Daily Archives: October 31, 2014

NASAs Hubble Space Telescope has detected a faint light, described as the ghostly glow of stars that were ejected from ancient galaxies, which themselves are believed to have been ripped apart by gravitational forces billions of years ago. The light is believed to emerge from inside a collection of about 500 galaxies known as Abell 2744, about four billion light-years away.

According to astronomers, the stars in this group of galaxies -- named Pandoras Cluster -- are scattered and their light has helped scientists gather evidence, suggesting that as many as six galaxies were torn to pieces inside the cluster over a period of six billion years. Astronomers expect the new findings to help them better understand the evolution of galaxy clusters.

The results are in good agreement with what has been predicted to happen inside massive galaxy clusters, Mireia Montes of The Instituto de Astrofsica de Canarias (IAC), Santa Cruz de Tenerife, Spain, and the lead author of the study published in the Astrophysical Journal earlier this month, said in a statement.

The astronomers estimate that the combined light of about 200 billion outcast stars contributes about 10 percent of the clusters brightness. According to data provided by Hubble, these stars have significant amounts of heavier elements, such as oxygen, carbon and nitrogen.The gravity in galaxy clusters deflects light passing through them, magnifying, brightening and distorting light in a phenomenon called gravitational lensing, which is used by astronomers to blow up the images of remote galaxies.

According to NASA, Abell 2744 is a target in the Frontier Fields program, a three-year-long mission that combines Hubble and NASAs other observatories to study massive galaxy clusters for answers to the universe.

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NASAs Hubble Telescope Spots Ghost Light From Dead Galaxies

It appears that spooky goings-on over the Halloween period are not just confined to Earth. The Hubble Space Telescope has made its own ghostly discovery by capturing the ghost light from dead galaxies ripped apart billions of years ago.

The ghost light comes from stars that were ejected from ancient galaxies ripped apart by gravity. These orphaned stars are no longer attached to any one galaxy, and instead wander between nearby galaxies.

But dont worry, they wont be wandering over here any time soon. This epic galaxy death happened over four billion light years away in a large group of galaxies known as the Pandora cluster, or Abel 2744.

Hubble astronomers have turned detective and used the ground-breaking images to deduce the dead galaxies last movements. Their evidence suggests that as many as six galaxies were torn apart over a time period of six billion years.

These galaxies were probably about the same size as our own Milky Way. Such smaller galaxies would have had no chance as they plunged through the centre of the galaxy cluster where gravitational tidal forces are at their strongest.

The source of the ghost light is actually coming from an estimated200 billion outcast stars. They make up about 10% of the total light being emitted by the Pandora cluster.

Measurements taken by Hubble show that these stars are rich inheavier elements like oxygen, carbon, and nitrogen. Thats a tell-tale sign that these are second or third-generation stars which have been enriched by elements that were originally created at the heart of the universes first-generation stars.

This kind of on-going star formation is most commonly found in spiral galaxies, which is where we think these orphan stars originated.

Well for a start its impressive that we even spotted these stars.

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Hubble Telescope makes a 'ghostly' discovery billions of light years away

October 31, 2014

Pandoras Cluster, which is also known as Abell 2744, is an immense grouping of nearly 500 galaxies, and the ghostly glow detected by Hubble was emitted by scattered stars that had been expelled from galaxies galaxies which themselves had been gravitationally torn apart several billion years ago, according to the US space agency.

[ Watch the Video: Abell 2744 Y1 Is The Most Distant Galaxy Discovered ]

The orphaned stars, which are located four billion light-years from Earth, are no longer bound to a single galaxy and drift freely from one to another in the cluster. By observing their light, Hubble astronomers have managed to gather forensic evidence suggesting that up to six galaxies were torn to pieces in the cluster over a period of six billion years. Their findings have been published in The Astrophysical Journal.

Computer modeling of the gravitational dynamics among galaxies in a cluster suggests that the stars originated from galaxies approximately the same size as the Milky Way. Those galaxies, the study authors explained, would have been pulled apart if they traveled through the center of the galaxy cluster, where the strongest gravitational tidal forces are found.

The Hubble data revealing the ghost light are important steps forward in understanding the evolution of galaxy clusters, research team member Ignacio Trujillo of the Instituto de Astrofsica de Canarias (IAC), La Laguna, Tenerife, Spain said in a statement. It is also amazingly beautiful in that we found the telltale glow by utilizing Hubbles unique capabilities.

While astronomers have long hypothesized that they should be able to detect the light from scattered stars left behind after galaxies become disassembled, it was difficult to detect this anticipated intracluster glow of stars because of how faint it was. The researchers estimate that the combined light of approximately 200 billion outcast stars contributes nearly one-tenth of the clusters brightness.

Because these extremely faint stars are brightest at near-infrared wavelengths of light, the team emphasized that this type of observation could only be accomplished with Hubbles infrared sensitivity to extraordinarily dim light, NASA explained. Hubble measurements determined that the phantom stars are rich in heavier elements like oxygen, carbon, and nitrogen. This means the scattered stars must be second or third-generation stars enriched with the elements forged in the hearts of the universes first-generation stars.

Spiral galaxies like the ones believed to be torn apart can sustain ongoing star formation that creates chemically-enriched stars, the US space agency added. Weighing more than 4 trillion solar masses, Abell 2744 is a target in the Frontier Fields program. This ambitious three-year effort teams Hubble and NASAs other Great Observatories to look at select massive galaxy clusters to help astronomers probe the remote universe.

Galaxy clusters are so massive that their gravity deflects light that passes through them. As a result, that light becomes brighter, magnified and distorted due to what is known as gravitational lensing. This phenomenon is exploited by astronomers, who use these clusters like a zoom lens to get a better look at distant galaxies that would otherwise be too faint for even telescopes as powerful as Hubble to detect.

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Ghost Light From Distant Dead Galaxies Detected By Hubble Telescope