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The place where the world comes together in honesty and mirth.
Windmills Tilted, Scared Cows Butchered, Lies Skewered on the Lance of Reality ... or something to that effect.

Sunday, May 4, 2014

The Daily Drift

Now, isn't just so nice of them ...!
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Today in History

1471 In England, the Yorkists defeat the Landcastians at the battle of Tewkesbury.
1626 Indians sell Manhattan Island for $24 in cloth and buttons.
1715 A French manufacturer debuts the first folding umbrella.
1776 Rhode Island declares independence from England.
1795 Thousands of rioters enter jails in Lyons, France, and massacre 99 Jacobin prisoners.
1814 Napoleon Bonaparte disembarks at Portoferraio on the island of Elba in the Mediterranean.
1863 The Battle of Chancellorsville ends when Union Army retreats.
1864 Union General Ulysses S. Grant's forces cross the Rapidan River and meet Robert E. Lee's Confederate army.
1927 A balloon soars over 40,000 feet for the first time.
1930 Mahatma Gandhi is arrested by the British.
1942 The Battle of the Coral Sea commences.
1942 The United States begins food rationing.
1961 13 civil rights activists, dubbed Freedom Riders, begin a bus trip through the South.
1970 Ohio National Guardsmen open fire on student protesters at Kent State University, killing four and wounding nine others.

Non Sequitur


Trying to understand chronic fatigue syndrome

Chronic fatigue syndrome is one of those vague-sounding disorders that seems like it could be total woo. But there's actually some intriguing evidence suggesting a biological basis. In a two-part story, Julie Rehmeyer explores the data that a lot of doctors ignore and the politics that gave a fairly specific disorder a comically broad definition.

Scientists create solar panel window

Boffins create solar panel window
Windows that double as solar panels could soon be a reality following a breakthrough in quantum dot research that could have significant implications on the way the sun’s energy is harvested in the future.
Researchers at Los Alamos National Laboratory and the University of Milano-Bicocca synthesised a new generation of quantum dots that they were able to embed in a transparent polymer to capture the sun’s energy.
Quantum dots – nanocrystals made of semiconductor materials – are already used in solar panel systems due to their low-cost and mechanical properties, as well as transistors, LEDs and lasers.

What's up with robotic snakes?

You've watched the videos. You've felt the weird sense of unease. But what's the point of making a robot that moves like a snake? From surgery helpers to search-and-rescue, Dana Liebelson at Mother Jones has the answers.

Antennae Help Flies ‘Cruise’ In Gusty Winds

A tracing of the flies' flight trajectories as they explore in a wind tunnel, as seen from above. Each observation by the cameras is scaled according to flight speed, as if the animal was dribbling paint as it was flying; the longer the residence time, the larger the dot. Each trajectory is shown in a different color. The stars indicate when the flies were subjected to a brief gust of wind. These experiments revealed how the wind-sensing antennae stabilize the fly's visual flight controller.Antennae Help Flies ‘Cruise’ In Gusty Winds

Caltech researchers uncover a mechanism for how fruit flies regulate […]

Social Science News

A number of prison escapes have been reported recently. But experts say getting out of prison isn't as easy as it may seem.

Health Science News

Could laziness be genetic? Join Laci as she discusses a new study arguing that there might be such a thing as a couch potato gene!
Australian researchers have found a new way to use cochlear technology to re-grow auditory nerves.

Health and Safety Science News

A new product called Palcohol allows people to get drunk off powdered alcohol. How does it get powdered, and is it safe to consume?
A powder that would give new meaning to mixed drinks may take time to hit the U.S. market, after regulators found a labeling problem. 
The FDA will soon begin regulating e-cigarettes, the agency has announced.

Life-style determines gut microbes

Life-style determines gut microbes

The gut microbiota is responsible for many aspects of human […]

Environmental Health News

Portland, Ore. is dumping 38 million gallons of water after a teenager peed into an open reservoir. The public is outraged, and the city decided it's the right decision, but is the water actually still safe to drink?
A U.S. study has found that cow manure, commonly used to fertilize vegetable crops, contains a high number of genes that can fuel resistance to antibiotics.

