A Star-Struck Galaxy Sparkles In The Ancient Cosmos
Article by: Judith E Braffman-Miller
The galaxy cluster Abell 2744, sometimes called Pandora's Cluster, is an enormous structure containing a myriad of starlit galaxies, as well as a rich abundance of gas that is so searing-hot that it shines only in X-rays. In February 2014, astronomers using NASA's Spitzer Space Telescope (SST) and Hubble Space Telescope (HST), announced that they had discovered what well may be one of the most ancient and remote galaxies known. In astronomy, long ago is the same as far away. The more distant a celestial object is in Space, the more ancient it is in Time. The galaxy, dubbed Abell 2744 Y1, may hearken back to a long ago and far away epoch when the approximately 13.8 billion year old Universe was a mere beautiful baby at 650 million years of age. The galaxy is about 30 times smaller than our large, barred-spiral Galaxy, the Milky Way--but it is churning out about 10 times more fiery neonatal stars, which is a characteristic of ancient galaxies inhabiting our primordial Cosmos.
If confirmed, the newly discovered star-blasted galaxy would serve to push back the Universe's galaxy-birthing timer by 100 million years to 650 million years, after our Universe was born in the runaway inflation of the Big Bang almost 14 billion years ago.
A second remote galaxy, which was detected in 2012, hearkens back to a mere 500 million years after the Bang.
Pandora's Cluster is a gigantic structure that is thought to have attained its immense size due to the simultaneous pile-up of at least a quartet of smaller, independent clusters, which occurred over a time span of approximately 350 million years. The galactic constituents of this richly endowed cluster account for less than 5% of its mass, while seething hot gas accounts for about 20%. Most of the mass sported by Pandora's Cluster is derived from the dark matter, which makes up approximately 75% of its impressive weight.
Dark matter is mysterious, transparent stuff, and it weaves a gigantic Cosmic Web throughout Spacetime. The magnificent and majestic star-splattered galaxies, that congregate in groups and clusters all over the Universe, are merely the sparkling sprinkles on a wonderful and mysterious Cosmic cake! The sparkling galaxies and clusters of galaxies are embedded in dark matter haloes, and they dance around this weird and lovely Cosmic Web, outlining with their wonderful light, the heavy, transparent filaments of dark matter that human eyes cannot see.
Dark matter is thought to be composed of exotic non-atomic particles that can only interact with "ordinary" atomic matter and radiation through the force of gravity. So-called "ordinary" matter makes up a mere 5% of the entire mass-energy component of the Cosmos. Dark matter is much more abundant, and accounts for about 25% of the mass-energy of the Universe.
Even more abundant, and more mysterious, is the dark energy that accounts for 70% of the mass-energy of the Cosmos. The dark energy is bizarre, probably an attribute of Space itself--and it is causing the Universe to accelerate in its relentless expansion!
Because of the still-unknown nature of the dark energy and dark matter, it is sometimes said that 95% of our Universe is missing! The "ordinary" atomic matter--that is the stuff of stars, planets, moons, and people, as well as all of the familiar elements that make up our world, is certainly the runt of the Cosmic litter.
Pandora's Cluster Is A Great Gravitational Lens!
Pandora's Cluster displays a radio halo, as do several other Abell Clusters. It also shows a powerful central halo, and sports an extended tail of undetermined origins. This tail could either be an extension of the central halo or remnant radiation.
Pandora's Cluster got its colorful nickname because astronomers realized that a weird multitude of unusual phenomena had been liberated by the monumental smashing collisions that it had experienced in the past.
The discovery of the ancient, star-struck galaxy comes courtesy of the Frontiers Field program, which is pushing further and further back in Time just how far astronomers can peer into the remote and ancient Cosmos. The astronomers who made this discovery used NASA's multi-wavelength array of Great Observatories: the SST, the HST, and the Chandra X-ray Observatory.
