Halley's comet 'was spotted by the ancient Greeks'

A celestial event seen by the ancient Greeks may be the earliest sighting of Halley's comet, new evidence suggests. According to ancient writers, a large meteorite smacked into northern Greece between 466BC and 467BC. The writers also described a comet in the sky at the time the meteorite fell to Earth, but this detail has received little attention, say the researchers.

Comet Halley would have been visible for about 80 days in 466BC, researchers write in the Journal of Cosmology. New Scientist magazine reports that, until now, the earliest probable sighting of the comet was an orbit in 240BC, an event recorded by Chinese astronomers.

If the new findings are confirmed, the researchers will have pushed back the date of the first observation of Comet Halley by 226 years. The latest idea is based on accounts by ancient authors and concerns a meteorite that is said to have landed in the Hellespont region of northern Greece in 466-467BC.

The space rock fell during daylight hours and was about the size of "a wagon load", according to ancient sources. The object, described as having a "burnt colour", became a tourist attraction for more than 500 years.

In his work Meteorology, Aristotle wrote about the event about a century after it occurred. He said that around the same time the meteorite fell, "a comet was visible in the west".

Astronomer Eric Hintz and philosopher Daniel Graham, both of Brigham Young University in Provo, Utah, reconstructed the likely path of Halley's comet, to see whether it agreed with the ancient observations.

They calculated that Halley's comet could have been visible for about 80 days between early June and late August in 466BC - depending on atmospheric conditions and the darkness of the sky.

"It's tough going back that far in time. It's not like an eclipse, which is really predictable," co-author Eric Hintz, from Brigham Young University in Provo, Utah, told BBC News.

"But we feel fairly good about this. If the [sighting] in 240BC is accepted, this has a fairly solid possibility." He added: "If accepted, this would be three orbits earlier [than the Chinese sighting]."Halley's Comet on the Bayeux Tapestry (Getty) In the 11th Century, Halley's Comet was depicted on the Bayeux Tapestry. The reconstruction of the comet's path agrees with the ancient reports, which say the comet was visible for about 75 days.

The researchers point out that while the Chinese and Babylonians kept meticulous records of heavenly phenomena for centuries, the ancient Greeks did not.Nevertheless, the Greek accounts do provide important information, say Graham and Hintz, such as the comet's period of visibility from Earth.

Source <www.bbc.co.uk>

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New Solar System Discovered

European astronomers on Tuesday said they had found a distant star orbited by at least five planets in the biggest discovery of so-called exoplanets since the first was logged 15 years ago.

The star is similar to our sun and its planetary lineup has an intriguing parallel with own solar system, although no clue has so far been found to suggest it could be a home from home, they said.

The star they studied, HD 10180, is located 127 light-years away in the southern constellation of Hydrus, the male water snake, the European Southern Observatory (ESO) said in a press release.

The planets were detected over six years using the world's most powerful spectograph, an instrument to capture and analyze light signatures, at ESO's telescope at La Silla, Chile.

The method consists of observing a star and seeing how the light that reaches Earth "wobbles" as a result of the gravitational pull of a passing planet.

The tiny fluctuation in light can then be used as a telltale to calculate the mass of the transiting planet.

The five detected planets are big, being the size of Neptune, although they orbit at a far closer range than our own gas giant, with a "year" ranging from between six and 600 days.

The astronomers also found tantalizing evidence that two other candidate planets are out there.

One would be a very large planet, the size of our Saturn, orbiting in 2,200 days.

The other would be 1.4 times the mass of Earth, making it the smallest exoplanet yet to be discovered. It orbits HD 10180 at a scorchingly close range, taking a mere 1.18 Earth days to zip around the star.

If confirmed, that would bring the distant star system to seven planets, compared with eight in our own solar system.

A total of 402 stars with planets have been logged since the first was detected in 1995, according to NASA's Jet Propulsion Laboratory (JPL). The tally of exoplanets stands at 472.

None, though, is even remotely similar to Earth, which is rocky and inhabits the famous "Goldilocks zone" where the temperature is just right to enable water, the stuff of life, to exist in liquid form.

ESO astronomer Christophe Lovis said knowledge was progressing fast.

"We are now entering a new era in exoplanet research -- the study of complex planetary systems and not just of individual planets," Lovis said. "Studies of planetary motions in the new system reveal complex gravitational interactions between the planets and give us insights into the long-term evolution of the systems.

