Will Antimatter Obey Gravity’s Pull?

What goes up must always come down, right? Well, the European Laboratory for Particle Physics (CERN) wants to test if that principle applies to antimatter.

Antimatter, most simply speaking, is a mirror image of matter. The concept behind it is that the particles that make up matter have an opposite counterpart, antiparticles. For example, if you consider that electrons are negatively charged, an antielectron would be positively charged.

This sounds like science fiction, but as NASA says, it is “real stuff.” In past experiments, CERN’s particle accelerator has created antiprotons, positrons and even antihydrogen. Properly harnessed, antimatter could be used for applications ranging from rocketry to medicine, NASA added. But we’ll need to figure out its nature first.

The experiment CERN described snares antihydrogen atoms in a powerful magnetic field (inside a container) for several minutes. As the researchers let these atoms go, they can watch on which walls the atoms crash into. The experiment is called ALPHA, for Antihydrogen Laser Physics Apparatus.

While researchers weren’t originally looking to learn more about gravity, the team working on the experiments came to realize their data “might be sensitive to gravitational effects,” CERN stated.

To be sure, these atoms would have a bit of energy when they are released, so one wouldn’t expect them to hit the ground right away. But what the scientists are doing now are figuring out, with reference to how the antihydrogen atoms moved, what the limit might be on “anomalous gravitational effects.”

The scientists have made new use of the ALPHA data they collected in 2010 and 2011 for other purposes, and now plan to do more experiments in 2014 with gravity specifically in mind.

So far, they’ve been able to begin constraining the gravitational to inertial mass ratio (the particle’s reaction to gravity), but it will take further work to learn more about how gravity affects these particles more generally.

“Based on our data, we can exclude the possibility that the gravitiational mass of antihydrogen is more than 110 times its inertial mass, or that it falls upwards with a gravitational mass more than 65 times its inertial mass,” CERN said on its website.

Already, though, the scientists are starting to talk about what could happen if antimatter behaves differently than matter in the face of gravity.

If antimatter fell up, stated Joel Fajans, an ALPHA physicist at the University of California, Berkeley, this could mean that gravity does not universally affect all types of particles.

“In the unlikely event that antimatter falls upwards, we would have to revise our view of the way the universe works,” he said. “We’ve taken the first steps toward a direct experimental test of questions that physicists and non-physicists have been wondering about for more than 50 years.”

image; What matter and antimatter might look like annihilating one another. credit: NASA/CXC/M. Weiss

What is Dark Energy?

A mysterious quantity known as dark energy makes up nearly three-fourths of the universe, yet scientists are unsure not only what it is but how it operates. How, then, can they know this strange source exists?

The expanding universe
In 1929, American astronomer Edwin Hubble studied exploding stars known as supernovae to determine that the universe is expanding. Since then, scientists have sought to determine just how fast. It seemed obvious that gravity, the force which draws everything together, would put the brakes on the spreading cosmos, so the question many asked was, just how much was the expansion slowing?

In the 1990s, two independent teams of astrophysicists again turned their eyes to distant supernovae to calculate the deceleration. To their surprise, they found that the expansion of the universe wasn’t slowing down, it was speeding up! Something must be counteracting gravity, something which the scientists dubbed “dark energy.”

Calculating the energy needed to overcome gravity, scientists determined that dark energy makes up roughly 68 percent of the universe. Dark matter makes up another 27 percent, leaving the “normal” matter that we are familiar with to make up less than 5 percent of the cosmos around us.

Quintessence
Knowing how dark energy affects the spreading universe only tells scientists so much. The properties of the unknown quantity are still up for grabs. Recent observations have indicated that dark energy has behaved constantly over the universe’s history, which provides some insight into the unseen material.

One possible solution for dark energy is that the universe is filled with a changing energy field, known as “quintessence.” Another is that scientists do not correctly understand how gravity works.

