Tag: gravity (page 2 of 7)

Citizen Scientists Find Green Blobs in Hubble Galaxy Shots

Excerpt from wired.com

In 2007, A Dutch schoolteacher named Hanny var Arkel discovered a weird green glob of gas in space. Sifting through pictures of galaxies online, as part of the citizen science project Galaxy Zoo, she saw a cloud, seemingly glowing, sitting next to a galaxy. Intrigued, astronomers set out to find more of these objects, dubbed Hanny’s Voorwerp (“Hanny’s object” in Dutch). Now, again with the help of citizen scientists, they’ve found 19 more of them, using the Hubble space telescope to snap the eight haunting pictures in the gallery above.

Since var Arkel found the first of these objects, hundreds more volunteers have swarmed to help identify parts of the universe in the Galaxy Zoo gallery. To find this new set, a couple hundred volunteers went through nearly 16,000 pictures online (seven people went through all of them), clicking yes/no/maybe as to whether they saw a weird green blob. Astronomers followed up on the galaxies they identified using ground-based telescopes, and confirmed 19 new galaxies surrounded by green gas.

What causes these wispy tendrils of gas to glow? Lurking at the center of each of these galaxies is a supermassive black hole, millions to billions times as massive as the sun, with gravity so strong that even light can’t escape them. As nearby gas and dust swirls into the black hole, like water circling a drain, that material heats up, producing lots of radiation—including powerful ultraviolet. Beaming out from the galaxy, that ultraviolet radiation strikes nearby clouds of gas, left over from past collisions between galaxies. And it makes the clouds glow an eerie green. “A lot of these bizarre forms we’re seeing in the images arise because these galaxies either interacted with a companion or show evidence they merged with a smaller galaxy,” says William Keel, an astronomer at the University of Alabama, Tuscaloosa.

The eight in this gallery, captured with Hubble, are especially weird. That’s because the quasar, the black-hole engine that’s supposed to be churning out the ultraviolet radiation, is dim—too dim, in fact, to be illuminating the green gas. Apparently, the once-bright quasar has faded. But because that UV light takes hundreds of thousands of years to travel, it can continue to illuminate the gas long after its light source has died away.

Hubble finds phantom objects close to dead quasars

That glowing gas can tell astronomers a lot about the quasar that brought it to light. “What I’m so excited about is the fact that we can use them to do archaeology,” says Gabriela Canalizo, an astronomer at the University of California, Riverside, who wasn’t part of the new research. Because the streaks of gas are so vast, stretching up to tens of thousands of light years, the way they glow reveals the history of the radiation coming from the quasar. As the quasar fades, so will the gas’s glow, with the regions of gas closer to the quasar dimming first. By analyzing how the glow dwindles with distance from the quasar, astronomers can determine how fast the quasar is fading. “This was something we’ve never been able to do,” Canalizo says.

Measuring how fast the quasar fades allows astronomers to figure out exactly what’s causing it to turn off in the first place. “What makes them dim is running out of material to eat,” Canalizo says. That could happen if the quasar is generating enough radiation to blow away all the gas and dust surrounding the black hole—the same gas and dust that feeds it. Without a steady diet, the quasar is powerless to produce radiation. Only if more gas happens to make its way toward the black hole can the quasar turn on again. The glowing gas can provide details of this process, and if other mechanisms are at play.

With more powerful telescopes, astronomers will likely find many more. Hanny’s Verwoort, it turns out, may not be that weird after all.

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Why Luke Skywalker’s binary sunset may be real after all

March 30, 2015 / Greg Giles / 0 Comments

Excerpt from csmonitor.com

Researchers have found Jupiter-scale gas giants orbiting binary stars and estimate that Earth-like planets orbiting binary stars could be as numerous as rocky planets orbiting single-star systems.

For all the sci-fi charm of watching a pair of suns sink below a distant horizon on a planet in a galaxy far, far away, conventional wisdom has held that binary-star systems can't host Earth-scale rocky planets.

As the two stars orbit each other like square-dance partners swinging arm in arm, regular variations in their gravitational tug would disrupt planet formation at the relatively close distances where rocky planets tend to appear.

Not so fast, say two astrophysicists. They argue that only are Tatooine-like planets likely to be out there. They could be as numerous as rocky planets orbiting single-star systems – which is to say, there could be large number of them.