Source <news.discovery.com>

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Brazil air force to record UFO sightings

Brazil's government has ordered its air force to officially record any sighting of unidentified flying objects.A government decree said all military and civilian pilots as well as air traffic controllers should register any UFO sightings with the national aerospace defence command.

The information will be stored in the national archives in Rio de Janeiro.It will be made available to researchers, including those seeking evidence of extraterrestrial life.Anything unusual that is seen, photographed or video filmed in Brazil's air space will now have to be reported and catalogued.

But the air force said it would limit itself to collecting information, and would not be chasing UFOs."Air force command does not have a specialized structure to carry out scientific experiments on these phenomena and will limit itself to recording any events" the air force said in a statement."Any unexplained atmospheric event is worthy of at least being keep track of"

There have been several reports of UFOs in Brazil in recent decades.In 1986, air force jets were scrambled to investigate unidentified objects in the skies above Sao Paulo, but the phenomenon was never fully explained.And in 1977 the Amazon town of Vigia asked for military help after some residents said they had been attacked by extra-terrestrials.One anonymous air traffic controller told the Brazilian newspaper O Dia that sightings had been reported at the highest level."I have heard of ministers and even a president who said they had seen a UFO", he said.

Brazilian UFO watchers have welcomed the decision to make such information public in future.

Source <www.bbc.com>

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Huge Diamond in Space

When choosing a Valentine's Day gift for a wife or girlfriend, you can't go wrong with diamonds. If you really want to impress your favorite lady this Valentine's Day, get her the galaxy's largest diamond. But you'd better carry a deep wallet, because this 10 billion trillion trillion carat monster has a cost that's literally astronomical!

"You would need a jeweler's loupe the size of the Sun to grade this diamond!" says astronomer Travis Metcalfe (Harvard-Smithsonian Center for Astrophysics), who leads a team of researchers that discovered the giant gem. "Bill Gates and Donald Trump together couldn't begin to afford it."

When asked to estimate the value of the cosmic jewel, Ronald Winston, CEO of Harry Winston Inc., indicated that such a large diamond probably would depress the value of the market, stating, "Who knows? It may be a self-deflating prophecy because there is so much of it." He added, "It is definitely too big to wear!"

The newly discovered cosmic diamond is a chunk of crystallized carbon 50 light-years from the Earth in the constellation Centaurus. (A light-year is the distance light travels in a year, or about 6 trillion miles.) It is 2,500 miles across and weighs 5 million trillion trillion pounds, which translates to approximately 10 billion trillion trillion carats, or a one followed by 34 zeros.

"It's the mother of all diamonds!" says Metcalfe. "Some people refer to it as 'Lucy' in a tribute to the Beatles song 'Lucy In The Sky With Diamonds.'"

The diamond star completely outclasses the largest diamond on Earth, the 530-carat Star of Africa which resides in the Crown Jewels of England. The Star of Africa was cut from the largest diamond ever found on Earth, a 3,100-carat gem.

The huge cosmic gem (technically known as BPM 37093) is actually a crystallized white dwarf. A white dwarf is the hot core of a star, left over after the star uses up its nuclear fuel and dies. It is made mostly of carbon and is coated by a thin layer of hydrogen and helium gases.

For more than four decades, astronomers have thought that the interiors of white dwarfs crystallized, but obtaining direct evidence became possible only recently.

"The hunt for the crystal core of this white dwarf has been like the search for the Lost Dutchman's Mine. It was thought to exist for decades, but only now has it been located," says co-author Michael Montgomery (University of Cambridge).

The white dwarf studied by Metcalfe, Montgomery, and Antonio Kanaan (UFSC Brazil), is not only radiant but also harmonious. It rings like a gigantic gong, undergoing constant pulsations.

"By measuring those pulsations, we were able to study the hidden interior of the white dwarf, just like seismograph measurements of earthquakes allow geologists to study the interior of the Earth. We figured out that the carbon interior of this white dwarf has solidified to form the galaxy's largest diamond," says Metcalfe.

Our Sun will become a white dwarf when it dies 5 billion years from now. Some two billion years after that, the Sun's ember core will crystallize as well, leaving a giant diamond in the center of our solar system.

"Our Sun will become a diamond that truly is forever," says Metcalfe.

