NASA reveals mystery behind identity of space centaurs

A study using sightings from a NASA telescope may have answered an old mystery surrounding centaurs, according to a NASA Jet Propulsion Laboratory (JPL) news release.The infrared images showed two-thirds of the population of centaurs to be blue-gray in color, indicating they are comets.

Centaurs are small stellar bodies orbiting the sun between Jupiter and Neptune and scientists have not been able to determine if they are comets or asteroids. A study based on images from NASA's Wide-field Infrared Survey Explorer (WISE) suggests they are comets.Centaurs get their name from the creature of Greek mythology with a human's torso and horse's legs. The galactic mystery was named "centaur" because it shared characteristics of both an asteroid and a comet.

"Cometary origin" means the centaur is made of the same material as a comet and may be inactive for now and could be active in the future. The study, published online July 22 in the Astrophysical Journal, analyzed infrared images of 52 centaurs in the sky, 15 of which were new discoveries.

Centaurs and their distant cousin, scattered disks, are part of an unstable belt orbiting the sun between Jupiter and Neptune. The two massive planets' gravitational force either pulls the centaurs and disks away from their locations or toward the sun.

Astronomers in the past have observed some centaurs and seen dark halos around them, regularly associated with outgassed comets. NEOWISE, WISE's asteroid-spotting component, can tell whether the centaur has a matte dark surface or a shiny reflective one.

Combined with what was already known about comet and asteroid colors, NEOWISE helped the scientists piece together the rest. Objects with a blue-gray color were more likely to be comets, while red objects were more likely asteroids.Results showed that about two-thirds of the population of centaurs was comets.

To know more about the study and its findings, click here.

Man may land on Red Planet by 2021

Can man set his foot on Mars? NASA says it can happen by 2033 at the earliest, but scientists at Imperial College London have come up with a mission that could land within eight years.

Mars has been the next stop for the human exploration of space ever since the Apollo missions. We have now come up with a mission concept that uses both robots and humans to get us to Mars and back. The robots will be sent to the northern plains of Mars, with a rocket to get back to Earth — but without fuel. Sending the tanks empty saves a huge amount of mass on launch. Instead, the robots will dig up ice on Mars. Once the ice is melted, we can use solar electricity to produce hydrogen and oxygen to fill the fuel tanks. Better still, combining hydrogen with the atmosphere can make powerful methane.

A three-man crew will then get from Earth to Mars, and in the nine months it takes to reach there, without weight from gravity, muscles weaken and bones become brittle — so they need artificial gravity. We can do this by splitting their spacecraft into two, tied together by a tether, and spinning the parts around each other. With the right spin speed, they will be fooled into thinking they feel gravity.

The landing on Mars will be an extreme ride lasting just a few minutes. The landing module will approach Mars at 14,000 mph. The atmosphere will cut the speed to 700 mph, then parachutes with rockets will slow the module, landing in the warmest place on Mars, near the equator. The mission will first focus on exploring their surroundings and collecting rocks.

To return, the crew will have to journey some 1,000 miles north via rover from their landing site to the return rocket. Such a mission will finally take us further than Apollo. We need not wait 60 years after Apollo 11 landed on the Moon to get the first human on Mars.

New theory: Universe isn't expanding... it's just getting fat

Conventional thinking says the Universe has been expanding ever since the Big Bang. But theoretical astrophysicist Christof Wetterich says it's not expanding at all. It’s just that the mass of all the particles within it is steadily increasing.

We think the Universe is expanding because all the galaxies within it are pushing away from one another. Scientists see this as the redshift — a kind of doppler effect that happens when atoms emit or absorb light.

We see these frequencies as appearing in the red, an indication that mass is moving away from us. Galaxies exhibit this redshift, which is why scientists say the Universe is expanding.

However, Wetterich, who works out of the University of Heidelberg in Germany, says the characteristic light emitted by atoms are also governed by the masses of the atoms’ elementary particles, particularly their electrons. He says his theory is useful for thinking about different cosmological models. And indeed, it may offer some fresh insights into the spooky dark energy that's apparently pushing the Universe outwards at an accelerating rate.