‘Water World’ Theory of Life’s Origins

New Study Outlines ‘Water World’ Theory of Life’s Origins

Life took root more than four billion years ago on […]

How Tsunamis Work

Alex Gendler explains the forces behind tsunamis in this TED-Ed animation. This gives us a pretty clear explanation of how tsunamis can sneak across oceans without being visible until they reach shore. The full lesson is at the TED-Ed site.



Why are diamonds clear, but coal black?

by Maggie Koerth-Baker
Maggie Koerth-Baker answers a new Science Question from a Toddler
When Superman wants to super impress Lois Lane, he takes a lump of coal and squeezes it in his super fist until it becomes a diamond. Which is super.
Unfortunately, it’s not a scientifically accurate analogy for the creation of diamonds in nature. So when journalist Stephen Ornes’ 6-year-old son, Sam, asks how coal, which is black, can turn into diamonds, which are clear, there are actually a couple of issues we have to address. First, we need to know where diamonds actually come from. Then, even though diamonds aren’t coal, you’re still left with the basic question Sam is trying to get at—why can pure carbon be black under some circumstances and clear under others? Turns out, the answer has a lot to do with why life, itself, is based on carbon.
Coal is the compressed remains of ancient plants, dinosaur swamps sitting in the palm of your hand. But there are diamonds that are older than terrestrial plants. That fact alone should tell you that diamonds are not actually made from compressed coal. Instead, diamonds are probably formed deep in the Earth—much further down than the levels at which we find coal—where heat and pressure fuse atoms of carbon together into crystalline structures. Later, those crystals get vomited up from the depths with the help of volcanic vents. 
It’s important to make the distinction between diamonds and coal because, if you don’t, then Sam’s question earns a misleadingly simple answer. Diamonds and coal are different colors because coal isn’t pure carbon. The stuff is loaded with impurities: Hydrogen, sulfur, mercury, and more. There’s a reason you don’t want to live next door to a coal-fired power plant and that reason is all the nasty stuff that gets released when the carbon in coal burns.
But that doesn’t mean pure carbon always looks like diamonds. As an example, George Bodner, professor of chemical education at Purdue University, points to carbon black—the black stuff you see when you burn something in the flame of a candle. Another good example, this one from David McMillin, a Purdue professor of inorganic chemistry, is graphite. Like diamond, graphite is carbon. Unlike diamond, it’s a shimmery, silvery black. So what gives?
This is where things get complicated, because the differences between diamonds and carbon black, or diamonds and graphite, happen at the molecular level.
Think about the illustration of an atom—the big ball of a nucleus surrounded by a cloud of electrons whirling through shells designated by energy level. An atom of carbon has six electrons. Two in the lowest shell, closest to the nucleus, and four in the second shell. The lowest shell can only hold two electrons, so, for carbon, that shell is full and stable—an old married couple with a minivan and a cat. But the second shell can hold eight electrons, and carbon only has half that number. That means the electrons in carbon’s outer shell are on the market. They can attract electrons from other atoms, swap and share, binding the atoms together and forming new molecules.
