Scientists probing what happened before big bang

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By Robert S. Boyd|McClatchy Newspapers

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WASHINGTON — When the huge subatomic-particle smasher under the Swiss-French border starts running, it’s supposed to reveal what happened the instant after the big bang, the theoretical beginning of our universe 13.7 billion years ago.

The Large Hadron Collider, which suffered a temporary setback last week, might find some answers. But it will leave other questions on many people’s minds, such as what happened BEFORE the big bang, and even whether there was a “before.”

A scientific mini-industry has popped up as deep-thinking physicists and cosmologists bat around various guesses as to what may have happened in a “pre-big bang.”

Some of the top minds in this field gathered at Columbia University earlier this month to debate these questions.

“What banged? Where did it come from?” was the question raised by Laura Mersini-Houghton, a cosmologist at the University of North Carolina at Chapel Hill.

“Is ours the only universe? If so, how did it come to exist?” asked Paul Davies, a cosmologist and authority on science and religion at Arizona State University in Tempe.

Respected scientists have proposed a flock of theories to describe what might have happened before the birth of our familiar universe of space and time.

The concepts have fanciful names such as “the big bounce,” “the multiverse,” “the cyclic theory,” “parallel worlds,” even “soap bubbles.” Some propose the existence of multiple universes. Others hold that there’s one universe that recycles itself endlessly, rather as Buddhists believe. Judeo-Christian theologians may have difficulty accepting any of these notions.

Most of the hypotheses are variations on an older idea that the universe has no beginning and no end, contrary to the big bang theory, which says that our universe originated at a specific point and will end sometime in the distant future.

“Neither time nor the universe has a beginning or an end,” two leading cosmologists, Paul Steinhardt of Princeton University and Neil Turok of Oxford University, wrote in their 2007 book, “Endless Universe: Beyond the Big Bang.”

“The evolution of the universe is cyclic, with big bangs occurring once every trillion years or so, each one accompanied by the creation of new matter and radiation that forms new galaxies, stars, planets and presumably life,” they wrote. “Ours is only the most recent cycle.”

Some scientists contend that observational evidence may be found to back up the speculation. They say that no scientific theory can be considered valid until it’s been tested.

“It is becoming increasingly clear that multiverse models grounded in modern physics can be empirically testable,” Max Tegmark, a theoretical physicist at the University of Pennsylvania, Philadelphia, wrote in “Parallel Universes,” a chapter in a 2003 book “Science and Ultimate Reality.”

Some researchers hope that the Large Hadron Collider will provide evidence to support or refute these conjectures. They say the particle smasher might discover extra dimensions, beyond our familiar three spatial dimensions plus time. More dimensions are the basis of several pre-big bang theories.

Michio Kaku, a professor of theoretical physics at the Graduate Center of the City University of New York, proposes that gravity, unlike light and matter, could travel between parallel universes and cast a “shadow” that scientists might be able to detect.

The shadow might take the form of “gravitational waves,” faint ripples in the fabric of space and time caused by violent explosions such as the big bang. Detectors in the United States and Europe are seeking such waves, and in the future satellites will watch for evidence of them in space.

Turok says his cyclic theory predicts a “distinctive pattern of gravitational waves that is very different from the one expected in the big bang theory . . . and may prove or disprove our theory within the next few years.”

Last August, ground and satellite observations revealed what appeared to be an enormous “hole in the universe,” a mostly empty region of the sky, 900 million light-years wide — about 5 billion trillion miles — in the constellation Eridanus. Mersini-Houghton, a believer in multiple universes, interpreted the empty spot as the “footprint” of the gravitational tug of another, smaller universe parked at the edge of our own.

“It’s like someone took a giant scoop and scooped all the matter away,” she told the Columbia cosmology conference. “All these universes are interacting with each other.”

Mersini-Houghton’s interpretation of the “hole” is controversial and so far lacks independent confirmation.