Such an interpretation could help physicists to understand problematic issues such as the so-called singularity present at the Big Bang, he said. "I think it's fascinating to explore this alternative representation. His treatment seems rigorous enough to be entertained," Journal Nature quoted Hongsheng Zhao, a cosmologist at the University of St Andrews, UK, as saying.

In the 1920s, astronomers including Georges Lemaitre and Edwin Hubble found that most galaxies exhibit a redshift -- and that the redshift was greater for more distant galaxies. From these observations, they deduced that the Universe must be expanding.

Read more about the theory here or about the entire study — which has not yet been peer reviewed — at arXiv: “A Universe without expansion.” 

Astronomers strike gold: Earth's precious metal comes from crashing of dead neutron stars!

Astronomers panning the heavens for glints of gamma-ray bursts have struck gold. They found gold -- so much of it, in fact, that they say they could potentially account for the universe's entire reserve of the precious metal prized by Earthlings for jewellery and industrial uses alike.

All the gold in the cosmos may have come from stellar cataclysms -- the collision of two neutron stars, which sends bursts of particles and radiation into the universe.Edo Berger of the Harvard-Smithsonian Center for Astrophysics, paraphrasing iconic astronomer Carl Sagan said, "We are all star stuff, and our jewelry is colliding-star stuff."

These neutron stars are the incredibly dense, deadened husks left from dramatic stellar explosions known as supernovas. Supernovas are what seeded a hydrogen-rich universe with heavier elements fused in the stars' cores, like carbon, oxygen or iron. But unlike carbon or iron, gold can’t be forged in the heart of a star, so its origin has remained a mystery.

Berger discovered an answer during his search for short gamma-ray bursts. Gamma-ray bursts are flashes of high-energy radiation that signal truly powerful explosions that can come from billions of light-years away. Some of them are long, lasting even a few minutes, and others are incredibly short – fractions of a second, making them very difficult to catch in the act.Berger was looking for the short ones. And it was a flash in what's called GRB 130603B, picked up by NASA’s Swift satellite, that caught his attention. When his phone rang at 2 a.m., he and his team quickly moved to examine the short burst – which lasted two-tenths of a second  -- captured with the powerful Magellan/Baade telescope in Chile.

The burst appeared to be coming from the collision of two neutron stars -- each roughly the size of Austin and filled with 1.5 times the mass of the sun -- an impact that produced a black hole and the bright burst of gamma rays that they picked up. But they also saw something else around the bright beacon: A strange glow of infrared radiation. This, the astrophysicists realized, was coming from  radioactive elements – like lead, thorium, uranium -- decaying and thus producing the infrared light.

Clearly, the explosion had been responsible for the creation of a whole menagerie of heavy elements. They estimated that an equivalent of 1 percent of the sun’s matter was being flung out from the collision in a tail, and about 10 parts per million of that tail was made of gold. They could be seeing perhaps 10 times the moon’s mass in gold, Berger said. The gold out there could be worth around $10 octillion. (That’s $100 trillion squared.)

Combining their estimate of the amount of gold from the neutron star mashup with the estimated number of such explosions since the beginning of time, it could even be that all the gold in the universe came from such exotic collisions, the scientists said. Their paper has been submitted to the Astrophysical Journal Letters.

So while there is indeed gold in them thar stars, should amateur prospectors still panning for the yellow metal lift their eyes from the ground and search the skies instead? Probably not. This exploding star system is 3.9 billion light-years away. 

Neptune's 14th moon discovered via Hubble images

Images taken by the Hubble Space telescope show that Neptune has another moon. Senior research scientist Mark Showalter of the SETI Institute, the private California-based organization, first discovered the new Neptune moon on July 1.Designated S/2004 N 1, the moon was previously overlooked by astronomers due to its small size and the speed at which the tiny body orbits the planet -- once every 23 hours.

