Circling the Web this week is an incredible video showing Valerie Taylor, a world-renowned shark expert, hand-feeding a great white shark off the side of a boat. After placing a fish into the fearsome creature's mouth, she even leans down and pats it on the nose.

"I think the shark and I had an understanding," Taylor says in a voiceover of the footage, which aired in a TV documentary called Shadow of the Shark. "This one, I had a feeling for."

Great white sharks, according to Yannis Papastamatiou, a research biologist in the Florida Program for Shark Research at the Florida Museum of Natural History, are intelligent and good learners. Despite the great white's reputation as a vicious hunter, like many wild animals, with enough practice and patience (and fish), researchers can condition them to take handouts from research vessels. It isn't unheard of, Papastamatiou said, for researchers to hand-feed them.

In the video, Taylor does just that, first coaxing the shark progressively closer to the boat using line baited with fish before finally feeding the shark by hand.

While this footage might be hair-raising to most of us, it's all in a day's work for Taylor, who, along with husband Ron, has worked in close quarters with great white sharks for decades. She even once swam among great whites with tuna filets stuffed in her chainmail diving suit just to learn more about the way they bite and feed.

An international team of researchers has, for the first time, mapped complete trajectories of single photons in Young's famous double slit experiment. The finding takes an important first step towards measuring complimentary variables of a quantum system - which until now has been considered impossible as a consequence of the Heisenberg uncertainty principle.

In the double slit experiment, a beam of light is shone onto a screen through two slits, which results in an interference pattern on the screen. The paradox was that one could not tell which slit single photons had passed through, as measuring this would directly distort the interference pattern on the screen. "In most science, it is possible to look at what a system is doing presently and so, determine its past or future. But in quantum mechanics, it is considered inconceivable to consider the past at all." says physicist Aephraim Steinberg of the Centre for Quantum Information and Quantum Control at the University of Toronto, Canada who has led this new research.

Now, using a technique known as "weak measurement" Steinberg and his team say they have managed to accurately measure both position and momentum of single photons in a two-slit interferometer experiment. The work was inspired by one of Steinberg's colleagues, Howard Wiseman of Griffith University, Australia, who proposed in 2007 that it may be possible to use weak measurements to determine momenta and positions in the double slit experiment. Steinberg was immediately fascinated and began to see how this would become experimentally viable.

It has been 780,000 years since the last reversal, so we may be long overdue one. But will lethal radiation from space bombard the Earth, as it drops its protective magnetic shield during the reversal? Italian scientists studying one of the most mysterious natural phenomena say that polarity reversals seem to occur in clusters, indicating some kind of "memory" of previous events.

Scientists now say that the Earth's magnetic poles were once near the equator, which could explain puzzling changes in the magnetism of rocks millions of years ago.

The Earth's magnetic poles are aligned along roughly the same axis as its rotational poles. Geologists have assumed this was also true in the past, so they use volcanic rocks, which when they formed took on an imprint of the direction and strength of the Earth's magnetic field, to deduce the rocks' original latitude and to trace continental motions over the past billion years, which has created a puzzle for rocks in North America and eastern Europe. In both regions, there appear to be rocks that were at the equator at some points between 550 and 600 million years ago and near the poles for other parts of this time period.

A new supernova (exploding star) has been discovered in the famous Whirlpool Galaxy, M51.

M51, The Whirlpool galaxy is a galaxy found in the constellation of Canes Venatici, very near the star Alkaid in the handle of the saucepan asterism of the big dipper. Easily found with binoculars or a small telescope.

The discovery was made on June 2nd by French astronomers and the supernova is reported to be around magnitude 14. More information (In French) can be found here or translated version here.

An unusual signal detected by the seismic monitoring station at the Smithsonian Tropical Research Institute's research facility on Barro Colorado Island results from waves in Lake Gatun, the reservoir that forms the Panama Canal channel, scientists report. Understanding seismic background signals leads to improved earthquake and tsunami detection in the Caribbean region where 100 tsunamis have been reported in the past 500 years.

As part of a $37.5 million U.S. presidential initiative to improve earthquake monitoring following the devastating tsunami in the Indian Ocean in 2004, a seismic sensor was installed on Barro Colorado Island in 2006. The sensor is one of more than 150 sensors that comprise the U.S. Geological Survey's Global Seismographic Network.

Barro Colorado Island is a hilltop that was isolated by the waters of the reservoir created when the Chagres River was dammed to form Lake Gatun, a critical part of the Panama Canal. The Barro Colorado seismic monitoring station is a collaboration between the U.S. Geological Survey, the U.S. National Oceanic and Atmospheric Administration, the University of Panama and STRI.

The targeted attack used by hackers to compromise e-mail accounts of top US officials is reaching 'epidemic' proportions, say security experts.

The scam, known as spear phishing, was used in a bid to get passwords of Gmail accounts so they could be monitored.

Via a small number of customised messages it tries to trick people into visiting a web page that looks genuine so users type in login names.