Building rocky planets in a binary system not only is possible, it's "not even that hard," says Scott Kenyon, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who along with University of Utah astrophysicist Benjamin Bromley performed the calculations.

Researchers have found Jupiter-scale gas giants orbiting binary stars and have estimated that such gas giants are likely to be as common in binary systems as they are in systems with a single star.

"If that's true, then Earth-like planets around binaries are just as common as Earth-like planets around single stars," Dr. Kenyon says. "If they're not common, that tells you something about how they form or how they interact with the star over billions of years."

The modeling study grew out of work the two researchers were undertaking to figure out how the dwarf planet Pluto and its largest moon Charon manage to share space with four smaller moons that orbit the two larger objects.

Pluto and Charon form a binary system that early in its history saw the two objects graze each other to generate a ring of dust that would become the additional moons.

The gravity the surrounding dust felt as Pluto and Charon swung about their shared center of mass would vary with clock-like precision.

Conventional wisdom held that this variable tug would trigger collisions at speeds too fast to allow the dust and larger chunks to merge into ever larger objects.

Kenyon and Dr. Bromley found that, in fact, the velocities would be smaller than people thought – no greater than the speeds would be around a single central object, where velocities are slow enough to allow the debris to bump gently and merge to build ever-larger objects.

They recognized that binary stars hosting planets are essentially scaled-up versions of the Pluto-Charon system. So they applied their calculations to a hypothetical binary star system with a circumstellar disk of dust and debris.

"The modest jostling in these orbits is the same modest jostling you'd get around a single star," Kenyon says, allowing rocky inner planets to form.

As for the Jupiter- or Neptune-scale planets found around binary stars, they would have formed farther out and migrated in over time, the researchers say, since there is too little material within the inner reaches of a circumstellar disk to build giant planets.

The duo's calculations imply that as more planets are discovered orbiting binary stars, a rising number of Tatooines will be among them.

Tatooine "was science fiction," Kenyon says. But "it's not so far from science reality."

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Jupiter May Be Behind The Mysterious ‘Gaping Hole’ In Our Solar System

March 30, 2015 / Greg Giles / 0 Comments

Excerpt from huffingtonpost.comWhen astronomers began studying other solar systems in the Milky Way galaxy back in the 1990s, they noticed something peculiar: most of these systems have big planets that circle their host stars in tight orbits, a fin...

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Was Roswell UFO Crash A Secret Nazi Aircraft?

March 28, 2015 / Greg Giles / 0 Comments

Excerpt from huffingtonpost.comThe Roswell, New Mexico, UFO crash of 1947 was the result of -- here it comes, wait for it -- top secret Nazi technology. No alien spacecraft, no alien bodies, but an aircraft called the "Bell" (depicted ab...

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Cleaning Up Old Satellites And Space Junk Could Soon Be Done With Giant Fishing Nets

March 28, 2015 / Greg Giles / 0 Comments

Excerpt from techtimes.com Spacecraft are all shiny and new when they leave Earth but being up in space can do a number on them, resulting into bits and pieces of junk flying around. The European Space Agency's Clean Space initiative is looking to l...

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Black Holes, the Large Hadron Collider, & Finding Parallel Universes

March 27, 2015 / Greg Giles / 0 Comments

Excerpt from huffingtonpost.comI am a huge science enthusiast and an unabashed science fiction fan. There are tons of really cool stories out there that fire the imagination and even inspire young people to go into science. (I know they did me.) ...

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NASA’s Plan to Give the Moon a Moon

