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News Article
Site: http://phys.org/space-news/

"As Hubble makes its 26th revolution around our home star, the sun, we celebrate the event with a spectacular image of a dynamic and exciting interaction of a young star with its environment. The view of the Bubble Nebula, crafted from WFC-3 images, reminds us that Hubble gives us a front row seat to the awe inspiring Universe we live in," said John Grunsfeld, Hubble astronaut and associate administrator of NASA's Science Mission Directorate at NASA Headquarters, in Washington, D.C. The Bubble Nebula is 7 light-years across—about one-and-a-half times the distance from our sun to its nearest stellar neighbor, Alpha Centauri, and resides 7,100 light-years from Earth in the constellation Cassiopeia. The seething star forming this nebula is 45 times more massive than our sun. Gas on the star gets so hot that it escapes away into space as a "stellar wind" moving at over 4 million miles per hour. This outflow sweeps up the cold, interstellar gas in front of it, forming the outer edge of the bubble much like a snowplow piles up snow in front of it as it moves forward. As the surface of the bubble's shell expands outward, it slams into dense regions of cold gas on one side of the bubble. This asymmetry makes the star appear dramatically off-center from the bubble, with its location in the 10 o'clock position in the Hubble view. Dense pillars of cool hydrogen gas laced with dust appear at the upper left of the picture, and more "fingers" can be seen nearly face-on, behind the translucent bubble. The gases heated to varying temperatures emit different colors: oxygen is hot enough to emit blue light in the bubble near the star, while the cooler pillars are yellow from the combined light of hydrogen and nitrogen. The pillars are similar to the iconic columns in the "Pillars of Creation" Eagle Nebula. As seen with the structures in the Eagle Nebula, the Bubble Nebula pillars are being illuminated by the strong ultraviolet radiation from the brilliant star inside the bubble. The Bubble Nebula was discovered in 1787 by William Herschel, a prominent British astronomer. It is being formed by a proto-typical Wolf-Rayet star, BD +60º2522, an extremely bright, massive, and short-lived star that has lost most of its outer hydrogen and is now fusing helium into heavier elements. The star is about 4 million years old, and in 10 million to 20 million years, it will likely detonate as a supernova. Hubble's Wide Field Camera 3 imaged the nebula in visible light with unprecedented clarity in February 2016. The colors correspond to blue for oxygen, green for hydrogen, and red for nitrogen. This information will help astronomers understand the geometry and dynamics of this complex system. The Bubble Nebula is one of only a handful of astronomical objects that have been observed with several different instruments onboard Hubble. Hubble also imaged it with the Wide Field Planetary Camera (WFPC) in September of 1992, and with Wide Field Planetary Camera 2 (WFPC2) in April of 1999. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.


News Article | January 29, 2016
Site: http://www.techtimes.com/rss/sections/science.xml

NASA's Hubble Space Telescope records a giant cloud of fiery gas taking a trajectory path as it goes back to the Earth's galaxy at a staggering speed of 700,000 mph. Normally, hundreds of high-velocity clouds pass through the borders of the galaxy. They move at constant speed and paths so they are kept out of the galactic plane. However, the fiery gas, dubbed the Smith Cloud, is considered unique since its route is well-studied. A doctoral astronomy student, Gail Smith, discovered the Smith Cloud in the '60s. It is much more distant and moves towards the Milky Way at an incredibly rapid speed. Astronomers suggest that this cloud was hurled from the external areas of the galactic plane by about 70 million years ago. Data shows that the giant cloud is likely to collide with the galaxy's disk in 30 million years, a long time for humans but a very short time for the galaxy. "Our galaxy is recycling its gas through clouds, the Smith Cloud being one example, and will form stars in different places than before. Hubble's measurements of the Smith Cloud are helping us to visualize how active the disks of galaxies are," Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, said. Since its discovery, astronomers have assumed that the cloud may be a starless galaxy. For the first time, thanks to the Hubble Space Telescope, they were able to observe and determine the amount of heavier elements relative to helium and hydrogen. They also identified sulfur in the cloud, which is known to absorb ultraviolet light. As expected, they found that the cloud is copious in sulfur, which means it was supplemented by compounds from stars. This somehow sheds light on the mystery of the Smith Cloud and its origin. Many other issues, however, arise. It is yet to be explained how it reached where it is today and what event happened that propelled it from the Milky Way's galactic disk. Future research will further elaborate on the Smith Cloud as to where it came from.


