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Tuesday, October 16, 2007Alien signals will be found by 2025
The skies are to be swept for signs of alien life in the most far reaching scan of its kind.
A total of 42 radio dishes have started collecting scientific data from the furthest reaches of the universe, part of the Allen Telescope Array (ATA) in Hat Creek, around 270 miles north of San Francisco.
Astronomer Seth Shostak has compared the project to the 1997 Hollywood film "Contact," in which Jodie Foster plays a scientist based at a remote monitoring station trying to decipher signals from a distant civilization.
"The Allen Telescope Array will be like 200 million Jodie Fosters sitting out there listening," said Shostak of the Search for Extraterrestrial Intelligence (SETI) Institute and the University of California, Berkeley.
"We don't know how many needles are in the galactic haystack of 400 billion stars, but I think we will find (signals from intelligent civilizations) by 2025," he said.
There are some 200 billion stars in our galaxy, depending on which estimate you believe, and a significant fraction of them have planets. Estimates of the number of intelligent civilizations in the galaxy have ranged from zero into the millions.
The dishes will be part of an eventual army of telescopes numbering around 350, each 20 ft in diameter, that are being deployed to help advance radio astronomy. Using the separate antennas as if they were one giant dish, radio astronomers will be able to map vast swaths of the sky cheaply and efficiently.
"The ATA's technical capabilities exponentially increase our ability to search for intelligent signals, and may lead to the discovery of thinking beings elsewhere in the universe," "It is the first major telescope in the world built specifically for undertaking a search for extraterrestrial intelligence," he added.
Leo Blitz, director of the radio astronomy laboratory at the University of California, Berkeley, said the ATA would help scientists discover more about how galaxies evolve. "This opens up a whole area in science," Blitz enthused.
The array, which will cost another $41 million to complete, will also help search for new phenomena like black holes eating each other and so-called dark galaxies without stars.
The first images based on data gleaned by the telescope battalion included radio maps of the nearby Andromeda and Triangulum Galaxies.
The project is named after Microsoft co-founder and billionaire philanthropist Paul Allen, who has donated around 25 million dollars towards the 50 million dollar venture.
Describing himself as "a child of the 50s, the golden age of space exploration and science fiction," Mr. Allen, a founder of Microsoft, said he first got interested in supporting the search ET after a conversation with the late Carl Sagan, the Cornell astronomer and populariser of science who wrote the book Contact.
Can changing your metabolic rate help you lose weight? You bet, says Veronica Karr, supporter of the Turbulence Training For Fat Loss program. In fact, she highly recommends it! There are three ways in which your body can burn calories.
The first is by doing, well, absolutely nothing. This is called your basal metabolic rate (a.k.a. BMR) and it accounts for the energy you expend while at rest. The calories burned are for the energy required to operate basic body functions, such as beating heart, pumping blood and so forth. This burns a whopping 60% of your daily calories.This means that if you had a 10 player football team, 6 team members would just have to stand on the field and you would still win the game! Great news, but why then, do we still gain weight?
Because 4 players on the team still have work to do in order to win. This can be accomplished by two other means.
One, by picking up the football and running down the field - the physical activity of walking, running, crouching, lifting, etc. account for approximately 30% of the daily calorie usage of the average person.
Secondly, by having your players eat their Wheaties. The process of thermogenesis is at work while we eat. The digestion and absorption of food leads to the production of heat within the body and this accounts for another large block of calorie expenditure.
Unfortunately, for those of us chronically challenged and who have been on the team for a while, our metabolic rate lowers as we age and to top it off, it also lowers as we lose muscle.
That being said, there is something you can do to influence your metabolic rate.
Strength training is number one for raising the metabolic rate. Adding a twenty minute weight training session to your work out regime three times a week can boost your metabolism by as much as 15%. To top if off, for every pound of muscle you acquire, you burn an additional 50 calories a day.
Choosing what you eat also plays a role in raising your metabolic rate. There is evidence to show that green tea, caffeinated drinks and spicy foods can raise your metabolic rate by as much as 50% for up to 3 hours. That’s the equivalent of adding 5 additional players to your team.
Not only what you eat, but how often is a factor in calorie burn. The ideal is to eat small but frequent meals to keep calorie burn in high gear. So if you want to win the championship, food selection and physical activity are your best bets to a better body.
Could "hypertime" help develop a theory of everything? Roger Highfield reports
A scientist has put forward the bizarre suggestion that there are two dimensions of time, not the one that we are all familiar with, and even proposed a way to test his heretical idea next year.