The oldest and most popular of the pre-big-bang theories is the multiverse. As outlined by Martin Rees, the British astronomer royal, in his 1997 book, “Before the Beginning: Our Universe and Others,” the theory declares that our universe is only one of many — perhaps an infinite number — of other worlds, each differing slightly from the others. These universes are continually forming new offspring, sprouting off from each other rather like soap bubbles.

The big bounce hypothesis — sometimes known as the big splat — contends that our universe was preceded by a twin that expanded to a certain limit, then contracted, collapsed and gave birth to our world. A leading proponent of this theory is Martin Bojowald, a theoretical physicist at Pennsylvania State University in University Park, who published it last year in the journal Nature.

In 2005, Kaku published a book titled “Parallel Worlds” in which he hypothesized that there may be millions of different, parallel universes, some that look like our own. They’re invisible to us because they lie outside our universe.

The big bang theory found favor with the Roman Catholic Church because it implied that the world has a single beginning at a definite point in time, as portrayed in Genesis. At a Vatican conference in 1951, Pope Pius XII said the big bang was consistent with church doctrine.

“Creation took place in time, therefore there is a creator, therefore God exists!” the pope declared.

The Rev. John Haught, an authority on science and religion at Georgetown University in Washington, said the idea that there might be many worlds and many beginnings, not just a single big bang, wouldn’t undermine Christian theology.

“Even if the universe, or multiverse, were around forever, this would not challenge the theological explanation of the world’s existence,” Haught said. “The biblical doctrine of creation . . . lies at a different level from scientific understanding. The world, theologians say, still gets its finite being from an infinite being.”

According to Francisca Cho, a professor of Buddhism and East Asian religions at Georgetown, these pre-big bang cosmologies are similar to the Hindu belief in a universe that cycles endlessly through creation and destruction.

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reference:http://news.yahoo.com/s/mcclatchy/20081027/sc_mcclatchy/3082054_1

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The Earth, the Energy Crisis and the Silver Bullet

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It’s getting harder to block awareness that the world is facing an energy crisis that isn’t going to solve itself (unless you’re George W. Bush); unfortunately awareness is only the first step in dealing with it. The crisis transcends rising prices at the gas pump or geopolitics in the Middle East. A number of trends are coming together in a way that recalls “The Year of the Jackpot”. Deeper understanding of just what the crisis is, is a prerequisite for making choices and developing effective solutions.

Supply is only one part of the problem. World oil supplies are maxing out even as growing economies and growing populations are pushing demand up. The decades-long trend of accelerating fossil fuel use which fills the atmosphere with greenhouse gases and drives climate change on a global level is another part of the problem. We can’t keep using fossil fuels to meet energy needs if it also means wrecking the planet. Third, the nature of our economic and political systems is such that we can’t keep things going as they are without vast supplies of energy. Too much social structure depends on the ability to keep the lights on, keep people driving, and buying stuff.

The most critical part of the problem however is getting people to SEE there is a problem, agree on the nature of the problem, agree on a solution, and work cooperatively to solve it – especially when the solution is going to involve changes in the way things are. People hate change, especially when it involves personal sacrifice, inconvenience, and real pain. Or even if it doesn’t.

The good news is, there may well be a Silver Bullet that can solve the energy crisis – or at least parts 1, 2, and 3.  Tackling number 4 is going to be a bit more difficult. Okay, what is a Silver Bullet? In this case it refers to a way to meet demands for energy while minimizing environmental and other costs. One of the frustrating things about implementing real solutions to the energy crisis is that there are multiple ways of attacking the problem, any combination of which could solve it, but figuring out just how to do it and pay for it is the major stumbling block. An ideal Silver Bullet would be one that is so superior to all the other solutions, it ipso facto becomes the default answer. It turns out there just might be one, and it’s one that’s coming in under the radar: nuclear power. Yeah, the “N” word – but not the one you’re thinking of.

First a little background. Every nuclear reactor built  to date runs on nuclear fission – the splitting of massive atoms in a controlled manner to produce heat to drive steam turbines which generate electrical power. A number of countries around the world use nuclear power reactors to provide a significant fraction of their energy. On the plus side, nuclear fission is an established technology, can provide power on demand, and produces no greenhouse gases at all.