A paper announcing this discovery has been submitted to The Astrophysical Journal Letters for publication.

Source <www.universetoday.com>

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The Earth and Moon formed later than previously thought

The Earth and Moon were created as the result of a giant collision between two planets the size of Mars and Venus. Until now it was thought to have happened when the solar system was 30 million years old or approx. 4,537 million years ago. But new research from the Niels Bohr Institute shows that the Earth and Moon must have formed much later – perhaps up to 150 million years after the formation of the solar system. The research results have been published in the scientific journal, Earth and Planetary Science Letters.

"We have determined the ages of the Earth and the Moon using tungsten isotopes, which can reveal whether the iron cores and their stone surfaces have been mixed together during the collision”, explains Tais W. Dahl, who did the research as his thesis project in geophysics at the Niels Bohr Institute at the University of Copenhagen in collaboration with professor David J. Stevenson from the California Institute of Technology (Caltech).

Turbulent collisions



The planets in the solar system were created by collisions between small dwarf planets orbiting the newborn sun. In the collisions the small planets melted together and formed larger and larger planets. The Earth and Moon are the result of a gigantic collision between two planets the size of Mars and Venus. The two planets collided at a time when both had a core of metal (iron) and a surrounding mantle of silicates (rock). But when did it happen and how did it happen? The collision took place in less than 24 hours and the temperature of the Earth was so high (7000º C), that both rock and metal must have melted in the turbulent collision. But were the stone mass and iron mass also mixed together?

Until recently it was believed that the rock and iron mixed completely during the planet formation and so the conclusion was that the Moon was formed when the solar system was 30 million years old or approximately 4,537 million years ago. But new research shows something completely different.

Dating with radioactive elements

The age of the Earth and Moon can be dated by examining the presence of certain elements in the Earth’s mantle. Hafnium-182 is a radioactive substance, which decays and is converted into the isotope tungsten-182. The two elements have markedly different chemical properties and while the tungsten isotopes prefer to bond with metal, hafnium prefers to bond to silicates, i.e. rock.

It takes 50-60 million years for all hafnium to decay and be converted into tungsten, and during the Moon forming collision nearly all the metal sank into the Earth’s core. But did all the tungsten go into the core?

"We have studied to what degree metal and rock mix together during the planet forming collisions. Using dynamic model calculations of the turbulent mixing of the liquid rock and iron masses we have found that tungsten isotopes from the Earth’s early formation remain in the rocky mantle”, explains Tais W. Dahl, Niels Bohr Institute at the University of Copenhagen.

The new studies imply that the moon forming collision occurred after all of the hafnium had decayed completely into tungsten.

"Our results show that metal core and rock are unable to emulsify in these collisions between planets that are greater than 10 kilometres in diameter and therefore that most of the Earth’s iron core (80-99 %) did not remove tungsten from the rocky material in the mantle during formation", explains Tais W. Dahl.

The result of the research means that the Earth and the Moon must have been formed much later than previously thought – that is to say not 30 million years after the formation of the solar system 4,567 million years ago but perhaps up to 150 million years after the formation of the solar system.

Source <http://insciences.org>

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Black hole 'hurled out of galaxy'

A supermassive black hole may have been observed in the process of being hurled from its parent galaxy at high speed.

The finding comes from analysis of data collected by the US Chandra space X-ray observatory.

However, there are alternative explanations for the observation.

The work, by an international team of astronomers, has been published in the journal Monthly Notices of the Royal Astronomical Society.

Normally, each galaxy contains a supermassive black hole at its centre.

Given that these objects can have masses equivalent to one billion Suns, it takes a special set of conditions to cause this to happen.

High-speed exit

The authors believe this could be the result of the merger of two smaller black holes.

But there are alternative explanations for the bright X-ray source; it could also be a Type IIn supernova, or an ultra-luminous X-ray source (ULX) with an optical counterpart (which could represent several phenomena).

Simulations using supercomputers suggest that when this happens, the larger black hole that results is shot away at high speed.

However, this depends on the direction and velocity at which the two black holes are rotating before their collision.

Marianne Heida of the University of Utrecht used data in the Chandra Source Catalogue to compare hundreds of thousands of sources of X-rays with the positions of millions of galaxies.

The material that falls into black holes heats up dramatically on its final journey, which often means that black holes are strong X-ray sources.