The leading theory, however, considers dark energy a property of space. Albert Einstein was the first to understand that space was not simply empty. He also understood that more space could continue to come into existence. In his theory of general relativity, Einstein included a cosmological constant to account for the stationary universe scientists thought existed. After Hubble announced the expanding universe, Einstein called his constant his “biggest blunder.”

But Einstein’s blunder may be the best fit for dark energy. Predicting that empty space can have its own energy, the constant indicates that as more space emerges, more energy would be added to the universe, increasing its expansion.

Although the cosmological constant matches up with observations, scientists still aren’t certain just why it fits.

Dark energy versus dark matter
Dark energy makes up most of the universe, but dark matter also covers a sizeable chunk. Comprising nearly 27 percent of the universe, and 80 percent of the matter, dark matter also plays a dominant role.

Like dark energy, dark matter continues to confound scientists. While dark energy is a force that accounts for the expanding universe, dark matter explains how groups of objects function together.

In the 1950s, scientists studying other galaxies expected gravity to cause the centers to rotate faster than the outer edges, based on the distribution of the objects inside of them. To their surprise, both regions rotated at the same rate, indicating that the spiral galaxies contained significantly more mass than they appeared to. Studies of gas inside elliptical galaxies and of clusters of galaxies revealed that this hidden matter was spread throughout the universe.

Scientists have a number of potential candidates for dark matter, ranging to incredibly dim objects to strange particles. But whatever the source of both dark matter and dark energy, it is clear that the universe is affected by things that scientists can’t conventionally observe.

image 1: The galaxy cluster Abell 1689 is famous for the way it bends light in a phenomenon called gravitational lensing. A new study of the cluster is revealing secrets about how dark energy shapes the universe.
credit: NASA, ESA, E. Jullo (JPL/LAM), P. Natarajan (Yale) and J-P. Kneib (LAM)

image 2: These galaxy clusters are representative of more than 80 clusters that were used to track the effects of dark energy on these massive objects over time. Most of the matter in galaxy clusters is in the form of very hot gas, which emits copious amounts of X-rays.
credit: NASA/CXC/SAO/A.Vikhlinin et al.

What is Dark Matter?

Roughly 80 percent of the mass of the universe is made up of material that scientists cannot directly observe. Known as dark matter, this bizarre ingredient does not emit light or energy. So why do scientists think it dominates?

Studies of other galaxies in the 1950s first indicated that the universe contained more matter than seen by the naked eye. Support for dark matter has grown, and although no solid direct evidence of dark matter has been detected, there have been strong possibilities in recent years.

The familiar material of the universe, known as baryonic matter, is composed of protons, neutrons and electrons. Dark matter may be made of baryonic or non-baryonic matter. To hold the elements of the universe together, dark matter must make up approximately 80 percent of its matter.

The missing matter could simply be more challenging to detect, made up of regular, baryonic matter. Potential candidates include dim brown dwarfs, white dwarfs and neutrino stars. Supermassive black holes could also be part of the difference. But these hard-to-spot objects would have to play a more dominant role than scientists have observed to make up the missing mass, while other elements suggest that dark matter is more exotic.

Most scientists think that dark matter is composed of non-baryonic matter. The lead candidate, WIMPS (weakly interacting massive particles), have ten to a hundred times the mass of a proton, but their weak interactions with “normal” matter make them difficult to detect. Neutralinos, massive hypothetical particles heavier and slower than neutrinos, are the foremost candidate, though they have yet to be spotted. The smaller neutral axion and the uncharched photinos are also potential placeholders for dark matter.

A third possibility exists — that the laws of gravity that have thus far successfully described the motion of objects within the solar system require revision.

Proving the unseen
If scientists can’t see dark matter, how do they know it exists?

Scientists calculate the mass of large objects in space by studying their motion. Astronomers examining spiral galaxies in the 1950s expected to see material in the center moving faster than on the outer edges. Instead, they found the stars in both locations traveled at the same velocity, indicating the galaxies contained more mass than could be seen. Studies of the gas within elliptical galaxies also indicated a need for more mass than found in visible objects. Clusters of galaxies would fly apart if the only mass they contained were visible to conventional astronomical measurements.