On the minus side, fission reactors produce radiation and radioactive wastes which can be harmful for thousands of years. They are expensive to build and unforgiving to operate. If things go wrong, as at Three Mile Island or Chernobyl, the results can be catastrophic. The fuel itself is scarce, environmentally challenging to mine, tricky to prepare for use, and inherently dangerous if not handled properly. Further, it can also be used to build nuclear weapons as well as  run nuclear reactors.

For these and other reasons, nuclear power has been on the back burner (so to speak) for many years. That is changing though. The rising prices/shrinking supplies of oil coupled with the increasingly difficult to ignore consequences of greenhouse gases are reviving interest in nuclear power once again. There are new designs for reactors that will be inherently safer to operate. But, that’s not where the real promise lies.

There is another way to generate power with nuclear energy, but it uses a completely different process. It takes a lot of energy to hold a large atom together. Fission reactors are based on the fact that when massive atoms like uranium or plutonium break apart into smaller more stable atoms, energy is released (I’m simplifying greatly here.) But there’s another way to get energy from nuclear reactions: FUSION.

Fusion works this way: when small atoms are squeezed together to make a larger atom, say two hydrogen atoms fused into a helium atom, it actually takes less energy to hold the helium atom together than was locked up in the two hydrogen atoms when they were separate. That left over energy is released by fusion. This is what makes the Sun and other stars shine – hydrogen atoms fusing into helium. (In a sense this means every alternative energy system that uses sunlight is effectively using nuclear power – if only second hand.)

The advantages of using fusion reactions to generate power are many. Again, no greenhouse gases are released. Fusion fuel is much more abundant than fission fuel (hydrogen versus uranium for example) and much safer to handle. It’s not spontaneously trying to break apart, and can’t be made into a bomb without tremendous difficulty. And, the nuclear reactions that lead to fusion don’t have to produce all the kinds of radioactive leftovers you get when big atoms fission.

So, why isn’t fusion power the Silver Bullet we’re all hoping for yet? Because it is much harder to get small atoms to fuse than it is to make big atoms fission when they’re already inclined to do that all on their own. Scientists can produce fusion reactions now – but only by putting in more energy than they can get out. The goal is to make atoms fuse in sufficient quantities that the amount of energy released is greater than the amount of energy needed to get the reaction running in the first place.

They’ve been trying to crack the problem literally for decades, and they’re not quite there yet. The best guess is that building a working fusion reactor will require billions of dollars and several more decades of research and development of machinery capable of dealing with temperatures in millions of degrees, radiation, and incredibly strong magnetic fields.Or, something scaled up from what a bright high school student and a completely different approach can accomplish on a table top .

The first installment of this series described the four main components of  the energy/global warming crisis: increasing demand coupled with decreasing supply, the need to get away from fossil fuels, the need for vast amounts of energy just to keep things running the way they are, and the huge social/political/economic inertia that has to be overcome to address the first three components. While there are a number of possible ways to do all of that, there may be an emerging technology that would be the “Silver Bullet” answer to all of the above – or at least the first three.

It’s nuclear energy – but not the kind that’s been in use for decades. Fission reactors using uranium, plutonium or other combinations of heavy elements come with too much baggage to be easily adopted as The Answer. Nope, the best candidate for a true Silver Bullet is nuclear energy based on fusion. The problem is, it’s much harder to get energy out of fusing little atoms together than it is from splitting great big atoms apart and no one has yet made it work well enough to be practical.  But first, some science!