Itzhak Bars explains two time physics
Time is no longer a simple line from the past to the future, in a four dimensional world consisting of three dimensions of space and one of time. Instead, the physicist envisages the passage of history as curves embedded in a six dimensions, with four of space and two of time.
"There isn't just one dimension of time," Itzhak Bars of the University of Southern California in Los Angeles tells New Scientist. "There are two. One whole dimension of time and another of space have until now gone entirely unnoticed by us."
Bars claims his theory of "two time physics", which he has developed over more than a decade, can help solve problems with current theories of the cosmos and, crucially, has true predictive power that can be tested in a forthcoming particle physics experiment.
If it is confirmed, it could point the way to a "theory of everything" that unites all the physical laws of the universe into one, notably general relativity that governs gravity and the large scale structure of the universe, and quantum theory that rules the subatomic world.
In the quest for that all embracing theory, scientists have been adding extra dimensions of space to their equations for decades. As early as the 1920s, mathematicians found that moving up to four dimensions of space, instead of the three we experience, helped in their quest to reconcile theories of electromagnetism and gravity.
Today, theoreticians are studying a theory of everything called M-theory that adds yet another dimension, taking the total to 11: 10 of space and one of time.
advertisementUntil now, they have been reluctant to meddle with time because it can lead to unexpected consequences, such as time travel.
Changing our picture of time from a line to a plane (one to two dimensions) means that the path between the past and future could loop back on itself, allowing you to travel back and forwards in time and allowing the famous grandfather paradox, where you could go back and kill your grandfather before your mother was born, thereby preventing your own birth.
Bars first found hints of an extra time dimension in M-theory in 1995 and, when he looked into it, discovered the grandfather paradox and other fears could be overcome by using a new kind of symmetry - a mathematical property to work out the relationship between the quantities of position and momentum. It is this symmetry that might help reconcile the two mighty pillars of 20th-century physics, quantum mechanics and relativity.
Simply adding an extra dimension of time doesn't solve everything, however. To produce equations that work with the new symmetry that describe the world accurately, an additional dimension of space is needed as well, giving a total of four space dimensions, he explained in the journal Physical Review D.
According to Bars, the familiar four dimensional world we see around us is merely a "shadow" of the six-dimensional reality, just as a hand makes many different shadows on a wall when lit from different angles.
Although we cannot experience the extra time dimension directly, we can effectively notice it through the different perspectives of the different "shadows".
In this sense, he points to already existing evidence of physical phenomena at both macroscopic and microscopic scales. Furthermore, he believes that more evidence for his theory could emerge next year, when particles are smashed together in CERN's Large Hadron Collider near Geneva, Switzerland to create hitherto unseen "supersymmetric" particles.
The work poses a question: is his proposal a mathematical fix, rather than a real physical entity?
Bars insists his extra dimensions are more than mathematical sleight of hand. "Absolutely not," he told New Scientist. "These extra dimensions are out there, as real as the three dimensions of space and one of time we experience directly."
Once food had been plentiful, but no longer. In the early days of the colony, the amoebas had feasted on a rich supply of bacteria. But as the generations passed and the population swelled, they had hunted out their food supply. Now starvation threatens. Their home– a scrap of deer dung which once provided all their needs– has become a trap which they must escape if they are to survive. At last, one amoeba sends out a cry for help.
The starving amoeba begins to emit a chemical signal in the form of cyclic adenosine monophosphate, or cAMP. Nearby individuals sprout new pseudopods and crawl toward the source. They also begin to give off cAMP themselves, amplifying the call until the signal spreads to the far reaches of the colony. Amoebas cannot concurrently detect and produce cAMP, so they alternate, and the cells trace out intricate spiral patterns as they surge forward in waves.
The amoebas pile on top of one another in growing numbers until so many of them have joined the heap that this pile of microscopic single-celled organisms becomes visible to the naked eye. At first their behavior might seem odd; to gather together in the face of starvation surely ought to end in cannibalism or death. Not so, for they are capable of an extraordinary and rare transformation. The amoebas set aside their lives as individuals and join ranks to form a new multicellular entity. Not all the amoebas will survive this cooperative venture, however. Some will sacrifice themselves to help the rest find a new life elsewhere.
These astonishing creatures are Dictyostelium discoideum, and they are a member of the slime mold family. They are also known as social amoebas. Aside from the novelty value of an organism that alternates between unicellular and multicellular existence, D. discoideum is highly useful in several areas of research. Among other things, this organism offers a stellar opportunity to study cell communication, cell differentiation, and the evolution of altruism.