Albert Einstein showed that massive objects in the universe bend and distort light, allowing them to be used as lenses. By studying how light is distorted by galaxy clusters, astronomers have been able to create a map of dark matter in the universe.

All of these methods provide a strong indication that the most of the matter in the universe is something yet unseen.

Dark matter versus dark energy
Although dark matter makes up most of the matter of the universe, it only makes up about a quarter of the composition. The universe is dominated by dark energy.

After the Big Bang, the universe began expanding outward. Scientists once thought that it would eventually run out of the energy, slowing down as gravity pulled the objects inside it together. But studies of distant supernovae revealed that the universe today is expanding faster than it was in the past, not slower, indicating that the expansion is accelerating. This would only be possible if the universe contained enough energy to overcome gravity — dark energy.

image 3: This Hubble Space Telescope composite image shows a ghostly “ring” of dark matter in the galaxy cluster Cl 0024+17.
credit: NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)

image 4: These illustrations, taken from computer simulations, show a swarm of dark matter clumps around our Milky Way galaxy. Image released July 10, 2012.
credit: J. Tumlinson (STScI)

mothernaturenetwork:

Have scientists really detected dark matter?

Researchers believe that an area high in weakly interacting massive particles, or WIMPs, may lead to a dark matter discovery.

pennyfournasa:

Hubble has found the most distant massive star explosion of its kind, one that could help us understand the very fabric of the Universe.

Supernova UDS10Wil, or SN Wilson, seems to have blown up over 10 *billion* years ago, which is why the resulting light from the explosion has taken that long to reach Earth. 

Classified as a special Type la supernovae, Wilson gives astronomers a consistent level of brightness that can be used to measure the expansion of space and also help with deductions about the nature of dark energy.

This discovery will allow astronomers to figure out which of two competing models is correct: 1. The explosion is caused by two white dwarf stars merging or 2. One white dwarf feeds off its partner, a normal star, until it greedily absorbs too much mass and explodes.

Figuring out the trigger for these explosions will also show how quickly the universe enriched itself with heavier elements such as iron, one of the raw materials for building planets and life.

Read more:

http://astronaut.com/incredibly-old-supernova-could-explain-everything/

Live on Wednesday, April 3: NASA Unveiling Alpha Magnetic Spectrometer Discovery

NASA will unveil the first science results from the powerful Alpha Magnetic Spectrometer on the International Space Station in a press conference on Wednesday, April 3, at 1:30 p.m. EDT (1830 GMT).

The $2 billion AMS was launched to the space station in May 2011 during the final flight of NASA’s space shuttle Endeavour. Scientists using the detector hope that the spectrometer will help shed some light on the nature of antimatter, dark matter and other space mysteries.

Several NASA scientists and administrators will take part in tomorrow’s briefing. They include:

+ William Gerstenmaier, NASA associate administrator for Human Exploration and Operations
+ Samuel Ting (participating by video link), AMS principal investigator, Massachusetts Institute of Technology
+ Michael Salamon, U.S. Department of Energy Office of Science program manager for AMS
+ Mark Sistilli, NASA AMS program manager

The Alpha Magnetic Spectrometer is an international project tested and operated by 56 institutes from 16 different countries. The bus-sized detector is managed by NASA’s Johnson Space Center in Houston.

Watch: The Alpha Magnetic Spectrometer | Sifting Through The Cosmic Sands For Dark Matter

abcstarstuff:

This week’s show…..

Bubbles could solve the Dark Matter mystery
Monster outflows of charged particles stretching far above and below the centre of the Milky Way, could contain tantalising evidence of mysterious dark matter. Although it constitutes 84 per cent of all matter in the cosmos, dark matter has never been seen, only inferred from its effects on the visible universe.

Scientists spot birth of giant planet
Astronomers have captured the first direct image of a brand new planet being born in a distant solar system. The embryonic new world, which will eventually become a gas giant like Jupiter, is orbiting a young star 335 light years away.