The SST has infrared vision, while HST sees the Universe in both visible and shorter-wavelength infrared light. NASA's Chandra X-ray Observatory has X-ray vision. These great space telescopes are also benefiting from one of Nature's own gifts--gravitational lenses, whereby gravity magnifies the light emanating from more remote galaxies. Gravitational lensing is a prediction of Albert Einstein's Theory of General Relativity, whereby the light of a background object can be magnified, bent, and warped by the mass of a foreground object. NASA's Great Observatories benefited from this precious little gift from Mother Nature, which enhanced their technological powers.
Abell 2744 served as the gravitational lens that magnified the light from more distant galaxies that bobbed around behind it--and were, therefore, more distant and ancient.
Occasionally, the warped or bent Space will bring into focus a more remote and ancient object--as it did with Abell 2774 Y1!
"The cluster of galaxies act as additional lens and can convert the mirror of the Hubble Space Telescope to a mirror at least 10 times larger," explained Dr. Nicolas Laporte to the press on February 10, 2014. Dr. Laporte is an astronomer with the Astrophysics Institute of the Canary Islands.
Clusters and superclusters of galaxies are the most massive structures known to dance around the Cosmos, and most galaxies dwell in groups and clusters--with clusters being considerably larger than groups. Superclusters of galaxies are often made up of literally thousands of individual galaxies that are all tied together by the force of gravity--creating the densest component of the large-scale structure of the Universe.
Our own Milky Way Galaxy is a large member of the Local Group, that hosts over 40 galactic constituents. Our Local Group, in turn, is a member of the Virgo Cluster of galaxies, whose core is about 50 million light-years away.
The sparkling, starlit galaxies ignited very long ago, and lit up the ancient Cosmos less than a billion years after the inflationary Big Bang.
Star-Struck Galaxy In The Ancient Cosmos!
With the right alignment, the team of astronomers hope that Cosmic gravitational lenses will uncover, and bring into focus, extremely ancient galaxies that were born as early as 300 million years after the Bang, Dr. Laporte told the press on February 10, 2014.
The Frontiers Fields program will image half a dozen galaxy clusters in all. HST images of the region will be used to detect candidate long ago and faraway galaxies, hearkening from the ancient Cosmos. Then the SST will be used to calculate if the candidate galaxies are, in fact, as long ago and far away as they appear to be. Information derived from the SST will also help determine the number of fiery, sparkling stars there are, jitter-bugging around in the candidate galaxies.
The distance to the candidate remote and ancient galaxy, Abell 2774 Y1, if confirmed, would make it one of the most remote and ancient of all galaxies currently known. The team of astronomers, who made the discovery, believe that the distant, star-struck galaxy has a redshift of 8. The redshift of a celestial object is a measurement of the amount to which its traveling light has been shifted to the redder wavelengths of the electromagnetic spectrum--as a result of the expansion of the Universe. The more distant a galaxy, the higher its redshift! So far, the most remote confirmed galaxy has a redshift of more than 7. A number of other galactic candidates have been detected with redshifts as high as 11!
"Just a handful of galaxies at these great distances are known. The Frontiers Fields program is already working to find more of these distant, faint galaxies. This is a preview of what's to come," Dr. Jason Surace told the press on February 9, 2014. Dr. Surace is of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena, California.
The study, that was led by astronomers from the Instituto de Astrofisica de Canarias and La Laguna University will be published in the journal Astronomy and Astrophysics Letters.
(Judith E. Braffman-Miller is a writer and astronomer whose articles have been published since 1981 in various magazines, newspapers, and journals. Although she has written on a variety of topics, she particularly loves writing about astronomy because it gives her the opportunity to communicate to others the many wonders of her field. Her first book, "Wisps, Ashes, and Smoke," will be published soon. Article Source: http://EzineArticles.com/?expert=Judith_E_Braffman-Miller "Image courtesy of nuttakit / FreeDigitalPhotos.net")
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