Once that happens, an idea called molecular orbital theory comes into play, because becoming part of a molecule seems to change how electrons go about their business. You can’t think of a molecule of two atoms as a couple of nuclei planets, each with its proprietary electron satellites still distinctly circling. Instead, the electrons of both atoms merge to the point that, when we talk about orbits, we’re talking about molecular orbits now, not atomic ones.
There are two types of molecular orbits, pi bonds and sigma bonds, and each of those has a bond and an antibond. (You can imagine them as twins, one of whom has an inherently evil moustache.) It’s the difference in bonding that makes diamonds clear and other forms of pure carbon black.
Diamonds are entirely constructed from sigma bonds. When two carbon atoms come together to form diamond, the electrons are snugly held, right in between the nuclei. The sigma bond is a tight bond. In molecular chemistry, the tightest bonds happen at the lowest orbitals … the lowest energy levels. So if your bond is very low energy, then its evil twin—the antibond—must be the opposite. Very, very high energy.
Why does this make the diamond clear? The secret is in that big difference between the bond and the antibond. When a photon of light energy slams into a stable material, it can pass through it, be absorbed, or be scattered back in the direction it came from. The net energy (or wavelength) of that photon is a critical factor. When a bunch of atoms are as tightly joined as the ones in a diamond, the photon has to have a lot of energy to be absorbed and excite an electron into an antibonding level; it’s like throwing a bowling ball at a brick wall. A molecule of diamond is like the wall. And by the time you get out the heavy construction equipment and hit that wall with enough force to take a piece out of it … well, that little piece is also going to contain a lot more energy. In this case of the photon is outside the relatively low-energy spectrum of visible light.
So it’s not really that diamonds are clear—that they don’t absorb any of the light that hits them. It’s that our eyes can’t see the colors of really high energy photons. “If you looked at it with UV eyes, you’d see something different,” McMillin said.
In graphite, on the other hand, one quarter of the bonds are pi bonds. In a pi bond, the electrons have a little bit more leeway, like toddlers on a tether. They’re still tightly held, but the nuclei don’t confine them so much and they roam more through the material. And the difference between the bond and the antibond is less extreme. If a sigma bond is a brick wall, the pi electrons are more like bowling pins. Relatively low energy photons can energize them. In fact, graphite virtually absorbs every colored photon in the visible spectrum. None come through or scatter back toward us and we therefore see black. (It’s worth noting that this absorption isn’t like a black hole, where energy has almost no chance of escaping. Instead, in graphite, the energy is absorbed, but then exits again in a changed state—as much smaller bundles of heat energy.)
The difference between sigma-bonded diamonds—which throw off photons outside the spectrum of visible light—and pi-bonded graphite—which absorbs all colors of visible light is extreme. The fact that both are carbon is pretty important, because it means that carbon is extremely versatile. And that, George Bodner said, is what makes carbon such a great element to build life around. “You need strong bonds because you want this thing held together. But there are also times when you want it to, under right conditions, to open up or react. Carbon is so good at that, better than anybody else. And life on this planet evolved around that.”

