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Showing posts from September, 2010

Hawking & Mlodinow: No 'theory of everything'

In a Scientific American essay based on their new book A Grand Design, Stephen Hawking and Leonard Mlodinow are now claiming physicists may never find a theory of everything. Instead, they propose a "family of interconnected theories" might emerge, with each describing a certain reality under specific conditions.

Most of the history of physics has been dominated by a realist approach. Scientists simply accepted that their observations could give direct information about an objective reality. In classical physics, such a view was easily defensible, but the emergence of quantum mechanics has shaken even the staunchest realist.

In a quantum world, particles don't have definite locations or even definite velocities until they've been observed. This is a far cry from Newton's world, and Hawking/Mlodinow argue that - in light of quantum mechanics - it doesn't matter what is actually real and what isn't, all that matters is what we experience as reality.

As an exam…

Time Moves Faster Upstairs

It's 2 a.m., and the noise from your upstairs neighbor is keeping you awake again. Take solace in the fact that by living above you he may be shortening his life, even if only by a tiny fraction of a second.

Nearly a century ago, Albert Einstein suggested that time should move faster the farther away you are from the surface of the Earth. Now scientists have tested this theory at the small distances we travel up and down every day. Using the world's most precise clocks, they confirmed that our wristwatches tick at a slightly different speed when we ride an elevator, climb a flight of stairs, or even sit upright in bed.

According to Einstein's theory of general relativity, big objects with lots of gravity -- planets or stars -- bend the fabric of time and space, like bowling balls on a trampoline. The closer you get to these objects, the stronger the pull of gravity and the slower time moves. An astronaut watching a clock fall into a black hole, for example, would see its han…

Podcast: Colliding Planets Part One

In today's podcast, PhysicsBuzz talks to Marc Kuchner from NASA Goddard about planets orbiting around binary stars. Kuchner and his colleagues recently reported their findings from the Spitzer Space Telescope, which showed that planets around binary stars can have a rough life. They discovered a ring of diffuse dust and believe it may be all that's left of an unfortunate planet that was too close to its dying star.

"These kinds of systems paint a picture of the late stages in the lives of planetary systems," Kuchner said in a NASA press release last month. "And it's a future that's messy and violent."

Click the audio link below to hear the podcast.

planets

Physicists confirm Hawking radiation in lab

In recent years, the ability to create laboratory analogs has become a popular way to examine theory that can't be directly observed in nature.

Last week, I blogged about how the properties of a vacuum might play a dramatic role in the evolution of relativistic stars, in the blog I talked about how the study authors said we wouldn't be able to directly detect Hawking Radiation in the universe. Now, it seems some clever physicists from the University of Milan have found a way to detect Hawking Radiation after all: sort of. The physicists say they've observed the radiation in a clever lab analogy with a so-called white hole, which is often thought of as the inverse of the black hole.

Normally, when an antiparticle-particle pair form they release their energy immediately and mutually annihilate. Hawking radiation proposes that when the pair starts to cross over the event horizon of a black hole, one photon can be sucked in while the other is released. Because the free photon c…

An alien's eye view of the solar system (w/ video)

Update: check out our podcast, which features another conversation with Marc Kuchner about his research on colliding planets and the prospects for life in binary star systems.

With help from a supercomputer capable of 67 trillion calculations per second, astronomers at NASA Goddard have determined what our solar system would look like to an alien astronomer. The simulations track the interactions of 75,000 dust grains in the Kuiper Belt, which is an icy region out beyond Neptune where millions of small bodies (including Pluto) orbit the sun.

"The planets may be too dim to detect directly, but aliens studying the solar system could easily determine the presence of Neptune -- its gravity carves a little gap in the dust," Goddard astrophysicist Marc Kuchner said in a press release yesterday. "We're hoping our models will help us spot Neptune-sized worlds around other stars."

The images were created from simulations on NASA's Discover supercomputer and are like a…

Tying String Theory Together

A new book attempts to explain string theory to the masses.



Reality comes in layers.

Everything we see in the world around us, scientists tell us, is made of atoms and combinations of atoms called molecules. Atoms are themselves made of tiny particles -- electrons, protons, and neutrons. Protons, in turn, are believed to be made of still tinier things called quarks. Is that the end of it? Probably not.

