I don't understand how the stars from our galaxy cause the "vertical blue sash". Is it like a glare on the telescope or what?
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 2:22 pm
by bystander
The Infrared Universe
This panoramic view encompasses the entire sky and reveals the distribution of galaxies beyond the Milky Way galaxy, which astronomers call extended sources, as observed by Two Micron All-Sky Survey. The image is assembled from a database of over 1.6 million galaxies listed in the surveyÕs All-Sky Survey Extended Source Catalog,; more than half of the galaxies have never before been catalogued. The colors represent how the many galaxies appear at three distinct wavelengths of infrared light (blue at 1.2 microns, green at 1.6 microns, and red at 2.2 microns). Quite evident are the many galactic clusters and superclusters, as well as some streamers composing the large-scale structure of the nearby universe. The blue overlay represents the very close and bright stars from our own Milky Way galaxy. In this projection, the bluish Milky Way lies predominantly toward the upper middle and edges of the image.
Credit: 2MASS/TH Jarrett, J Carpenter, & R Hurt
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 2:28 pm
by biddie67
Good Morning - Could someone explain where the camera was located and how it generated this oval picture. I'm sorry but I can't figure out the geometry of the prospective.
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 2:52 pm
by bystander
it's a projection, much the same as
WMAP. The
cameras were at two telescopes located one each in the northern and southern hemispheres (Mt. Hopkins Arizona and Cerro Tololo/CTIO Chile, respectively) to ensure coverage of the entire sky.
About 2MASS
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 3:58 pm
by lenka
So, does it mean that even though the galaxies are farther away from us,but as huge structures, they emit more heat visible in infrared, than brighter and closer stars from our Milky Way, and so in the picture we see galaxies as clear structures in reddish color and stars in our Milky Way just as blue sash without any clear structures?
By the way, it looks like a Monster City.
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 4:22 pm
by neufer
bystander wrote:
It's a projection, much the same as
WMAP.
It is an Aitoff projection much the same as WMAP ... EXCEPT that unlike most modern celestial maps
it is based upon an equatorial celestial coordinate system rather than a galactic celestial coordinate system.
Therefore the Milky Way ungulates across the 2MASS projection much like a
Wally Pacholka panorama
rather than lying passively along the equator a la WMAP:
http://en.wikipedia.org/wiki/Celestial_coordinate_system wrote:
Equatorial coordinate system [e.g., 2MASS]
<<The equatorial coordinate system is centered at Earth's center and fixes the sky around us, so that it appears fixed while earth, and we on its surface, revolves around its own axis. The equatorial describes the sky, as seen from the solar system, and modern star maps are almost exclusively perusing equatorial coordinates. Ancient Eastern astronomers used this for their star charts.
Popular choices of pole and equator are the older B1950 and the modern J2000 systems, but a pole and equator "of date" can also be used, meaning one appropriate to the date under consideration, such as that at which a measurement of the position of a planet or spacecraft is made. There are also subdivisions into "mean of date" coordinates, which average out or ignore nutation, and "true of date," which include nutation.>>
---------------------------------------------
Galactic coordinate system [e.g., WMAP]
<<The galactic coordinate system has our solar system as the center, a position nearly pointing towards the center of the Milky way as the zero direction, and otherwise has a fundamental plane that approximately coincides with the disk of the Milky Way, but which is fixed by standard. The galactic system is of course used for interstellar positioning of objects in relation to our galaxy.>>
---------------------------------------------
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 4:27 pm
by Boomer12k
I disagree with the non-random distribution conclusion of the Article. I include two pictures, of a Tangent function. The Straight Tangent is uniform, the Changed tangent had RANDOM functions inserted so angles change, just like a Universe in MOTION, and it shows very similar structures to the picture. Clumps, and voids, and circular patterns. I see no symmetry in the article photo. I see no straight distribution pattern. I see random placement, otherwise things would be clumped together, or show more uniform pattern, evenly distributed, etc... I don't think it is the correct conclusion. My opinion.
![Straight Tangent Function.](./download/file.php?id=1567&sid=d63080636e33e7fd92174fdc5067647c)
- Straight Tangent Function.
- Tangent.jpg (49.4 KiB) Viewed 4021 times
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 4:50 pm
by neufer
Boomer12k wrote:
I disagree with the non-random distribution conclusion of the Article.