March 25, 2015 / Greg Giles / 0 Comments

Excerpt from wired.com

It sounds almost like a late ’90s sci-fi flick: NASA sends a spacecraft to an asteroid, plucks a boulder off its surface with a robotic claw, and brings it back in orbit around the moon. Then, brave astronaut heroes go and study the space rock up close—and bring samples back to Earth.
Except it’s not a movie: That’s the real-life idea for the Asteroid Redirect Mission, which NASA announced today. Other than simply being an awesome space version of the claw arcade game (you know you really wanted that stuffed Pikachu), the mission will let NASA test technology and practice techniques needed for going to Mars.
The mission, which will cost up to $1.25 billion, is slated to launch in December 2020. It will take about two years to reach the asteroid (the most likely candidate is a quarter-mile-wide rock called 2008 EV5). The spacecraft will spend up to 400 days there, looking for a good boulder. After picking one—maybe around 13 feet in diameter—it will bring the rock over to the moon. In 2025, astronauts will fly NASA’s still-to-be-built Orion to dock with the asteroid-carrying spacecraft and study the rock up close.
Although the mission would certainly give scientists an up-close opportunity to look at an asteroid, its main purpose is as a testing ground for a Mars mission. The spacecraft will test a solar electronic propulsion system, which uses the power from solar panels to pump out charged particles to provide thrust. It’s slower than conventional rockets, but a lot more efficient. You can’t lug a lot of rocket fuel to Mars.
Overall, the mission gives NASA a chance at practicing precise navigation and maneuvering techniques that they’ll need to master for a Mars mission. Such a trip will also require a lot more cargo, so grabbing and maneuvering a big space rock is good practice. Entering lunar orbit and docking with another spacecraft would also be helpful, as the orbit might be a place for a deep-space habitat, a rendezvous point for astronauts to pick up cargo or stop on their way to Mars.
And—you knew this part was coming, Armageddon fans—the mission might teach NASA something about preventing an asteroid from striking Earth. After grabbing the boulder, the spacecraft will orbit the asteroid. With the added heft from the rock, the spacecraft’s extra gravity would nudge the asteroid, creating a slight change in trajectory that NASA could measure from Earth. “We’re not talking about a large deflection here,” says Robert Lightfoot, an associate administrator at NASA. But the idea is that a similar technique could push a threatening asteroid off a collision course with Earth.
NASA chose this mission concept over one that would’ve bagged an entire asteroid. In that plan, the spacecraft would’ve captured the space rock by enclosing it in a giant, flexible container. The claw concept won out because its rendezvous and soft-landing on the asteroid will allow NASA to test and practice more capabilities in preparation for a Mars mission, Lightfoot says. The claw would’ve also given more chances at grabbing a space rock, whereas it was all or nothing with the bag idea. “It’s a one-shot deal,” he says. “It is what it is when we get there.” But the claw concept offers some choices. “I’ve got three to five opportunities to pull one of the boulders off,” he says. Not bad odds. Better than winning that Pikachu

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Young Jupiter wiped out solar system’s early inner planets, study says

March 24, 2015 / Greg Giles / 0 Comments

(Photo : NASA/ESA) In early days of solar system, Jupiter destroyed everything that came in its way, researchers have found.

Excerpt from latimes.com

Before Mercury, Venus, Earth and Mars occupied the inner solar system, there may have been a previous generation of planets that were bigger and more numerous – but were ultimately doomed by Jupiter, according to a new study.

If indeed the early solar system was crowded with so-called super-Earths, it would have looked a lot more like the planetary systems found elsewhere in the galaxy, scientists wrote Monday in the Proceedings of the National Academy of Sciences.

As NASA’s Kepler space telescope has found more than 1,000 planets in orbit around other stars, along with more than 4,000 other objects that are believed to be planets but haven’t yet been confirmed. Kepler finds these planets by watching their host stars and registering tiny drops in their brightness – a sign that they are being ever-so-slightly darkened by a planet crossing in front of them.

In addition, ground-based telescopes have detected hundreds of exoplanets by measuring the wiggles of distant stars. Those stars wiggle thanks to the gravitational pull of orbiting planets, and the Doppler effect makes it possible to estimate the size of these planets.

The more planetary systems astronomers discovered, the more our own solar system looked like an oddball. Exoplanets – at least the ones big enough for us to see – tended to be bigger than Earth, with tight orbits that took them much closer to their host stars. In multi-planet systems, these orbits tended to be much closer together than they are in our solar system. For instance, the star known as Kepler-11 has six planets closer to it than Venus is to the sun.

Why does our solar system look so different? Astrophysicists Konstantin Batygin of Caltech and Greg Laughlin of UC Santa Cruz summed it up in one word: Jupiter.

Here’s what could have happened, according to their models:

In Solar System 1.0, the region closest to the sun was occupied by numerous planets with masses several times bigger than that of Earth. There were also planetesimals, “planetary building blocks” that formed within the first million years after the birth of the sun, Batygin and Laughlin wrote.

This is how things might have stayed if the young Jupiter had stayed put at its initial orbit, between 3 and 10 astronomical units away from the sun. (An astronomical unit, or AU, is the distance between the Earth and the sun. Today, Jupiter’s orbit ranges between 5 and 5.5 AUs from the sun.)