X-rays are also able to penetrate the dust and gas that obscures the centre of a galaxy, giving astronomers a clear view of the region around the black hole, with the bright source appearing as a star-like point.

Looking at one galaxy in the Catalogue, Ms Heida noticed that the point of light was offset from the centre and yet was so bright that it could be associated with a supermassive black hole.

Ms Heida said: "We have found many more objects in this strange class of X-ray sources. With Chandra we should be able to make the accurate measurements we need to pinpoint them more precisely and identify their nature."

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We Could Be Discovering Earthlike Planets By 2013

There are probably billions of Earthlike planets in our galaxy alone, predicts scientist Alan Boss. With NASA launching the Kepler satellite, seeking other Earths, you can expect the first discoveries in a few years.


The Kepler satellite will use the same planet-finding method that's already found a few hundred planets outside our solar system: looking for subtle dips in stellar brightness. But it'll use more sensitive methods, looking for smaller, cooler planets that are closer to Earth and more hospitable to life.

Boss, who's just written a new book called The Crowded Universe, argues that Earthlike planets should be quite common:

First, if you talk to astronomers who look at young stars, they will tell you that when stars form, they tend to have a little bit of angular momentum, which means that they can't accrete all of their matter and they end up having a disk around them. Such disks are what planetary systems form out of, basically the leftovers from the star-formation process. Essentially all young stars have these disks, so we expect that these young stars at least have the possibility of having planetary systems.

Second, those who worry about planet-formation processes find that it's very hard to stop Earth-like planets, or some sort of large, rocky object, from forming. Earths in some sense are easier to build than Jupiters, but we already know from our extrasolar planet census that Jupiters exist around at least 10 percent, and probably around 20 percent, of stars. So Earths should be even more common than that.

Finally, and even more directly, the planetary searches are already beginning to find a new class of planets called super-Earths with masses maybe five, 10 or 15 times the mass of Earth that orbit a little closer to their star than our planet does. These guys occur on roughly one third of nearby solar-type stars. And these are sort of the oddballs in some sense, which I think are very much just the tip of the iceberg of the spectrum of Earth-like planets. In any theoretical model of planet formation that people talk about, there should be a ton of Earths compared to these oddball super-Earths, so when we do a complete census we should find a lot of Earths. If these oddballs are there 30 percent of the time and the Jupiters are there 20 percent of the time, that means the ones we can't quite see should be there essentially all the time. So it's a very compelling story, and all the evidence from several different directions points toward Earths being quite common.

He also believes that life is quite tenacious and it's likely that many of these planets have water on them, and comets dumping amino acids and other prebiotic chemicals, making life pretty likely. So many of these Earthlike worlds could turn out to have our alien cousins on them.

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Hidden asteroids are stalking the Earth

TINY asteroid that buzzed Earth last week highlighted our planet's vulnerability to objects whose peculiar orbits put them in a game of hide-and-seek with us.

An Earth-based telescope spotted the 10-metre space rock hurtling our way just three days before a near miss on 13 January, when it flew by at just one-third of the distance to the moon (see Object headed towards Earth an asteroid, not junk). The asteroid is never expected to hit Earth and would burn up before hitting the ground in any case. But its unusual orbit (see diagram) seems ingeniously designed to evade our surveys. It is likely that a handful of objects large enough to cause harm are hiding under similar circumstances.

Large asteroids are relatively easy to spot because they reflect the most sunlight. But smaller asteroids - which can still damage Earth if they span at least 30 to 50 metres - are usually too dim for telescopes to detect except during brief close approaches to Earth. For a typical near-Earth asteroid, these occurrences are a few years or decades apart.

However, last week's unexpected visitor, called 2010 AL30, kept far enough from Earth to be invisible for more than a century. The prolonged avoidance occurred because the period of its solar orbit was 366 days - very close to Earth's year (though the close pass shifted the space rock into a 390-day orbit). Like a slightly slower race car that is periodically lapped by its competitor on a circular track, it stays far from Earth for long stretches.

"2010 AL30 may become a sort of 'poster child' for hiding asteroids," says Alan Harris of the Space Science Institute in Boulder, Colorado.