Two comets streak across southern skies
The second of three comets bright enough to see with the naked eye this year, has just made its closest approach to Earth. Comet Pan-STARRS together with Comet Lemmon can both be seen at the same time in the western sky just after sunset.

Catching a Dragon by the tail
Mission managers breathe a sigh of relief as SpaceX’s Dragon capsule successfully docks with the International Space Station after a potentially fatal glitch almost ended the flight. SpaceX is the first private company to fly supplies to the orbiting outpost.

Space Station crash
A main computer crash aboard the International Space Station puts the orbiting outpost in a communications blackout with Earth for three hours.

Progress launch
The Rapid Rendezvous flight profile brings Russian Progress cargo ship to the space station only six hours after liftoff.

Arianespace Soyuz launch
Europe and Russia team up to launch a fleet of new communications satellites.

New Ariane 5 heavy lift record
The European Space Agency’s Ariane 5 heavy lift launcher sets a new record for carrying a payload to geostationary orbit.

Mars rover crashes
NASA’s Mars rover Curiosity has suffered a computer glitch, forcing mission control to switch to a backup system.

Humans to Mars by 2018
A private company wants to send humans to Mars in just five years time. The world’s first space tourist Dennis Tito is behind the project which would see a couple preferably married undertake the 501 day mission .

StarStuff is broadcast weekly on the best ABC Radio stations in Australia,
On the National Science Foundation’s Science 360 Radio across the United States.
As audio on demand and as a free podcast at….
http://www.abc.net.au/science/starstuff

Distance to Milky Way’s Neighbor Galaxy Refined

The distance to one of the Milky Way’s next-door neighbors, a satellite galaxy that orbits its outskirts, has been determined more accurately than ever before, astronomers announced today (March 6).

The achievement could help scientists calibrate other cosmic distances, which are essential for understanding how quickly the universe is expanding and solving the mystery of dark energy. Dark energy is the name given to whatever is tugging the universe apart and causing its expansion to accelerate.

According to the new measurement, the nearby dwarf galaxy called the Large Magellanic Cloud lies 163,000 light-years away.

“I am very excited because astronomers have been trying for a hundred years to accurately measure the distance to the Large Magellanic Cloud, and it has proved to be extremely difficult,” Wolfgang Gieren, an astronomer at Chile’s Universidad de Concepción, Chile, said in a statement. “Now we have solved this problem by demonstrably having a result accurate to 2 percent.”

The finding was nearly a decade in the making, and required repeated precise measurements of rare pairs of binary stars that are oriented so that they eclipse each other as they orbit, from the perspective of Earth.

Using telescopes at the European Southern Observatory’s La Silla Observatory and the Las Campanas Observatory, both in Chile, Gieren and his colleagues identified eight pairs of eclipsing binaries in the Large Magellanic Cloud.

By tracking the changes in the star pairs’ brightness when one star passed in front of the other, and vice versa, as well as measuring the stars’ orbital speeds, the scientists could deduce the stars’ sizes and masses, as well as details regarding their orbits. With this information, combined with measurements of the stars’ total brightness and colors, their precise distances could be determined.

These measurements improve on previous estimates of the Large Magellanic Cloud’s distance, which were all based on methods that had inherent uncertainties.

“Because the LMC is close and contains a significant number of different stellar distance indicators, hundreds of distance measurements using it have been recorded over the years,” said team member Ian Thompson of the Carnegie Institution for Science in Washington, D.C. “Unfortunately, nearly all the determinations have systemic errors, with each method carrying its own uncertainties.”

Pinning down the distance of the LMC, in turn, allows scientists to refine their estimates of other, farther cosmic distances. That’s because the measurements of close distances are used to calibrate measurements of far-off objects. The new findings should help astronomers narrow down the Hubble Constant, which denotes the rate of the universe’s expansion, and is integral for the study of dark energy.

