There is no death certificate for Jesus of Nazareth - and many believe that he still lives on in a spiritual sense. But that hasn't stopped physicians and medical scholars from trying to diagnose the exact physiological mechanisms that caused the crucified revolutionary to die 2 millennia ago. Now, an American doctor has offered a new hypothesis involving Christ's blood-clotting ability - but other researchers are skeptical.

"As a kid going to church, I'd heard that Jesus died of a 'broken heart,' " says Joseph Bergeron, a private physician associated with The Pain Clinic in Terre Haute, Indiana. But that idea - technically known as the "cardiac rupture" hypothesis, and first published in 1847 by British physician William Stroud - "didn't really make sense, given what we know about the crucifixion." Bergeron became even more intrigued after he was asked to speak to a group of Christian medical students and started looking for a topic that they might find interesting. He discovered that a flock of researchers have tried to explain exactly how Jesus died, and "I just couldn't stop reading," he says.

There are at least six major hypotheses about Christ's death, Bergeron notes in a paper published online this month in the Journal of Forensic and Legal Medicine. Beatings and the stress associated with being nailed to a cross could have caused a blood clot to block a vessel in Christ's lung, for example, leading to death by pulmonary embolism. Other possibilities are that he was unable to breathe due to his awkward hanging position and suffocated, or that he went into lethal shock - ideas supported by studies of what has killed modern torture victims. And although the Bible's book of John reports that Roman soldiers found that Jesus was already dead when they removed him from the cross, it's possible he wasn't and that the final blow was a subsequent spear thrust to his chest that caused a "sudden flow of blood and water," Bergeron writes, quoting from the New Testament. "The idea ... is based on the assumption blood cannot flow from a corpse."

A scientific detective story if there ever was one, Slava Turyshev of JPL and his colleagues have spent years tracking down their villain, the Pioneer Anomaly: an unexplained acceleration in the motion of Pioneer 10 and 11, twin spacecraft that were launched by NASA in the 1970s and radar-tracked for over 30 years. Turyshev and his team have recovered files from NASA dumpsters, converted 1970s punch card data to digital, and spent untold man hours crunching numbers beamed to Earth decades ago from spacecraft billions of miles away.

Finally, the case is solved, and the villain is dead.

As the two spacecraft retreated into the distance, the data they beamed back showed that they were slowing down a little more than they should have been. Long vaunted as evidence that something was amiss in physics - perhaps that Einstein's theory of gravity was wrong - the anomaly spawned entire academic conferences and thousands of papers.

The mass extinction that opened the door for the rise of the dinosaurs about 201 million years ago may have been caused by a spike in carbon pumped into the atmosphere - most likely by methane released from the seafloor, a new study indicates.

This spike appears to have accelerated the climate change already under way, ultimately leading to the end-Triassic extinction, the researchers say.

Scientists already suspected that rapid warming and changes to ocean chemistry at the time killed off the dinosaurs' competitors, allowing their era to begin. And they knew that, at the time, eruptions of lava through fissures in the Earth's crust pumped carbon dioxide into the atmosphere.

But this new study indicates that something more than the 600,000 years of eruptions, more massive than anything in human history, pushed about half of species to extinction.

For decades, scientists have known that DNA consists of four basic units -- adenine, guanine, thymine and cytosine. In recent history, scientists have expanded that list from four to six. Now researchers from the University of North Carolina School of Medicine have discovered the seventh and eighth bases of DNA.

Fermilab today announced that scientists working at the CDF (Collision Detector at Fermilab) experiment confirmed the observation of a new particle, the Xi-sub-b.

The Xi-sub-b is categorized as are baryon, which are formed of three quarks. Commonly known baryons include the proton ( two up quarks and one down quark) as well as the neutron (two down quarks and one up quark). The existence of the Xi-sub-b has been predicted for some time, but it has been observed for the very first time just recently. It is described as a heavy relative of the neutron and is six times heavier than the proton or neutron. Conclusively, it is a member of the bottom baryons.