News Article
Site: http://phys.org/space-news/

GN-z11, as they named it, seemed small, reddish and unexpectedly bright. It appeared far away even by cosmic standards. But because it was beyond the optimal reach of NASA's Hubble Space Telescope, it left them puzzled. Now they're certain it represents history. The international team, which includes an astronomer based in Baltimore, pushed Hubble to its limits this year to demonstrate that GN-z11 is the most distant galaxy ever observed. "The light that left this galaxy that we're observing now left the galaxy 13.4 billion years ago," said Gabriel Brammer, an astronomer at the Space Telescope Science Institute in Baltimore and the study's second author. "As far as we know, the universe itself is about 13.8 billion years old. We're seeing a galaxy as it was when the universe was about 3 percent of its current age." The light from GN-z11 is 200 million years closer to the Big Bang than that of the previous record-holder, a galaxy called EGSY8p7 that was found last year. That puts GN-z11 about 32 billion light years away. Because expansion of the universe over billions of years makes distance calculation complex, astronomers generally represent distance as a function of time -how long it takes light rays originating at a given object to reach us. Another way they express distance is through a unit of measurement called redshift. The farther away an object, the longer - and therefore redder - the light wavelengths are when they reach us. The spectroscopic redshift of EBSY8p7 was measured at a sizable 8.8, then believed to be at or beyond the outer edge of Hubble's range. GN-z11 has a redshift of 11.1, such a big jump that few saw it coming. The findings - described in a recent article in The Astrophysical Journal - give scientists what appears to be their best view yet of conditions near the end of the so-called Dark Ages of the Universe, when the cosmos was still opaque and just before the first stars and quasars formed. "We've taken a major step back in time, beyond what we'd ever expected to be able to do with Hubble," said Pascal Oesch, a Yale University astronomer and the study's principal investigator. Oesch and his team discovered GN-z11 in 2014 during a routine survey of a small patch of sky. In addition to taking note of the galaxy, they used imaging from both the orbiting Hubble - the most powerful telescope in history - and NASA's Spitzer Space Telescope, an infrared instrument in Pasadena, Calif., to ascertain its color to estimate its distance. They came up with an estimated redshift of 10.2, which in itself would have been a record for Hubble, but the image came with enough visual interference, or "noise," that the number had a sizable margin of error. Also, Brammer said, team members couldn't be sure they weren't seeing an "interloper" - a much closer object - by mistake. But the galaxy's unusual brightness gave investigators a lucky second option: to use a more exacting measurement method known as spectroscopy - a way of splitting the visible light into its component colors - to firm up the distance estimate. Analyzed with this method, GN-z11 registered the record redshift of 11.1 - and it exhibited many of the clear properties of an infant galaxy, not an interloper. For one thing, the team found, even though it's only 0.04 percent the size of our Milky Way galaxy, GN-z11 appears to be forming stars at a staggering rate, about three times more rapidly than expected and 20 times more quickly than the Milky Way. That, they say, is why it's so much more luminous than many models predicted. "Our earlier work had suggested that such bright galaxies should not exist so early in the universe," Marijn Franx, a team member from the University of Leiden in the Netherlands, told Astronomy Magazine. "What we're seeing is young stars, massive stars, stars just being formed. At first glance, this galaxy appeared to be red, but that was because it's so far away. On closer look, it's actually very blue," Oesch said. Hubble has amassed hundreds of images of galaxies in the range of redshift 7 or 8 in its 26-year existence, Brammer said, allowing astronomers to develop a relatively clear picture of those galaxies' general properties - their star formation rates, their chemical makeup, their brightness - at those times and distances. That has helped scientists create a fuller, more credible map of how the universe evolved back to about half a billion years after the Big Bang. It's harder to extrapolate such a clear picture from a single example of a redshift higher than 11, but astronomers say it's still striking to see evidence that at least one galaxy was up, running and fully active so much earlier than many previously believed. Astronomers believed there had to be a sizable time gap between the Big Bang and the eras in which the first stars took shape, forming the groups that would become galaxies, Oesch said. The team's work suggests the gap is smaller and the primordial population more active. Some in the field remain skeptical of the findings. Astronomer Richard Ellis of the European Southern Observatory said in an email that the luminosity the group claims is three times higher than that of similar bodies "at much later times," and that astronomers seeking to measure distances greater than redshift 10 usually do so in conjunction with powerful ground-based telescopes such as the ones at the W.M. Keck Observatory in Hawaii. Ellis said, "The ultimate proof can only come from a higher resolution spectrum such as those published for previous record-holders, either via a long integration with a ground-based telescope or, shortly, with the James Webb Space Telescope" - the Hubble's more powerful successor, which is now under construction and expected to be launched in 2018. Everyone agrees that the Hubble has looked as far off in the universe as it's going to, given the size of its primary mirror (2.4 meters in diameter) and other limitations. The Space Telescope Science Institute, which calibrates Hubble's instruments and interprets its raw data, is well along in the process of helping NASA build the Webb telescope, with a 6.5-meter mirror. Astronomers say Hubble's recent feats suggest the Webb will routinely be able to look farther, providing better answers to what Oesch calls "the very, very big" questions. "Where do these galaxies come from? Where did we all come from? Where did everything start?" he asked. "That's what we're really asking. We're getting closer all the time." Explore further: Spitzer and Hubble telescopes find rare galaxy at dawn of time