Similar "synchronised" asteroids may be hiding with periods of very close to two, three, four years and so on, Harris says. Those with periods of about four years pose the greatest risk to Earth, because they would be in sync with both Earth and Jupiter, says Timothy Spahr of the Minor Planet Center in Cambridge, Massachusetts. Such asteroids would be particularly influenced by Jupiter's gravity, which could nudge them onto a collision course with Earth.

Read more here

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Search for universe's hidden 'dark' objects

By Moises Velasquez-Manoff Staff Writer / December 13, 2009

Early Monday morning, after two delays, NASA is scheduled to launch an unmanned orbiting observatory that promises to greatly enhance, and significantly change, humanity's understanding of the heavens.

The Wide-field Infrared Survey Explorer (WISE) is expected to launch from Vandenberg Air Force Base near Santa Barbara, Calif., between 9:09 and 9:23 a.m. Eastern time. From its eventual orbit 325 miles above earth, it will begin a blitz of picture-taking with equipment of unprecedented sensitivity. WISE will map the heavens on four infrared channels, frequencies of long-wave radiation that are invisible to the human eye and many telescopes.

The end-product of the 10-month mission will be a publicly available catalog of photos that, once stitched together and processed, will offer a portrait of the whole sky in unequaled crispness and detail.

"It really is going to be our GPS [Global Positioning System] for astronomers," says Amy Mainzer, WISE deputy project scientist, from the launch site at the Vandenberg Air Force Base near Santa Barbara, Calif. "No matter what you like, we'll have something for you."

Seeing 'dark' celestial bodies

Looking at long-wave radiation offers several advantages compared with viewing just the visible light spectrum – the colors of the rainbow. All matter does not reflect light, nor do all stars emit it. Some asteroids are blacker than coal, and some young solar systems and galaxies are shrouded in light-blocking dust. Certain small stars, the so-called brown dwarfs, aren't quite massive enough to ignite a nuclear reaction. These "failed stars" emit heat, but no light.

All of these "dark" celestial bodies are invisible to standard telescopes.

But unless matter is at a temperature of absolute zero – an impossibility in a universe containing other energetic things, say scientists – it always emits heat. So scientists liken the launch of WISE to donning a very powerful pair of night-vision goggles. And once the goggles are in place, they expect to discover celestial bodies in many now seemingly empty areas of the sky.

After all, WISE is hundreds of times more powerful than its predecessor, the Infrared Astronomical Satellite, which was launched in 1983.

Brown dwarfs, colliding galaxies, and more

WISE's sensors will pick up dark – and potentially threatening – near-Earth objects, like asteroids. The satellite will see the rings of dust around young stars that scientists think eventually build into planets like ours. Colliding galaxies, which are shrouded in dust, will also be visible. And brown dwarfs, which are thought to be more numerous than light-emitting stars in our galaxy, will be revealed.

Many researchers suspect that we have brown dwarf neighbors closer than Alpha Centauri, which, at 4.37 light years away, is usually considered the star nearest the Sun.

"It will be completing the census of these cold objects in the solar neighborhood," says Jonathan Fortney, assistant professor of astronomy and astrophysics at the University of California at Santa Cruz, who is not involved with the mission. "We'll finally know what our solar neighborhood looks like."

One million pictures

Once in orbit – and after a systems-test phase – the 10-foot tall WISE will begin snapping pictures every 11 seconds. Armed with a 4 megapixel sensor, WISE will take more than 1 million photos during its mission.

"Having a list of objects from something like WISE provides you with ... targets” to look at more closely, says Marcia Rieke, a professor of astronomy at the University of Arizona in Tucson. As principal investigator on the James Webb Space Telescope, scheduled for launch in 2014, she plans to do just that.

Without the information from WISE, "there's no big sign post in space saying, 'Look here,' " Dr. Rieke says.

WISE's pictures of near-earth objects and minor planets will be immediately available as they're taken. The entire WISE catalog, part of which will be released during the mission, is slated for public release in 2011. Who knows what WISE will reveal.

"We're exploring the universe in a new way, and we're sure to find surprises," says Dr. Mainzer of the WISE team. "In fact, one thing I'm sure of is that I'm sure to be surprised."
 
Source: http://www.csmonitor.com/Science/2009/1213/WISE-set-to-search-for-universe-s-hidden-dark-objects

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UFO :The greatest story ever denied

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Most Earth-Like Extrasolar Planet Found Right Next Door

Meet GJ 1214b, the most Earth-like planet ever found outside our solar system.