Many physicists now believe that at a still lower level, matter consists of a network of vibrating strings. For several thousand researchers worldwide, using strings to explain complex phenomena is practically a crusade. The book "String Theory for Dummies" by Andrew Zimmerman Jones tries to capture the excitement of these developments without using any equations.

The reason strings are such a hot topic nowadays, Jones explains, is that the new theory not only helps to solve some long-standing problems in physics, but it also attempts to explain other, not-yet-observed phenomena…

Playing With Parallel Universes

The new season of 'Fringe' focuses on the science of choice.

There are moments in everyone’s life where a decision is made that affects everything that comes after it. Making a different choice long ago may have changed your life as well as your personality forever.

This is one of the themes that will play out for each character in season three of Fox’s hit television show "Fringe." At the end of the last season, two parallel universes collided. In season three, the cast will be using science fact and fiction to untangle them.

"Well, one area where we are letting the cat out of the bag is that season three will be very different than the first two," said Robert Chiappetta, one of the story editors for "Fringe." "In season one, science was neutral. Some of the characters used it for good and some for evil, viewers saw both sides. In season three, we are going deeper to understand why things have turned out the way they did."

Connecting physic…

President Obama announces major STEM initiative

Last week, surrounded by a cadre of big name CEOs, scientists, astronauts and educators, President Obama announced a major addition to the STEM program Educate to Innovate. The new initiative is a non-profit organization called Change the Equation, and is composed of hundreds of CEOs from large corporations dependent on science and math students, as well as science museums, libraries and even Nature Publishing - the group that owns Scientific American and the journal Nature.

In a public-private partnership backed by millions in donations from corporate America, the non-profit will focus specifically on improving science and technology teachers and inspiring kids to pursue degrees in the sciences.

In his speech on Thursday, President Obama said that while profits might come from innovations at research labs and workshops, they don't start there. "It starts when a child learns that every star in the night sky is another sun," Obama said, "when a young girl swells with a…

Why 'the nothing,' is really something

"A nightmare, long engendered in the modern mind by the mythology that follows in the wake of science, was falling off him. He had read of 'Space': at the back of his thinking for years had lurked the dismal fancy of the black, cold vacuity, the utter deadness, which was supposed to separate the worlds. He had not known how much it affected him till now..."

- C.S. Lewis, Out of the Silent Planet


Like Lewis, many initially envision the vacuum of space as a place of "utter deadness" and it fuels cold thoughts of a universe devoid of action. But for decades, physicists attempting to unify quantum mechanics and relativity have been accidentally painting a contradictory and compelling picture of what actually separates the worlds. The subtle, yet critical properties of the vacuum are now needed to fully describe many bizarre phenomena in the cosmos.

From the Dirac sea model of a vacuum as an ocean of negatively charged particles to the Casimir effect that dictate…

iPhone Controlled Quadcopter!

iPhone apps seem like they can do anything these days. Need to answer an email? No problem! Want to see when the next bus is? Piece of cake! Want to toss virtual cows for fun? I don't know why you'd want to, but sure thing, coming right up!

Want to remote pilot a Micro Aerial Vehicle?


Yes, there IS an app for that!



PhysicsBuzz visited the lab of Dr. Missy Cummings, Director of the Humans and Automation Lab at MIT and former Navy fighter pilot who has been researching how to make complex automated systems people friendly (Extra points if you noticed the acronym for the lab is HAL).

Machines are capable of great things, but really are only as good as their operators.

That's where Dr. Cummings and her iPhones come in.


Her research focuses on looking at ways humans control machines and how to design control systems that people can intuitively "get." Because people interact with machines on a daily basis in countless ways, this research encompasses a lot of ground. One o…

An Astronaut Field Trip

NASA practices for a visit to the planet Mars and other destinations in the deserts of the Southwest.



What's it like to be on an alien planet? According to NASA, it could be pretty similar to a trip to the Grand Canyon.

For many first time visitors to the southwestern United States, the high deserts between the magnificent Grand Canyon and the spires of Monument Valley in northern Arizona seem like an alien world -- and NASA feels the same way.

For the last two weeks, NASA's Desert Research and Technology Studies team -- or Desert RATS -- have tested rovers and equipment in the Arizona high country to prepare for the day when astronauts set foot on Mars and beyond.