Using a method similar to one often employed by action photographers, Showalter stumbled across the moon in Hubble images of Neptune taken between 2004 and 2009."The moons and arcs orbit very quickly, so we had to devise a way to follow their motion in order to bring out the details of the system," he said in a statement released by NASA on Monday.The astronomer further detailed the process he used to spot Neptune's moon in a blog on Cosmic Diary.

Showalter notes in his blog post, the discovery is also significant since astronomers studying Neptune's moons previously thought that the smallest moons orbit closer to the planet. However, S/2004 N 1 is located between Proteus and Larissa, Neptune's second- and third-largest moons.

Cloud cover influences habitable zone around stars in Milky Way

Factors in cloud cover and its influence on alien climate has extended the habitable zone around red dwarf stars to include double the number of planets in the life-supporting region, according to new research. This could mean  that some 60 billion habitable planets are orbiting red dwarf stars in the Milky Way galaxy alone.

Scientists had previously believed that each red dwarf had just one Earth-sized planet in its habitable zone – the sweet spot just far enough from the sun that the planet’s water doesn’t turn to vapor in the overwhelming heat, and just close enough that water doesn’t freeze without the reassuring warmth of the sun’s glow.

But now the habitable zone, once thought to be fairly small around the eponymously named red dwarfs (the stars are small and faint, relative to our sun) has been expanded. That’s because the formula for calculating the habitable zone of far-flung planets had not previously included how cloud cover might mitigate the star’s influence planets.

Building 3D computer models that simulate how clouds behave on alien planets, researchers at the University of Chicago and Northwestern University found that where there is surface water there are also water clouds. On planets close to their sun, those clouds exert a significant cooling effect, which allows those planets to retain their water, despite their closeness to the dwarf star’s heat. In other words, the habitable zone has been extended inward, closer to the star, than had been imagined to be possible.

The researchers plan to test their findings with the James Webb Telescope, which will go into orbit into 2018, taking the temperature of those alien planets during their days and nights to measure cloud cover. But the big question is, when an alien looks up at that planet’s clouds, what strange shapes, what foreign animals or objects or ideas, does he or she see?

Did Milky Way collide with Andromeda 10 billion years ago?

Yes. Our Milky Way did smash into its neighbouring Andromeda galaxy around 10 billion years ago, according to European astronomers. Previous studies have suggested that our galaxy is set to crash into Andromeda in 3-4 billion years, and that this will be the first time such a collision has taken place.

However, now a European team of astronomers led by Hongsheng Zhao of the University of St Andrews propose that the two star systems collided some 10 billion years ago and that our understanding of gravity is fundamentally wrong.

This would neatly explain the observed structure of the two galaxies and their satellites, something that has been difficult to account for until now, researchers said. The Milky Way, made up of about 200 billion stars, is part of a group of galaxies called the Local Group. Astrophysicists often theorize that most of the mass of the Local Group is invisible, made of so-called dark matter.

Zhao and his team argue that at present the only way to successfully predict the total gravitational pull of any galaxy or small galaxy group, before measuring the motion of stars and gas in it, is to make use of a model first proposed by Professor Mordehai Milgrom of the Weizmann Institute in Israel in 1983. This modified gravity theory (Modified Newtonian Dynamics or MOND) describes how gravity behaves differently on the largest scales, diverging from the predictions made by Newton and Einstein, researchers said.

Zhao and his colleagues have for the first time used this theory to calculate the motion of Local Group galaxies. Their work suggests that the Milky Way and Andromeda galaxies had a close encounter about 10 billion years ago. If gravity conforms to the conventional model on the largest scales then taking into account the supposed additional pull of dark matter, the two galaxies would have merged. "Dark matter would work like honey: in a close encounter, the Milky Way and Andromeda would get stuck together, figuratively speaking," said team member Pavel Kroupa from Bonn University.

Mars rover Curiosity tracks Martian moonrise

One of Mars' two tiny moons climbs high into the Red Planet sky in an otherworldly new video recorded by NASA's Curiosity rover. The video, which stitches together 86 frames snapped by Curiosity's navigation camera, shows the Mars moon Phobos rising shortly after sunset on June 28, 2013.
Though the video lasts just 32 seconds, the action it depicts actually took place over the course of 27 minutes. The large, diffuse ring visible in the video is an artifact caused by the scattering of light inside the camera, officials said.

