NASA Cassini image: Birth of a Saturn moon

The disturbance visible at the outer edge of Saturn's A ring in this image from NASA's Cassini spacecraft could be caused by an object replaying the birth process of icy moons. 

Credit: JPL/NASA

NASA's Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn that may be a new moon, and may also provide clues to the formation of the planet's known moons.

Images taken with Cassini's narrow angle camera on April 15, 2013, show disturbances at the very edge of Saturn's A ring, the outermost of the planet's large, bright rings.

One of these disturbances is an arc about 20 percent brighter than its surroundings, 750 miles (1,200 kilometers) long and 6 miles (10 kilometers) wide.

Scientists also found unusual protuberances in the usually smooth profile at the ring's edge.

Scientists believe the arc and protuberances are caused by the gravitational effects of a nearby object. Details of the observations were published online today by the journal Icarus.

The object is not expected to grow any larger, and may even be falling apart but the process of its formation and outward movement aids in our understanding of how Saturn's icy moons, including the cloud-wrapped Titan and ocean-holding Enceladus, may have formed in more massive rings long ago.

It also provides insight into how Earth and other planets in our solar system may have formed and migrated away from our star, the sun.

Carl Murray

"We have not seen anything like this before," said Carl Murray of Queen Mary University of London, the report's lead author.

"We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right."

The object, informally named Peggy, is too small to be seen in images so far. Scientists estimate it is probably no more than about a half mile (about a kilometer) in diameter.

Saturn's icy moons range in size depending on their proximity to the planet—the farther from the planet, the larger, and many of Saturn's moons are composed primarily of ice, as are the particles that form Saturn's rings.

Based on these facts, and other indicators, researchers recently proposed that the icy moons formed from ring particles and then moved outward, away from the planet, merging with other moons on the way.

"Witnessing the possible birth of a tiny moon is an exciting, unexpected event," said Cassini Project Scientist Linda Spilker, of NASA's Jet Propulsion Laboratory in Pasadena, Calif.

According to Spilker, Cassini's orbit will move closer to the outer edge of the A ring in late 2016 and provide an opportunity to study Peggy in more detail and perhaps even image it.

It is possible the process of moon formation in Saturn's rings has ended with Peggy, as Saturn's rings now are, in all likelihood, too depleted to make more moons.

Because they may not observe this process again, Murray and his colleagues are wringing from the observations all they can learn.

"The theory holds that Saturn long ago had a much more massive ring system capable of giving birth to larger moons," Murray said.

"As the moons formed near the edge, they depleted the rings and evolved, so the ones that formed earliest are the largest and the farthest out."

More information: Carl D. Murray, Nicholas J. Cooper, Gareth A. Williams, Nicholas O. Attree, Jeffrey S. Boyer, The discovery and dynamical evolution of an object at the outer edge of Saturn's A ring, Icarus, Available online 28 March 2014, ISSN 0019-1035, dx.doi.org/10.1016/j.icarus.2014.03.024.

Astronomers witness birth of Milky Way's most massive star

a) Mid-infrared Spitzer composite image. 

b) Herschel column density image of SDC335. 

c) ALMA 3.2 mm dust continuum emission of the central region of SDC335 where two cores are identified, MM1 and MM2. 

Credit: A&A 555, A112 (2013)

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."

Different theories exist as to how these massive stars form but the team's findings lend weight to the idea that the entire cloud core begins to collapse inwards, with material raining in towards the centre to form one or more massive stars.

Co-author Professor Gary Fuller, from The University of Manchester, said: "Not only are these stars rare, but their births are extremely rapid and childhood short, so finding such a massive object so early in its evolution in our Galaxy is a spectacular result.

More information: 'Global collapse of molecular clouds as a formation mechanism for the most massive stars,' Astronomy & Astrophysics, www.aanda.org/articles/aa/pdf/2013/07/aa21318-13.pdf

Cosmic Flash may reveal Birth of a Black Hole

A computer-generated image of the light distortions created by a black hole. Credit: Alain Riazuelo, IAP/UPMC/CNRS

When a massive star exhausts its fuel, it collapses under its own gravity and produces a black hole, an object so dense that not even light can escape its gravitational grip.

According to a new analysis by an astrophysicist at the California Institute of Technology (Caltech), just before the black hole forms, the dying star may generate a distinct burst of light that will allow astronomers to witness the birth of a new black hole for the first time.

Tony Piro

Tony Piro, a postdoctoral scholar at Caltech, describes this signature light burst in a paper published in the May 1 issue of the Astrophysical Journal Letters.