Newfound Mineral Is Like No Other

A new pinkish, purplish mineral has a chemical composition and crystalline structure unlike any of the known 4,000 minerals.

How US Heat Waves Melted Greenland's Ice

Greenland's two record-shattering surface melts, though more than a century apart, were both triggered by U.S. heat waves.

Global Warming News

The 2007 climate report was wrong about Himalayan glaciers: They will not disappear soon, says a 2014 report. But what do we know that we didn't know then?
NASA is monitoring a chunk of sea ice 10 times the size of Manhattan, which broke off from Antarctica.
Some effects of the long-lasting, sub-freezing temperatures are only now becoming apparent. One surprise was the discovery that starving rats in New York City had attacked the trees in urban parks for sustenance.
Antarctica enjoyed California-like temperatures 50 to 40 million years ago. This temperate climate shows us how the greenhouse effect can alter the Earth.

Earth Science News

Whether made of wood, brick or straw, buildings face various hazards during an eruption.
BP is refusing requests to pay for evaluations of the damage caused after the company's Deepwater Horizon spill.
The coldest place on Earth is also one of the rare spots where a roiling lava lake offers a window into the heart of a volcano.

Scientists discover first Earth-sized planet that could support life

by Miriam Kramer
'Earth's Cousin': Scientists Find Alien Planet That's Most Like Home
For the first time, scientists have discovered an Earth-sized alien planet in the habitable zone of its host star, an "Earth cousin" that just might have liquid water and the right conditions for life.
The newfound planet, called Kepler-186f, was first spotted by NASA's Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth. While the host star is dimmer than Earth's sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say. You can learn more about the amazing alien planet find in a video produced by Space.com.
"One of the things we've been looking for is maybe an Earth twin, which is an Earth-sized planet in the habitable zone of a sunlike star," Tom Barclay, Kepler scientist and co-author of the new exoplanet research, told Space.com. "This [Kepler-186f] is an Earth-sized planet in the habitable zone of a cooler star. So, while it's not an Earth twin, it is perhaps an Earth cousin. It has similar characteristics, but a different parent." [9 Exoplanets That Could Host Alien Life]
Potentially habitable planet
Scientists think that Kepler-186f — the outermost of five planets found to be orbiting the star Kepler-186 — orbits at a distance of 32.5 million miles (52.4 million kilometers), theoretically within the habitable zone for a red dwarf.
Earth orbits the sun from an average distance of about 93 million miles (150 million km), but the sun is larger and brighter than the Kepler-186 star, meaning that the sun's habitable zone begins farther out from the star by comparison to Kepler-186.
Found! First Earth-Size Planet That Could Support  …
This artist illustration shows what it might be like to stand on the surface of the planet Kepler-18 …
"This is the first definitive Earth-sized planet found in the habitable zone around another star," Elisa Quintana, of the SETI Institute and NASA's Ames Research Center and the lead author of a new study detailing the findings, said in a statement.
Other planets of various sizes have been found in the habitable zones of their stars. However, Kepler-186f is the first alien planet this close to Earth in size found orbiting in that potentially life-supporting area of an extrasolar system, according to exoplanet scientists.
'An historic discovery'
"This is an historic discovery of the first truly Earth-sized planet found in the habitable zone around its star," Geoff Marcy, an astronomer at the University of California, Berkeley, who is unaffiliated with the research, told Space.com via email. "This is the best case for a habitable planet yet found. The results are absolutely rock-solid. The planet itself may not be, but I'd bet my house on it. In any case, it's a gem."
The newly discovered planet measures about 1.1 Earth radii, making it slightly larger than Earth, but researchers still think the alien world may be rocky like Earth. Researchers still aren't sure what Kepler-186f's atmosphere is made of, a key element that could help scientists understand if the planet is hospitable to life.  [Kepler-186f: Earth-Size World Could Support Oceans, Maybe Life (Infographic)]
This diagram shows the position of Kepler-186f in relation to Earth.
"What we've learned, just over the past few years, is that there is a definite transition which occurs around about 1.5 Earth radii," Quintana said in a statement. "What happens there is that for radii between 1.5 and 2 Earth radii, the planet becomes massive enough that it starts to accumulate a very thick hydrogen and helium atmosphere, so it starts to resemble the gas giants of our solar system rather than anything else that we see as terrestrial."
The edge of habitability
Kepler-186f actually lies at the edge of the Kepler-186 star's habitable zone, meaning that liquid water on the planet's surface could freeze, according to study co-author Stephen Kane of San Francisco State University.
Because of its position in the outer part of the habitable zone, the planet's larger size could actually help keep its water liquid, Kane said in a statement. Since it is slightly bigger than Earth, Kepler-186f could have a thicker atmosphere, which would insulate the planet and potentially keep its water in liquid form, Kane added.
"It [Kepler-186f] goes around its star over 130 days, but because its star is a lower mass than our sun, the planet orbits slightly inner of where Mercury orbits in our own solar system," Barclay said. "It's on the cooler edge of the habitable zone. It's still well within it, but it receives less energy than Earth receives. So, if you're on this planet [Kepler-186f], the star would appear dimmer."