“We are working to improve our method still further and hope to have a 1 percent LMC distance in a very few years from now,” said researcher Dariusz Graczyk . “This has far-reaching consequences not only for cosmology, but for many fields of astrophysics.”

The findings are detailed in the March 8 issue of the journal Nature.

image: This illustration shows an eclipsing binary star system. As the two stars orbit each other they pass in front of one another and their combined brightness, seen from a distance, decreases. By studying how the light changes, and other properties of the system, astronomers can measure the distances to eclipsing binaries very accurately.
CREDIT: ESO/L. Calçada

Watch: Eclipsing Stars’ Light Shift Quantifies Distance To Earth

christinetheastrophysicist:

Can Dark Energy be Explained by Symmetrons?

A field that permeates the universe and gives rise to a new force, or “fifth force,” between massive objects may be a candidate for dark energy and an explanation for why the expansion of the universe is accelerating. This field, called the symmetron field, is so named because it has a symmetry in regions of high density, while in regions of low density, such as a vacuum, the symmetry is broken and the field mediates the new force.

Read More.

Has Dark Matter Finally Been Found? Big News Coming Soon

Big news in the search for dark matter may be coming in about two weeks, the leader of a space-based particle physics experiment said today (Feb. 17) here at the annual meeting of the American Association for the Advancement of Science.

That’s when the first paper of results from the Alpha Magnetic Spectrometer, a particle collector mounted on the outside of the International Space Station, will be submitted to a scientific journal, said MIT physicist Samuel Ting, AMS principal investigator.

Though Ting was coy about just what, exactly, the experiment has found, he said the results bear on the mystery of dark matter, the invisible stuff thought to outnumber regular matter in the universe by a factor of about six to one.

“It will not be a minor paper,” Ting said, hinting that the findings were important enough that the scientists rewrote the paper 30 times before they were satisfied with it. Still, he said, it represents a “small step” in figuring out what dark matter is, and perhaps not the final answer.

Some physics theories suggest that dark matter is made of WIMPS (weakly interacting massive particles), a class of particles that are their own antimatter partner particles. When matter and antimatter partners meet, they annihilate each other, so if two WIMPs collided, they would be destroyed, releasing a pair of daughter particles — an electron and its antimatter counterpart, the positron, in the process.

The Alpha Magnetic Spectrometer has the potential to detect the positrons and electrons produced by dark matter annihilations in the Milky Way. The $2 billion machine was installed on the International Space Station in May 2011, and so far, it has detected 25 billion particle events, including about 8 billion electrons and positrons. This first science paper will report how many of each were found, and what their energies are, Ting said.

If the experiment detected an abundance of positrons peaking at a certain energy, that could indicate a detection of dark matter, because while electrons are abundant in the universe around us, there are fewer known processes that could give rise to positrons.

“The smoking gun signature is a rise and then a dramatic fall” in the number of positrons with respect to energy, because the positrons produced by dark matter annihilation would have a very specific energy, depending on the mass of the WIMPs making up dark matter, said Michael Turner, a cosmologist at the University of Chicago who is not involved in the AMS project. “That’s the key signature that would arise.”

Another telling sign will be the question of whether positrons appear to be coming from one direction in space, or from all around. If they’re from dark matter, scientists expect them to be spread evenly through space, but if they’re created by some normal astrophysical process, such as a star explosion, then they would originate in a single direction.

“There is a lot of stuff that can mimic dark matter,” said theoretical physicist Lisa Randall of Harvard University, who is also not involved in the project but said she’s eagerly awaiting the AMS results. “In these experiments the question is when do you have antimatter that could be explained by astrophysical sources, and when do you have something that really could be an indication that you have something new?”

Regardless of whether AMS has found dark matter yet, the scientists said they expected the question of dark matter’s origin to become clearer soon. In addition to AMS, other experiments such as the Large Hadron Collider in Switzerland, and underground dark matter detectors buried around the world, could also make a discovery in the near future.

“We believe we’re on the threshold of discovery,” Turner said. “We believe this will be the decade of the WIMP.”

mothernaturenetwork:

Has dark matter finally been found?

