TED Ed Video: The Higgs Field explained - Don Lincoln

One of the most significant scientific discoveries of the early 21st century is surely the Higgs boson, but the boson and the Higgs Field that allows for that magic particle are extremely difficult to grasp.

Fermilab's Don Lincoln outlines an analogy (originally conceived by David Miller) that all of us can appreciate, starring a large dinner party, a raucous group of physicists, and Peter Higgs himself.

Lesson by Don Lincoln, animation by Powerhouse Animation Studios Inc.

Other informative animated videos are available here

Ultracold Big Bang Experiment Simulates Evolution of Early Universe

Scientists created this detailed, all-sky picture of the infant universe from nine years of data from the orbiting Wilkinson Microwave Anisotropy Probe. 

The image reveals 13.77 billion year old temperature fluctuations—shown as color differences—that correspond to the seeds that grew to become the galaxies. 

Physicists now are using clouds of ultracold atoms in a vacuum chamber to simulate the growth of structure in the early universe. 

Credit: NASA/WMAP Science Team

Physicists have reproduced a pattern resembling the cosmic microwave background radiation in a laboratory simulation of the big bang, using ultracold cesium atoms in a vacuum chamber at the University of Chicago.

"This is the first time an experiment like this has simulated the evolution of structure in the early universe," said Cheng Chin, professor in physics.

Cheng Chin

Chin and his associates reported their feat in the Aug. 1 edition of Science Express, and it will appear soon in the print edition of Science.

Chin pursued the project with lead author Chen-Lung Hung, PhD'11, now at the California Institute of Technology, and Victor Gurarie of the University of Colorado, Boulder.

Their goal was to harness ultracold atoms for simulations of the big bang to better understand how structure evolved in the infant universe.

The cosmic microwave background is the echo of the big bang. Extensive measurements of the CMB have come from the orbiting Cosmic Background Explorer in the 1990s, and later by the Wilkinson Microwave Anisotropy Probe and various ground-based observatories, including the UChicago-led South Pole Telescope collaboration.

These tools have provided cosmologists with a snapshot of how the universe appeared approximately 380,000 years following the Big Bang, which marked the beginning of the universe.

It turns out that under certain conditions, a cloud of atoms chilled to a billionth of a degree above absolute zero (-459.67 degrees Fahrenheit) in a vacuum chamber displays phenomena similar to those that unfolded following the big bang, Hung said.

"At this ultracold temperature, atoms get excited collectively. They act as if they are sound waves in air," he said.

The dense package of matter and radiation that existed in the very early universe generated similar sound-wave excitations, as revealed by COBE, WMAP and the other experiments.

The synchronized generation of sound waves correlates with cosmologists' speculations about inflation in the early universe.

"Inflation set out the initial conditions for the early universe to create similar sound waves in the cosmic fluid formed by matter and radiation," Hung said.

Journal Reference:
C.-L. Hung, V. Gurarie, C. Chin. From Cosmology to Cold Atoms: Observation of Sakharov Oscillations in a Quenched Atomic Superfluid. Science, 2013; DOI: 10.1126/science.1237557

HD 189733b: A Giant Blue Alien Planet where it Rains Molten Glass

This illustration shows HD 189733b, a huge gas giant that orbits very close to its host star HD 189733. 

The planet's atmosphere is scorching with a temperature of over 1000 degrees Celsius, and it rains glass, sideways, in howling 7000 kilometer-per-hour winds.

Credit: NASA, ESA, M. Kornmesser

There's a "blue marble" alien planet just 63 light-years from Earth, but the world is anything but friendly to life.

Researchers say the blue colour in the atmosphere likely comes from a rain of molten glass.

This super-hot glass rain is just one consequence of the close proximity between the gas giant alien planet HD189733b and its sun, which causes daytime temperatures to soar as high as 1,700 degrees Fahrenheit (930 degrees Celsius), scientists said.

A fresh set of observations of the planet in X-rays also suggest HD189733b has an outer atmosphere that is far larger than expected.

These surprise finds are all signals that so-called hot Jupiter alien planets are worthy of study on their own, even though they are hostile planets to life, researchers said.