Phobos is just 14 miles (22 kilometers) wide on average, while Mars' other moon, Deimos, is even smaller. Many scientists think both Phobos and Deimos are former asteroids captured by the Red Planet's gravity long ago. Curiosity landed inside Mars' huge Gale Crater last August, kicking off a planned two-year surface mission to determine if the Red Planet could ever have supported microbial life. The rover has already checked off this big milestone; in March, mission scientists announced that a site called Yellowknife Bay was indeed habitable billions of years ago.

Curiosity has yet to venture far from its landing site, but that will change soon. The rover is getting set to start heading for its ultimate destination, the base of the mysterious Mount Sharp, which rises 3.4 miles (5.5 kilometers) into the sky from Gale Crater's center. Mount Sharp's many layers hold a history of Mars' changing environmental conditions over time, and Curiosity scientists want the 1-ton robot to read this history like a book as it climbs up through the mountain's lower reaches. The foothills of Mount Sharp lie about 5 miles (8 kilometers) from Curiosity's current location as the crow flies. The rover is wrapping up its last activities near its landing site and could begin the roughly year-long drive any day now.

The new video does not mark Curiosity's first observations of Phobos. In September of last year — just five weeks after touching down — the rover used its workhorse MastCam camera to photograph the moon as it crossed the face of the sun, taking a tiny bite out of the star. Such eclipse photos can help refine scientists' understanding of the orbits and orbital evolution of Phobos and Deimos, researchers have said. And the gee-whiz factor may be a motivator as well, especially since these images are not terribly difficult for the Curiosity rover to collect.

You can watch the video here.

Looking for life beyond Earth? Explore the habitable zone of planets

You now have twice as many planets to explore for the so-called habitable zone because there may be as many as 60 billion exoplanets in our galaxy alone in the space around their stars - double the number previously thought of.

A study by astronomers at the University of Chicago shows how cloud patterns can alter the temperature of a planet enough that planets that were previously considered too close to their stars to support liquid water might be able to support it. Using a 3-D climate model originally created to forecast global warming on Earth, the scientists were able to model cloud patterns on planets that orbit red dwarf stars, the most common star in our galaxy.

Red dwarf stars are less massive and cooler than our sun, and planets have to get pretty close to them in order to get enough heat to keep liquid water from freezing on their surface. Because the planets are so close to the star, they eventually get tidally locked with it, meaning the same side of the planet is always facing the star.

To be in a habitable zone, a planet needs to be just the right distance from its star so that liquid water (considered a requisite for life as we know it)  can exist on the planet's surface.If the planet is too near its star, the liquid water would turn to vapor; too far away, and the water would turn to ice.For decades, scientists have determined whether a planet is in this liquid-water-friendly Goldilocks zone by calculating how far the planet is from its star, and how hot the star is burning.

According to the researchers' models at the university, thick, giant clouds develop over the part of the planet that directly faces the star, reflecting light and heat back at the star and keeping the planet from getting too warm.Dorian Abbot, an associate professor of geophysical sciences at the University of Chicago and one of the study's authors, said his team's findings could easily be tested using the James Webb Space Telescope, which will go into orbit in 2018.

NASA's new satellite to explore mysteries of the sun

A winged Pegasus rocket recently lifted a compact solar observatory into orbit around Earth's poles, kicking off a $181 million mission to shed light on a major mystery: What heats up the sun's outer atmosphere to extreme temperatures and how that, in turn, affects Earth's space weather.

NASA's Interface Region Imaging Spectrograph, or IRIS spacecraft will focus on the dynamic zone between the sun's 6,000-degree visible surface -- the photosphere -- and the tenuous corona, which is somehow heated to more than a million degrees over a span of a few thousand miles.

