Cosmic inflation: 'Spectacular' discovery hailed

Scientists say they have extraordinary new evidence to support a Big Bang Theory for the origin of the Universe.

Researchers believe they have found the signal left in the sky by the super-rapid expansion of space that must have occurred just fractions of a second after everything came into being.

It takes the form of a distinctive twist in the oldest light detectable with telescopes.

The work will be scrutinised carefully, but already there is talk of a Nobel.

"This is spectacular," commented Prof Marc Kamionkowski, from Johns Hopkins University.

"I've seen the research; the arguments are persuasive, and the scientists involved are among the most careful and conservative people I know," he told BBC News.

The breakthrough was announced by an American team working on a project known as BICEP2.

This has been using a telescope at the South Pole to make detailed observations of a small patch of sky.

The aim has been to try to find a residual marker for "inflation" - the idea that the cosmos experienced an exponential growth spurt in its first trillionth, of a trillionth of a trillionth of a second.

Theory holds that this would have taken the infant Universe from something unimaginably small to something about the size of a marble. Space has continued to expand for the nearly 14 billion years since.

Inflation was first proposed in the early 1980s to explain some aspects of Big Bang Theory that appeared to not quite add up, such as why deep space looks broadly the same on all sides of the sky. The contention was that a very rapid expansion early on could have smoothed out any unevenness.

But inflation came with a very specific prediction - that it would be associated with waves of gravitational energy, and that these ripples in the fabric of space would leave an indelible mark on the oldest light in the sky - the famous Cosmic Microwave Background.

The BICEP2 team says it has now identified that signal. Scientists call it B-mode polarisation. It is a characteristic twist in the directional properties of the CMB. Only the gravitational waves moving through the Universe in its inflationary phase could have produced such a marker. It is a true "smoking gun".

Speaking at the press conference to announce the results, Prof John Kovac of the Harvard-Smithsonian Center for Astrophysics, and a leader of the BICEP2 collaboration, said: "This is opening a window on what we believe to be a new regime of physics - the physics of what happened in the first unbelievably tiny fraction of a second in the Universe."

The signal is reported to be quite a bit stronger than many scientists had dared hope. This simplifies matters, say experts. It means the more exotic models for how inflation worked are no longer tenable.

The results also constrain the energies involved - at 10,000 trillion gigaelectronvolts. This is consistent with ideas for what is termed Grand Unified Theory, the realm where particle physicists believe three of the four fundamental forces in nature can be tied together.

But by associating gravitational waves with an epoch when quantum effects were so dominant, scientists are improving their prospects of one day pulling the fourth force - gravity itself - into a Theory of Everything.

The sensational nature of the discovery means the BICEP2 data will be subjected to intense peer review.

It is possible for the interaction of CMB light with dust in our galaxy to produce a similar effect, but the BICEP2 group says it has carefully checked its data over the past three years to rule out such a possibility.

Other experiments will now race to try to replicate the findings. If they can, a Nobel Prize seems assured for this field of research.

Who this would go to is difficult to say, but leading figures on the BICEP2 project and the people who first formulated inflationary theory would be in the running.

One of those pioneers, Prof Alan Guth from the Massachusetts Institute of Technology, told the BBC: "I have been completely astounded. I never believed when we started that anybody would ever measure the non-uniformities of the CMB, let alone the polarisation, which is now what we are seeing.

"I think it is absolutely amazing that it can be measured and also absolutely amazing that it can agree so well with inflation and also the simplest models of inflation - nature did not have to be so kind and the theory didn't have to be right."

British scientist Dr Jo Dunkley, who has been searching through data from the European Planck space telescope for a B-mode signal, commented: "I can't tell you how exciting this is. Inflation sounds like a crazy idea, but everything that is important, everything we see today - the galaxies, the stars, the planets - was imprinted at that moment, in less than a trillionth of a second. If this is confirmed, it's huge."

Source: BBC News

Full Moon Rises Sunday: Live Webcast Seeks Record-Breaking Lunar Crash Site

The March full moon will rise on Sunday night (March 16) in a brilliant display that will allow Internet denizens to investigate the site of the most brilliant lunar explosion in a free live webcast, weather permitting.