The non-random lumpiness in the large-scale structure of the universe is on scales SMALLER than 100 Mpc.
http://en.wikipedia.org/wiki/Large-scale_structure_of_the_cosmos#Large-scale_structure wrote:
<<The End of Greatness is an observational scale discovered at roughly 100 Mpc where the lumpiness seen in the large-scale structure of the universe is homogenized and isotropized as per the Cosmological Principle. The superclusters and filaments seen in smaller surveys are randomized to the extent that the smooth distribution of the universe is visually apparent. It was not until the redshift surveys of the 1990s were completed that this scale could accurately be observed.
Walls, filaments and voids
The organization of structure arguably begins at the stellar level, though most cosmologists rarely address astrophysics on that scale. Stars are organized into galaxies, which in turn form clusters and superclusters that are separated by immense voids, creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that virialized galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the universe in every direction. However, based on redshift survey data, in 1989 Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light-years long and 200 million wide, but only 15 million light-years thick. The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from redshifts. In April 2003, another large-scale structure was discovered, the Sloan Great Wall. In August 2007, a possible supervoid was detected in the constellation Eridanus.[28] It coincides with the 'WMAP Cold Spot', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This supervoid could cause the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across.
In more recent studies the universe appears as a collection of giant bubble-like voids separated by sheets and filaments of galaxies, with the superclusters appearing as occasional relatively dense nodes. This network is clearly visible in the 2dF Galaxy Redshift Survey. In the figure a 3-D reconstruction of the inner parts of the survey is shown, revealing an impressive view on the cosmic structures in the nearby universe. Several superclusters stand out, such as the Sloan Great Wall, the largest structure in the universe known to date.>>
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 4:59 pm
by NoelC
Cool. The word that comes to my mind to describe the visual distribution is "splatter".
-Noel
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 7:01 pm
by neufer
http://en.wikipedia.org/wiki/Cosmic_egg wrote:
NoelC wrote:
The word that comes to my mind to describe the visual distribution is "splatter".
![Image](http://www.newforestobservatory.com/wordpress/wp-content/gallery/projects/img_4751_cs3_nfo.jpg)
<<The cosmic egg is an ancient mythological concept resurrected by modern science in the 1930s and explored by theoreticians during the following two decades. Georges Lemaitre proposed in 1927 that the cosmos originated from what he called the primeval atom. In the late 1940s, George Gamow's assistant cosmological researcher Ralph Alpher, proposed the name ylem for the primordial substance that existed between the big crunch of the previous universe and the big bang of our own universe. Current cosmological models maintain that 13.7 billion years ago, the entire mass of the universe was compressed into a singularity, from which it expanded to its current state (following the Big Bang), the so-called cosmic egg.
Hindu concepts of Hiranyagarbha (golden womb) and Brahmanda (the first egg), are comparable to cosmic egg origin systems. The Bhagavata Purana, Brahmanda Purana, Vayu Purana among others contain references to the initial process of the origins of the universe as a cosmic egg: "The whole universe including sun, moon, planets, and galaxies was all inside the egg, and the egg was surrounded by ten qualities from outside... At the end of thousand years, the Egg was divided in two by Vayu." - Vayu Purana.
"Furthermore the god Mithras is often depicted as appearing from within an egg."
____ Metaphysics and philosophy
In Hindu tantra, based on the Hindu philosophy of Kashmir Shaivism, the Shri Yantra represents the expansion of the universe from the cosmic egg after its creation by Shiva through the power of Shakti. The cosmic egg is represented by a dot in the center of the Shri Yantra mandala called the bindu.
____ Influences on science fiction and popular culture
In the 1970 science fiction novel Tau Zero by Poul Anderson, a starship forced to travel very close to the speed of light by an engine malfunction survives traversing our universe collapsing via a big crunch into a cosmic egg and re-exploding in a new big bang. The crew of the starship finds a planet similar to Earth in the new universe, upon which they land and establish a colony. In 1972 science fiction novel The Gods Themselves by Isaac Asimov baby universes, in their cosmic egg stage, are used as alternative fuel.>>
http://en.wikipedia.org/wiki/World_egg wrote:
<<A world egg or cosmic egg is a mythological motif found in the creation myths of many cultures and civilizations. Typically, the world egg is a beginning of some sort, and the universe or some primordial being comes into existence by "hatching" from the egg.
