How do we define intelligence? SETI, the Search for Extraterrestrial Intelligence, clearly equates intelligence with technology (or, more precisely, the building of radio or laser beacons). Some, such as the science fiction writer Isaac Asimov, suggested that intelligence wasn't just the acquisition of technology, but the ability to develop and improve it, integrating it into our society.

By that definition, a dolphin, lacking limbs to create and manipulate complex tools, cannot possibly be described as intelligent. It's easy to see why such definitions prove popular; we are clearly the smartest creatures on the planet, and the only species with technology. It may be human hubris, or some kind of anthropocentric bias that we find difficult to escape from, but our adherence to this definition narrows the phase space in which we're willing to search for intelligent life.

Technology is certainly linked to intelligence - you need to be smart to build a computer or an aircraft or a radio telescope - but technology does not define intelligence. It is just a manifestation of it, perhaps one of many.

Astrobiologists see intelligence a little differently. The dictionary defines intelligence as the ability to learn, while others see it as the capacity to reason, to empathize, to solve problems and consider complex ideas, and to interact socially.

The new flat-topped rock in Endeavour has been informally named "Tisdale 2"

In the 7.5 years that NASA rover Opportunity has spent on Mars, it has uncovered valuable information about the red planet. For instance, Opportunity initially landed in an ancient lakebed that was rich with water-forming materials, which proved that the now-dry planet was once wet and tropical billions of years ago.

In January 2004, Opportunity and its twin rover, Spirit, were parachuted onto opposite ends of the planet Mars. Their purpose was to explore the Martian surface including rocks, craters and hills, record the data to their flash memory, and send it to deep space antennas in California, Australia and Spain.

Unfortunately, Spirit was the clumsy sibling of the two who would occasionally break down and send "nonsense data" back to Earth. Eventually, it got stuck in a sand pit and fell silent. Spirit's career officially ended in January 2010 while Opportunity remained the overachiever.

There have been several species that have come back from the brink of extinction. Here are some examples.

Dormice and water voles: Two of Britain's best-loved countryside mammals, are recovering from the brink of extinction thanks to conservation programmes to save them. Both animals are well known through popular fiction: the dormouse was immortalised in Alice's Adventures in Wonderland and Ratty in Wind in the Willows is a water vole. Intensive farming techniques, pollution and climate change had threatened to wipe out both species across much of England.

Bumblebees: The five most threatened bumblebees in England have made an unprecedented comeback in the South East this year thanks to environmental work by farmers. The large garden bumblebee, the shrill carder bee, the red shanked carder bee, the moss carder bee and the brown banded carder bee are all considered under threat. The species have suffered from intensive farming, that means there are less wildflowers and the spread of towns and cities.

Maastricht, The Netherlands - Scientists are on the verge of growing artificial meat in laboratories without the need for animal slaughter, according to a report cited Thursday by The Herald Sun -- with one expert predicting a stem cell sausage might be just six months away.

Researchers say the advent of "pain-free" meat produced from stem cells could save millions of animals from the abattoir and help the environment through substantially reduced energy, land and water use.

Dutch researcher Dr. Mark Post, of Maastricht University, predicts the first synthetic sausage could be just six months away.

"I'm hopeful we can have a hamburger in a year," he told New Scientist.

But a major stumbling block will be turning cultured meat into a tasty, textured and nutritious option that could make mouths water in supermarkets and restaurants. The time and cost involved are also major hurdles.

In a mind-bending, and light-bending, discovery, scientists have produced a fun-house-like warping of light that defies existing laws of physics.

For centuries, simple equations (taught every year to high-school physics students) have described how light moves through different media, for example from air into glass. Now, however, researchers have found that if the boundary between media is sufficiently complex (in this case, coated with nano-sized wires), those laws no longer apply.

The discovery has prompted the physicists to rewrite the traditional equations to account for the characteristics of the boundary surface. In most cases where these tweaked equations are applied, the new laws simplify back to their traditional forms, but sometimes, they show that light can behave in incredibly strange ways.

"Using designer surfaces, we've created the effects of a fun-house mirror on a flat plane," researcher Federico Capasso of the Harvard School of Engineering and Applied Sciences said in a statement. "Our discovery carries optics into new territory and opens the door to exciting developments in photonics technology."

In addition to stirring up the laws of physics, the new finding allowed the researchers to create some wacky pictures. For instance, they simulated an image of their lab group as it would appear in a mirror coated with nano-wires. The result: a portrait of conehead-looking scientists. [See images]

Field test by British academics marks first step towards recreating an artificial volcano that would inject particles into the stratosphere and cool the planet

It sounds barmy, audacious or sci-fi: a tethered balloon the size of Wembley stadium suspended 20km above Earth, linked to the ground by a giant garden hose pumping hundreds of tonnes of minute chemical particles a day into the thin stratospheric air to reflect sunlight and cool the planet.