In response to the cAMP distress call, up to one hundred thousand of the amoebas assemble. They first form a tower, which eventually topples over into an oblong blob about two millimeters long. The identical amoebas within this pseudoplasmodium– or slug– begin to differentiate and take on specialized roles.
The slug begins to seek out light, leaving a slimy trail behind. Some of the amoebas take on the difficult role of sentinel, or immune-like functions. They circulate through the slug, hunting for pathogens. If they find any, they will engulf them in a process similar to the feeding behavior they once displayed when in solitary form. The pseudoplasmodium periodically sloughs off the sentinels– and any pathogens they have engulfed– and abandons them in the trail of slime. More cells will then be tapped to fill their place.
Dictyostelium discoideum slugOnce the slug finds a suitably sunny location, the unlucky cells at the "head" of the slug form a stalk for the others to climb. These cells–which make up roughly a fifth of the total population–will sacrifice themselves in order to provide a path up for their comrades.
The remaining cells then climb the stalk and collect on its tip, eventually resulting in a structure resembling a ping-pong ball balanced on top of a floppy wire. This formation is known as a "fruiting body." They then form spores, which are carried away by wind or passing animals or insects. Once carried to a suitable location, the amoebas emerge from spore form and begin the cycle again.
So long as all the amoebas which make up the slug are related, this impressive display of self-sacrifice on the part of the stalk cells makes sense. Though they will perish in the act of creating the stalk, they will pass along their genetic legacy via their kin. In fact, when the amoebas reproduce by division, they create an ever-increasing pool of genetically identical clones. These clones suffer no genetic cost at all from sacrificing their lives for each other.
More familiar multicellular organisms pool resources in a similar way. For example, in a human being, a liver cell fills a very different role from a lung or skin cell, but all of them harbor the same chromosomes. The result is that the liver doesn't need to compete with the lungs concerning reproduction. So long as the germ cells get lucky, all of the cells can be (metaphorically) content knowing they will pass on their genetic legacy.
However, when the cAMP call goes out, it isn't only related amoebas that answer it. Those of differing strains will come together to form a single slug. If one strain could figure out a way to duck out of stalk and sentinel duty, it would be expected to reproduce faster than its nobler compatriots.
As is true with all organisms, some will evolve in such a way that they can– and will– benefit from the colony's resources without contributing anything back. In theory, such "leeches" could potentially have a survival and reproductive advantage, thereby undermining the cooperative Dictyostelid lifestyle. Such cheating does take place, but nonetheless D. discoideum has been around for millions of years with no signs of imminent extinction. Thus the mechanisms for keeping cheating under control must be effective.
For one thing, the amoebas prefer to unite with kin. The amoebas are able to recognize each other through molecular markers. They mingle with other strains only when populations are low. At such times, the ability to form a larger slug outweighs the risk of cooperating with strangers.
A typical amoebaIn addition, evidence suggests that some social amoebas have evolved to link reproductive genes with altruistic ones. In the case of D. discoideum, researchers created a mutant strain of cells which are "deaf" to the chemical signal to become a self-sacrificing stalk cell. They then watched to see if these cells would gain a reproductive advantage. Just the opposite took place. The "cheater" mutant cells did not join in stalk formation, yet they rarely made it up the stalk to become spores, and therefore they died out. The traits of self-sacrifice and reproduction had become genetically entangled, it seems, allowing only the altruistic amoebas to produce offspring.
Finally, opportunities for cheating simply aren't very common. In the wild, these creatures spend much of their lives reproducing via division, and surrounding themselves with identical copies. Outside of laboratory experiments, cases where social amoebas run across strangers to exploit are rare. Cheater genes peter out once the cheaters run out of nobler amoebas to sponge off of. When exploiting one's clone mates, greed doesn't pay.
In addition to studies of altruism, study of D. discoideum is shedding light on how cells communicate. D. discoideum uses many of the same signaling processes found in all multicellular creatures. But unlike fish or frogs, D. discoideum can be frozen, thawed, grown by the millions in a matter of days, and stored away for years if need be. A website called DictyBase offers an impressive list of breakthroughs which can be credited to the social amoeba.
The consistency with which these amoebas act in the common good might inspire admiration in many. Yet a more cynical observer might point out that the amoebas are moved not by love of family and friends, nor by moral scruples, but by the cold mechanics of natural selection. Amoebas behave altruistically only because natural selection has led to a stable state in which self-sacrifice is the best way for them to pass on their genes. But the end result is the same, regardless of the natural forces that have shaped it. Altruism triumphs, and through their mutual selflessness the amoebas arrive at a new patch of bacteria-laden dung to call home.