But Jupiter was restless, according to a scenario known as the “Grand Tack.” In this version of events, Jupiter was swept up by the currents of gas that surrounded the young sun and drifted toward the center of the solar system.

Jupiter, however, was too big to travel solo. All manner of smaller objects would have been dragged along too. With so many bodies in motion, there would have been a lot of crashes.

The result was “a collisional cascade that grinds down the planetesimal population to smaller sizes,” the astrophysicists wrote. For the most part, these planetary crumbs were swept toward the sun and ultimately destroyed, like disintegrating satellites falling back to Earth.

The planetesimals wouldn’t have been Jupiter’s only victims. Assuming the early solar system resembled the planetary systems spied by Kepler and other telescopes, there would have been “a similar population of first-generation planets,” the pair wrote. “If such planets formed, however, they were destroyed.”

Jupiter probably got about as close to the sun as Mars is today before reversing course, pulled away by the gravity of the newly formed Saturn. That would have ended the chaos in the inner solar system, allowing Earth and the other rocky planets to form from the debris that remained.

“This scenario provides a natural explanation for why the inner Solar System bears scant resemblance to the ubiquitous multi-planet systems” discovered by Kepler and other survey efforts, Batygin and Laughlin wrote.

Although their models show that this is what might have happened, they don’t prove that it actually did. But there may be a way to get closer to the truth.

The scientists’ equations suggest that if a star is orbited by a cluster of close-in planets, there won’t be a larger, farther-out planet in the same system. As astronomers find more exoplanetary systems, they can see whether this prediction holds up.

Also, if far-away solar systems are experiencing a similar series of events, telescopes ought to be able to detect the extra heat thrown off by all of the planetesimal collisions, they added.

Sadly for those hoping to find life on other planets, the pair’s calculations also imply that most Earth-sized planets are lacking in water and other essential compounds that can exist in liquid or solid form. As a result, they would be “uninhabitable,” they wrote.

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Amazing Images of Comet 67P/Churyumov-Gerasimenko

March 21, 2015 / Greg Giles / 0 Comments

Comet 67P/C-G is about as large as Central Park of Manhattan Island, New York

Excerpt from nytimes.com

By JONATHAN CORUM

The European Space Agency’s Rosetta spacecraft caught up with Comet 67P/Churyumov-Gerasimenko last August, then dropped a lander onto the comet in November. Now Rosetta will follow the rubber-duck-shaped comet as it swings closer to the sun.

Scale in miles

Scale in km

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March 9 Rosetta was 45 miles from Comet 67P/C-G when it photographed the comet’s head ringed with a halo of gas and dust. These jets extend from active areas of the comet’s surface and will become much more prominent over the next few months as the comet approaches the sun.

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March 6 The comet’s head is angled down in this image of crisscrossing sunlit jets taken from 53 miles away.

Comet’s location when Rosetta was launched Rosetta launched in March 2004

Earth

Sun

Mars

Rendezvous

with Comet

67P/C-G

Orbit of

Jupiter

Rosetta today

Where is Rosetta? The Rosetta spacecraft took 10 years to match speed and direction with Comet 67P/C-G. The chase ended last August, and Rosetta will now follow the comet in its elliptical orbit as it moves closer to the sun. The spacecraft is no longer orbiting the comet because of increasing dust, but it is planning a series of close flybys.

1/2 MILE

March 6 Rosetta was 52 miles away when it looked up at the comet’s flat underbelly. The smooth plain at center covered with large boulders is named Imhotep.

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Feb. 28 Rosetta captured a profile of the comet surrounded by curving jets of gas and dust from active regions. The spacecraft was 64 miles away.

Feb. 25–27 One day on Comet 67P/C-G is about 12 hours, the time it takes the comet to spin on its axis. The jets of gas and dust surrounding the comet are thought to curve from a combination of the comet’s rotation and the uneven gravity of its two-lobed structure.

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Feb. 20 The comet’s sunlit underbelly casts a shadow obscuring the neck that joins the two lobes. Rosetta took this image from 74 miles away.

1 MILE

Feb. 18 Pale jets of gas and dust surround Comet 67P/C-G, seen from 123 miles away. Bright marks in the background are a mix of stars, camera noise and streaks from small particles ejected from the comet.

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Panorama by The New York Times

Feb. 14 On Valentine’s Day, Rosetta made its first close flyby of the comet, passing within four miles of the surface. Here the spacecraft looks down on the large depression at the top of the comet’s head.