This month's full moon — which officially turns full at 1:08 p.m. EDT (1708 GMT) Sunday — is called the "Full Worm Moon." The seemingly odd name comes from the appearance of earthworms as the ground softens after winter thaws. The online Slooh community telescope website will use the full moon event to examine an impact site in the Mare Nubium lunar basin. The webcast begins at 9 p.m. EDT (0100 March 17 GMT). You can view it directly through the Slooh website, or watch the full moon webcast live on Space.com. 

The target of Sunday's Slooh lunar webcast is a region of Mare Nubium, where brightest asteroid strike on the moon ever seen was spoted last year. The asteroid was traveling at about 37,900 mph (61,000 km/h) when it slammed into the moon, creating a crater about 131 feet wide (40 meters) on Sept. 11, 2013. Scientists announced the discovery on Feb. 24 of this year. 

Scientists estimate that the asteroid was between 2 and 4.5 feet (0.6 and 1.4 meters) across. If an observer on Earth has been looking up at the moon during impact, they may have seen a long flash almost as bright as the North Star Polaris, brighter than any lunar impact recorded. [See a video of the bright lunar impact]

If a space rock of the size of the lunar hit struck the Earth, it would likely create an amazing fireball in the sky, but it would pose no threat to people on the ground, researchers have said. The impact was so spectacular on the moon because the natural satellite's extremely thin atmosphere (called an exosphere) does not protect the lunar surface from strikes like this one.

"Ever since Luis and Walter Alvarez astonished the world in 1980 by presenting convincing evidence that an asteroid impacted our planet and wiped out the dinosaurs 65 million years ago, the threat of an Earth-altering collision has remained in the public awareness," Slooh astronomer Bob Berman said in a statement. "The astonishing double-whammy of Feb. 15, 2013, when an asteroid-near miss occurred on the same day that an asteroid fragment exploded over Siberia, injuring 1,500 people, underscores the reality of thousands of uncharted asteroid fragments that can cross our path at any time. In the past year, Slooh has managed to track and image several of these in real-time, and displayed these encounters to the public as they happened." 

Sunday night's full moon is not only known as the Full Worm Moon. It also carries the name "Full Crow Moon" for the cawing crows that signal the end of winter, and the "Full Crust Moon" for the crusted snow created by repeated thawing and freezing.

Source: Space.com

Scientists May Get Best View Yet of a Black Hole in Action

It’s the cosmic event of the year. Right now, telescopes all over the world are turning to our galaxy’s center, where for the first time ever they may have a front-row look at a supermassive black hole consuming a gas cloud.

By observing this galactic snack fest, astronomers should be able to figure out what’s going on in the black hole’s immediate vicinity and potentially even witness some gas disappear into the massive object’s maw. What they see may help scientists solve a decades-old puzzle about why our galaxy’s central black hole is so quiet.

Astronomers are gearing up to watch this show using many different telescopes with different wavelengths of light to capture all the information they can. But they are still unsure what exactly they will see.

“It’s a bit like the moment before a penalty shot in soccer,” said astrophysicist Stefan Gillessen of the Max Planck Institute for Extraterrestrial Physics in Germany, one of the leaders of the observation campaign. Everyone knows a shot is about to be taken, but nobody knows outcome will be. “This is the most tense moment when one player is trying to shoot against someone on the other side.”

Though we think of them as cosmic vacuum cleaners, black holes are actually just like any other massive body, such as a star. This means other objects can safely orbit them, until they get within a particular distance and pass what’s known as the event horizon, after which there is no escaping being sucked in.

The gas cloud currently headed for the central black hole could either continue on its current orbit and slingshot around the black hole or it could run into surrounding gas and dust, which will make it lose speed and start sliding down toward the black hole. The first scenario could give scientists insight into the evolution of galaxies and better understand the history of our Milky Way’s own black hole. In the second case, they might get to watch the black hole consume a sizable dinner.

No matter the outcome, “it will be absolutely stunning to see the physics at work,” said Gillessen.

