A blindingly bright star bursts into view in a corner of the night sky - it wasn't there just a few hours ago, but now it burns like a beacon.

That bright star isn't actually a star, at least not anymore. The brilliant point of light is the explosion of a star that has reached the end of its life, otherwise known as a supernova.

Supernovas can briefly outshine entire galaxies and radiate more energy than our sun will in its entire lifetime. They're also the primary source of heavy elements in the universe.

On average, a supernova will occur about once every 50 years in a galaxy the size of the Milky Way. Put another way, a star explodes every second or so somewhere in the universe.

Exactly how a star dies depends in part on its mass. Our sun, for example, doesn't have enough mass to explode as a supernova (though the news for Earth still isn't good, because once the sun runs out of its nuclear fuel, perhaps in a couple billion years, it will swell into a red giant that will likely vaporize our world, before gradually cooling into a white dwarf).

This is the face of the first anatomically-modern human to live in Europe. It belonged to a man - or woman - who inhabited the ancient forests of the Carpathian Mountains in what is now Romania about 35,000 years ago.

The artist's reconstruction - a face that could be male or female - is based on the partial skull and jawbone found in a cave where bears were known to hibernate. The facial features indicate the close affinity of these early Europeans to their immediate African ancestors, although it was still not possible to determine the person's sex.

A solar wind stream flowing from the indicated coronal hole should reach Earth on May 6th or 7th.

Professor Wei-Chyung Wang is a star scientist in the Atmospheric Sciences Research Center at the University at Albany, New York. He is a key player in the climate change debate (see his self-description here). Wang has been accused of scientific fraud.

I have no inclination to "weigh in" on the topic of climate change. However the case involves issues of integrity that are at the very core of proper science. These issues are the same whether they are raised in a pharmaceutical clinical trial, in a basic science laboratory, by a climate change "denialist" or a "warmist". The case involves the hiding of data, access to data, and the proper description of "method" in science.

The case is also of interest because it provides yet another example of how *not* to create trust in a scientific misconduct investigation. It adds to the litany of cases suggesting that Universities cannot be allowed to investigate misconduct of their own star academics. The University response has so far been incoherent on its face.

The most celebrated inscription at the Central Intelligence Agency's headquarters in Langley, Virginia, used to be the biblical phrase chiseled into marble in the main lobby: "And ye shall know the truth, and the truth shall make you free." But in recent years, another text has been the subject of intense scrutiny inside the Company and out: 865 characters of seeming gibberish, punched out of half-inch-thick copper in a courtyard.

It's part of a sculpture called Kryptos, created by DC artist James Sanborn. He got the commission in 1988, when the CIA was constructing a new building behind its original headquarters. The agency wanted an outdoor installation for the area between the two buildings, so a solicitation went out for a piece of public art that the general public would never see. Sanborn named his proposal after the Greek word for hidden. The work is a meditation on the nature of secrecy and the elusiveness of truth, its message written entirely in code.

Almost 20 years after its dedication, the text has yet to be fully deciphered. A bleary-eyed global community of self-styled cryptanalysts - along with some of the agency's own staffers - has seen three of its four sections solved, revealing evocative prose that only makes the puzzle more confusing. Still uncracked are the 97 characters of the fourth part (known as K4 in Kryptos-speak). And the longer the deadlock continues, the crazier people get.

Whether or not our top spooks intended it, the persistent opaqueness of Kryptos subversively embodies the nature of the CIA itself - and serves as a reminder of why secrecy and subterfuge so fascinate us. "The whole thing is about the power of secrecy," Sanborn tells me when I visit his studio, a barnlike structure on Jimmy Island in Chesapeake Bay (population: 2). He is 6'7", bearded, and looks a bit younger than his 63 years. Looming behind him is his latest work in progress, a 28-foot-high re-creation of the world's first particle accelerator, surrounded by some of the original hardware from the Manhattan Project. The atomic gear fits nicely with the thrust of Sanborn's oeuvre, which centers on what he calls invisible forces.

The first tantalising signs of gas within a filament of dark matter have been glimpsed at the site of a cataclysmic collision between galaxy clusters. If future observations confirm the preliminary detection, it would provide an important test of computer simulations that show how large-scale cosmic structures form.

The simulations suggest that matter is distributed in a cosmic web, with material flowing along filamentary structures and pooling where the filaments intersect. Dark matter is thought to act as the scaffolding for this web, and researchers say as much as 40% of all dark matter in the universe may lie in the filaments.

But although observations have found that galaxies and galaxy clusters do indeed lie in filaments, so far no gas or dark matter have been confirmed in the highway-like structures.

"It's only logical that the gas and the dark matter trace the same structure, but quantitatively, we do not know whether the simulations and the observations match," says Harald Ebeling of the University of Hawaii.

A continuing low in sunspot activity on the sun's surface has scientists speculating on whether the lull will continue, and if it extends for decades, as has happened in the past, whether the planet would see another "Little Ice Age."

Centuries of observations have shown that sunspot activity goes through a 22-year cycle, with an 11-year period of sunspot activity from greatest to least, then an ascent to another peak.

The sun currently is in an 11-year valley, or solar minimum. However, it seems to be idling there, rather than ticking back upward. The least active stage for sunspots was in August 2008, which led scientists to expect an uptick by March of this year - but it hasn't yet occurred.

Sunspots are evidence of solar regions with increased magnetic activity. They can have a strength thousands of times stronger than the Earth's magnetic field. They usually come in groups, normally with two sets of spots, and are the sources of solar flares, coronal mass ejections, and intense ultraviolet radiation.

Engineers have finished the major work of fixing the broken "Big Bang" machine, the largest scientific instrument ever built.

The last of 53 replacement magnets for the Large Hadron Collider (LHC) has been lowered into the 16-mile tunnel straddling the Swiss-French border which houses the machine.

Scientists said they were on track to re-start the particle accelerator in the autumn.

The LHC, based at the Swiss headquarters of the European nuclear research organisation Cern, was switched on in September last year amid a fanfare of publicity.

Stony Brook, N.Y. - Six years after their discovery, the extinct little people nicknamed hobbits who once occupied the Indonesian island of Flores remain mystifying anomalies in human evolution, out of place in time and geography, their ancestry unknown. Recent research has only widened their challenge to conventional thinking about the origins, transformations and migrations of the early human family.

Indeed, the more scientists study the specimens and their implications, the more they are drawn to heretical speculation.

Were these primitive survivors of even earlier hominid migrations out of Africa, before Homo erectus migrated about 1.8 million years ago? Could some of the earliest African toolmakers, around 2.5 million years ago, have made their way across Asia?

Rome's underground Christian, Jewish and pagan burial sites, the Catacombs, date back to the 2nd Century AD.

There are more than 40 of them stretching over 170km (105 miles).

But, until now, they have never been fully documented, their vast scale only recorded with handmade maps.

That is now changing, following a three-year project to create the first fully comprehensive three-dimensional image using laser scanners.