News Article | February 1, 2016
Site: http://www.techtimes.com/rss/sections/science.xml

To form new stars, galaxies depend on a hydrogen gas supply. When the galactic food supply runs out, galaxies can't form new stars but survive using its own gas reservoir. At this point, galaxies are believed to be on a downhill slope towards its imminent death. Along with several scientists, Swiss Federal Institute of Technology Zurich professor Kevin Schawinski conducted an investigation to determine the current shape of galaxies. They found that our Milky Way is nearing its end. In fact, it may have actually died billions of years ago already. This means, the Earth is living in the so-called "zombie galaxy." But a new food supply is on its way. The Hubble space telescope detected a giant cloud of fiery gas hurling towards the Milky Way at breakneck speed. The gas cloud was dubbed the "Smith Cloud" and named after PhD astronomy student Gail Smith who first discovered it in the 1960s. Ironically, the Smith Cloud has been rotating around the Milky Way's outskirts in the past 70 million years. It was once part of our own galaxy but was booted out in millions of years ago. Like the prodigal son, it's coming back home. The Smith Cloud is currently traveling towards the Milky Way at approximately 700,000 miles per hour. If the Smith Cloud will become visible from Earth, it would have the diameter of 30 times bigger than the size of a full moon. What comes up must come down. The old saying is true even in space. Experts said the Smith Cloud will probably reach the outskirts of the Milky Way in about 30 million years. Its entrance location is light years away from Earth but it doesn't mean that the Smith Cloud collision won't affect our solar system. The collision will give birth to new stars and will provide enough gas to generate 2 million suns. "It's telling us that the Milky Way is a bubbling, very active place where gas can be thrown out of one part of the disk and then return back down into another," said Andrew Fox from the Space Telescope Science Institute, stressing that the Smith Cloud shows the galaxy is evolving with time.


News Article | January 30, 2016
Site: http://www.techtimes.com/rss/sections/science.xml

Experts say the Milky Way is dying or have actually already died, implying that we are already living in a zombie galaxy. There is a way to bring it back from the undead though, as a giant cloud of fiery gas is on its way to save the day. Kevin Schawinski, a professor from Swiss Federal Institute of Technology Zurich collaborated with citizen scientists to help him classify galaxies, particularly its shape. Schawinski gets a consensus about the shape of the galaxies and delve into how this classification influences the lifespan of galaxies. As he goes through with his investigation, he realized that the Milky Way may be slowly shutting down or may have completely died many years ago. "It's entirely possible that the Milky Way galaxy is a zombie, having died a billion years ago," he writes. Galaxies thrive through a supply of hydrogen gas so it can form new stars. When this food supply runs out and star formation stops, then it is a signal that the galaxy is about to reach its end. Gas conversion continues just like in factories, but imagine the day when the supply of raw materials, or in the case of galaxies, fresh outside gas, runs out. What is there left to process? Such possibility leaves just the remaining gas and its reservoir. Since the reservoir is massive and the gas formation is slow, just like in the Milky Way, it continues to look alive with new stars. The truth is, the rate of star formation plummets over several billion years. There are two types of galaxies in terms of star formation. The first one is the blue star-forming galaxies and the red passively-evolving galaxies. There is another one and it is represented by the green color. Galaxies living in the so-called "green valley" have star formations in the brink of turning off. Star formation still continues, indicating that the process has just stopped, probably a hundred million years ago. The Milky Way may possibly belong to this category. Help On The Way A new capture of the Hubble space telescope implies that help is on the way for our dear, dying galaxy. The telescope was able to detect a giant cloud of fiery gas that can help the galaxy continue its star formation and survive. Called the "Smith Cloud," this giant gas is hurtling towards the Milky Way at 700,000 miles per hour. Experts say it may be a part of the Milky Way 70 million years ago and is now boomeranging home with a large bag of goodies: sufficient hydrogen and helium gas supply that is enough to form 2 million suns. "The cloud is an example of how the galaxy is changing with time," says Andrew Fox from the Space Telescope Science Institute. Whether there is truth to the Milky Way being at the edge of the green valley or not, people may find peace in the fact that the Hubble was able to detect the Smith Cloud, which will hit the galaxy about 30 million years from now.

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