If space travelers wanted to pick the best landing spot to explore and study the Earth, they would very likely consider northern Arizona, said David Portree of the United States Geological Survey in Flagstaff, Ariz. "There are so many geologic processes at work here in one relatively small area."

The Desert RAT…

Cereal And Saturday Morning Physics

A well-known effect in breakfast cereal helps scientists understand the universe.



Have you ever noticed how the last bits of cereal in the bowl always seem to cling to one another, making it easy to spoon up the remaining stragglers? Physicists have -- and they've given it a name: the "Cheerios effect".

But this effect isn't exclusive to breakfast cereals. It also reveals itself in the way particles move in the air, pollen floats on the surface of water and galaxies cluster throughout the universe.

"If you put Cheerios in a bowl, they aggregate," said Arshad Kudrolli of Clark University in Worcester, Mass, who wrote a paper on the effect for the journal Physical Review Letters. "Or if you look at foam floating on a beer, you get clumps. That's because of surface tension."

Molecules in a fluid have a mutual attraction for each other and the effect creates surface tension -- a naturally resistant force that repels back against anything that pushes o…

Construction underway at ITER

They say fusion is 50 years away. There were those who also said it was 50 years away two decades ago.

Either way, this week marks a significant date in whatever history fusion energy might have. Digging has begun at the ITER (thermonuclear was a bad word, so there's no longer an acronym) site in the south of France for the facility's Tokamak building. A tokomak is a torus shaped magnetic confinement device which is necessary to withstand the temperatures associated with fusion that are so high, solid materials can't hold them. As such, the building represents the future core of ITER.

The construction start comes after decades of research, bureaucracy, politics infused debates and massive cost increases. In fact, the estimated cost has already tripled. Yet, a contract agreement was reached in May of this year that paved the way for digging to finally begin - 25 years after efforts towards an international thermonuclear fusion reactor were first crafted.

From Fusion for E…

Stanford and Berkeley teams create 'electric skin'

For an amputee, the body may continue feeling a phantom limb for long after the original is gone. Every arm or leg movement can carry the imaginary weight of a lost appendage, regardless of the presence of a prosthetic.

Yesterday, researchers from two groups in California published discoveries in the journal Nature Materials that should be well received by those with prosthetics. The two teams have each separately made significant advances in the ability to mimic human skin. Appropriately, the materials are being called "electric skin."

The thin, flexible pressure sensing surfaces both have similar aims, yet use quite distinct approaches. Zhenan Bao, an associate professor of chemistry at Stanford University, and her team used organic electronics – with an elastic polymer called polydimethylsiloxane (PDMS) – to make their electric skin 1,000 times more sensitive than human skin.

From Nature News:

"Bao took a piece of PDMS measuring six centimetres square with pyramid-shaped…

Astronomy photographer of the year

An american named Tom Lowe has nabbed the Royal Observatory's prize for astronomy photographer of the year with this stunning image of an ancient Bristlecone pine with the cosmos as a back drop. The contest was broken into three categories for individual images and a prize was given for Earth and Space (which Lowe also won), Deep Space and Our Solar System. Another prize was also awarded for young astronomy photographer of the year.

Image description from the contest website:

The gnarled branches of an ancient tree align with a view of our Milky Way galaxy. The Milky Way is a flat, disc-like structure of stars, gas and dust measuring more than 100,000 light years across. Our Sun lies within the disc, about two-thirds of the way out from the centre, so we see the Milky Way as a bright band encircling the sky. This view is looking towards the centre of our galaxy, 26,000 light years away, where dark clouds of dust blot out the light of more distant stars. What appears to be an artiļ¬ci…

Binge eating black holes eventually commit suicide

Death is a fact of life; even for galaxies.



It can happen when massive galaxies collide, or it can be predetermined by the conditions the galaxies formed under. But new observations published by the journal Astronomy and Astrophysics show that black holes at the centers of galaxies can strip precious star forming material from the surrounding area and hurl it out into the blackness of space, eventually robbing the galaxy of what it needs to produce new stars.

From the paper:
"The depletion of gas resulting from quasar driven outflows should eventually stop star formation across the host galaxy and lead to 'suicide' by starvation." In the research, which was released last month, astronomers from France and Italy used the Plateau de Bure Interferometer in the French Alps to observe a distant galactic center expel as much as 700 solar masses of material from the galaxy per year.