500 FEET

Feb. 14 An image of the comet’s underbelly taken six miles above the surface during the Valentine’s Day flyby. The smooth plain in the foreground is called Imhotep.

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Feb. 9 The comet is upside down in this image from 65 miles away, and a fan-shaped jet of dust streams from the comet’s neck region.

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Feb. 6 Jets of gas and dust extend from the comet’s neck and other sunlit areas in this image taken from 77 miles away.

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Feb. 3 This close-up image of the comet’s neck was taken from 18 miles away, and was the last image taken from orbit around Comet 67P/C-G. Rosetta will continue to follow the comet, but will leave its gravity-bound orbit because of increasing dust and instead begin a series of flybys.

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Jan. 31 The comet’s head, neck and back are sunlit in this image taken from 17 miles away. A prominent jet of gas and dust extends from an active region of the surface near the comet’s neck.

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Jan. 16 The tail of the comet’s larger lobe points up, revealing a smooth plain named Imhotep at left. Rosetta was 18 miles away when it took this image.

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Jan. 3 The smooth plain named Imhotep, at center right, lies on the comet’s flat underbelly, seen here from a distance of about 18 miles.

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Cheops

IMHOTEP

Dec. 14, 2014 The large triangular boulder on the flat Imhotep plain is named Cheops, after the Egyptian pyramid. The spacecraft was about 12 miles from the comet when it took this image.

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Dec. 10 Sunlight falls between the body and head of the comet, lighting up a large group of boulders in the smooth Hapi region of the comet’s neck. To the right of the boulders, the cliffs of Hathor form the underside of the comet’s head. Rosetta took this image from a distance of 12 miles.

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Dec. 2 The round depression in the middle of the comet’s head is filled with shadow in this image taken 12 miles above the comet.

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Nov. 22 An overexposed image of Comet 67P/C-G from 19 miles away shows faint jets of gas and dust extending from the sunlit side of the comet.

Philae photo from the surface of Comet 67P/C-G.

Nov. 12 Rosetta’s washing-machine sized lander Philae successfully touched down on the comet’s head. But anchoring harpoons failed and Philae bounced twice before going missing in the shadow of a cliff or crater (above). Without sunlight Philae quickly lost power, but might revive as the comet gets closer to the sun. On March 12, Rosetta resumed listening for radio signals from the missing lander.

Photo illustration by The New York Times

How big is the comet? The body of Comet 67P/C-G is about as long as Central Park. For images of Rosetta’s rendezvous and the Philae landing, see Landing on a Comet, 317 Million Miles From Home.

Sources: European Space Agency and the Rosetta mission. Images by ESA/Rosetta, except where noted. Some images are composite panoramas created by ESA, and most images were processed by ESA to bring out details of the comet’s activity.

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Scientists: Enceladus may have warm water ocean with ingredients for life

March 15, 2015 / Greg Giles / 0 Comments

This artist's impression of the interior of Saturn's moon Enceladus shows that interactions between hot water and rock occur at the floor of the subsurface ocean -- the type of environment that might be friendly to life, scientists say. (NASA/JPL-Caltech)

Excerpt from latimes.com

Scientists say they’ve discovered evidence of a watery ocean with warm spots hiding beneath the surface of Saturn’s icy moon Enceladus. The findings, described in the journal Nature, are the first signs of hydrothermal activity on another world outside of Earth – and raise the chances that Enceladus has the potential to host microbial life.

Scientists have wondered about what lies within Enceladus at least since NASA’s Cassini spacecraft caught the moon spewing salty water vapor out from cracks in its frozen surface. Last year, a study of its gravitational field hinted at a 10-kilometer-thick regional ocean around the south pole lying under an ice crust some 30 to 40 kilometers deep.

Another hint also emerged about a decade ago, when Cassini discovered tiny dust particles escaping Saturn’s system that were nanometer-sized and rich in silicon.

“It’s a peculiar thing to find particles enriched with silicon,” said lead author Hsiang-Wen Hsu, a planetary scientist at the University of Colorado, Boulder. In Saturn’s moons and among its rings, water ice dominates, so these odd particles clearly stood out.

The scientists traced these particles’ origin to Saturn’s E-ring, which lies between the orbits of the moons Mimas and Titan and whose icy particles are known to come from Enceladus. So Hsu and colleagues studied the grains to understand what was going on inside the gas giant’s frigid satellite.
Rather than coming in a range of sizes, these particles were all uniformly tiny – just a few nanometers across. Studying the spectra of these grains, the scientists found that they were made of silicon dioxide, or silica. That’s not common in space, but it’s easily found on Earth because it’s a product of water interacting with rock.