This installment is intended as a primer for some of the basic concepts needed to understand the nuclear physics involved in fission and fusion. The really neat stuff will be in Part 4: The Dynamic Alternative, but for those who may be a little uncertain on some of the fundamental stuff, I’m going to sketch it out here first with lots of links. For those who find it oversimplified or incomplete, my apologies. I’m going to try to put in enough links to supplement what I gloss over. (Lots of wikipedia et. al., in other words.)
And of course, many of you are probably looking at Pennsylvania today anyway instead of reading this, looking for reports of another ‘meltdown’ – though hopefully not nuclear!
Know Your Particles

Let’s start with some basics – what atoms are made of, how they fit together, and how they work! An atom is an assembly of three kinds of particles: electrons, protons, and neutrons. Protons and neutrons are big, massive particles compared to electrons. Protons have a positive charge, electrons have a negative charge, and neutrons (as you might guess) have no charge at all.

Protons and neutrons clump together in what is called a nucleus at the center of the atom; the electrons orbit around the nucleus in a cloud. Left to its own devices, an atom will have exactly as many protons as it has electrons. That’s because the opposite electric charges of the electrons and the protons have to be balanced. When atoms have an electric charge (become ionized), it’s because they’ve somehow gained or lost some of their electrons. Lose an electron, and an atom become positively charged. Gain one, and it has a negative charge.

Swapping electrons around is the basis of chemical reactions. Swapping around protons and/or neutrons is what nuclear reactions are all about. It’s much harder to do because protons and neutrons are held together pretty tightly in the nucleus (by the strong nuclear force), and they’re really massive compared to electrons. (Think bowling balls versus gnats.) On the other hand, the amount of energy that can be obtained from nuclear reactions is orders of magnitude greater than that from chemical reactions. MUCH more bang for the buck. (Sometimes literally- that was the rationale behind the first A bombs after all.)

The number of protons and the associated electrons are what make an atom of Boron (5 protons) different from an atom of Carbon (6 protons). Each element has a specific number of protons (the atomic number), from the simplest – Hydrogen with one – all the way up to big atoms like Uranium with 92 protons. Once the atomic number gets up around a hundred or higher, atoms of that size tend to be very unstable.

The number of neutrons in an atom can vary. A certain amount helps provide packing material between the protons in effect, but some combinations will make a nucleus unstable and it will tend to start shedding particles to adjust. (radioactive decay) It’s one of the sources of natural radiation.

The Same but Different

When two atoms have the same number of protons but different numbers of neutrons, they are said to be isotopes. Chemically, isotopes of the same element are pretty much identical – but their different weights (protons plus neutrons = atomic mass) means they can be separated by mechanical means. That’s what the fuss is about over Iran and centrifuges. A really special kind of centrifuge can spin down Uranium isotopes to separate out the ones that can be used to make nuclear reactors and/or nuclear weapons.

Uranium 238 has 92 protons and 146 neutrons; Uranium 235 has 92 protons but only 143 neutrons. U235 is the one used for fuel in nuclear fission reactors – and atomic bombs – because it is less stable than U238. Deuterium is the name for a Hydrogen atom that’s got a neutron keeping company with its single proton. Tritium is a Hydrogen atom that has 2 neutrons packed in there with that proton. Both isotopes are more massive than a plain vanilla Hydrogen atom (aka Protium) – and that has implications for fusion reactions.

Breaking Up Is Easy To Do

As I mentioned before, fission reactors are comparatively easy to build, because they use elements like Uranium isotope 235 for fuel; U235 is ready to fission all by itself. It’s so unstable atoms of U235 will spontaneously spit out neutrons at random, and that starts a sequence of further break down (chain reaction) that eventually ends up with all of the Uranium turning to Lead – plus a lot of radiation and other forms of energy along the way.

If you put enough U235 atoms together (a critical mass), at any given time there are enough neutrons getting spat out that they start hitting the nuclei of other Uranium atoms that are still waiting their turn, and that sets them off! If they all go at once, you have an atomic bomb. If you have some elaborate machinery to control how many neutrons are shooting around at any given time, you have a nuclear reactor with controlled fission.

If you want a vivid image to picture this, think of a bunch of hand grenades all equipped with timers that will set them off at random intervals. Scattered around, with stuff piled up around them, you get random explosions that don’t do much outside the immediate blast area. Start putting them closer together, and every time one grenade goes off, it may set off another one or two or three so you get a constant series of explosions which can be contained and put to work. Pile them all together, the first one to go off will set them all off! Best to be elsewhere when that happens.