While some dying stars that result in black holes explode as gamma-ray bursts, which are among the most energetic phenomena in the universe, those cases are rare, requiring exotic circumstances, Piro explains.

"We don't think most run-of-the-mill black holes are created that way." In most cases, according to one hypothesis, a dying star produces a black hole without a bang or a flash: the star would seemingly vanish from the sky—an event dubbed an unnova. "You don't see a burst," he says. "You see a disappearance."

But, Piro hypothesizes, that may not be the case. "Maybe they're not as boring as we thought," he says.

According to well-established theory, when a massive star dies, its core collapses under its own weight. As it collapses, the protons and electrons that make up the core merge and produce neutrons.

For a few seconds—before it ultimately collapses into a black hole—the core becomes an extremely dense object called a neutron star, which is as dense as the sun would be if squeezed into a sphere with a radius of about 10 kilometers (roughly 6 miles).

This collapsing process also creates neutrinos, which are particles that zip through almost all matter at nearly the speed of light.

As the neutrinos stream out from the core, they carry away a lot of energy—representing about a tenth of the sun's mass (since energy and mass are equivalent, per E = mc2).

According to a little-known paper written in 1980 by Dmitry Nadezhin of the Alikhanov Institute for Theoretical and Experimental Physics in Russia, this rapid loss of mass means that the gravitational strength of the dying star's core would abruptly drop.

When that happens, the outer gaseous layers—mainly hydrogen—still surrounding the core would rush outward, generating a shock wave that would hurtle through the outer layers at about 1,000 kilometers per second (more than 2 million miles per hour).

Stan Woosley

Using computer simulations, two astronomers at UC Santa Cruz, Elizabeth Lovegrove and Stan Woosley, recently found that when the shock wave strikes the outer surface of the gaseous layers, it would heat the gas at the surface, producing a glow that would shine for about a year—a potentially promising signal of a black-hole birth.

Although about a million times brighter than the sun, this glow would be relatively dim compared to other stars.

"It would be hard to see, even in galaxies that are relatively close to us," says Piro.

But now Piro says he has found a more promising signal. In his new study, he examines in more detail what might happen at the moment when the shock wave hits the star's surface, and he calculates that the impact itself would make a flash 10 to 100 times brighter than the glow predicted by Lovegrove and Woosley.

"That flash is going to be very bright, and it gives us the best chance for actually observing that this event occurred," Piro explains. "This is what you really want to look for."

Such a flash would be dim compared to exploding stars called supernovae, for example, but it would be luminous enough to be detectable in nearby galaxies, he says.

The flash, which would shine for 3 to 10 days before fading, would be very bright in optical wavelengths—and at its very brightest in ultraviolet wavelengths.

Piro estimates that astronomers should be able to see one of these events per year on average. Surveys that watch the skies for flashes of light like supernovae—surveys such as the Palomar Transient Factory (PTF), led by Caltech—are well suited to discover these unique events, he says.

The intermediate Palomar Transient Factory (iPTF), which improves on the PTF and just began surveying in February, may be able to find a couple of these events per year.

Neither survey has observed any black-hole flashes as of yet, says Piro, but that does not rule out their existence. "Eventually we're going to start getting worried if we don't find these things." But for now, he says, his expectations are perfectly sound.

Autumn of your Life: Longevity Tied to Season of your Birth

Autumn Colours

People born in autumn are more likely to live for 100 years compared to those born in summer, according to a report in the Journal of Aging Research.

Researchers from the University of Chicago have found that people, who are born in autumn, from September to November, are likely to live for 100 years compared to those who are born in March.

The discovery was made while analysing data from the Rootsweb ancestry website.

Researchers conducted a study on more than 1,500 centenarians born in the United States between 1880 and 1895. The data obtained from the study was compared with 10,855 shorter-lived siblings and 1,083 spouses.

"Centenarians (cases) were compared to their "normal" shorter-lived siblings (controls) or spouses using a within-family analysis.

This approach allows investigators to study the within-family differences, not being confounded by the between-family variation.

Long-lived persons born in 1880-1895 were used as cases," said Leonid A Gavrilov, researcher at the University of Chicago, in a statement.

The study found that people who are born in September, October and November have a longer life span compared to their siblings born in March, April, May, June, July and August.

"These results demonstrate that persons born in September-November have significantly higher chances of exceptional longevity than persons born in March.

