Gaia: Here Comes the Sun

Gaia: Here Comes the Sun

What would it look like to return home from outside our galaxy?

Although designed to answer greater questions, recent data from ESA’s robotic Gaia mission is helping to provide a uniquelymodern perspective on humanity’s place in the universe. Gaia orbits the Sun near the Earth and resolves star’s positions so precisely that it can determine a slight shift from its changing vantage point over the course of a year, a shift that is proportionately smaller for more distant stars — and so determines distance.

In the first sequence of the video, an illustration of the Milky Way is shown that soon resolves into a three-dimensional visualization of Gaia star data. A few notable stars are labelled with their common names, while others stars are labelled with numbers from Gaia’s catalog. Eventually the viewer arrives at our home star Sol (the Sun), then resolving the reflective glow of its third planet: Earth.

The featured video is based on just over 600,000 stars, but Gaia is on track to measure the parallax distances to over one billion stars over its planned five year mission.

Credit: Galaxy Illustration: Nick Risinger (skysurvey.org), Star Data: Gaia Mission, ESA, Antoni Sagristà Sellés (U. Heidelberg) et al.

Milky Way’s Center Unveils Supernova ‘Dust Factory’

Milky Way’s Center Unveils Supernova ‘Dust Factory’

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Sifting through the center of the Milky Way galaxy, astronomers have made the first direct observations – using an infrared telescope aboard a modified Boeing 747 – of cosmic building-block dust resulting from an ancient supernova.

“Dust itself is very important because it’s the stuff that forms stars and planets, like the sun and Earth, respectively, so to know where it comes from is an important question,” said lead author Ryan Lau, Cornell postdoctoral associate for astronomy, in research published March 19 in Science Express. “Our work strongly reinforces the theory that supernovae are producing the dust seen in galaxies of the early universe,” he said.

Lau explains that one of astronomy’s big questions is why galaxies – forming as recently as 1 billion years after the Big Bang – contain so much dust. The leading theory is that supernovae – stars that explode at the end of their lives – contain large amounts of metal-enriched material that, in turn, harbors key ingredients of dust, like silicon, iron and carbon.

The astronomers examined Sagittarius A East, a 10,000-year-old supernova remnant near the center of our galaxy. Lau said that when a supernova explodes, the materials in its center expand and form dust. This has been observed in several young supernova remnants – such as the famed SN1987A and Cassiopeia A. In the turbulent supernova environment, scientists expect the churning dust to be destroyed. “That is theoretically,” Lau said. “There have been no direct observations of any dust surviving the environment of the supernova remnant … until now, and that’s why our observations of an ‘old’ supernova are so important,” he said.

The astronomers captured the observations via FORCAST (the Faint Object Infrared Camera Telescope) aboard SOFIA (the Stratospheric Observatory for Infrared Astronomy), a modified Boeing 747 and a joint project of NASA, the German Aerospace Center and the Universities Space Research Association. It is the world’s largest airborne astronomical observatory. Currently, no space-based telescope can observe at far-infrared wavelengths, and ground-based telescopes are unable to observe light at these wavelengths due to the Earth’s atmosphere.

Story Source:

The above story is based on materials provided by Cornell University. The original article was written by Blaine Friedlander. Note: Materials may be edited for content and length.

The Corrugated Galaxy: Milky Way May Be Much Larger Than Previously Estimated

The Corrugated Galaxy: Milky Way May Be Much Larger Than Previously Estimated

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The Milky Way galaxy is at least 50 percent larger than is commonly estimated, according to new findings that reveal that the galactic disk is contoured into several concentric ripples. The research, conducted by an international team led by Rensselaer Polytechnic Institute Professor Heidi Jo Newberg, revisits astronomical data from the Sloan Digital Sky Survey which, in 2002, established the presence of a bulging ring of stars beyond the known plane of the Milky Way. “In essence, what we found is that the disk of the Milky Way isn’t just a disk of stars in a flat plane—it’s corrugated,” said Heidi Newberg, professor of physics, applied physics, and astronomy in the Rensselaer School of Science. “As it radiates outward from the sun, we see at least four ripples in the disk of the Milky Way.