But Getting Together is Hard

Fission reactors need elements that are already breaking down on their own to operate. Fusion is something altogether different. It doesn’t happen spontaneously; it involves the nuclei of two or more atoms being forced together hard enough to overcome the repulsion of the positive charges on the protons in the nucleus. The larger the nucleus (the more protons), the greater the repulsive force. That’s why most fusion work is concentrated on fusing the smallest atoms (Hydrogen in its various isotopic forms) into the next larger atom, Helium. It’s possible to use other atoms though, and the end products can be different. The new, bigger atom may be stable as it is, or it in turn may divide into smaller atoms and stray particles, and so on until the final result is an assortment of stable atoms and debris – and energy.

Theoretically, any two atoms of lighter elements can be fused together up to the atomic mass of iron or nickel and there will be some excess mass that gets converted to energy in the process. (Yes, this is the classic Einstein E = mc squared equation.) Fusing atoms heavier than Iron requires more energy than is released. That’s why it only happens naturally inside exploding stars. It takes the energy of a supernova to slam atoms together hard enough to make the really big elements.

So, in practice the bigger the atoms, the harder it is to fuse them. But, pick the right combination of atoms and the net result is a new set of atoms along with the release of energy. And – this is where fusion differs from fission – it’s theoretically possible to select elements for fusion fuel such that when they combine, the results are not radioactive, or only minimally so. Potentially, fusion reactors have none of the radioactive hazards of fission reactors, don’t produce long-lived radioactive wastes, and do not emit any green house gases when they operate. And, the fuel itself doesn’t have to be dangerous and can’t be used to make weapons.

Theoretically, potentially, practically – weasel words that suggest fusion is still a long ways off. Maybe yes, maybe no. Possibly, a practical fusion power reactor will be built somewhere around 2050. Or, thanks to some fresh ideas and research that is only now being made public, it could be a lot sooner and much easier than anyone could have expected.

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reference:http://www.dailykos.com/story/2008/4/21/133412/301/71/499278

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China’s “spacewalker” heads backs to earth

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By GILLIAN WONG, Associated Yahoo! Press Writer.

BEIJING – Three Chinese astronauts made a jubilant return to Earth on Sunday after successfully completing the country’s first-ever spacewalk, an event the premier said was “a stride forward” in China’s space history

The spacewalk was mainly aimed at testing China’s mastery of the technology involved. The sole task of mission commander Zhai Zhigang was to retrieve a rack attached to the outside of the orbital module. He remained outside for about 13 minutes.

“It was a glorious mission, full of challenges with a successful end,” Zhai said after the Shenzhou 7 module landed under clear skies in the grasslands of China’s northern Inner Mongolia region. “We feel proud of the motherland.”

State broadcaster CCTV showed the astronauts emerge from their capsule, which floated gently down under a giant red-and-white-striped parachute, and wave at cameras as they celebrated the end of their 68-hour mission.

Zhai, Liu Boming and Jing Haipeng stayed inside for about 46 minutes to adapt to Earth’s gravity before crawling out of the narrow entrance. They were declared healthy after medical examinations inside the module.

“This mission’s success is a milestone; a stride forward,” Premier Wen Jiabao said at mission control.

Saturday’s space walk, which was broadcast live and watched by crowds gathered around outdoor television screens, further stoked national pride one month after the close of the Beijing Olympics.

“A small step by Zhai Zhigang in space is a big step in the history of the Chinese nation,” said a commentary by the official Xinhua News Agency carried Sunday by the Beijing Daily newspaper.

On most newspaper front pages were pictures of Zhai clutching a Chinese flag as he hovered in space outside the Shenzhou 7 vessel, alongside photos of Chinese President Hu Jintao on a telephone as he spoke to the astronauts.

While successful, the spacewalk wasn’t without anxious moments.