Knowing how silica interacts in given conditions such as temperature, salinity and alkalinity, the scientists could work backward to determine what kind of environment creates these unusual particles.

A scientist could do the same thing with a cup of warm coffee, Hsu said.

“You put in the sugar and as the coffee gets cold, if you know the relation of the solubility of sugar as a function of temperature, you will know how hot your coffee was,” Hsu said. “And applying this to Enceladus’s ocean, we can derive a minimum [temperature] required to form these particles.”

The scientists then ran experiments in the lab to determine how such silica particles came to be. With the particles’ particular makeup and size distribution, they could only have formed under very specific circumstances, the study authors found, determining that the silica particles must have formed in water that had less than 4% salinity and that was slightly alkaline (with a pH of about 8.5 to 10.5) and at temperatures of at least 90 degrees Celsius (roughly 190 degrees Fahrenheit).

The heat was likely being generated in part by tidal forces as Saturn’s gravity kneads its icy moon. (The tidal forces are also probably what open the cracks in its surface that vent the water vapor into space.)
Somewhere inside the icy body, there was hydrothermal activity – salty warm water interacting with rocks. It’s the kind of environment that, on Earth, is very friendly to life.

“It’s kind of obvious, the connection between hydrothermal interactions and finding life,” Hsu said. “These hydrothermal activities will provide the basic activities to sustain life: the water, the energy source and of course the nutrients that water can leach from the rocks.”

Enceladus, Hsu said, is now likely the “second-top object for astrobiology interest” – the first being Jupiter’s icy moon and fellow water-world, Europa.
This activity is in all likelihood going on right now, Hsu said – over time, these tiny grains should glom together into larger and larger particles, and because they haven’t yet, they must have been recently expelled from Enceladus, within the last few months or few years at most.

Gabriel Tobie of the University of Nantes in France, who was not involved in the research, compared the conditions that created these silica particles to a hydrothermal field in the Atlantic Ocean known as Lost City.

“Because it is relatively cold, Lost City has been posited as a potential analogue of hydrothermal systems in active icy moons. The current findings confirm this,” Tobie wrote in a commentary on the paper. “What is more, alkaline hydrothermal vents might have been the birthplace of the first living organisms on the early Earth, and so the discovery of similar environments on Enceladus opens fresh perspectives on the search for life elsewhere in the Solar System.”

However, Hsu pointed out, it’s not enough to have the right conditions for life – they have to have been around for long enough that life would have a fighting chance to emerge.

“The other factor that is also very important is the time.… For Enceladus, we don’t know how long this activity has been or how stable it is,” Hsu said. “And so that’s a big uncertainty here.”

One way to get at this question? Send another mission to Enceladus, Tobie said.

“Cassini will fly through the moon’s plume again later this year,” he wrote, “but only future missions that can undertake improved in situ investigations, and possibly even return samples to Earth, will be able to confirm Enceladus’ astrobiological potential and fully reveal the secrets of its hot springs. ”

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Earth’s address within a massive supercluster of 100,000 galaxies ~ Video

March 11, 2015 / Greg Giles / 0 Comments

Excerpt from cnet.com

Astronomers have mapped the Milky Way's position to the outskirts of a supercluster of galaxies, newly dubbed Laniakea, meaning "Immense Heaven".

The distribution of galaxies throughout the universe is not more-or-less even; instead, galaxies tend to cluster together, bound together by the pull of each other's gravity. These groups can be a variety of sizes. The Milky Way Galaxy, for instance, is part of what is called the Local Group, which contains upwards of 54 galaxies, covering a diameter of 10 megalight-years (10 million light-years).

Click to zoom

But this Local Group is just a small part of a much, much bigger structure, which researchers at the University of Hawai'i Mānoa have now mapped in detail. Coming in at over 100,000 galaxies, the massive supercluster has been given the name Laniakea -- "immense heaven" in Hawaiian.
The new 3D map was created by examining the positions and movements of the 8000 closest galaxies to the Milky Way. After calculating which galaxies were being pulled away from us and which were being pulled towards us -- accounting for the universe's expansion -- the team, led by astronomer R. Brent Tully, was able to map the paths of galactic migration -- and define the boundaries of Laniakea.