Do people believe good and bad luck can be washed away? Yes, according to an advanced online publication in the Journal of Experimental Psychology that was co-authored by Rami Zwick, a University of California, Riverside marketing professor in the School of Business Administration.

Zwick, working with Alison Jing Xu of the University of Toronto, and Norbert Schwarz of the University of Michigan, designed two experiments that showed risk taking depends on whether participants recalled a past episode of good or bad luck and whether they washed their hands before engaging in a risky decision making task.

The experimental findings, in the paper "Washing Away Your (Good or Bad) Luck: Physical Cleansing Affects Risk-Taking Behavior," converge with anecdotal reports of superstitious practices, such as an athlete wearing the same unwashed shirt during a winning streak, and show that magical beliefs about luck have behavioral consequences.

Magical beliefs are exhibited, for example, by having confidence in one's ability to predict the outcome of a random event beyond the known probabilities if one can exert irrelevant control on the situation. For example, research has shown people are more confident they will have a winning scratch-off lottery ticket if they pick the ticket instead of being given one by a clerk.

For centuries they've been a part of maritime legend, inspiring curiosity and terror in equal measure. Lurking in the depths of the oceans, shocking in size and appearance, gigantic serpents and prehistoric monsters are as much a source of fascination as ever, especially in Hollywood.

In the past two or three years alone, attacks by huge undersea beasts have provided the centrepiece battles at the ends of blockbusters such as Pirates Of The Caribbean, Clash Of The Titans and The Voyage Of The Dawn Treader.

But are such tales of strange sea beasts more than mythology? Is there any evidence to suggest that some of these monsters of the watery deep - from Jules Verne's giant squid in Twenty Thousand Leagues Under The Sea to the legendary Kraken, a leviathan sending sailors to their doom - might actually exist?

Certainly, the study of the possible existence of sea monsters and other creatures of legend - known as cryptozoology - remains an area that captures the imagination of scientists and laymen alike.

Did you feel that? Gravity just got a little weaker. The National Institute of Standards and Technology and has just posted the latest internationally recommended adjustments to the values for the fundamental constants of nature. The results: Gravity is a bit weaker, the electromagnetic force a smidgeon stronger, and the whole of physics a little less uncertain.

The NIST and its international partners reconsider the values placed upon the fundamental constants every four years to take into account advances in technology and science that beget better, more accurate values for things like the speed of light, the Newtonian constant of gravitation (G), the Planck constant, and other values preceded by famous names.

The real news here isn't really that we've discovered anything new but that science on the whole has reduced uncertainty, and that in turn impacts all physical science going forward. For instance, uncertainty in the constant alpha (that's the fine-structure constant or the electromagnetic constant) has been reduced by 0.3 parts per billion, or cut in half based on the last evaluation of the constants in 2006.

Get ready for the next big bombshell in the man-made warming debate. The world's most sophisticated particle study laboratory - CERN in Geneva - will soon announce that more cosmic rays do, indeed, create more clouds in earth's atmosphere. More cosmic rays mean a cooler planet. Thus, the solar source of the earth's long, moderate 1,500-year climate cycle will finally be explained.

Cosmic rays and solar winds are interesting phenomena - but they are vastly more relevant when an undocumented theory is threatening to quadruple society's energy costs. The IPCC wants $10 gasoline, and "soaring" electric bills to reduce earth's temperatures by an amount too tiny to measure with most thermometers.

In 2007, when Fred Singer and I published Unstoppable Global Warming Every 1,500 Years, we weren't terribly concerned with cosmic rays. We knew the natural, moderate warming/cooling cycle was real, from the evidence in ice cores, seabed sediments, fossil pollen and cave stalagmites. The cycle was the big factor that belied the man-made warming hysteria of the Intergovernmental Panel on Climate Change.

Many enigmatic cases of infertility could be explained by a newfound mutation that keeps sperm from reaching eggs, a new study suggests.

These findings could improve screening and treatment of infertile couples, an international team of researchers said.

Infertility affects 10 to 15 percent of the U.S. population, with about half of those cases involving problems with male fertility. One of the mysteries of infertility is that sperm quality and quantity seem to have little to do with whether or not a man is fertile.