While we can only look at part of the galaxy with this data, we assume that this pattern is going to be found throughout the disk.” Importantly, the findings show that the features previously identified as rings are actually part of the galactic disk, extending the known width of the Milky Way from 100,000 light years across to 150,000 light years, said Yan Xu, a scientist at the National Astronomical Observatories of China (which is part of the Chinese Academy of Science in Beijing), former visiting scientist at Rensselaer, and lead author of the paper. “Going into the research, astronomers had observed that the number of Milky Way stars diminishes rapidly about 50,000 light years from the center of the galaxy, and then a ring of stars appears at about 60,000 light years from the center,” said Xu. “What we see now is that this apparent ring is actually a ripple in the disk.

And it may well be that there are more ripples further out which we have not yet seen.” The research, funded in part by the National Science Foundation and titled “Rings and Radial Waves in the Disk of the Milky Way,” was published today in the Astrophysical Journal. Newberg, Xu, and their collaborators used data from the Sloan Digital Sky Survey (SDSS) to show an oscillating asymmetry in the main sequence star counts on either side of the galactic plane, starting from the sun and looking outward from the galactic center. In other words, when we look outward from the sun, the mid-plane of the disk is perturbed up, then down, then up, and then down again. “Extending our knowledge of our galaxy’s structure is fundamentally important,” said Glen Langston, NSF program manager. “The NSF is proud to support their effort to map the shape of our galaxy beyond previously unknown limits.”

The new research builds upon a 2002 finding in which Newberg established the existence of the “Monoceros Ring,” an “over-density” of stars at the outer edges of the galaxy that bulges above the galactic plane. At the time, Newberg noticed evidence of another over-density of stars, between the Monoceros Ring and the sun, but was unable to investigate further. With more data available from the SDSS, researchers recently returned to the mystery. “I wanted to figure out what that other over-density was,” Newberg said. “These stars had previously been considered disk stars, but the stars don’t match the density distribution you would expect for disk stars, so I thought ‘well, maybe this could be another ring, or a highly disrupted dwarf galaxy.”  When they revisited the data, they found four anomalies: one north of the galactic plane at 2 kilo-parsecs (kpc) from the sun, one south of the plane at 4-6 kpc, a third to the north at 8-10 kpc, and evidence of a fourth to the south 12-16 kpc from the sun. The Monoceros Ring is associated with the third ripple.

The researchers further found that the oscillations appear to line up with the locations of the galaxy’s spiral arms. Newberg said the findings support other recent research, including a theoretical finding that a dwarf galaxy or dark matter lump passing through the Milky Way would produce a similar rippling effect. In fact, the ripples might ultimately be used to measure the lumpiness of dark matter in our galaxy.  “It’s very similar to what would happen if you throw a pebble into still water – the waves will radiate out from the point of impact,” said Newberg. “If a dwarf galaxy goes through the disk, it would gravitationally pull the disk up as it comes in, and pull the disk down as it goes through, and this will set up a wave pattern that propagates outward. If you view this in the context of other research that’s emerged in the past two to three years, you start to see a picture is forming.”

The research was funded by the NSF, as well as the Chinese National Science Foundation and the National Basic Research Program of China. Newberg currently researches the structure and evolution of our own galaxy, using stars as tracers of the galactic halo and disks. These stars in turn are used to trace the density distribution of dark matter in the Milky Way. She has been a participant of the Sloan Digital Sky Survey and is currently head of participants in LAMOST U.S., a partnership allowing U.S. astronomers to take part in a survey of more than 7 million stars by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope in China (LAMOST).

Story Source:

The above story is based on materials provided by Rensselaer Polytechnic Institute (RPI). Note: Materials may be edited for content and length.

Milky Way Core Drives Wind At 2 Million Miles Per Hour

Milky Way Core Drives Wind At 2 Million Miles Per Hour

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At a time when our earliest human ancestors had recently mastered walking upright, the heart of our Milky Way galaxy underwent a titanic eruption, driving gases and other material outward at 2 million miles per hour.

Now, at least 2 million years later, astronomers are witnessing the aftermath of the explosion: billowing clouds of gas towering about 30,000 light-years above and below the plane of our galaxy.