Hot Jupiters are large, roughly Jupiter-sized planets that become very hot by circling tight around their stars.

These worlds have been described as planetary daredevils because they orbit so close to their parent stars that they risk being consumed.

Often, one side of the planet is tidally locked to the star, exposing that side to scorching hot temperatures, while leaving the other side permanently turned away.

Hot Jupiters are easy to spot from a distance because as they pass in front of a star, their disc blots out a large portion of the star's light; HD189733b causes a three per cent drop in its star's light, for example.

The planets' gravitational pull often causes their parent stars to wobble, too.

While common in the universe, however, Hot Jupiters are totally different than what denizens of Earth's solar system encounter.

In our case, small, rocky planets orbit close to the star and the gas giants are much farther out.

The latest observations of HD189733b are challenging some theories of planetary formation and are just one of the reasons Hot Jupiters are earning more attention from astronomers these days.

"At first considered to be the 'chaff' researchers would have to wade through to get to the fainter Earth-like worlds, hot Jupiters are now attracting their own attention," NASA scientists wrote in a recent Science@NASA post.

ISS Astronauts Take Time Off for US Labour Day Holiday

Five of the six Expedition 36 crew members are pictured in the International Space Station's Kibo laboratory during a daily planning conference. 

Pictured from bottom left are European Space Agency astronaut Luca Parmitano, NASA astronaut Chris Cassidy, both flight engineers; Russian cosmonaut Pavel Vinogradov, commander; NASA astronaut Karen Nyberg and Russian cosmonaut Fyodor Yurchikhin, both flight engineers. 

Credit: NASA

Americans across the United States will pause to celebrate the Labor Day holiday on Monday (Sept. 2), even space travelers soaring high above Earth aboard the International Space Station.

There are two American astronauts — NASA's Karen Nyberg and Chris Cassidy — currently serving on the space station's six-person crew, and they are expecting a light work day Monday, NASA officials said.

While station astronauts typically take a break from their usual duties on holidays, they still may need to do a little work.

Nyberg and European Space Agency (ESA) astronaut Luca Parmitano might take part in a quick training session to prepare for the arrival of an unmanned cargo-carrying Cygnus spacecraft, NASA spokesman Josh Byerly told reporters.

The Cygnus capsule is scheduled to launch from NASA's Wallops Flight Facility on Wallops Island, Va., atop an Antares rocket on Sept. 17.

It will mark the first Cygnus test flight to International Space Station.

The unmanned cargo ship was built by the commercial spaceflight company Orbital Sciences Corp.

But aside from Cygnus training, Nyberg and the rest of the station's Expedition 36 crew will likely have the chance to chat with their loved ones in honor of the U.S. holiday.

Space station residents can call their families whenever they have time and they can send emails and video link with the ground.

This year's Labor Day in space should be more subdued than last year's holiday. In 2012, astronauts on the space station were prepping for an extra spacewalk after a sticky bolt prevented NASA astronaut Sunita Williams and Japanese (JAXA) spaceflyer Akihiko Hoshide from replacing a faulty piece of hardware on the outside of the station.

The station is about the size of a five bedroom house has the wingspan of a football field. Construction of the station began in 1998 and it has been continuously staffed with crews of spaceflyers since 2000.

NASA Chandra: Astronomers discover why SMBHs consume less material

A composite image of the region around Sagittarius A* (Sgr A*), the supermassive black hole in the center of the Milky Way. 

X-ray emission from NASA's Chandra X-ray Observatory is shown in blue, and infrared emission from the Hubble Space Telescope is shown in purple and yellow. 

The inset shows a close-up view of Sgr A* in X-rays only, covering a region half a light year wide.

The diffuse emission is from hot gas captured by the black hole and being pulled inwards. 

Less than 1% of this material reaches the black hole's event horizon, or point of no return, because much of it is ejected. 

Credit: X-ray: NASA/UMass/Q.D. Wang et al.; IR: NASA/STScI

Using NASA's super-sensitive Chandra X-ray space telescope, a team of astronomers led by Q. Daniel Wang at the University of Massachusetts Amherst has solved a long-standing mystery about why most super massive black holes (SMBH) at the centers of galaxies have such a low accretion rate—that is, they swallow very little of the cosmic gases available and instead act as if they are on a severe diet.