Zhai, a 41-year-old fighter pilot, appeared to struggle with the hatch and a fire alarm was triggered in the orbiter as he began the spacewalk.

Wang Zhaoyao, deputy director of manned space flight, conceded that the combined effects of weightlessness and depressurization on the hatch opening operation hadn’t been fully anticipated. He blamed a faulty sensor for the fire alarm.

The spacewalk required the astronauts to first depressurize and then repressurize the orbital module and proved the effectiveness of Zhai’s Feitian space suit, produced by China at a cost of $4.4 million. Liu wore a nearly identical Russian-made Orlan suit, according to the reports.

The spacewalk paves the way for assembling a space station from two Shenzhou orbital modules, the next major goal of China’s manned spaceflight program.

China is also pursuing lunar exploration and may attempt to land a man on the moon in the next decade — possibly ahead of NASA’s 2020 target date for returning to the moon.

China launched its first manned mission, Shenzhou 5, in 2003, becoming only the third country after Russia and the United States to launch a man into space. That was followed by a two-man mission in 2005.

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reference:http://news.yahoo.com/s/ap/20080928/ap_on_re_as/as_china_space

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Interesting facts about ants

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Like all insects, ants have six legs. Each leg has three joints. The legs of the ant are very strong so they can run very quickly. If a man could run as fast for his size as an ant can, he could run as fast as a racehorse. Ants can lift 20 times their own body weight. An ant brain has about 250 000 brain cells. A human brain has 10,000 million so a colony of 40,000 ants has collectively the same size brain as a human.

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The average life expectancy of an ant is 45-60 days. Ants use their antenae not only for touch, but also for their sense of smell. The head of the ant has a pair of large, strong jaws. The jaws open and shut sideways like a pair of scissors. Adult ants cannot chew and swallow solid food. Instead they swallow the juice which they squeeze from pieces of food. They throw away the dry part that is left over. The ant has two eyes, each eye is made of many smaller eyes.

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They are called compound eyes. The abdomen of the ant contains two stomachs. One stomach holds the food for itself and second stomach is for food to be shared with other ants. Like all insects, the outside of their body is covered with a hard armour this is called the exoskeleton. Ants have four distinct growing stages, the egg, larva, pupa and the adult. Biologists classify ants as a special group of wasps. (Hymenoptera Formicidae) There are over 10000 known species of ants. Each ant colony has at least one or more queens.

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The job of the queen is to lay eggs which the worker ants look after. Worker ants are sterile, they look for food, look after the young, and defend the nest from unwanted visitors. Ants are clean and tidy insects. Some worker ants are given the job of taking the rubbish from the nest and putting it outside in a special rubbish dump! Each colony of ants has its own smell. In this way, intruders can be recognized immediately. Many ants such as the common Red species have a sting which they use to defend their nest.

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The common Black Ants and Wood Ants have no sting, but they can squirt a spray of formic acid. Some birds put ants in their feathers because the ants squirt formic acid which gets rid of the parasites. The Slave-Maker Ant (Polyergus Rufescens) raids the nests of other ants and steals their pupae. When these new ants hatch,they work as slaves within the colony. The worker ants keep the eggs and larvae in different groups according to ages.

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At night the worker ants move the eggs and larvae deep into the nest to protect them from the cold. During the daytime, the worker ants move the eggs and larvae of the colony to the top of the nest so that they can be warmer. If a worker ant has found a good source for food, it leaves a trail of scent so that the other ants in the colony can find the food. Army Ants are nomadic and they are always moving. They carry their larvae and their eggs with them in a long column.

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The Army Ant (Ecitron Burchelli) of South America, can have as many as 700,000 members in its colony. The Leaf Cutter Ants are farmers. They cut out pieces of leaves which they take back to their nests. They chew them into a pulp and a special fungus grows it. Ants cannot digest leaves because they cannot digest cellulose. Many people think ants are a pest but I like them. To stop them coming into my kitchen I put some sugar outside. They they have so much to eat that they are not interested in coming into my kitchen.

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Reference

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