Tag Archive: Milky Way


Astronomers at the European Southern Observatory’s Paranal Observatory in Chile have released a breathtaking new photograph showing the central area of our Milky Way galaxy. The photograph shows a whopping 84 million stars in an image measuring 108500×81500, which contains nearly 9 billion pixels.

It’s actually a composite of thousands of individual photographs shot with the observatory’s VISTA survey telescope, the same camera that captured the amazing 55-hour exposure that we shared back in March. Three different infrared filters were used to capture the different details present in the final image.

The VISTA’s camera is sensitive to infrared light, which allows its vision to pierce through much of the space dust that blocks the view of ordinary optical telescope/camera systems.

To give you an idea of how crazy this photo is (and what 84 million stars looks like), here are a couple of 100% crops we made while fully zoomed in. The first one shows the bright area seen in the center of the frame:

The Atlantic notes that if you were to print out this image as a standard book photograph, it would be nearly 30-feet wide and 23-feet tall.

Check out the zoomable version of the photograph yourself to get a sense of how massive this photo (and space) is.

Many Earths

Space is vast, but it may not be so lonely after all: A study finds the Milky Way is teeming with billions of planets that are about the size of Earth, orbit stars just like our sun, and exist in the Goldilocks zone — not too hot and not too cold for life.

Astronomers using NASA data have calculated for the first time that in our galaxy alone, there are at least 8.8 billion stars with Earth-size planets in the habitable temperature zone.

The study was published Monday in the journal Proceedings of the National Academy of Science.

For perspective, that’s more Earth-like planets than there are people on Earth.

As for what it says about the odds that there is life somewhere out there, it means “just in our Milky Way galaxy alone, that’s 8.8 billion throws of the biological dice,” said study co-author Geoff Marcy, a longtime planet hunter from the University of California at Berkeley.

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OUR home galaxy has been weighed, and it is surprisingly lean. The latest gauge of the dark matter mass of the Milky Way suggests it weighs only a quarter to a third of the amount previously estimated.

This could explain the dearth of smaller galaxies buzzing around the Milky Way. But it also means we may live in a cosmic anomaly.

It is thought the first galaxies were born as normal matter coalesced around globs of dark matter, the invisible stuff thought to make up about 80 per cent of the matter in the universe. We can’t see dark matter itself, but we can trace its effects in the motions of stars in modern galaxies.

Stars on the edges of large spirals like the Milky Way are orbiting so fast that they should fly off, so something must be holding on to them. That thing is thought to be a halo of dark matter encircling the visible disc.

Knowing our galaxy’s total mass will tell us a lot about it. “Is our Milky Way typical, or is it actually quite weird?” asks Alis Deason of the University of California, Santa Cruz.

A smattering of stars live in the Milky Way’s dark matter halo, and previous studies have used their motion to figure out the halo’s mass. But we are embedded in a spiral arm, which means dust and gas blocks much of our view of our relatively flat galaxy, so those models had to make assumptions about the parts we can’t see.

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It has long been believed that our solar system has a tail, just like any other object moving through another medium. This movement causes particles to form a tail behind it. However, the tail of our heliosphere has been a theory, something never seen. NASA’s Interstellar Boundary Explorer (IBEX) has mapped this tail, something that might have once been considered impossible.

The tail, which scientists are calling the heliotail, was mapped out after combining observations from three years of images taken by IBEX. Looking at these images, astronomers discovered that the heliotail consists of two lobes of slower particles on its sides with faster particles above and below that. This gives the tail a twisted appearance as it undergoes the pushing and pulling of magnetic fields outside the solar system.

David McComas, principal investigator for IBEX at Southwest Research Institute in San Antonio, Texas, said:

“By examining the neutral atoms, IBEX made the first observations of the heliotail. Many models have suggested the heliotail might be like this or like that, but we’ve had no observations. We always drew pictures where the tail of the heliosphere just disappears off the page, since we couldn’t even speculate about what it really looked like.”

Tails around stars have been spotted by telescopes before, but it has been difficult to see our own. Conventional methods to view the heliotail have been difficult because the particles in the tail and throughout the heliosphere don’t shine. However, IBEX can map this area by measuring neutral particles created by collisions at the edge of the heliosphere. This data about what the heliotail looks like offers a new understanding of our movement through the galaxy.