The enormous structure was discovered five years ago as a gamma-ray glow on the sky in the direction of the galactic center. The balloon-like features have since been observed in X-rays and radio waves. But astronomers needed NASA’s Hubble Space Telescope to measure for the first time the velocity and composition of the mystery lobes. They now seek to calculate the mass of the material being blown out of our galaxy, which could lead them to determine the outburst’s cause from several competing scenarios.

Astronomers have proposed two possible origins for the bipolar lobes: a firestorm of star birth at the Milky Way’s center or the eruption of its supermassive black hole. Although astronomers have seen gaseous winds, composed of streams of charged particles, emanating from the cores of other galaxies, they are getting a unique, close-up view of our galaxy’s own fireworks.

“When you look at the centers of other galaxies, the outflows appear much smaller because the galaxies are farther away,” said Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, lead researcher of the study. “But the outflowing clouds we’re seeing are only 25,000 light-years away in our galaxy. We have a front-row seat. We can study the details of these structures. We can look at how big the bubbles are and can measure how much of the sky they are covering.”

Fox’s results will be published in The Astrophysical Journal Letters and will be presented at the American Astronomical Society meeting in Seattle, Washington.

The giant lobes, dubbed Fermi Bubbles, initially were spotted using NASA’s Fermi Gamma-ray Space Telescope. The detection of high-energy gamma rays suggested that a violent event in the galaxy’s core aggressively launched energized gas into space. To provide more information about the outflows, Fox used Hubble’s Cosmic Origins Spectrograph (COS) to probe the ultraviolet light from a distant quasar that lies behind the base of the northern bubble. Imprinted on that light as it travels through the lobe is information about the velocity, composition, and temperature of the expanding gas inside the bubble, which only COS can provide.

Fox’s team was able to measure that the gas on the near side of the bubble is moving toward Earth and the gas on the far side is travelling away. COS spectra show that the gas is rushing from the galactic center at roughly 2 million miles an hour (3 million kilometers an hour).

“This is exactly the signature we knew we would get if this was a bipolar outflow,” explained Rongmon Bordoloi of the Space Telescope Science Institute, a co-author on the science paper. “This is the closest sightline we have to the galaxy’s center where we can see the bubble being blown outward and energized.”

The COS observations also measure, for the first time, the composition of the material being swept up in the gaseous cloud. COS detected silicon, carbon, and aluminum, indicating that the gas is enriched in the heavy elements produced inside stars and represents the fossil remnants of star formation.

COS measured the temperature of the gas at approximately 17,500 degrees Fahrenheit, which is much cooler than most of the super-hot gas in the outflow, thought to be at about 18 million degrees Fahrenheit. “We are seeing cooler gas, perhaps interstellar gas in our galaxy’s disk, being swept up into that hot outflow,” Fox explained.

This is the first result in a survey of 20 faraway quasars whose light passes through gas inside or just outside the Fermi Bubbles — like a needle piercing a balloon. An analysis of the full sample will yield the amount of mass being ejected. The astronomers can then compare the outflow mass with the velocities at various locations in the bubbles to determine the amount of energy needed to drive the outburst and possibly the origin of the explosive event.

One possible cause for the outflows is a star-making frenzy near the galactic center that produces supernovas, which blow out gas. Another scenario is a star or a group of stars falling onto the Milky Way’s supermassive black hole. When that happens, gas superheated by the black hole blasts deep into space. Because the bubbles are short-lived compared to the age of our galaxy, it suggests this may be a repeating phenomenon in the Milky Way’s history. Whatever the trigger is, it likely occurs episodically, perhaps only when the black hole gobbles up a concentration of material.

“It looks like the outflows are a hiccup,” Fox said. “There may have been repeated ejections of material that have blown up, and we’re catching the latest one. By studying the light from the other quasars in our program, we may be able to detect the fossils of previous outflows.”

Galactic winds are common in star-forming galaxies, such as M82, which is furiously making stars in its core. “It looks like there’s a link between the amount of star formation and whether or not these outflows happen,” Fox said. “Although the Milky Way overall currently produces a moderate one to two stars a year, there is a high concentration of star formation close to the core of the galaxy.”

At a time when our earliest human ancestors had recently mastered walking upright, the heart of our Milky Way galaxy underwent a titanic eruption, driving gases and other material outward at 2 million miles per hour.