A forthcoming paper represents a ‘small step’ in figuring out what dark matter is, and perhaps not the final answer.

cozydark:

Dynamic, Dark Energy in an Accelerating Universe |

The models proposed by the UPV/EHU-University of the Basque Country researcher are contributing towards understanding the nature of dark energy.

It was cosmology that drew Irene Sendra from Valencia to the Basque Country. Cosmology also gave her the chance to collaborate with one of the winners of the 2011 Nobel Prize for Physics on one of the darkest areas of the universe. And dark matter and dark energy, well-known precisely because so little is known about them, are in fact the object of the study by Sendra, a researcher in the Department of Theoretical Physics and History of Science of the UPV/EHU’s Faculty of Science and Technology.

“Observations tell us that about 5% of the universe is made up of ordinary matter; 22% corresponds to dark matter, which we know exists because it interacts gravitationally with ordinary matter; another 73% is dark energy, which is known to be there because otherwise one would not be able to account for the accelerating expansion of the universe,” explains Irene Sendra; “We are trying to find out a bit more about what dark energy is,” she adds.

If dark energy did not exist, the gravitational pull exerted by matter would slow down the expansion of the universe, but observations have concluded that the opposite is the case.Dark energy is what makes the universe expand in an accelerating way, and contributing towards understanding its nature is the basis of the research Sendra has done as part of her PhD thesis entitled: “Cosmology in an accelerating universe: observations and phenomenology.”

The research starts with the hypothesis that dark energy could be dynamic.The most widely accepted model, known as the Lambda-CDM, explains the acceleration of the universe by means of the cosmological constant, whose equation of state would have a value of -1, constant throughout the whole evolution of the universe.However, there are observations which this model cannot account for.”We look for a dynamic, dark energy that would vary over time; we apply various models to the observable data, we play around with small disturbances, and we see whether they adapt better than a constant,” explains Sendra.

Making use of mathematical and statistical tools, the values that the observation proposes for the parameters studied are compared with those proposed by the model.”So,throughmany iterations, we can see which values would take the constants of our model.The equation of state of dark energy is worth practically -1 now, but it appears to have evolved from different values in the past; however, there is still a high percentage of error in determining these values.”According to Sendra’s calculations, these data are consistent with dynamic dark energy, which would vary with the redshift observed in the universe.Results that have yet to be published and obtained in collaboration with Adam Riess, the 2011 Nobel Prize Winner for Physics, go further in that direction. continue reading

astrodidact:

(CNN) — A $10 billion machine that smashes particles together is shutting down this weekend, taking a staycation in its 17-mile tunnel near the French-Swiss border while receiving maintenance and upgrades. The Large Hadron Collider, one of the world’s largest science experiments, will resume operations in 2014 or 2015 at unprecedented energies.

Do you care?

Judging from the many comments that we get at CNN.com about what people perceive as a “waste” of money for scientific exploration, you might not. That may be because what happens at the LHC seems far removed from everyday life, and even farther from the study of stars.

“Everybody is, in some sense, an amateur astronomer. We all look up at the stars and wonder how the universe works,” says Joel Primack, professor of physics and astrophysics at the University of California, Santa Cruz. “People are not amateur particle physicists.”

Our window into outer space is visible and dazzling. We can see spaceships and telescopes launch into the sky, and we can see the images they send back.

Inner space, the fundamental building-blocks of everything on a ridiculously small scale, isn’t visible. A lot of our understanding is based on theory and probability. Even the greatest achievement at the LHC isn’t certain; we can only say that a particle was found resembling a theorized entity called the Higgs boson.

But exploring the very small and the very big and distant are both important for understanding the world in which we live, scientists say, and are necessary for completing the same puzzle.

“The basic story is really that understanding particles and interactions helps us understand the evolution and structure of the whole universe, and hopefully will give us technologies that will allow us to explore it more efficiently and solve energy problems and so forth,” said Joe Incandela, spokesperson for the LHC’s Compact Muon Solenoid experiment, a large particle detector.