“The tail is our footprint on the galaxy, and it’s exciting that we’re starting to understand the structure of it,” said Eric Christian, IBEX mission scientist at NASA’s Goddard Space Flight Center. “The next step is to incorporate these observations into our models and start the process of really understanding our heliosphere.”

Scientists have observed in unprecedented detail the birth of a massive star within a dark cloud core about 10,000 light years from Earth.

The team used the new ALMA (Atacama Large Millimetre/submillimetre Array) telescope in Chile – the most powerful radio telescope in the world – to view the stellar womb which, at 500 times the mass of the Sun and many times more luminous, is the largest ever seen in our galaxy.

The researchers say their observations – to be published in the journal Astronomy and Astrophysics – reveal how matter is being dragged into the centre of the huge gaseous cloud by the gravitational pull of the forming star – or stars – along a number of dense threads or filaments.

“The remarkable observations from ALMA allowed us to get the first really in-depth look at what was going on within this cloud,” said lead author Dr Nicolas Peretto, from Cardiff University. “We wanted to see how monster stars form and grow, and we certainly achieved our aim. One of the sources we have found is an absolute giant — the largest protostellar core ever spotted in the Milky Way!

“Even though we already believed that the region was a good candidate for being a massive star-forming cloud, we were not expecting to find such a massive embryonic star at its centre. This cloud is expected to form at least one star 100 times more massive than the Sun and up to a million times brighter. Only about one in 10,000 of all the stars in the Milky Way reach that kind of mass.”

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Artists impression of the invisible Van Allen radiation belts. Credit: NASA

Researchers say data from NASA space probes has forced a revision of theories about radiation belts around the Earth just a few thousand miles above our heads.

Instruments designed and built by the University of Colorado Boulder have returned new finding on the Van Allen radiation belts — donut-shaped rings of electrons that encircle the Earth that were one of the first discoveries of the space age.

Two spacecraft launched in 1958 carrying instruments built by James Van Allen showed the presence of two distinct rings of high-energy electrons.

A new NASA mission was launched Aug. 30 to learn more about the belts, which are known to be hazardous to satellites, astronauts and technological systems on Earth.

Just a few days after launch, CU-Boulder researcher said, the instruments on board returned a shocking result: the formation of a third radiation belt.

The instruments initially showed the expected two Van Allen belts, but after a few days the outer ring appeared to compress into an intense, tightly packed electron band and a third, less compact belt of electrons formed further out, creating a total of three rings.

The middle “storage ring” persisted as the belt furthest away from Earth began to decay away until a powerful interplanetary shockwave traveling from the sun virtually annihilated both the storage ring and the rest of the outer belt.

In the following months the Van Allen radiation zones re-formed into the originally expected two-belt structure, researchers said.

“We have no idea how often this sort of thing happens,” CU-Boulder researcher Dan Baker said. “This may occur fairly frequently but we didn’t have the tools to see it.”

The findings could yield better understanding of how and when solar storms can wreak havoc on Earth, researchers said.

“Nature presents us with this event — it’s there, it’s a fact, you can’t argue with it — and now we have to explain why it’s the case,” Shri Kanekal at NASA’s Goddard Space Flight Center in Greenbelt, Md., said. “Why did the third belt persist for four weeks? Why does it change? All of this information teaches us more about space.”

Researchers have discovered that dung beetles can navigate in straight lines using nothing more than the soft glow from our home galaxy.

That’s kind of awesome, but it’s worth asking, at this point, just why the heck dung beetles have any need to navigate. They find poo. They make poo into balls. They roll the balls off somewhere, and then lay their eggs in them and bury them. Seems straightforward, right? But that’s the amazing thing: it’s absolutely straightforward. Once a dung beetle has created a ball of poo, it heads away from the pile as fast as it can go in a dead nuts straight line. It goes around whatever obstacles are in its way, but continues going straight, which is quite remarkable considering that it’s often traveling backwards and partially upside-down.

So why do they care about straight lines? The answer seems to be that the beetles with poo balls are just trying to get away from all the other beetles in ’round the pile as fast as they possibly can.

Making a ball of excrement that’s larger than you are is a lot of work, and once you put one together, other beetles will try and steal it. The quickest and most efficient route of escape from a poo pile is a straight line, so that’s what the beetles do. They’re quite clever about it, too, able to sense when they’ve veered off course and using light from the sun to reorient themselves. That’s all well and good during the day, when the sun’s out, but what happens at night?