Now, at least 2 million years later, astronomers are witnessing the aftermath of the explosion: billowing clouds of gas towering about 30,000 light-years above and below the plane of our galaxy.

The enormous structure was discovered five years ago as a gamma-ray glow on the sky in the direction of the galactic center. The balloon-like features have since been observed in X-rays and radio waves. But astronomers needed NASA’s Hubble Space Telescope to measure for the first time the velocity and composition of the mystery lobes. They now seek to calculate the mass of the material being blown out of our galaxy, which could lead them to determine the outburst’s cause from several competing scenarios.

Astronomers have proposed two possible origins for the bipolar lobes: a firestorm of star birth at the Milky Way’s center or the eruption of its supermassive black hole. Although astronomers have seen gaseous winds, composed of streams of charged particles, emanating from the cores of other galaxies, they are getting a unique, close-up view of our galaxy’s own fireworks.

“When you look at the centers of other galaxies, the outflows appear much smaller because the galaxies are farther away,” said Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, lead researcher of the study. “But the outflowing clouds we’re seeing are only 25,000 light-years away in our galaxy. We have a front-row seat. We can study the details of these structures. We can look at how big the bubbles are and can measure how much of the sky they are covering.”

Fox’s results will be published in The Astrophysical Journal Letters and will be presented at the American Astronomical Society meeting in Seattle, Washington.

The giant lobes, dubbed Fermi Bubbles, initially were spotted using NASA’s Fermi Gamma-ray Space Telescope. The detection of high-energy gamma rays suggested that a violent event in the galaxy’s core aggressively launched energized gas into space. To provide more information about the outflows, Fox used Hubble’s Cosmic Origins Spectrograph (COS) to probe the ultraviolet light from a distant quasar that lies behind the base of the northern bubble. Imprinted on that light as it travels through the lobe is information about the velocity, composition, and temperature of the expanding gas inside the bubble, which only COS can provide.

Fox’s team was able to measure that the gas on the near side of the bubble is moving toward Earth and the gas on the far side is travelling away. COS spectra show that the gas is rushing from the galactic center at roughly 2 million miles an hour (3 million kilometers an hour).

“This is exactly the signature we knew we would get if this was a bipolar outflow,” explained Rongmon Bordoloi of the Space Telescope Science Institute, a co-author on the science paper. “This is the closest sightline we have to the galaxy’s center where we can see the bubble being blown outward and energized.”

The COS observations also measure, for the first time, the composition of the material being swept up in the gaseous cloud. COS detected silicon, carbon, and aluminum, indicating that the gas is enriched in the heavy elements produced inside stars and represents the fossil remnants of star formation.

COS measured the temperature of the gas at approximately 17,500 degrees Fahrenheit, which is much cooler than most of the super-hot gas in the outflow, thought to be at about 18 million degrees Fahrenheit. “We are seeing cooler gas, perhaps interstellar gas in our galaxy’s disk, being swept up into that hot outflow,” Fox explained.

This is the first result in a survey of 20 faraway quasars whose light passes through gas inside or just outside the Fermi Bubbles — like a needle piercing a balloon. An analysis of the full sample will yield the amount of mass being ejected. The astronomers can then compare the outflow mass with the velocities at various locations in the bubbles to determine the amount of energy needed to drive the outburst and possibly the origin of the explosive event.

One possible cause for the outflows is a star-making frenzy near the galactic center that produces supernovas, which blow out gas. Another scenario is a star or a group of stars falling onto the Milky Way’s supermassive black hole. When that happens, gas superheated by the black hole blasts deep into space. Because the bubbles are short-lived compared to the age of our galaxy, it suggests this may be a repeating phenomenon in the Milky Way’s history. Whatever the trigger is, it likely occurs episodically, perhaps only when the black hole gobbles up a concentration of material.

Story Source:

The above story is based on materials provided by Space Telescope Science Institute (STScI). Note: Materials may be edited for content and length.

You Won’t Believe How Beautiful The Night Sky Can Be

You Won’t Believe How Beautiful The Night Sky Can Be

We present you some of the most amazing night sky photos by Mike Taylor .
He has been working as a  photographer for 20 years.
Here are few words from Mike;

I have always been a “night owl” – I can remember sneaking out of the back door of my home as a teenager on warm summer nights to go sit somewhere in my neighborhood and wonder about Man’s existence while looking up at the stars. Most folks are so busy with day-to-day life that they rarely contemplate the radical idea that we all live on a small rock which is rotating and flying through the cosmos at a speed we can barely fathom.

