North magnetic pole racing toward Siberia?

The north magnetic pole (NMP), also known as the dip pole, is the point on Earth where the planet's magnetic field points straight down into the ground. Scottish explorer James Clark Ross first located the NMP in 1831 on the Boothia Peninsula in what is now northern Canada, and with the planting of a flag claimed it for Great Britain. 

But the NMP drifts from year to year as geophysical processes within Earth change. For more than 150 years after Ross's measurement its movement was gradual, generally less than 15 kilometers per year. But then, in the 1990s, it picked up speed in a big way, bolting north–northwest into the Arctic Ocean at more than 55 kilometers per year. If it keeps going it could pass the geographic north pole in a decade or so and carry on toward Siberia. But why?

One compelling explanation appears in the December 21 Eos, the weekly transactions of the American Geophysical Union. In their Eos article (subscription required), and ina longer paper published earlier in 2010 in the Journal of Geophysical Research–Solid Earth, Arnaud Chulliat of the Institute of Earth Physics of Paris and his colleagues venture that a twisting molten plume beneath the Artic could be the cause:

 According to some recent models, plumes of less dense fluid form at the inner core boundary and subsequently rise within [a cylinder] whose central axis is the Earth’s rotation axis. Such plumes undergo a strong helical motion due to the Earth’s rapid rotation, a phenomenon also observed in laboratory experiments with water. In the core, helical plumes advect and twist the magnetic field lines, forming what scientists call "polar magnetic upwellings." 

Those upwellings, unloaded into the Arctic mantle, could produce intense patches of magnetic activity on the sort of decade-long timescales needed to explain the NMP's sudden acceleration. (The authors compare these patches to a kind of terrestrial version of sunspots.) And magnetic field measurements show dramatic shifts near the New Siberian Islands that seem to fit the bill.

"What happened under the New Siberian Islands at the core surface is that the rate of change of the magnetic field changed by a large amount during the 1990s," Chulliat says. That activity, he and his colleagues have found, could account for a large portion of the NMP's acceleration. But whether magnetic field changes under the New Siberian Islands and the speeding north magnetic pole ultimately arise from a twisted plume of fluid rising through the core remains unproved, Chulliat and his co-authors note. A resolution of the mystery will await better modeling, along with more data from satellites monitoring the Arctic's magnetic environment. The necessity of satellites, interestingly enough, is a consequence of the pole's recent movement—as the NMP drifts farther out to sea, it becomes harder and harder to reach the region with magnetometer-equipped aircraft. Compass Photo credit:http://schools.bcsd.com

Scientists find first evidence that many universes exist

The signatures of a bubble collision: A collision (top left) induces a temperature modulation in the CMB temperature map (top right). The “blob” associated with the collision is identified by a large needlet response (bottom left), and the presence of an edge is determined by a large response from the edge detection algorithm (bottom right). Image credit: Feeney, et al.

 By looking far out into space and observing what’s going on there, scientists have been led to theorize that it all started with a Big Bang, immediately followed by a brief period of super-accelerated expansion called inflation. Perhaps this was the beginning of everything, but lately a few scientists have been wondering if something could have come before that, setting up the initial conditions for the birth of our universe.

In the most recent study on pre-Big Bang science posted at arXiv.org, a team of researchers from the UK, Canada, and the US, Stephen M. Feeney, et al, have revealed that they have discovered four statistically unlikely circular patterns in the cosmic microwave background (CMB). The researchers think that these marks could be “bruises” that our universe has incurred from being bumped four times by other universes. If they turn out to be correct, it would be the first evidence that universes other than ours do exist.

The idea that there are many other universes out there is not new, asscientists have previously suggested that we live in a “multiverse” consisting of an infinite number of universes. The multiverse concept stems from the idea of eternal inflation, in which the inflationary period that our universe went through right after the Big Bang was just one of many inflationary periods that different parts of space were and are still undergoing. When one part of space undergoes one of these dramatic growth spurts, it balloons into its own universe with its own physical properties. As its name suggests, eternal inflation occurs an infinite number of times, creating an infinite number of universes, resulting in the multiverse.

These infinite universes are sometimes called bubble universes even though they are irregular-shaped, not round. The bubble universes can move around and occasionally collide with other bubble universes. As Feeney, et al., explain in their paper, these collisions produce inhomogeneities in the inner-bubble cosmology, which could appear in the CMB. The scientists developed an algorithm to search for bubble collisions in the CMB with specific properties, which led them to find the four circular patterns.

Still, the scientists acknowledge that it is rather easy to find a variety of statistically unlikely properties in a large dataset like the CMB. The researchers emphasize that more work is needed to confirm this claim, which could come in short time from the Planck satellite, which has a resolution three times better than that of WMAP (where the current data comes from), as well as an order of magnitude greater sensitivity. Nevertheless, they hope that the search for bubble collisions could provide some insight into the history of our universe, whether or not the collisions turn out to be real.

“The conclusive non-detection of a bubble collision can be used to place stringent limits on theories giving rise to eternal inflation; however, if a bubble collision is verified by future data, then we will gain an insight not only into our own universe but a multiverse beyond,” the researchers write in their study.

This is the second study in the past month that has used CMB data to search for what could have occurred before the Big Bang. In the first study, Roger Penrose and Vahe Gurzadyan found concentric circles with lower-than-average temperature variation in the CMB, which could be evidence for a cyclic cosmology in which Big Bangs occur over and over.