It’s not exactly Earth’s twin: It’s about six times bigger, a whole lot hotter and made mostly of water. But compared to the giant gas balls that account for nearly every other extrasolar planet ever found, it’s pretty darn close. And through a fortunate happenstance of cosmic geometry, astronomers will be able to study GJ 1214b in great detail.

“If you want to describe in one sentence what this planet is, it’s a big, hot ocean,” said Harvard University astronomer David Charbonneau. “We can even study its atmosphere. This planet will occupy us for years. That’s part of what’s so exciting about it.”

Described by Charbonneau and 17 other astronomers in a paper published Wednesday in Nature, GJ 1214b is the latest of roughly 400 planets detected by earthly telescopes. Of these, 28 are considered “super-Earths” — planets with a mass roughly comparable to our own.

The super-Earths themselves are too distant to be seen. Instead, astronomers infer their presence from subtle distortions in starlight, caused when photons travel through the super-Earths’ gravitational fields. Depending on the degree of distortion, astronomers can even calculate a planet’s mass.

That’s how Corot-7b, a rocky planet with roughly twice the heft of Earth, was spotted in February. Ditto Gliese 581c, identified two months later, and orbiting its star at a distance consistent with human notions of habitability.

Unfortunately, not much more will ever be known about those planets. Corot-7b is 500 light-years away, too distant for our telescopes to discern more detail. And from our viewing angle, Gliese 581c never quite crosses directly in front of its sun, causing photons to warp in ways that would reveal its atmospheric character.

GJ 1214b does pass in front of its sun. Separated from Earth by a distance of just 42 light years, it’s close enough to be studied. Scientists will finally get to look at another Earth-like world.

“Only rarely does a long-sought scientific frontier loom so prominently just beyond the horizon, that the next generation of instruments seems sure to reach it,” wrote Geoffrey Marcey, a University of California, Berkeley astronomer, in a commentary accompanying the findings. “They provide the most-watertight evidence so far for a planet that is something like our own Earth, outside our solar system.”

Based on its radius and mass — about 2.7 and 6.6 times that of Earth’s — Charbonneau and the other astronomers have calculated GJ 1214b’s density. It appears to be composed of extraordinarily deep oceans, surrounding a rocky core.

The planet’s atmosphere and precise composition remain a mystery, but it’s likely composed of many of the same elements found elsewhere at sites of planetary formation, in swirling disks of dust and gas that have yet to accrete: hydrogen, helium, nitrogen, magnesium, oxygen, carbon.

That list of ingredients raises at least the possibility of life. With an estimated temperature of 370 degrees Fahrenheit, GJ 1214b is an unlikely incubator (Earth’s toughest extremophile, a microbe that lives in deep-sea volcanic vents, maxes out at 284 degrees) but it’s not impossible.

“I don’t want to imply that there’s any indication of life as we know it. It might have life, but it would have to be a strange kind of life,” said Charbonneau.

The telescopes sure to be trained on GJ 1214b in the near future will try to answer that question. But even if it proves barren, other planets await. The telescopes that spotted GJ 1214b were custom designed to find Earth-like planets around nearby stars, and had only operated for a few months before striking water.

“We only look at a handful of stars before finding this planet, said Charbonneau. “Either we got lucky, or the planets are very common.”

Source<http://www.wired.com/wiredscience/2009/12/super-earth/>

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LHC Restarts operations at CERN

Geneva, 23 November 2009. Today the LHC circulated two beams simultaneously for the first time, allowing the operators to test the synchronization of the beams and giving the experiments their first chance to look for proton-proton collisions.

With just one bunch of particles circulating in each direction, the beams can be made to cross in up to two places in the ring.

From early in the afternoon, the beams were made to cross at points 1 and 5, home to the ATLAS and CMS detectors, both of which were on the look out for collisions.

Later, beams crossed at points 2 and 8, ALICE and LHCb.

“It’s a great achievement to have come this far in so short a time,” said CERN¹Director General Rolf Heuer. “But we need to keep a sense of perspective – there’s still much to do before we can start the LHC physics programme.”



Beams were first tuned to produce collisions in the ATLAS detector, which recorded its first candidate for collisions at 14:22 this afternoon. Later, the beams were optimised for CMS. In the evening, ALICE had the first optimization, followed by LHCb.