Traditionally, the borders of galactic superclusters have been difficult to map, but studying the gravitational force acting on our neighbouring galaxies has provided some important clues. All objects inside Laniakea are being slowly but surely drawn to a single point -- a force known as the Great Attractor, a gravitational anomaly with a mass tens of thousands of times the mass of the Milky Way.

Everything that is being pulled towards the Great Attractor is part of Laniakea -- although it's possible that Laniakea itself might in turn be part of a structure that is larger still.

"We probably need to measure to another factor of three in distance to explain our local motion," Tully said. "We might find that we have to come up with another name for something larger than we're a part of -- we're entertaining that as a real possibility."

The full paper, "The Laniakea supercluster of galaxies", can be read online in the journal Nature.

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Billionaire teams up with NASA to mine the moon

March 10, 2015 / Greg Giles / 0 Comments

Excerpt from cnbc.com
By Susan Caminiti

Moon Express, a Mountain View, California-based company that's aiming to send the first commercial robotic spacecraft to the moon next year, just took another step closer toward that lofty goal.

Earlier this year, it became the first company to successfully test a prototype of a lunar lander at the Kennedy Space Center in Florida. The success of this test—and a series of others that will take place later this year—paves the way for Moon Express to send its lander to the moon in 2016, said company co-founder and chairman Naveen Jain.

Moon Express conducted its tests with the support of NASA engineers, who are sharing with the company their deep well of lunar know-how. The NASA lunar initiative—known as Catalyst—is designed to spur new commercial U.S. capabilities to reach the moon and tap into its considerable resources.In addition to Moon Express, NASA is also working with Astrobotic Technologies of Pittsburgh, Pennsylvania, and Masten Space Systems of Mojave, California, to develop commercial robotic spacecrafts.

Jain said Moon Express also recently signed an agreement to take over Space Launch Complex 36 at Cape Canaveral. The historic launchpad will be used for Moon Express's lander development and flight-test operations. Before it was decommissioned, the launchpad was home to NASA's Atlas-Centaur rocket program and its Surveyor moon landers.

"Clearly, NASA has an amazing amount of expertise when it comes to getting to the moon, and it wants to pass that knowledge on to a company like ours that has the best chance of being successful," said Jain, a serial entrepreneur who also founded Internet companies Infospace and Intelius. He believes that the moon holds precious metals and rare minerals that can be brought back to help address Earth's energy, health and resource challenges.

Among the moon's vast riches: gold, cobalt, iron, palladium, platinum, tungsten and Helium-3, a gas that can be used in future fusion reactors to provide nuclear power without radioactive waste. "We went to the moon 50 years ago, yet today we have more computing power with our iPhones than the computers that sent men into space," Jain said. "That type of exponential technological growth is allowing things to happen that was never possible before."

An eye on the Google prize

Source: MoonExpress

Helping to drive this newfound interest in privately funded space exploration is the Google Lunar X Prize. It's a competition organized by the X Prize Foundation and sponsored by Google that will award $30 million to the first company that lands a commercial spacecraft on the moon, travels 500 meters across its surface and sends high-definition images and video back to Earth—all before the end of 2016.

Moon Express is already at the front of the pack. In January it was awarded a $1 million milestone prize from Google for being the only company in the competition so far to test a prototype of its lander. "Winning the X prize would be a great thing," said Jain. "But building a great company is the ultimate goal with us." When it comes to space exploration, he added, "it's clear that the baton has been passed from the government to the private sector."

Testing in stages

Jain said Moon Express has been putting its lunar lander through a series of tests at the space center. The successful outing earlier this year involved tethering the vehicle—which is the size of a coffee table—to a crane in order to safely test its control systems. "The reason we tethered it to the crane is because the last thing we wanted was the aircraft to go completely haywire and hurt someone," he said.

At the end of March, the company will conduct a completely free flight test with no tethering. The lander will take off from the pad, go up and sideways, then land back at the launchpad. "This is to test that the vehicle knows where to go and how to get back to the launchpad safely," Jain explained.

Once all these tests are successfully completed, Jain said the lander—called MX-1—will be ready to travel to the moon. The most likely scenario is that it will be attached to a satellite that will take the lander into a low orbit over the Earth. From there the MX-1 will fire its own rocket, powered by hydrogen peroxide, and launch from that orbit to complete its travel to the moon's surface.