More information: Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, and Hiranya V. Peiris. "First Observational Tests of Eternal Inflation." arXiv:1012.1995v1 [astro-ph.CO] 

via: The Physics arXiv Blog

GSLV rocket now taller, heavier

India's geosynchronous satellite launch vehicle (GSLV), scheduled to blast off on Monday with an advanced communication satellite (GSAT-5P), is now taller by two metres and heavier by four tonnes as compared to its standard configuration. The Indian Space Research Organisation's standard configuration for the GSLV rocket is a height of 49 metres and 414 tonnes in weight at lift-off.

The rocket that would lift off Monday stands 51 metres tall and weighs 418 tonnes.

PS Veeraraghavan, director of the Vikram Sarabhai Space Centre, told IANS: "This time the fuel quantity for the cryogenic engine has increased and its thrust power has also gone up. The rocket will be carrying a heavier satellite (GSAT-5P) weighing 2,310 kg."

The Russian made cryogenic engine will be powered with 15.2 tonnes of fuel (liquid hydrogen as fuel and liquid oxygen as oxidizer), an increase of around three tonnes, and the engine's length has also increased.

The rocket has a bigger heat shield - four-metres in diameter and made of fibre reinforced plastic (FRP) - as compared to the standard configuration of 3.4-metre diameter made of aluminium alloy metal.

With the changes in rocket's configuration, necessary calibrations have been carried out in the rocket's navigational systems, control dynamics and aerodynamics so that the flight is smooth and the mission is successful, a source associated with ISRO told IANS.

Over the years, the carrying capacity of the GSLV has also increased -- from 1,530 kg in 2001 for GSAT-1 to 2,220 kg for GSAT-4 in April 2010.

The latest has a payload of 2,310 kg with 36 transponders -- an automatic receiver and transmitter of communication or broadcast signals. Successful launch of the satellite will take the agency's transponder capacity to around 235 from 200 in orbit now.

Post List[Operation Ice Bridge]

Post List[Operation Ice Bridge]

'Living Dinosaurs' in Space: Galaxies in Today's Universe Thought to Have Existed Only in Distant Past

Using Australian telescopes, Swinburne University astronomy student Andy Green has found 'living dinosaurs' in space: galaxies in today's Universe that were thought to have existed only in the distant past.The report of his finding -- Green's first scientific paper -- appears on the cover of the Oct. 7 issue of Nature.

"We didn't think these galaxies existed. We've found they do, but they are extremely rare," said Professor Karl Glazebrook, Green's thesis supervisor and team leader.

The Swinburne researchers have likened the galaxies to the 'living dinosaurs' or Wollemi Pines of space -- galaxies you just wouldn't expect to find in today's world.

"Their existence has changed our ideas about how star formation is fuelled and understanding star formation is important. Just look at the Big Bang, which is how we all got here," Glazebrook said.

The galaxies in question look like disks, reminiscent of our own galaxy, but unlike the Milky Way they are physically turbulent and are forming many young stars.

"Such galaxies were thought to exist only in the distant past, ten billion years ago, when the Universe was less than half its present age," Glazebrook said.

"Stars form from gas, and astronomers had proposed that the extremely fast star formation in those ancient galaxies was fuelled by a special mechanism that could exist only in the early Universe -- cold streams of gas continually falling in."

But finding the same kind of galaxy in today's Universe means that that mechanism can't be the only way such rapid star formation is fuelled. Instead it seems that when young stars form, they create turbulence in their surrounding gas. The more stars are forming in a galaxy, the more turbulence it has.

"Turbulence affects how fast stars form, so we're seeing stars regulating their own formation," Green said.

"It's a bit like a little girl deciding how many siblings she should have." "We still don't know where the gas to make these stars comes from though," he said.

Understanding star formation is one of the most basic, unsolved problems of astronomy. Another significant aspect of the paper is that it was authored by a PhD student.

As Glazebrook pointed out, being first author of a Nature paper as a student is as rare as the galaxies they've discovered. This is an achievement not lost on the young scientist.

"Nature is one of the most prestigious journals in science. It was a pleasant surprise for our work to receive this kind of accolade," Green said.

The study was based on selected galaxies from the Sloan Digital Sky Survey, a kind of census of modern galaxies.

"We studied extreme galaxies to compare them with the ancient Universe," Green said.

He observed them using the Anglo-Australian Telescope (AAT) and the Australian National University's 2.3 metre telescope, both located at Siding Spring Observatory in New South Wales. Professor Matthew Colless, Director of the Australian Astronomical Observatory, which operates the AAT, said that the study highlighted the value of the instruments found at Australia's telescopes.

"They are ideal for studying in detail the nearby counterparts of galaxies seen in the distant Universe by the eight and 10 metre telescopes," he said.

For the next stage of his research, Green plans to use one of these 10 metre telescopes -- in fact the largest optical telescope in the world at the Keck Observatory -- to take an even closer look at the rare galaxies he has discovered.

Green admitted: "Really, we need a bigger telescope, the Giant Magellan Telescope, to understand star formation. But, until it's constructed, Keck is the best tool available."

Green's access to the Keck will be possible thanks to Swinburne's agreement with Caltech, which gives the Swinburne astronomers access to the Keck Observatory in Hawaii for up to 20 nights per year.