Full story here

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From a Distant Comet, a Clue to Life

For the first time, a building block of proteins — and hence of life as we know it — has been found in a comet.

That adds to the prevailing notion that many of the ingredients for the origin of life showered down on the early Earth when asteroids (interplanetary rocks orbiting the inner solar system) and comets (dirty ice balls that generally congregate in the outer solar system beyond Neptune) made impact with the planet.

In the new research, scientists at the Goddard Space Flight Center, in Greenbelt, Md., detected the amino acid glycine in comet bits brought back in 2006 by the NASA space probe Stardust.
“It tells us more about the inventory of organics in the early solar system,” said Jamie Elsila, an astrochemist at Goddard who led the research.

Amino acids are small molecules that, when strung together into chains, form a diversity of proteins. For four decades, scientists have found a multitude of amino acids in some meteorites, the bits of asteroids that land on Earth. More recently, astronomers reported that amino acids might float throughout the cosmos, a belief resulting from their detection of the color signatures of glycine, the simplest of the amino acids, in distant interstellar gas clouds.

Some doubts remain about that claim, but if it is true, it would then not be surprising that when the clouds condense into stars and planets, the building blocks of life might be readily available there.
As for our solar system, meteorite data show that amino acids are present in its inner neighborhood, where asteroids orbit, but until now nothing has been known for certain about what might have formed farther out, where comets gather.

But on Jan. 2, 2004, the Stardust spacecraft flew through the tail of dust and gas of the comet Wild 2 (pronounced vilt two). Two years later, the probe returned to Earth, sending collected samples to the ground by parachute for scientists to analyze. Comets are thought to preserve material of the early solar system, largely unchanged for the last 4.5 billion years.

Within a few months, the Goddard scientists found glycine embedded in aluminum foil of the collecting apparatus. They had spent the time since then confirming that the glycine indeed came from the comet and not from contamination.

“It’s not necessarily particularly surprising,” Dr. Elsila said of her extraterrestrial glycine in a phone conversation Tuesday. “I would have been surprised if it wasn’t there.”
Dr. Elsila and her colleagues were able to show that the glycine from the comet had heavier quantities of the isotope carbon 13 than what occurs on Earth. They also detected a second amino acid, beta-alanine, but the quantities were too minuscule to confirm.

The findings were presented Sunday at a Washington meeting of the American Chemical Society and will be published in the journal Meteoritics & Planetary Science.

Donald E. Brownlee, a professor of astronomy at the University of Washington and principal investigator of the Stardust mission, said the discovery indicated that the chemical reactions that produce glycine, and presumably other amino acids, occurred throughout the early solar system.

“That means production of amino acids is fairly common,” Dr. Brownlee said.
That had not been a foregone conclusion, he said. Some scientists had suggested that the chemical reactions might have required warm and wet conditions that existed in early asteroids but not comets.

Source http://www.nytimes.com/2009/08/19/science/space/19comet.html?ref=space

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Mega-star explosion most distant object ever seen

PARIS (AFP) – It took 13 billion years to reach Earth, but astronomers have seen the light of an exploding mega-star that is the most distant object ever detected, two studies published Thursday reported.

The stunning gamma-ray burst (GRB) was observed by two teams of researchers in April, and opens a window onto a poorly known period when the Universe was in its infancy.

GRBs are the most violent explosions known to exist, and can be 10 million times more luminous than the brightest of galaxies.
They accompany the catastrophic death of a massive star, and are probably triggered by the collapse of the star's centre into a black hole.

Dubbed GRB 090423, the new discovery was first spotted by the NASA satellite Swift.
Astronomers alerted to the find trained several of Earth's largest telescopes skyward just in time to see the gamma-ray burst's fading afterglow.

The discovery is especially exciting for scientists because the explosion occurred during the so-called "cosmic dark ages", which started a mere 400,000 years after the Big Bang set the Universe in motion some 13.7 billion years ago.

During this period, free electrons and protons combined to form neutral atoms with the same number of positive and negative charges, resulting in an opaque -- or "dark" -- universe.
Not until 800 to 900 million years after the Big Bang were atoms and molecules "re-ionised", or electrically charged, resulting in the relatively transluscent inter-galactic medium we see today.