Sanskrit scriptures and Vedanta
The earliest ideas of "Egg-shaped Cosmos" comes from some of the Sanskrit scriptures. The Sanskrit term for it is Brahmanda (Brahm means 'Cosmos' or 'expanding', Anda means 'Egg'). The Rig Veda uses a similar name for the source of the universe: Hiranyagarbha, which literally means "golden fetus" or "golden womb". The Upanishads elaborate that the Hiranyagarbha floated around in emptiness for a while, and then broke into two halves which formed Dyaus (Heaven) and Prithvi (Earth) - concepts that existed in nearly every ancient culture, and were also articulated by the Abrahamic religions. The Rig Veda has a similar coded description of the division of the universe in its early stages.
____ Chinese mythology
In the myth of Pangu, developed by Taoist monks hundreds of years after Lao Zi, the universe began as an egg. A god named Pangu, born inside the egg, broke it into two halves: the upper half became the sky, while the lower half became the earth. As the god grew taller, the sky and the earth grew thicker and were separated further. Finally Pangu died and his body parts became different parts of the earth.
____ Egyptian mythology
In the original myth concerning the Ogdoad, the Milky Way arose from the waters as a mound of dirt, which was deified as Hathor. Ra was contained within an egg laid upon this mound by a celestial bird. In the earliest version of this myth, the bird is a goose (it is not explained where the goose originates). However, after the rise of the cult of Thoth, the egg was said to have been a gift from Thoth and laid by an ibis, the bird with which he was associated.
![Image](http://upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Orphic-egg.png/220px-Orphic-egg.png)
Jacob Bryant's Orphic Egg (1774)
____ Finnish mythology
In the Kalevala, the Finnish national epic, there is a myth of the world being created from the fragments of an egg laid by a diving duck on the knee of Ilmatar, goddess of the air:
- One egg's lower half transformed
And became the earth below,
And its upper half transmuted
And became the sky above;
From the yolk the sun was made,
Light of day to shine upon us;
From the white the moon was formed,
Light of night to gleam above us;
All the colored brighter bits
Rose to be the stars of heaven
And the darker crumbs changed into
Clouds and cloudlets in the sky.
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 7:16 pm
by biddie67
(( grin )) well then, after all, we just might be part of a cosmic yolk ....
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 7:42 pm
by Beyond
biddie67 wrote:(( grin )) well then, after all, we just might be part of a cosmic yolk ....
OR - It could be that "the yolk" is on US!!
Hmm......Perhaps we should think bigger and change the song title " we are the world", to "we are the yolk?"
After all, one of the Beatles sang "i am the eggman". coo-coo-ka-choo.
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Mon Dec 27, 2010 10:37 pm
by lenka
Oh, today I learned new word on APOD
NoelC wrote: "splatter"
Thanks
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Tue Dec 28, 2010 12:08 am
by Boomer12k
Another observation.
It reminds me of Magnetic lines. If you took 20 small disk magnets, put them under a piece of paper, threw filings on them, I bet you would see a similar structure. Filings would gather in-between and along the magnetic lines causing "clumping"-like structures. The loops would be voids where magnetic lines do not exert much force and are canceled by other lines. The loops of the picture remind me of Solar Prominences.
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Fri Dec 31, 2010 12:54 am
by bluemarkus
if you look at the picture intensely like it was a 3D picture, it seems to move.
thats kinda cool...
Re: APOD: One Million Galaxies (2010 Dec 27)
Posted: Wed Jan 05, 2011 4:06 pm
by dougettinger
Boomer12k wrote:Another observation.
It reminds me of Magnetic lines. If you took 20 small disk magnets, put them under a piece of paper, threw filings on them, I bet you would see a similar structure. Filings would gather in-between and along the magnetic lines causing "clumping"-like structures. The loops would be voids where magnetic lines do not exert much force and are canceled by other lines. The loops of the picture remind me of Solar Prominences.
Boomer, I like your basement experiment. Perhaps the disk magnets may represent powerful black holes from distant times that create the "filament affect" of the tapestry of galaxies.
Another experiment is packing small stick magnets into one monolith. It actually works. What do you think that experiment may represent in the real world?
Doug Ettiinger
Pittsburgh, PA