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Without the Moon, there would have been no life on Earth. Four billion years ago, when life began, the Moon orbited much closer to us than it does now, causing massive tides to ebb and flow every few hours. These tides caused dramatic fluctuations in salinity around coastlines which could have driven the evolution of early DNA-like biomolecules. This hypothesis, which is the work of Richard Lathe, a molecular biologist at Pieta Research in Edinburgh, UK, also suggests that life could not have begun on Mars. According to one theory for the origin of life, self-replicating molecules such as DNA...

Howard Smith, a senior astrophysicist at Harvard, made the claim that we are alone in the universe after an analysis of the 500 planets discovered so far showed all were hostile to life. Dr Smith said the extreme conditions found so far on planets discovered outside out Solar System are likely to be the norm, and that the hospitable conditions on Earth could be unique. “We have found that most other planets and solar systems are wildly different from our own. They are very hostile to life as we know it,” he said. He pointed to stars such as HD10180,...

The first detection of intelligent extraterrestrial life will likely come within the next quarter-century, a prominent alien hunter predicts. By 2040 or so, astronomers will have scanned enough star systems give themselves a great shot of discovering alien-produced electromagnetic signals, said Seth Shostak of the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, Calif. "I think we'll find E.T. within two dozen years using these sorts of experiments," Shostak said here Thursday (Feb. 6) during a talk at the 2014 NASA Innovative Advanced Concepts (NIAC) symposium here at Stanford University "Instead of looking at a few thousand star systems,...

We explore the general astrobiological significance of F-type main-sequence stars with masses between 1.2 and 1.5 Msun. Special consideration is given to stellar evolutionary aspects due to nuclear main-sequence evolution. DNA is taken as a proxy for carbon-based macromolecules following the paradigm that extraterrestrial biology may be most likely based on hydrocarbons. Consequently, the DNA action spectrum is utilized to represent the impact of the stellar UV radiation. Planetary atmospheric attenuation is taken into account based on parameterized attenuation functions. We found that the damage inflicted on DNA for planets at Earth-equivalent positions is between a factor of 2.5 and...

NASA's Curiosity rover has uncovered signs of an ancient freshwater lake on Mars that may have teemed with tiny organisms for tens of millions of years, far longer than scientists had imagined, new research suggests. The watering hole near the Martian equator existed about 3.5 billion years ago. Scientists say it was neither salty nor acidic, and contained nutrients _ a perfect spot to support microbes....

An important discovery has been made concerning the possible inventory of molecules available to the early Earth. Scientists led by Sandra Pizzarello, a research professor in ASU's Department of Chemistry and Biochemistry, found that the Sutter's Mill meteorite, which exploded in a blazing fireball over California last year, contains organic molecules not previously found in any meteorites. These findings suggest a far greater availability of extraterrestrial organic molecules than previously thought possible, an inventory that could indeed have been important in molecular evolution and life itself... "The analyses of meteorites never cease to surprise you ... and make you wonder,"...

Evidence is building that Earth life originated on Mars and was brought to this planet aboard a meteorite, said biochemist Steven Benner of The Westheimer Institute for Science and Technology in Florida. An oxidized form of the element molybdenum, which may have been crucial to the origin of life, was likely available on the Red Planet's surface long ago, but unavailable on Earth, said Benner, who presented his findings today (Aug. 28; Aug. 29 local time) at the annual Goldschmidt geochemistry conference in Florence, Italy. [The Search for Life on Mars (Photo Timeline)] "It's only when molybdenum becomes highly oxidized...

It might not just be men who are from Mars, claims a new study which suggests that all life on Earth actually began on the red planet. An element believed to be crucial to the origin of life would only have been available on the surface of Mars, it is claimed. Geochemist Professor Steven Benner argues that the 'seeds' of life probably arrived on Earth in meteorites blasted off Mars by impacts or volcanic eruptions. Professor Steven Benner will tell geochemists gathering today at the annual Goldschmidt conference that an oxidised mineral form of the element molybdenum, which may have...

"It does have the right ingredients," said Robert Pappalardo, a scientist at the Jet Propulsion Laboratory and lead author of a new study outlining what might be learned from a spacecraft that landed on the mysterious moon. Sending a lander to Europa is not officially part of NASA's plans, but the agency asked Pappalardo and a far-flung team of planetary scientists to lay out what they would hope to learn if and when a spacecraft landed on the tantalizing moon. In a study published in the journal Astrobiology, the team said it was mostly interested in Europa's chemical composition -...

Did comets flood Earth’s oceans? Did comets flood Earth's oceans? 16 June 2004 Did the Earth form with water locked into its rocks, which then gradually leaked out over millions of years? Or did the occasional impacting comet provide the Earth’s oceans? The Ptolemy experiment on Rosetta may just find out… The Earth needed a supply of water for its oceans, and the comets are large celestial icebergs - frozen reservoirs of water orbiting the Sun. Did the impact of a number of comets, thousands of millions of years ago, provide the Earth with its supply of water? Finding hard...