Exoplanet hunting in the future
Kepler-186f could be too dim for follow-up studies that would probe the planet's atmosphere. NASA's James Webb Space Telescope — Hubble's successor, expected to launch to space in 2018 — is designed to image planets around relatively nearby stars; however, the Kepler-186 system might be too far off for the powerful telescope to investigate, Barclay said.
Scientists using the Kepler telescope discovered Kepler-186f using the transit method: When the planet moved across the face of its star from the telescope's perspective, Kepler recorded a slight dip in the star's brightness, allowing researchers to learn more about the planet itself. Kepler suffered a major malfunction last year and is no longer working in the same fashion, but scientists are still going through the spacecraft's trove of data searching for new alien worlds.
"I find it simply awesome that we live in a time when finding potentially habitable planets is common, and the method to find them is standardized," MIT exoplanet hunter and astrophysicist Sara Seager, who is unaffiliated with the research, told Space.com via email.

Before, During, and After the Big Bang

Carolina Naturally is proud to bring you an excerpt from the book NOTHING: Surprising Insights Everywhere from Zero to Oblivion, from the magazine New Scientist. It features thoughts from 21 different writers and scientists on subjects from the nature of nothingness to the cosmos to the inner workings of the human mind. They harness the latest research to explain complicated concepts in ways we can understand. For example:  
Why does the placebo effect—essentially, feeling better after taking nothing—work?
Can meditation—clearing the mind of everything—cause structural changes in the brain?
What was happening immediately after the big bang, and, even more mysterious, what came before?
Is the appendix—a body part that supposedly does nothing—truly a vestigial organ?
Why was it so hard to invent the number zero?
How might cooling elements down to nearly absolute zero solve our energy crisis?
This excerpt on the big bang is from New Scientist cosmology consultant Marcus Chown.

“Astronomy leads us to a unique event, a universe which was created out of nothing,” said Arno Penzias, the American physicist and Nobel laureate. He was talking about the mother of all beginnings, the big bang. It’s the obvious place for us to start. To add some variety, we’ll bounce you to ancient Babylon and then to the most modern of brain-scanning laboratories. You’ll find out about the birth of a symbol that you almost certainly take for granted and discover that your head is home to an organ you’ve probably never heard of. Along the way, we’ll look at the fruits of an infant scientific field—the mind’s power to heal the body.

The big bang
Our universe began in an explosion of sorts, what’s called the big bang. The $64,000 question is how the cosmos emerged out of nothing. But before we tackle that, we need to understand what the big bang entailed. Here’s Marcus Chown.

In the beginning was nothing. Then the universe was born in a searing hot fireball called the big bang. But what was the big bang? Where did it happen? And how have astronomers come to believe such a ridiculous thing?

About 13.82 billion years ago, the universe that we inhabit erupted, literally, out of nothing. It exploded in a titanic fireball called the big bang. Everything—all matter, energy, even space and time—came into being at that instant.

In the earliest moments of the big bang, the stuff of the universe occupied an extraordinarily small volume and was unimaginably hot. It was a seething cauldron of electromagnetic radiation mixed with microscopic particles of matter unlike any found in today’s universe. As the fireball expanded, it cooled, and more and more structure began to “freeze out.”

Step by step, the fundamental particles we know today, the building blocks of all ordinary matter, acquired their present identities. The particles condensed into atoms and galaxies began to grow, then fragment into stars such as our sun. About 4.55 billion years ago, Earth formed. The rest, as they say, is history.

It is an extraordinarily grand picture of creation. Yet astronomers and physicists, armed with a growing mass of evidence to back their theories, are so confident of the scenario that they believe they can work out the detailed conditions in the early universe as it evolved, instant by instant. 

It is an extraordinarily grand picture of creation. Yet astronomers and physicists, armed with a growing mass of evidence to back their theories, are so confident of the scenario that they believe they can work out the detailed conditions in the early universe as it evolved, instant by instant.

That’s not to say we can go back to the moment of creation. The best that physics can do is to attempt to describe what was happening when the universe was already about 10–35 seconds old—a length of time that can also be written as a decimal point followed by 34 zeroes and a 1.

This is an exceedingly small interval of time, but you would be wrong if you thought it was so close to the moment of creation as to make no difference. Although the structure of the universe no longer changes much in even a million years, when the universe was young, things changed much more rapidly.