The lander's first mission is a one-way trip, meaning that it's not designed to travel back to the Earth, said Jain. "The purpose is to show that for the first time, a company has developed the technology to land softly on the moon," he said. "Landing on the moon is not the hard part. Landing softly is the hard part."

That's because even though the gravity of the moon is one-sixth that of the Earth's, the lander will still be traveling down to the surface of the moon "like a bullet," Jain explained. Without the right calculations to indicate when its rockets have to fire in order to slow it down, the lander would hit the surface of the moon and break into millions of pieces. "Unlike here on Earth, there's no GPS on the moon to tell us this, so we have to do all these calculations first," he said.

Looking ahead 15 or 20 years, Jain said he envisions a day when the moon is used as a sort of way station enabling easier travel for exploration to other planets. In the meantime, he said the lander's second and third missions could likely involve bringing precious metals, minerals and even moon rocks back to Earth. "Today, people look at diamonds as this rare thing on Earth," Jain said.
He added, "Imagine telling someone you love her by giving her the moon."

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Dawn Enters Orbit Around Dwarf Planet Ceres ~ Video

March 9, 2015 / Greg Giles / 0 Comments

Dwarf Planet Ceres

Excerpt from spacenews.com

NASA’s Dawn spacecraft arrived in orbit around the dwarf planet Ceres March 6, completing a journey of nearly seven and a half years and five billion kilometers. In a statement, NASA’s Jet Propulsion Laboratory said Dawn entered orbit about 61,000 kilometers above Ceres at 7:39 am EST March 6, sending a signal to Earth about an hour later confirming it was in orbit and in good health. “We feel exhilarated,” Dawn principal investigator Chris Russell said in the statement. “We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.”

Dawn will gradually spiral down to its initial science orbit, 13,500 kilometers above Ceres, by April. Later in its mission Dawn will move gradually closer to the surface, eventually moving into an orbit of 375 kilometers. The Dawn spacecraft, built by Orbital ATK, launched on a United Launch Alliance Delta 2 rocket in September 2007. After making a gravity assist flyby of Mars in February 2009, it entered orbit around the large main-belt asteroid Vesta in July 2011. It remained there for more than a year, using its ion thrusters to leave orbit in September 2012 to head to Ceres.

Ceres, the largest object in the main asteroid belt between the orbits of Mars and Jupiter, was the first asteroid discovered by astronomers, in 1801. The International Astronomical Union designated Ceres a “dwarf planet” in 2006, a new category of objects that also includes the former planet Pluto.

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Dawn will gradually spiral down to its initial science orbit, 13,500 kilometers above Ceres, by April. Later in its mission Dawn will move gradually closer to the surface, eventually moving into an orbit of 375 kilometers.
The Dawn spacecraft, built by Orbital ATK, launched on a United Launch Alliance Delta 2 rocket in September 2007. After making a gravity assist flyby of Mars in February 2009, it entered orbit around the large main-belt asteroid Vesta in July 2011. It remained there for more than a year, using its ion thrusters to leave orbit in September 2012 to head to Ceres.
Ceres, the largest object in the main asteroid belt between the orbits of Mars and Jupiter, was the first asteroid discovered by astronomers, in 1801. The International Astronomical Union designated Ceres a “dwarf planet” in 2006, a new category of objects that also includes the former planet Pluto.
- See more at: http://spacenews.com/dawn-enters-orbit-around-ceres/#sthash.yoclEQI4.dpuf

WASINGTON — NASA’s Dawn spacecraft arrived in orbit around the dwarf planet Ceres March 6, completing a journey of nearly seven and a half years and five billion kilometers.
In a statement, NASA’s Jet Propulsion Laboratory said Dawn entered orbit about 61,000 kilometers above Ceres at 7:39 am EST March 6, sending a signal to Earth about an hour later confirming it was in orbit and in good health.
“We feel exhilarated,” Dawn principal investigator Chris Russell said in the statement. “We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.”
- See more at: http://spacenews.com/dawn-enters-orbit-around-ceres/#sthash.yoclEQI4.dpuf

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Tag: gravity (page 2 of 7)

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Black Holes, the Large Hadron Collider, & Finding Parallel Universes

NASA’s Plan to Give the Moon a Moon

Young Jupiter wiped out solar system’s early inner planets, study says

Scientists: Enceladus may have warm water ocean with ingredients for life

Dawn Enters Orbit Around Dwarf Planet Ceres ~ Video

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