In 2011, Gillessen and his colleagues made a chance discovery of a small cloud of gas and dust near the galactic center. Dubbing it G2, they soon plotted the cloud’s orbit, which showed that it was headed directly for the supermassive black hole at the Milky Way’s center and would reach it in 2013. With further data refinements, they realized their initial prediction was a bit off and the cloud would be swinging near the black hole this month. Now that G2 is finally starting to make its closest approach, it’s feeling pulled by the black hole’s enormous gravity.

“This gas thing has been shredded into an extremely long spaghetti configuration,” said astrophysicistReinhard Genzel, also of the Max Planck Institute, who helped discover G2.

G2 started as a blob with approximately three times the mass of Earth. It has been falling in almost a perfectly straight line toward the central black hole at speeds exceeding 5 million mph. Because it is a diffuse and elongated object, there is no specific time when G2 is expected to be closest to the black hole (“We can’t say this will happen some Friday afternoon at 5 p.m.,” said Genzel.) You should of course keep in mind that the Milky Way’s center is 26,000 light-years from Earth so all this actually happened 26,000 years ago.

Some models predict that G2 will slam into an atmosphere of gas and dust that hangs around in a disk around the central black hole, a remnant of previous feeding binges. If so, the cloud could heat up to temperatures greater than 10 million degrees, producing X-rays and other radiation that will be visible to our telescopes. Some of G2’s dust could even start spiraling into the black hole like water circling a drain, which would also heat it up and produce radiation.

But the galactic center is a place of many mysteries and a great deal of weirdness. In addition to the gargantuan black hole – with its mass of four million suns – scientists predict that there could be around 10,000 solar mass black holes in the Milky Way’s central region. These are the leftovers of enormous stars that once blazed in the galactic center but burned through their fuel, exploding as a dramatic supernova and crunching down into black holes. Other dead stellar cores, such as white dwarfs and neutron stars, also litter this area.

“There’s a reasonable chance that one of those might be hit, and that would be absolutely fantastic,” said Gillessen. The event might be detectable by telescopes on Earth and could give astronomers insight into the dynamics of these smaller black holes.

There is also the possibility that the gas and dust surrounding our galactic supermassive black hole is too diffuse for G2 to slam into it. In this case, the gas cloud will drift serenely through this region with little interaction, following a path set by gravity. Its closest approach to the central black hole will bring it only within about 20 light-hours, or about five times the distance between the sun and Neptune, at the edge of our solar system. Thus far, this is what G2 has been doing. Though observations have only begun, astronomers have seen no substantial increase in radiation coming from the central Milky Way region, putting constraints on the amount and density of gas and dust there.

If this is true, and the area around the black hole is relatively empty, it could help explain why our galaxy’s black hole doesn’t produce much radiation. Distant supermassive black holes that we see out in the universe are often spewing copious amounts of energy in the form of radiation jets. These objects, known as quasars, are some of the brightest things ever seen. Scientists don’t yet know how they work but they are thought to be an early stage of galactic evolution, when their central supermassive black hole is consuming huge amounts of material, producing tons of energy. How and why quasars turn off is an ongoing area of research.

Astronomers know that as recently as a few hundred years ago, the Milky Way’s central supermassive black hole was producing much more radiation. The reflected X-ray echoes of this era have been observed bouncing off clouds of gas and dust. Why this energetic period stopped is a mystery. With future data from G2’s trajectory, we might find out that our galactic black hole simply ran out of things to eat.

As far as being able to actually witness material slip beyond the black hole’s event horizon and disappear forever, that will have to wait for another day. Because it’s so far away, no current telescope has the resolution to see that well in the galactic center. Astronomers are trying to coordinate different telescopes right now as part of the Event Horizon Telescope project, which could image the area just around the supermassive black hole. But the earliest that this project will be up and running is 2016. Perhaps some blobs from G2 will get torn off and be hurtling right into the black hole at this time?

“If we’re lucky we could see the effects of special and general relativity,” said Genzel, talking about the Event Horizon Telescope. “But probably not with this cloud.”

Testing relativity requires a reliable clock, he added, and G2 doesn’t emit any sort of periodic radiation that would be useful for this.

Source: WIRED