This survival advantage of persons born in the fall months is consistent across different lifespan cut-offs suggesting long-lasting influence of season of birth on longevity," said Natalia S Gavrilova, researcher at the University of Chicago, in a statement.

Researchers are not sure as how month of the birth affects mortality and health in later life but they have suggested some theories.

One is that the nutritional status of mother during pregnancy might have a long lasting effect on the child in later life, which in turn can increase the mortality risk.

Another theory is that children born between March and August are likely to be affected by several infections and disease, which in turn increase their mortality rate.

According to the researchers, the human enterovirus and it's cousin, poliovirus have epidemic peaks, only in the months of July and August.

The effect of environmental temperature during the time of birth may be another possible explanation for low proportion of centenarians among individuals born during the summer and spring months.

For example, Britons, who had experienced higher summer temperatures during their first year of life, had severe diarrhea and dehydration in infancy and they had higher blood pressure at older ages, according to the Journal of Aging Research.

The Sperm Bike - Home deliveries

Biological analyst Alan Dowden of the Seattle Sperm Bank rides the Sperm Bike, a custom-designed, high-tech bicycle used to deliver donated sperm to fertility clinics.

Donor sperm is transported by medical technicians aboard the bike in liquid nitrogen cooled vacuum containers.

The first Sperm Bike was adopted by Seattle Sperm Bank's sibling company, the European Sperm Bank, in Cophenhagen.

Picture: REUTERS/Anthony Bolante

NASA - Firestorm of Star Birth in the Active Galaxy Centaurus A

Resembling looming rain clouds on a stormy day, dark lanes of dust crisscross the giant elliptical galaxy Centaurus A.

Hubble's panchromatic vision, stretching from ultraviolet through near-infrared wavelengths, reveals the vibrant glow of young, blue star clusters and a glimpse into regions normally obscured by the dust.

The warped shape of Centaurus A's disk of gas and dust is evidence for a past collision and merger with another galaxy. The resulting shockwaves cause hydrogen gas clouds to compress, triggering a firestorm of new star formation. These are visible in the red patches in this Hubble close-up.

At a distance of just over 11 million light-years, Centaurus A contains the closest active galactic nucleus to Earth. The center is home for a supermassive black hole that ejects jets of high-speed gas into space, but neither the supermassive or the jets are visible in this image.

This image was taken in July 2010 with Hubble's Wide Field Camera 3.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

THE birth of the US Appalachian mountain chain caused mass extinction

THE birth of the US Appalachian mountain chain may have been behind a major ice age and a mass extinction.

The extinction event at the end of the Ordovician 450 million years ago was the second largest Earth has ever seen. It has long been believed that an ice age caused it, but no one knew what triggered the freeze.

Seth Young of Indiana University in Bloomington, and colleagues, believe two factors conspired to create the deep freeze. First, layers of lava show that climate-warming volcanic activity slowed down at this time. The second factor was an increase in the weathering of the Appalachian rocks between 462 and 454 million years ago, which is indicated by changes in strontium isotope ratios in Ordovician oceanic rocks (Geology, DOI: 10.1130/g30152a.1).

Born to Cuddle - Hormone Oxytocin

The cuddle chemical has a dark side. Oxytocin – a hormone thought to play a role in maternal bonding, trust and even attraction – amplifies feelings of envy and gloating, research suggests.

Volunteers who played a game involving monetary gains and losses felt more envy after an imaginary opponent's wins if they had received a dose of oxytocin, compared with a placebo.

Similarly, oxytocin boosted feelings of schadenfreude – pleasure at another's misfortune – after volunteers won more money than their opponent.

"The bottom line is that [oxytocin] doesn't only work on pro-social, positive emotions, it has a general effect on social emotions and it depends on the context," says Simone Shamay-Tsoory, a cognitive scientist at the University of Haifa, Israel, who led the study.

Attraction to aggression

Previous work on animals has hinted at oxytocin's double life. Female hamsters that received an infusion of oxytocin into a brain area where the hormone is known to have an effect responded more aggressively to intruders than hamsters that got no oxytocin.

Newborn female voles that received an injection of oxytocin later responded more aggressively to males than other females.

Studies with humans, on the other hand, have suggested that oxytocin makes us more likely to trust others, find them attractive, and remember their faces. We even receive a flood of the stuff when we play with our pooches. "No one actually examined if it can be involved in negative social emotions," says Shamay-Tsoory.

However, she admits her team expected to find that feelings of envy and gloating were tempered by the hormone.