For example, physicists think that as many important events happened between the end of the first tenth of a second and the end of the first second as in the interval from the first hundredth of a second to the first tenth of a second, and so on, logarithmically, back to the very beginning. As they run the history of the universe backward, like a movie in reverse, space is filled with ever more frenzied activity.

This is because the early universe was dominated by electromagnetic radiation—in the form of little packets of energy called photons—and the higher the temperature, the more energetic the photons. Now, high-energy photons can change into particles of matter because one form of energy can be converted into another, and, as Einstein revealed, mass (m) is simply a form of energy (E), hence his famous equation E=mc2, where c is the speed of light.

What Einstein’s equation says is that particles of a particular mass, m, can be created if the packets of radiation, the photons, have an energy of at least mc2. Put another way, there is a temperature above which the photons are energetic enough to produce a particle of mass, m, and below which they cannot create that particle.

If we look far enough back, we come to a time when the temperature was so high, and the photons so energetic, that colliding photons could produce particles out of radiant energy. What those particles were before the universe was 10–35 seconds old, we do not know. All we can say is that they were very much more massive than the particles we are familiar with today, such as the electron and top quark.

As time progressed and temperature fell, so the mix of particles in the universe changed to a soup of less and less massive particles. Each particle was “king for a day,” or at least for a split second. For the reverse process was also going on—matter was being converted back to radiant energy as particles collided to produce photons.

What do physicists think the universe was like a mere 10–35 seconds after the big bang?

Well, the volume of space that was destined to become the “observable universe,” which today is 84 billion light years across, was contained in a volume roughly the size of a pea. And the temperature of this superdense material was an unimaginable 1028 ºC.

At this temperature, physicists predict, colliding photons had just the right amount of energy to produce a particle called the X-boson that was a million billion times more massive than the proton. No one has yet observed an X-boson, because to do so we would have to recreate, in an Earth bound laboratory, the extreme conditions that existed just 10–35 seconds after the big bang.

How far back can physicists probe in their laboratories?

The answer is to a time when the universe was about one-trillionth (10–12) of a second old. By then, it had cooled down to about 100 million billion degrees—still 10 billion times hotter than the center of the sun. In 2012, physicists at CERN, the European center for particle physics in Geneva, recreated these conditions in the giant particle accelerator called the Large Hadron Collider. They conjured into being a particle that resembles the Higgs boson, a particle that vanished from the universe a trillionth of a second after the big bang.

The gulf between 10–35 seconds and a trillionth of a second is gigantic. We know that for most of this period, matter was squeezed together more tightly than the most compressed matter we know of—that inside the nuclei of atoms. And, as the temperature fell, so the energy level of photons declined, creating particles of lower and lower masses.

At some point, the hypothetical building blocks of the neutron and proton—known as quarks—came into being. And by the time the universe was about one-hundredth of a second old, it had cooled sufficiently to be dominated by particles that are familiar to us today: photons, electrons, positrons and neutrinos. Neutrons and protons were around, but there weren’t many of them. In fact, they were a very small contaminant in the universe.

About one second into the life of the universe, the temperature had fallen to about 10 billion ºC, and photons had too little energy to produce particles easily. Electrons and their positively charged “antimatter” opposites, called positrons, were colliding and annihilating each other to create photons. However, because of a slight and, to this day, mysterious lopsidedness in the laws of physics, there were roughly 10 billion + 1 electrons for every 10 billion positrons. So, after an orgy of annihilation, the universe was left with a surplus of matter, and with about 10 billion photons for every electron, a ratio that persists today.

The next important stage in the history of the universe was at about one minute.

The temperature had dropped to a mere 1 billion ºC—the temperature in the hearts of the hottest stars. Now the particles were moving more slowly. In the case of protons and neutrons, it meant that they stayed close to each other long enough for the strong nuclear forces, which bind them together in the nuclei of atoms, to have a chance to take hold. In particular, two protons and two neutrons could combine to form nuclei of helium.