Research (performed by outfitting the beetles with little hats to block their view) has shown that the bugs’ compound eyes are sensitive enough to detect light from the Moon, the stars, and most impressively, the Milky Way itself. Apparenty, all a dung beetle needs is one fixed pattern in the sky that it can recognize, and then it’s able to use that pattern to make sure that it’s always moving in a straight line. Along with its giant ball of poo. Thank you, science!

100,000 Stars is a new experiment for Chrome web browsers (or any other WebGL browser like Firefox or Safari) that lets you interactively explore the Milky Way galaxy with your mouse and scroll wheel. MIND = BLOWN

100,000 Stars: An Interactive Exploration of the Milky Way Galaxy website space science interactive

100,000 Stars: An Interactive Exploration of the Milky Way Galaxy website space science interactive

Artist concept of the gas halo surrounding the Milky Way galaxy

Astronomers have used NASA’s Chandra X-ray Observatory to find evidence our Milky Way Galaxy is embedded in an enormous halo of hot gas that extends for hundreds of thousands of light years. The estimated mass of the halo is comparable to the mass of all the stars in the galaxy.

If the size and mass of this gas halo is confirmed, it also could be an explanation for what is known as the “missing baryon” problem for the galaxy.

Baryons are particles, such as protons and neutrons, that make up more than 99.9 percent of the mass of atoms found in the cosmos. Measurements of extremely distant gas halos and galaxies indicate the baryonic matter present when the universe was only a few billion years old represented about one-sixth the mass and density of the existing unobservable, or dark, matter. In the current epoch, about 10 billion years later, a census of the baryons present in stars and gas in our galaxy and nearby galaxies shows at least half the baryons are unaccounted for.

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What Earth looked like from between 13 billion years ago to how it will likely look 250 million years in the future.

Harvard scientists use 1,024-core supercomputer to produce a partial simulation of the life of the universe, modelling thousands of individual stars and galaxies with a Arepo, new software for cosmological simulations of galaxy formation across billions of years.

Our galaxy, the Milky Way, is a large spiral galaxy surrounded by dozens of smaller satellite galaxies. Scientists have long theorized that occasionally these satellites will pass through the disk of the Milky Way, perturbing both the satellite and the disk. A team of astronomers from Canada and the United States have discovered what may well be the smoking gun of such an encounter, one that occurred close to our position in the galaxy and relatively recently, at least in the cosmological sense.

“We have found evidence that our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago,” said Larry Widrow, professor at Queen’s University in Canada. “We clearly observe unexpected differences in the Milky Way’s stellar distribution above and below the Galaxy’s midplane that have the appearance of a vertical wave — something that nobody has seen before.”

The discovery is based on observations of some 300,000 nearby Milky Way stars by the Sloan Digital Sky Survey. Stars in the disk of the Milky Way move up and down at a speed of about 20-30 kilometers per second while orbiting the center of the galaxy at a brisk 220 kilometers per second. Widrow and his four collaborators from the University of Kentucky, the University of Chicago and Fermi National Accelerator Laboratory have found that the positions and motions of these nearby stars weren’t quite as regular as previously thought.

“Our part of the Milky Way is ringing like a bell,” said Brian Yanny, of the Department of Energy’s Fermilab. “But we have not been able to identify the celestial object that passed through the Milky Way. It could have been one of the small satellite galaxies that move around the center of our galaxy, or an invisible structure such as a dark matter halo.”

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Unfortunately, stars don’t have birth certificates. So, astronomers have a tough time figuring out their ages. Knowing a star’s age is critical for understanding how our Milky Way galaxy built itself up over billions of years from smaller galaxies.

White dwarfs

Jason Kalirai of the Space Telescope Science Institute and The Johns Hopkins University’s Center for Astrophysical Sciences, both in Baltimore, Md., has found the next best thing to a star’s birth certificate. Using a new technique, Kalirai probed the burned-out relics of Sun-like stars, called white dwarfs, in the inner region of our Milky Way galaxy’s halo. The halo is a spherical cloud of stars surrounding our galaxy’s disk.

Those stars, his study reveals, are 11.5 billion years old, younger than the first generation of Milky Way stars. They formed more than 2 billion years after the birth of the universe 13.7 billion years ago. Previous age estimates, based on analysing normal stars in the inner halo, ranged from 10 billion to 14 billion years.

Kalirai’s study reinforces the emerging view that our galaxy’s halo is composed of a layer-cake structure that formed in stages over billions of years.