"In principle, super massive black holes suck in everything," Wang says, "but we found this is not correct."

Astronomers once thought SMBHs with their intense gravitational pull indiscriminately devoured all sorts of stars, dust and other matter in epic amounts.

But in recent years, using X-ray emissions as a measure of heat given off by powerful gravitational forces, they unexpectedly found that most SMBH accrete matter at very low levels.

In fact, SMBHs' signature X-ray emissions, which come from an area much larger than the black holes themselves, are often so surprisingly faint that the objects are difficult to distinguish from their galaxy centers.

"There has been a big mystery about why most of these black hole signals are so faint," says Wang, an expert in deep space X-ray analysis.

Now, taking advantage of very long observation times with the Chandra instrument and their detailed knowledge of the nearest SMBH, Sagittarius A* (Sgt A*), about 26,000 light years away at the center of our own Milky Way galaxy, he and an international team of astronomers tested the leading accretion models.

For the first time, they were able to pinpoint and discriminate among X-ray sources near Sgt A* and identify exactly what the SMBH is feeding on. The advance is described in the current issue of Science.

To explain the faint X-ray signals, some astronomers had theorized that emissions from regions around SMBH had nothing to do with the black hole itself but rather with concentrations of low-mass stars associated with SMBHs.

Wang adds, "There are also a huge number of young, massive stars as well as low-mass stars near these SMBHs, so it's very crowded in the downtown area of the galaxy. Hard to tell what was going on."

This artist's illustration shows the environment around Sgr A*, the supermassive black hole found some 26,000 light years away at the center of our Galaxy. 

The red disk depicts hot gas that has been captured by the black hole and is being pulled inwards. 

The source of the hot gas is young, massive stars, shown in blue, orbiting around Sgr A*. 

The illustration also shows a large amount of material being thrown outwards, a key factor in explaining why there is so little radiation from material near black holes. 

Credit: NASA/CXC/M. Weiss

"The massive stars have extremely high winds associated with them and the winds are colliding and swirling at very high speeds, which make the gases in this environment very hot. We found that first, the SMBH has difficulty in accreting such gases.

"Second, the gases are too hot for the black hole to swallow. Instead it rejects about 99 percent of this super hot material, only letting a small amount in. This makes sense because the hotter the gases, the more difficult it is for the black hole to pull them in."

A diet of cooler gases would accrete in a more orderly fashion, but the SMBH's sphere of influence and its ability to accrete or draw in new material both decrease with increasing gas temperatures, he points out.

Wang, who did this NASA-supported work while on four-month sabbatical as a Raymond and Beverly Sackler Distinguished Visiting astronomer at the University of Cambridge, U.K., points out, "Now we have physically resolved it and for the first time we've made the connection observationally between the massive stars moving around black holes and the X-ray emitting material."

"We can definitively rule out that these X-rays are coming from a concentration of low-mass stars. We don't see the expected energy signature predicted by that scenario."

The astronomers not only detected the X-ray source, he adds, but for the first time can describe its shape, which is elongated.

"Now we know what kind of material is getting into the black hole, though exactly how it happens is still another question."

More information: "Dissecting X-Ray–Emitting Gas Around the Center of Our Galaxy," by Q.D. Wang et al Science, 2013. On Arxiv: arxiv.org/abs/1307.5845

NASA Solar Dynamics Observatory (SDO): Untangling motion inside the Sun

Observations by the Helioseismic and Magnetic Imager on NASA's Solar Dynamics Observatory show a two-level system of circulation inside the sun. 

Such circulation is connected to the flip of the sun's north and south magnetic poles that occurs approximately every 11 years. 

Credit: Stanford University

Using an instrument on NASA's Solar Dynamics Observatory, called the Helioseismic and Magnetic Imager (HMI), scientists have overturned previous notions of how the sun's writhing insides move from equator to pole and back again, a key part of understanding how the dynamo works.

Modeling this system also lies at the heart of improving predictions of the intensity of the next solar cycle.

Using SDO, scientists see a performance of explosions and fountains on the solar surface. Shots of solar material leap into the air.