It recent years, observations have shown that supermassive black holes exist at the center of…

Tractor beams get real

WASHINGTON (ISNS) -- Tractor beams, energy rays that can move objects, are a science fiction mainstay. But now they are becoming a reality -- at least for moving very tiny objects.

Researchers from the Australian National University have announced that they have built a device that can move small particles a meter and a half using only the power of light.

Physicists have been able to manipulate tiny particles over miniscule distances by using lasers for years. Optical tweezers that can move particles a few millimeters are common.

Andrei Rode, a researcher involved with the project, said that existing optical tweezers are able to move particles the size of a bacterium a few millimeters in a liquid. Their new technique can move objects one hundred times that size over a distance of a meter or more.

The device works by shining a hollow laser beam around tiny glass particles. The air surrounding the particle heats up, while the dark center of the beam stays cool. When the particle starts to d…

How not to: The Fire Tornado

You should absolutely, under no circumstances, attempt to recreate the following; but if you were to, here's what you would need and what it would look like.



In the last two weeks, both water and fire tornadoes have been widely covered by the media. First there was the dramatic shots from Japan of a so-called "waterspout," then there was the unbelievable footage of this fire tornado in Brazil, followed immediately by this one from Hawaii. And as any good physicists would have, we immediately thought 'I want to do that!'

Of course, APS requires me to tell you not to try this at home. So, here's how you would do this, if you were to find yourself attempting to do it, which you should absolutely under no circumstances try to do.

First, you should not acquire a bottle of lighter fluid, Play-Doh, a fire extinguisher, a few small pieces of sponge, a metal cup, a lazy Susan and a large metal screen. But if you did have all of those in the same place, certainly do not …

Taking The Temperature Of A Dinosaur

Rare isotopes preserved in fossil teeth could serve as an ancient thermometer.


Tyrannosaurus rex is often portrayed as a cold-blooded killer, but whether the Cretaceous-era dinosaur actually had a slow, reptilian-like metabolism or a faster, more bird-like metabolism is still a mystery.

Now a new technique using rare isotopes preserved in tooth enamel is proving to be a reliable way of determining body temperatures of recently extinct animals like woolly mammoths and researchers are hoping the method will work on even older fossils, including dinosaurs.

A team of researchers led by Robert Eagle, a biologist at the California Institute of Technology in Pasadena, California, found that rare, heavy isotopes of carbon-13 and oxygen-18 clump together differently depending on temperature.

"It's basic thermodynamics: At warmer temperatures, you get a more random distribution of these isotopes with less clumping," Eagle said. "As temperature decreases things slow down and you b…

Fermilab to continue hunt for the Higgs

Yesterday an advisory panel at Fermilab doubled down on the center's Tevatron once again, giving the aging accelerator one last push to find the elusive Higgs Boson in the race with CERN. The panel is recommending that the instrument receive continued funding of $150-million, extending its operations through 2014. The Tevatron is currently scheduled to end operations after 2011.

The information came on the heels of protests at CERN last week over the half-billion dollar budget cut imposed on that facility by European governments. CERN researchers were quick to warn that such a massive cut back might further increase the risk of another breakdown similar to the one that forced the collider to close for 14-months.

The Tevatron has been battling against obsolescence since the Large Hadron Collider first came online, but after the LHC's embarrassing breakdown and a rash of recent discoveries made on the Tevatron, Fermilab is showing they might be able to find the Higgs despite being…

An experiment to test string theory?

Michael Duff, a professor at the Imperial College in London, was at a conference in Tasmania watching a colleague give a talk on quantum entanglement when he realized the equations being presented looked rather similar to a set of equations he had created to describe string theory inside black holes. When he returned to London, he checked the formulas against each other and discovered that not only were they similar, but the equations were in fact the same.

It's now thought that Duff's discovery might allow physicists to predict the behavior of entangled quantum particles with string theory. They're calling it the "stringy black hole/qubit correspondence." If true, this could prove to be the method needed to take string theory from a "framework" to an experimentally testable theory, something its critics have chided it over for two decades.

The research is set to be published tomorrow in the journal Physical Review Letters and does not itself confirm stri…