Solitary neutrons decay into protons in about 15 minutes, so any neutrons left over after helium formed became protons. According to physicists’ calculations, roughly ten protons were left over for every helium nucleus that formed. And these became the nuclei of hydrogen atoms, which consist of a single proton.

This is one of the strongest pieces of evidence that the big bang really did happen. For much, much later, when the temperature had cooled considerably, the hydrogen and helium nuclei picked up electrons to become stable atoms. Today, when astronomers measure the abundance of elements in the universe—in stars, galaxies and interstellar space—they still find roughly one helium atom for every ten hydrogens.

The point at which it was cool enough for electrons to combine with protons to make the first atoms was about 380,000 years after the big bang. The universe was now cooling very much more slowly than in its early moments, and the temperature had reached a modest 3,000 ºC. This also marked another significant event in the early history of the universe.

Until the electrons had combined with the hydrogen and helium nuclei, photons could not travel far in a straight line without running into an electron. Free electrons are very good at scattering, or redirecting, photons. As a consequence, every photon had to zigzag its way across the universe. This had the effect of making the universe opaque. If this happened today and light from the stars zigzagged its way across space to your eyes, rather than flying in straight lines, you would see only a dim milky glow from the whole sky rather than myriad stars.

We can still detect photons from this period. They have been flying freely through the universe for billions of years, and astronomers observe them as what’s called the cosmic microwave background. Whereas these photons started their journey when the temperature was 3,000 ºC, the universe has expanded about 1100 times while they have been in flight. This has decreased their energy by this factor, so that we now record the signals as just 2.725 degrees above absolute zero.

The temperature dropping to about 3,000 ºC also signalled another event—the point at which the energy levels of the radiation, or photons, in the universe fell below that of the matter. From then on, the universe was dominated by matter and by the force of gravity acting on that matter.

The building of elements, which had begun when the universe was about one minute old, had stopped by the time it had been in existence for ten minutes, and the protons and neutrons had formed the nuclei of hydrogen and helium. For elements such as carbon and oxygen to form, hotter and denser conditions were needed, but the universe was getting colder and more rarefied all the while. The heavy elements in the planets and in your body were created, billions of years later, in the nuclear furnaces of stars.

Instead, as the universe continued to expand, gravity caused clumps of matter to accumulate in large islands. Those islands were to become the galaxies. The galaxies continued their headlong rush into the void, fragmenting into smaller clumps which became individual stars, producing heat and light by nuclear reactions deep in their cores. At one point, about 9 billion years after the big bang, a yellow star was born toward the outer edge of a great spiral whirlpool of stars called the Milky Way. The star was our sun.

How do we know there was a big bang?
Our modern picture of the universe is due in large part to an American astronomer, Edwin Hubble. In 1923, he showed that the Milky Way, the great island of stars to which our sun belongs, was just one galaxy among thousands of millions of  others scattered throughout space.

Hubble also found that the wavelength of the light from most of the galaxies is “red shifted.” Astronomers initially interpreted this as a Doppler effect, familiar to anyone who has noticed how the pitch of a police siren drops as it passes by. The siren becomes deeper because the wavelength of the sound is stretched out. Similarly with light, the wavelength of light from a galaxy which is moving away from us is stretched out to a longer, or redder, wavelength.

Hubble discovered that most galaxies are receding from the Milky Way. In other words, the universe is expanding. And the farther away a galaxy is, the faster it is receding.

One conclusion is inescapable: the universe must have been smaller in the past. There must have been a moment when the universe started expanding: the moment of its birth. By imagining the expansion running backward, astronomers deduce that the universe came into existence about 13.82 billion years ago.

This idea of a big bang means that the red shifts of galaxies are not really Doppler shifts. They arise because in the time that light from distant galaxies has been traveling across space to Earth, the universe has grown, stretching the wavelength of light.