But a team of British academics will next month formally announce the first step towards creating an artificial volcano by going ahead with the world's first major "geo-engineering" field-test in the next few months. The ultimate aim is to mimic the cooling effect that volcanoes have when they inject particles into the stratosphere that bounce some of the Sun's energy back into space, so preventing it from warming the Earth and mitigating the effects of man-made climate change.

Before the full-sized system can be deployed, the research team will test a scaled-down version of the balloon-and-hose design. Backed by a £1.6m government grant and the Royal Society, the team will send a balloon to a height of 1km over an undisclosed location. It will pump nothing more than water into the air, but it will allow climate scientists and engineers to gauge the engineering feasibility of the plan. Ultimately, they aim to test the impact of sulphates and other aerosol particles if they are sprayed directly into the stratosphere.

Woolly rhinos, some of the hairiest beasts to roam Ice Age landscapes, may have had a surprising ancestral home. The discovery of a number of fossils indicates that these iconic beasts may have evolved in the frigid environment of the Tibetan Plateau more than 1 million years before global cooling allowed the creatures' descendants to spread throughout much of northern Eurasia. The findings upend the notion that many if not all of the cold-adapted creatures roaming Ice Age landscapes evolved in the high Arctic.

Ice ages have struck North America and northern Eurasia every 100,000 years or so since about 2.8 million years ago. Many of the large creatures roaming the landscape during these cycles, including woolly mammoths, mastodons, and saber-toothed cats, mysteriously went extinct about 10,000 years ago, as the latest episode of global cooling waned. But when and where many of those megafauna originally evolved has been an even larger mystery, says Xiaoming Wang, a vertebrate paleontologist at the Natural History Museum of Los Angeles County in California.

In the new study, Wang and colleagues uncovered a variety of fossils - including a skull, a jawbone, and a couple of neck vertebrae in the Himalayan foothills along the southwest Tibetan Plateau. The plateau is often called "the roof of the world" because its 2.5-million-square-kilometer area - the largest and tallest in the world - has an average elevation that exceeds 4500 meters (14,800 feet). Based on the age of the sediments surrounding the fossils, which was estimated using the magnetic characteristics of the rock as well as the other fossils entombed therein, the researchers say the fossils belong to a new species of woolly rhino that roamed the region about 3.7 million years ago. The team has dubbed the rhino, which was about the size of its modern kin but covered with shaggy fur to help preserve its body heat, Coelodonta thibetana, or "the pit-toothed creature from Tibet."

Astronomers have discovered Earth's closest infant star: a baby red dwarf, just 27 light-years away.

Astronomers have discovered the closest known infant star to our planet, and it wasn't born until 25 million years after the extinction of the dinosaurs.

The star, called AP Columbae, is closer to Earth than previously thought and is around 40 million years old - a stellar newborn when compared to our own Sun which was created 4.6 billion years ago.

"The star has been known about and studied for the past 15 years, but it wasn't realised it was so young and so close, until now," says co-author Simon Murphy, a PhD student from the Australian National University in Canberra. He says that highly accurate measurements from telescopes in Coonabarabran, NSW, and Chile, Hawaii and California, allowed the international team to build a much better picture of the star.

A subterranean river said to be flowing beneath the Amazon region of Brazil is not a river in the conventional sense, even if its existence is confirmed.

The "river" has been widely reported, after a study on it was presented to a Brazilian science meeting last week.

But the researchers involved told BBC News that water was moving through porous rock at speeds measured in cm, or inches, per year - not flowing.

Another Brazilian expert said the groundwater was known to be very salty.

Valiya Hamza and Elizabeth Tavares Pimentel, from the Brazilian National Observatory, deduced the existence of the "river" by using temperature data from boreholes across the Amazon region.

A primordial star at the outer edges of our Milky Way galaxy may upset current theories of star formation in the universe. The star simply shouldn't exist since it lacks the materials astronomers have long thought necessary for low-mass stars to form, scientists say.

The star, with the somewhat cumbersome name of SDS J102915+172927, hails from the beginning of the universe. At 13 billion years old, it formed from the death of the first generation of stars. (The universe itself is estimated to be about 13.7 billion years old.)

An analysis of the star's makeup reveals that it formed relatively quickly after the supernova-explosion deaths of a few of the short-lived original stars.