Comet Hartley 2 contains water more like that found on Earth than prior comets seem to have, researchers say. A study using the Herschel space telescope aimed to measure the quantity of deuterium, a rare type of hydrogen, present in the comet's water. The comet had just half the amount of deuterium seen in comets. The result, published in Nature, hints at the idea that much of the Earth's water could have initially came from cometary impacts. Just a few million years after its formation, the early Earth was rocky and dry; something must have brought the water that covers...

Given the reality of the dark spots, which soon became known as "atmospheric holes" because of their appearance in the images, there is only one explanation which has endured over all these years to present. That is, the holes are due to the shadowing of the atmospheric light by an object above the atmosphere. This object simply cannot be a stony or iron meteor because the holes are very large, tens of miles in diameter. A rock of this size would provide a disastrous impact on the Earth's surface. As it turns out, water vapor is very good at absorbing...

While investigating the chemical make-up of comets, Prof. Akiva Bar-Nun of the Department of Geophysics and Planetary Sciences at Tel Aviv University found they were the source of missing ingredients needed for life in Earth's ancient primordial soup. "When comets slammed into the Earth through the atmosphere about four billion years ago, they delivered a payload of organic materials to the young Earth, adding materials that combined with Earth's own large reservoir of organics and led to the emergence of life," says Prof. Bar-Nun.

Clandestine comets found in main asteroid belt 19:00 23 March 2006 NewScientist.com news service Kimm Groshong You do not have to look to the outer edges of the solar system, or even out beyond Neptune to observe a reservoir of comets. A bevy of the ice-containing bodies lies disguised as main-belt asteroids between Mars and Jupiter, claim astronomers from the University of Hawaii, US. David Jewitt and Henry Hsieh have dubbed the new population "main belt comets". They describe three objects with near circular, flat orbits in the asteroid belt that stream volatile materials, producing an observable tail for weeks...

An investigation by the University of Kansas' Adrian Melott and colleagues reveals a promising new method of detecting past comet strikes upon Earth and gauging their frequencyLAWRENCE, Kan. — It's the stuff of a Hollywood disaster epic: A comet plunges from outer space into the Earth's atmosphere, splitting the sky with a devastating shock wave that flattens forests and shakes the countryside. But this isn't a disaster movie plotline. "Comet impacts might be much more frequent than we expect," said Adrian Melott, professor of physics and astronomy at the University of Kansas. "There's a lot of interest in the rate...

On 26 May, JPL's unique orbital calculation software determined that Comet Catalina was on what could possibly be a collision course with Earth, though the odds of such an impact were small: just 1 chance in 300,000 of a strike on June 11, 2085. Based on the 980-metre size estimate, that would produce a 6-gigaton impact - equivalent to 6 billion tonnes of TNT. Astronomers expected the addition of further observations to the calculations to rule out any possibility of a collision, as happens with most newly-seen objects. But that did not quite happen. The comet's predicted pathway actually drew...

Man owes a lot to chunks of rock and ice floating through space. From ancient jewellery to water and possibly even the beginnings of life itself, scientists are discovering that comets have contributed in many ways to the development of life on the planet, Robert Matthews writes Since their discovery in an Egyptian cemetery more than a century ago, a handful of metal beads have perplexed archaeologists. As jewellery, the beads seem decidedly downmarket, being made of nothing more glamorous than iron. Yet clearly their owner, dead for more than 5,000 years, held them in great esteem - as do...

“It is dangerous to assume life is common across the Universe.” These were the words of Charles Cockell at a Royal Society event on March 11 this year. While many people have freely debated the existence of extraterrestrial life, Cockell’s words carry a bit more weight than most. He happens to be the director of the U.K. Center for Astrobiology, based at the University of Edinburgh. Bringing to mind the argument made by Fermi’s paradox — if the universe is teeming with life, where exactly is everyone? — this may seem at first to be a slightly pessimistic outlook. Evidently,...

A fireball that appeared over the Sri Lankan province of Polonnaruwa on December 29, 2012 was a meteorite containing algae fossils, according to a paper published in the Journal of Cosmology. A team of researchers, led by Jamie Wallis of Cardiff University, believes that these fossils provide evidence of cometary panspermia, the hypothesis that life originated in outer space and comets brought it to Earth. Scientists at the Sri Lankan Medical Research Institute in Colombo forwarded 628 stone fragments that allegedly fell from the fireball to Cardiff University, where Wallis' team indentified three as originating from a carbonaceous chondrite. The...

NASA is reporting that an analysis of a rock powder sample collected by the Curiosity rover suggests that ancient Mars could have supported living microbes. The sample contained traces of sulfur, nitrogen, hydrogen, oxygen, phosphorus, and carbon -- key chemical ingredients for life. For astronomers, the news constitutes the latest clue in their pursuit of a scientific holy grail: Answering the big question about whether life ever existed on the Red Planet. Their challenge until now has been to confirm whether the Martian atmosphere could have supported a habitable environment. The preliminary evidence now suggests the answer is yes...