Dark blemishes called sunspots grow, combine and disappear as they travel across the sun's face. Bright loops of charged particles – captured by magnetic fields dancing around the sun – hover in the atmosphere.

This dynamic display is all powered by a complex, ever-changing magnetic current inside the sun known as the dynamo.

This magnetic system flips approximately every 11 years, with magnetic north and magnetic south switching poles.

This process is an integral part of the sun's progression toward a pinnacle of solar activity, known as solar maximum.

The team's recent results show that, instead of a simple cycle of flow moving toward the poles near the sun's surface and then back to the equator, the material inside the sun shows a double layer of circulation, with two such cycles on top of each other.

The results appear online in the Astrophysical Journal Letters on Aug. 27, 2013.

"For decades people have known that the solar cycle depends on the poleward flow or material, changing the magnetic fields from one cycle to the next," said Philip Scherrer, principal investigator for HMI at Stanford University in Stanford, Calif.

"We mapped out what we believed to be the flow pattern in the 1990s, but the results didn't quite make sense."

Since the mid-1990s researchers have been observing movement inside the sun using a technique called helioseismology.

The technique makes use of the fact that waves course across the sun, back and forth, oscillating with an approximately five minute period.

Such waves are similar to the seismic waves that spread out under the ground during an earthquake. By monitoring the oscillations seen at the surface of the sun, scientists can gather information about the material through which the waves traveled, including what the material is made of and how fast and in what direction it is moving.

More information: iopscience.iop.org/2041-8205/774/2/L29/pdf/2041-8205_774_2_L29.pdf

NASA Cassini: Data from Titan indicate a rigid, weathered ice shell

A rigid ice shell resists the upward pressure of a buoyant root, whose low density produces a negative gravity anomaly. 

Upward deflection of the ice shell creates positive topography, but surface weathering keeps that topography small. 

Credit: Doug Hemingway

An analysis of gravity and topography data from Saturn's largest moon, Titan, has revealed unexpected features of the moon's outer ice shell.

The best explanation for the findings, the authors said, is that Titan's ice shell is rigid and that relatively small topographic features on the surface are associated with large roots extending into the underlying ocean.

The study is published in the August 29 issue of the journal Nature.

Led by planetary scientists Douglas Hemingway and Francis Nimmo at the University of California, Santa Cruz, the study used new data from NASA's Cassini spacecraft.

The researchers were surprised to find a negative correlation between the gravity and topography signals on Titan.

"Normally, if you fly over a mountain, you expect to see an increase in gravity due to the extra mass of the mountain. On Titan, when you fly over a mountain the gravity gets lower. That's a very odd observation," said Nimmo, a professor of Earth and planetary sciences at UC Santa Cruz.

To explain that observation, the researchers developed a model in which each bump in the topography on the surface of Titan is offset by a deeper "root" big enough to overwhelm the gravitational effect of the bump on the surface.

The root is like an iceberg extending below the ice shell into the ocean underneath it. "Because ice is lower density than water, you get less gravity when you have a big chunk of ice there than when you have water," Nimmo explained.

An iceberg floating in water is in equilibrium, its buoyancy balancing out its weight. In this model of Titan, however, the roots extending below the ice sheet are so much bigger than the bumps on the surface that their buoyancy is pushing them up against the ice sheet.

"It's like a big beach ball under the ice sheet pushing up on it, and the only way to keep it submerged is if the ice sheet is strong," said Hemingway, a doctoral candidate in planetary geophysics at UCSC and lead author of the paper.

"If large roots are the reason for the negative correlation, it means that Titan's ice shell must have a very thick rigid layer."

The researchers calculated that, in this model, Titan's ice shell would have to have a rigid layer at least 40 kilometers thick.

They also found that hundreds of meters of surface erosion and deposition are needed to account for the observed imbalance between the large roots and small surface topography.

The results from their model are similar to estimates obtained by geo-morphologists studying the erosion of impact craters and other features on Titan.

These findings have several implications. For example, a thick rigid ice shell makes it very difficult to produce ice volcanoes, which some have proposed to explain certain features seen on the surface.

More information: Nature paper: dx.doi.org/10.1038/nature12400