Scientists hope to gain insights into the energy transport mechanisms that drive the solar wind -- the supersonic stream of atomic particles blasted away from the sun -- solar flares and explosive eruptions known as coronal mass ejections that occasionally disrupt power grids, satellite operations and communications on Earth.

Alan Title, IRIS principal investigator at Lockheed Martin's Advanced Technology Center said, "What we want to discover is what the basic physical processes are that transfer energy and material from the surface of the sun to the outer atmosphere of the sun, the corona.The visible surface (is) the place where virtually all of the light that leaves the sun leaves from. Immediately above that, the temperature rises to the million-degree corona. How that happens is a mystery. What are the processes that occur there?"

Making the program's 42nd flight, the Orbital Sciences Pegasus XL rocket was carried aloft from Vandenberg Air Force Base, Calif., by an L-1011 carrier jet.The Orbital Sciences "Stargazer" jet carried the 51,000-pound rocket to a pre-determined drop point over the Pacific Ocean and, after final tests were completed, released the Pegasus at a planned altitude of 39,000 feet at 10:27 p.m. EDT (GMT-4; 7:27 p.m. local time).

Read about the sun's violent dance from here.

Milky Way much bigger than estimated earlier

New observations with Hubble's $70 million Cosmic Origins Spectrograph, or COS, designed by CU-Boulder show that normal spiral galaxies are surrounded by halos of gas that can extend to over 1 million light-years in diameter. A new study has revealed that spiral galaxies like our own Milky Way appear to be much larger and more massive than previously believed.

The current estimated diameter of the Milky Way, for example, is about 100,000 light-years. One light-year is roughly 6 trillion miles. The material for galaxy halos detected by the CU-Boulder team originally was ejected from galaxies by exploding stars known as supernovae, a product of the star formation process, Stocke of CU-Boulder’s astrophysical and planetary sciences department said.

University of Colorado Boulder Professor John Stocke, study leader said, “This gas is stored and then recycled through an extended galaxy halo, falling back onto the galaxies to reinvigorate a new generation of star formation. In many ways this is the ‘missing link’ in galaxy evolution that we need to understand in detail in order to have a complete picture of the process.”

Voyager-I spacecraft surfs edge of Solar System

Latest data from some extraordinary probe by Ed Stone who has worked on the Voyager-1 spacecraft project from the beginning,  suggests it is surfing right on the very edge of our Sun's domain. The particles streaming away from our star have reduced to a trickle at its present location, 18.5 billion km from Earth, according to a report in this week's Science journal.

Particles flying towards it from interstellar space, by contrast, have jumped markedly in the past year. It all points to an imminent departure, which would make Voyager the first man-made object to cross into the space between the stars.

Dr Stone said, "It's hard to imagine there's another layer between the one we're in and the outside. Topologically, it makes sense that this is the outermost layer. The only question is: how thick is it?"

Launched way back in 1977, the probe has now travelled so far from home that its constant chatter of data takes 17 hours to arrive at the US space agency's receiving network. Voyager's instruments are busy sampling the far-flung environment. This has allowed Dr Stone and colleagues to map the shape and reach of the heliosphere - the giant bubble of charged particles blown off from our Sun.

In 2004, it reached a turbulent region referred to as the heliosheath, where particles bounced around in all directions. It was expected this would be the final stage before the leap to interstellar space. But, as has been the case throughout this 35-year mission, Voyager threw up yet another surprise.
Last year, it detected what appears to be a discrete boundary layer that Ed Stone's team call the "heliosheath depletion region" in Friday's three Science papers.

It is a kind of magnetic highway where energetic particles on the inside can get out easily, and the galactic cosmic ray particles on the outside can zoom in. "It is where the Sun's magnetic field has piled up, compressed up against itself. It has also doubled in strength. It's smoother than anything we've ever seen with Voyager," Dr Stone explained.

The team is now watching the direction of the field lines very carefully. Currently, they orientate east-west, wound into a spiral by the rotating Sun. But when Voyager finally breaks through into interstellar space, they are expected to shift dramatically, running north-south.

Read more about the journey of the Voyager from here.