Observing and photographing the features of the night sky is an awe-inspiring experience that so few people ever get to enjoy. The atmosphere of the night, the sights and sounds, are so very contrary from normal daytime hours that it is literally a different world – a radical world of diffused light, excessive shadows and noises that you will simply never see or hear when the sun is up. These existential awakenings always spark my inner child to marvel at the world again. There is so much to see, so much to hear, so much to enjoy during the dark hours of each day – the Moon, the stars, the Milky Way, the occasional meteor, and the spectacular Northern Lights displays.

 

1 Three AmigosThe Three Amigos – Landscape Astrophotographers on Maine’s Bold Coast.

 

1 marshall pt pano 2This is a 7 image panorama of the Milky Way rising over the Atlantic Ocean at Marshall Point Lighthouse – Port Clyde, Maine. Photographed August 5, 2013.

 

1 mm milky way & star trails 2The Motion of the Night Sky

81 frames from a static time lapse of the Milky Way moving across the sky. Mike stacked the frames of this sequence to make a standard star trails image and then blended/masked in a single frame of the Milky Way.

 

Albion Aurora IIAn intense October aurora in central Maine!

 

1 Pemaquid MW Star TrailsStar Trails & The Milky Way At Pemaquid Point Lighthouse

This image is a composite of 65 frames from a static time lapse of the Milky Way moving across the sky. Mike stacked the frames of this sequence to make a standard star trails image and then blended/masked in a single frame of the Milky Way. Shooting straight into the light at a lighthouse tower is always difficult but I like the final result here. And oh yeah this is also a selfie because I jumped into the last frame and pointed at the sky.

 

1 MW at MPL RE-EDITSpring Milky Way at Marshall Point Light

 The Milky Way makes a dramatic background for Marshall Point Light in Port Clyde, Maine. This is one single shot, not a composite image. I light-painted the foreground rocks and the tower with a flashlight.

Aurora At Unity Pond 1Aurora At Unity Pond #1 – one frame captured at 2:36 AM from a time lapse that I set up on the train tracks next to Unity Pond, Maine. Photographed May 18, 2013.

 

Bog Brook Milky WayThe Milky Way rises along the Bold Coast of Maine. Photographed September 8, 2013.

 

December AuroraFeatures of the Night Sky

 The familiar green and pink hues of the Aurora Borealis light up the background of this image which also features the North end of the Milky Way and the Andromeda galaxy. Photographed at a Mike’s friend farmhouse in central Maine.

Katahdin Star TrailsThis is 90 frames stacked from a 45 minute static time lapse Mike set up on the edge of Sunday Pond, Maine located about 6 miles South of Mt Katahdin – truly dark sky country.

 

Lily Bay Boatlaunch 2The Milky Way reflecting in the calm waters at the Dunn Point boat launch in Lily Bay State Park – Moosehead Lake, Maine. Photographed October 3, 2013.

 

Long Exposure Ocean ShotThis is a 3 minute exposure shooting out over the Atlantic Ocean on the Eastern Shore of Maryland. Orion the Hunter can be seen in the upper right-hand corner.

 

Moosehead Lake AuroraThe awe-inspiring green and red hues of the Northern Lights spiked and swirled on the horizon while Mike was photographing the night sky next to Mt. Kineo at Moosehead Lake – October 10, 2013.

 

mw @ pemquid shack 3Milky Way at Pemaquid III

The Milky Way rising above the Atlantic Ocean just a few feet away from Pemaquid Point Light in Bristol, Maine. The small brick building bordering the rocks was used to store fuel for the lighthouse before it became automated. Photographed June 16, 2013.

MW & Trees at Sand BeachThe “other end” of the Milky Way photographed at Sand Beach in Acadia National Park, Maine.

 

Northern Lights & Milky Way at Pemaquid 2The Northern Lights and part of the Milky Way photographed at Pemaquid Point Light at 5:09 AM – March 17, 2013.

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Credit: Mike Taylor