This illustration shows the Milky Way galaxy's inner and outer halos. A halo is a spherical cloud of stars surrounding a galaxy. Astronomers have proposed that the Milky Way's halo is composed of two populations of stars. The age of the stars in the inner halo, according to measurements by the Paranal Observatory, is 11.5 billion years old. The measurements suggest the inner-halo stars are younger than the outer-halo population, some of which could be 13.5 billion years old. Credit: NASA, ESA, and A. Feild (STScI)

One of the biggest questions in astronomy is, when did the different parts of the Milky Way form?” Kalirai said. “Sun-like stars live for billions of years and are bright, so they are excellent tracers, offering clues to how our galaxy evolved over time. However, the biggest hindrance we have in inferring galactic formation processes in the Milky Way is our inability to measure accurate ages of Sun-like stars. In this study, I chose a different path: I studied stars at the end of their lives to determine their masses and then connected those masses to the ages of their progenitors. Given the nature of these dead stars, their masses are easier to measure than Sun-like stars.”

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Whatta view!

The antennas of the European Southern Observatory’s Atacama Large Millimeter/Submillimeter Array, also known as ALMA, are set against the splendor of the Milky Way.

Watch the Milky Way spin

The International Space Station’s crew has been sending down tons of stunning imagery of the planet below, but the main appeal of this video goes in a different direction — toward the gorgeous galaxy right above our heads.

The time-lapse video is based on pictures taken on Dec. 29 while the space station sailed high above Africa, crossing over to the South Indian Ocean. You can make out the flashes of lightning storms, and if you look very closely you can see the long streak of Comet Lovejoy against the backdrop of the Milky Way. The best frame for seeing the comet comes around the 12-second mark in the 23-second clip.

A statistical analysis based on a survey of millions of stars suggests that there’s at least one planet for every star in the sky, and probably more. That would add up to 160 billion planets or so in the Milky Way.

“We conclude that stars are orbited by planets as a rule, rather than the exception,” an international research team reports today in the journal Nature.

The estimate may sound amazing: Just a year ago, the world was wowed by the claim that at least half of the 100 billion or more stars in the Milky Way possessed planets, yielding a figure of 50 billion planets. The latest survey now suggests that there’s an average of 1.6 planets per star system, which would work out to 160 billion. But perhaps the most amazing thing about the findings is … astronomers don’t find them amazing at all.

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Trust Us: Tempest Milky Way

A meteor, the Milky Way and the Northern Lights. Capturing just one of these natural beauties in a photo is a feat many photographers would be proud of.

Amateur photographer Tommy Eliassen struck photo gold in this beautifully composed image he shot in Ifjord, Finnmark, Norway.

Eliassen made the photo on Sept. 25 using a Nikon D700 with a wide angle lens and long exposures between 25-30 seconds.

In an interview with Caters News, The 33-year-old, who capitalized on a narrow window of clear skies, talked about the experience.

I quickly went and took some pictures in a regular spot of mine, and thought to myself that I had got some good aurora shots and also some separate good milky way shots. But just as the clouds started to come in over the mountains I noticed this faint aurora lining up perfectly beside the milky way. Normally the lights from the aurora is much, much stronger than the lights from the stars, so getting the right exposure on both is difficult. But it was ideal conditions – almost once in a lifetime.

He was able to snap seven images of the scene before clouds moved back in.

“I was so focused on getting it right that I didn’t think about it at the time. But afterwards I realised that this was something special and that it might be years before I get an opportunity like it again,” he said. More here.

Astronomers at The Australian National University have found evidence for the textile that forms the fabric of the Universe.

In findings published in the October Astrophysical Journal, the researchers discovered proof of a vast filament of material that connects our Milky Way galaxy to nearby clusters of galaxies, which are similarly interconnected to the rest of the Universe.

The team included Dr. Stefan Keller, Dr. Dougal Mackey and Professor Gary Da Costa from the Research School of Astronomy and Astrophysics at ANU.

“By examining the positions of ancient groupings of stars, called globular clusters, we found that the clusters form a narrow plane around the Milky Way rather than being scattered across the sky,” Dr. Keller said.

“Furthermore, the Milky Way’s entourage of small satellites are seen to inhabit the same plane.

“What we have discovered is evidence for the cosmic thread that connects us to the vast expanse of the Universe.

“The filament of star clusters and small galaxies around the Milky Way is like the umbilical cord that fed our Galaxy during its youth.” More here.

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