Such attacks are often aimed at top officials or chief executives.

Such attacks are not new, say security professionals, but they are becoming more commonplace.

"What is happening more and more is the targeting of a couple of high value individuals with the one goal of acquiring valuable information and valuable data," said Dan Kaminsky, chief scientist at security firm DKH.

"The most interesting information is concentrated in the accounts of a few people," he said. "Attackers using information to impersonate the users is at epidemic proportions and why computer security is in the state it is in."

Total access

In March, security firm RSA was hit by a sophisticated spear-phishing attack that succeeded despite only two attacking e-mails being sent. The phishing e-mail had the subject line "2011 Recruitment Plan" and contained a booby-trapped spreadsheet.

In California, a research team including members of the Keasling lab at the DOE's Joint BioEnergy Institute and LS9 announced a major breakthrough in their ability to make renewable diesel and other advanced biofuels directly from cellulosic biomass in a one-step process.

Consolidated bio-processing - converting pretreated biomass in one step to a renewable fuel, eliminating the two-step procedure of using acids or enzymes to extract sugars, and then fermenting sugars into fuel - is considered a critical path element in driving down the costs of cellulosic biofuel towards cost parity with gasoline, and has been widely described as "the holy grail of biofuels".

The particular breakthrough here is that - to this point, the small number of companies that have developed an organism capable of CBP - most notably, Mascoma and Qteros - have been working with ethanol as a target fuel.

In the announcement, the research team has been able to achieve a one-step process to create a renewable drop-in fuel - at this point, renewable diesel - that would require no change in distribution or vehicle infrastructure to be deployed in the transportation fleet.

Like many physicists, Michio Kaku thinks our universe will end in a "big freeze." However, unlike many physicists, he thinks we might be able to avoid this fate by slipping into a parallel universe.

One of the most fascinating discoveries of our new century may be imminent if the Large Hadron Collider outside Geneva produces nano-blackholes when it goes live again. According to the best current physics, such nano blackholes could not be produced with the energy levels the LHC can generate, but could only come into being if a parallel universe were providing extra gravitational input. Versions of multiverse theory suggest that there is at least one other universe very close to our own, perhaps only a millimeter away. This makes it possible that some of the effects, especially gravity, "leak through," which could be responsible for the production of dark energy and dark matter that make up 96% of the universe.

"The multiverse is no longer a model, it is a consequence of our models," says Aurelien Barrau, particle physicist at CERN

While it hasn't been proven yet, many highly respected and credible scientists are now saying there's reason to believe that parallel dimensions could very well be more than figments of our imaginations.

"The idea of multiple universes is more than a fantastic invention - it appears naturally within several scientific theories, and deserves to be taken seriously," stated Aurelien Barrau, a French particle physicist at the European Organization for Nuclear Research (CERN).

Our distant female relatives may have cruised around for mates while the guys may have been more stay-at-home types, scientists find.

Until now, much of what was known about our human ancestors' biology and lifestyle was deduced with little hard evidence.

In the new study, scientists analyzed fossils of extinct apelike hominids from the Sterkfontein and Swartkrans caves in South Africa. These 1.8 million to 2.2 million-year-old specimens included eight members of Australopithecus africanus, which may have been a direct ancestor of humans, as well as 11 members of Paranthropus robustus, which dead-ended on a side branch of the hominid family tree for reasons still unknown. These landscapes were much the same back then as they are now - hilly grasslands with rivers - although they had a bit more water and vegetation.

The investigators concentrated on traces of naturally occurring strontium isotopes in the enamel of 19 molar and canine teeth. Isotopes of an element all have the same number of protons in their atoms, but they differ from each other in how many neutrons they have; for instance, strontium-86 has 48, while strontium-87 has 49.

Johns Hopkins team discovers brain defense in mice and a possible new strategy for treating neurologic disorders.

Johns Hopkins scientists say that a newly discovered "survival protein" protects the brain against the effects of stroke in rodent brain tissue by interfering with a particular kind of cell death that's also implicated in complications from diabetes and heart attack.

Reporting in the May 22 advance online edition of Nature Medicine, the Johns Hopkins team says it exploited the fact that when brain tissue is subjected to a stressful but not lethal insult a defense response occurs that protects cells from subsequent insult. The scientists dissected this preconditioning pathway to identify the most critical molecular players, of which a newly identified protein protector - called Iduna -- is one.

Named for a mythological Norwegian goddess who guards a tree full of golden apples used to restore health to sick and injured gods, the Iduna protein increased three- to four-fold in preconditioned mouse brain tissue, according to the scientists.

"Apparently, what doesn't kill you makes you stronger," says Valina Dawson, Ph.D., professor of neurology and neuroscience in the Johns Hopkins Institute of Cell Engineering. "This protective response was broad in its defense of neurons and glia and blood vessels - the entire brain. It's not just a delay of death, but real protection that lasts for about 72 hours."