Whole story here

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32 New Exoplanets Found

Today, at an international ESO/CAUP exoplanet conference in Porto, the team who built the High Accuracy Radial Velocity Planet Searcher, better known as HARPS, the spectrograph for ESO's 3.6-metre telescope, reports on the incredible discovery of some 32 new exoplanets, cementing HARPS's position as the world’s foremost exoplanet hunter. This result also increases the number of known low-mass planets by an impressive 30%. Over the past five years HARPS has spotted more than 75 of the roughly 400 or so exoplanets now known.

"HARPS is a unique, extremely high precision instrument that is ideal for discovering alien worlds," says Stéphane Udry, who made the announcement. “We have now completed our initial five-year programme, which has succeeded well beyond our expectations.”

The latest batch of exoplanets announced today comprises no less than 32 new discoveries. Including these new results, data from HARPS have led to the discovery of more than 75 exoplanets in 30 different planetary systems. In particular, thanks to its amazing precision, the search for small planets, those with a mass of a few times that of the Earth — known as super-Earths and Neptune-like planets — has been given a dramatic boost. HARPS has facilitated the discovery of 24 of the 28 planets known with masses below 20 Earth masses. As with the previously detected super-Earths, most of the new low-mass candidates reside in multi-planet systems, with up to five planets per system.

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The sound of Earth from space

Compare it with Jupiter

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Glimpses of Solar System's edge

The first results from Nasa's Interstellar Boundary Explorer (Ibex) spacecraft have shown unexpected features at our Solar System's edge.

Ibex was launched nearly one year ago to map the heliosphere, the region of space defined by the extent of our Sun's solar wind.

Ibex's first glimpses show that the heliosphere is not shaped as many astronomers have believed.

A series of papers in the journal Science outlines the results.

Our Solar System is whipping around the centre of the galaxy. Just like a hand held out of a moving car, the Solar System feels a "wind" of particles from the region between our star and its nearest neighbours.

At the same time, the solar wind - a constant stream of fast-moving particles in all directions - blows outwards from the Sun.

The boundary at which the incoming and outgoing particles are at equivalent pressures, known as the heliopause, defines the heliosphere - the "bubble" in space generated by our own Sun's exhalations.

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Dancing black hole twins spotted

Researchers have seen the best evidence yet for a pair of black holes orbiting each other within the same galaxy.

While such "binary systems" have been postulated before, none has ever been conclusively shown to exist.

The new black hole pair is dancing significantly closer than the prior best binary system candidate.

The work, published in the journal Nature, is in line with the theory of the growth of galaxies, each with a black hole at their centre.

The theory has it that as galaxies near one another, their central black holes should orbit each other until merging together.

But evidence for black holes nearing and orbiting has so far been scant.

Dancing cheek-to-cheek

As matter falls into black holes, it emits light of a characteristic colour that in turn gives information about the direction in which the black hole is moving.

In a binary system, two beams should be emitted, each a slightly different colour.


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Galaxy's 'cannibalism' revealed

The vast Andromeda galaxy appears to have expanded by digesting stars from other galaxies, research has shown.

When an international team of scientists mapped Andromeda, they discovered stars that they said were "remnants of dwarf galaxies".

The astronomers report their findings in the journal Nature.

This consumption of stars has been suggested previously, but the team's ultra-deep survey has provided detailed images to show that it took place.

This shows the "hierarchical model" of galaxy formation in action.

The model predicts that large galaxies should be surrounded by relics of smaller galaxies they have consumed.


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Hellish Exoplanet Rains Hot Pebbles, Has Lava Oceans

Ker Than for National Geographic News

October 6, 2009

The first rocky planet ever discovered outside our solar system has a hellish environment where hot pebbles rain down on oceans of lava, a new study suggests. Located about 500 light-years away in the constellation Monoceros, CoRoT-7b was first discovered in February by the French and European space agencies' CoRoT space telescope. The exoplanet was recently confirmed to be a rocky, Earth-like world—but that's where the similarities with our planet end. CoRoT-7b is about twice the size and five times the mass of Earth, and it's separated from its star by only 1.5 million miles (2.5 million kilometers)—that's about 23 times closer than Mercury is to our sun. On CoRoT-7b a year lasts only 20.4 hours. "It's actually the closest orbit of any exoplanet that's been discovered," said study team member Laura Schaefer, an astronomer at Washington University in St. Louis, Missouri.

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