The picture of a universe that is expanding need not have been a surprise to anyone. If Albert Einstein had only had faith in his equations, he could have predicted it in 1915 with his theory of gravity, known as the general theory of relativity. But Einstein, like Newton before him, hung on to the idea that the universe was static—unchanging, without beginning or end. He can be forgiven because, at the time, he did not even know about the existence of galaxies.

The vision of a static universe also appealed strongly to astronomers. In 1948, Hermann Bondi, Thomas Gold and Fred Hoyle proposed the steady-state theory of the universe. The universe was expanding, they said, but perhaps it was unchanging in time.

Their theory said that space is expanding at a constant rate but, at the same time, matter is created continuously throughout the universe. This matter is just enough to compensate for the expansion and keep the density of the universe constant. Where this matter would come from, nobody could say. But neither could the proponents of the big bang.

The steady-state theory held its own as the principal challenger to the big bang theory for two decades. Then, in the 1960s, two astronomical discoveries dealt it a fatal blow.

The first discovery came from Martin Ryle and his colleagues at the University of Cambridge. They were studying radio galaxies—enormously powerful sources of radio waves. In the early 1960s, the Cambridge astronomers found that there were many more radio galaxies at large distances than nearby.

The radio waves from these distant objects have taken billions of years to reach us. Ryle and his colleagues, therefore, were observing our universe as it was in an earlier time. The excess of radio galaxies at great distances had to mean that conditions in the remote past were different from those today. A universe which changes with time ran counter to the steadystate theory.

Then in 1965, Arno Penzias and Robert Wilson, two scientists at the Bell Telephone Labs in Holmdel, New Jersey, detected an odd signal with a radio horn they had inherited from engineers working on Echo 1 and Telstar, the first communication satellites.

The signal did not come from Earth or the sun. It seemed to come from all over the sky, and it was equivalent to the energy emitted by a body at about 3 degrees above absolute zero (–270 °C).

There could be no doubt. Penzias and Wilson had discovered the “afterglow” of the big bang fireball—the cosmic microwave background. For their proof of the big bang, they shared the 1978 Nobel prize in physics.

Looking backward in time
Physicists can run the expansion of the universe backward. In this way, they can watch it get hotter as it gets smaller, just as the air in a bicycle pump heats up as it is compressed. But theory proposes that, at the big bang itself, the temperature was infinite. And infinities warn physicists that theories are flawed.

At the moment, the theories which take us furthest back in time are the Grand Unified Theories. These GUTs are an attempt to show that three of the basic forces that govern the behavior of all matter—the strong and weak nuclear forces and the electromagnetic force—are no more than facets of a single “superforce.”

Each force of nature arises from the exchange of a different “messenger” particle, or boson. The messenger transmits a force between two particles, just as a tennis ball transmits to a player the force of an opponent’s shot. At high enough temperatures— such as those when the universe was 10–35 seconds old—physicists believe the electromagnetic and strong and weak nuclear forces were identical, and mediated by a messenger dubbed the X-boson.

Physicists want to show that gravity, too, is a facet of the superforce. They suspect that gravity split apart from the other three forces at about 10–43 seconds after the big bang. But before they can “unify” the four forces, they must describe gravity using quantum theory, which is hugely successful for describing the other forces. To say that physicists are finding this difficult is an understatement.

When they have their unified theory, physicists believe that they will be able to probe right back to the moment of creation and explain how the universe popped suddenly into existence from nothing 13.82 billion years ago.

The rings of Saturn are either giving birth to a moon, or destroying one

In a series of photos dating back to May 2012, NASA scientists have identified a bright object at the edge of Saturn's outermost ring. Nicknamed "Peggy", the object is a kilometer across and could be a moon about to calve off the rings. Or, alternately, it could be a moon that got too close to the rings and is in the process of disintegrating.

Astronomical News

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A helium leak on the launch pad has forced SpaceX to cancel their planned Falcon 9 rocket launch today, postponing the private company's third International Space Station resupply mission until another attempt on Friday.
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Apr 14, 2014 07:56 AM ET
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