What the universe is made of

Over the last few decades, scientists have come to the conclusion that the universe’s composition is only about 5% atoms — in other words, the stuff that we see and know around us. That means the rest is stuff we can’t see. About 71% is something called “dark energy,” and another 24% is “dark matter.”

Research is ongoing to figure out precisely what these “dark” components are, because they do not interact with ordinary matter and have never been directly detected.

But the large-scale structure of the universe depends on dark matter. “Without the dark matter, all the stars would fly away,” said Adam Riess, physicist at Johns Hopkins University and the Space Telescope Science Institute.

Dark energy is thought to be responsible for the accelerating expansion of the universe, and Riess’s Nobel-prize winning work supports this theory.

In principle, these phenomena are everywhere — but how can we find them?

What particle physicists are really looking for

All that space in between star clusters is not empty at all. Particle physicists are hoping to get a better understanding of space time, the fabric of the universe.

There are particles hiding behind this fabric that we don’t normally see, but with enough energy you can draw them into existence, Incandela said. Scientists expect several as-yet-unseen particles to be there because they help fill gaps in the Standard Model of particle physics. The LHC uses high-energy particle collisions to try to find them.

Incandela likens this to being in a boat with fish underneath, which are nibbling at the surface. It takes a lot of energy to pull one out. The Higgs boson, being so hard to pin down, would be like a whale, Incandela said.

One pitfall of this analogy is that you can easily identify real fish, but it’s a lot harder to classify particles that slip in and out of existence in less than a second.

The particle that has made headlines recently is the Higgs boson, aka “God particle” — a term a lot of scientists hate. Nobel Prize-winning physicist Leon Lederman wrote a book with “God Particle” in the title, but reportedly said he’d actually wanted to call it the “Goddamn Particle.”

This particle is a component of something called the Higgs field. Brian Greene, theoretical physicist at Columbia University and “NOVA” host, describes it this way:

“You can think of it as a kind of molasses-like bath that’s invisible, but yet we’re all immersed within it,” he said. “And as particles like electrons try to move through the molasses-like bath, they experience a resistance. And that resistance is what we, in our big everyday world, think of as the mass of the electron.”

Without this “substance,” made up of Higgs particles, the electron would have no mass, and we would not be here at all. It’s not a perfect metaphor, though; we don’t feel particularly sticky.

The collision energy at the LHC went up to 8 TeV (trillion electron volts) in 2012, a record for the amount of energy in particle collisions. After downtime of about two years, it will come back online with 13 TeV.

“It really feels like we’re on the verge of a breakthrough.”
Joel Primack, physicist at UCSC

With higher energies, it may be possible to detect the signature of dark matter, learn more precise properties of the particle that looks like the Higgs, find evidence of extra dimensions and perhaps find out whether gravity itself has a particle.

“If you want to understand the big, you have to understand the small,” Primack said.

Dark matter and energy

Primack proposed an idea for dark matter in 1982 that is still a leading contender: The notion that supersymmetry is responsible for dark matter.

That means that for every particle we know, even the Higgs, there is a partner particle with similar interactions but that is more massive. All these partner particles are unstable except for the lightest one, which can’t decay into anything else. Dark matter would be this lightest particle, called a weakly interacting massive particle, or WIMP.

There are several underground experiments worldwide that are aiming to detect these dark matter “WIMPs,” such as the LUX Dark Matter experiment in the Black Hills of South Dakota, where liquid xenon is stored a mile underground.

Similar experiments include the Xenon 100 experiment at the Gran Sasso Mountain in central Italy. Scientists will go even deeper at the PandaX experiment at the China Jin-Ping Underground Laboratory, located under 1.5 miles of rock.

The principle behind these experiments is that particles hitting the xenon cause the nucleus of the atom to give off a little bit of light. By examining the resulting charge and light produced in this collision, scientists can determine whether dark matter was involved. At least, in theory — so far, no dark matter has been detected that way.

These experiments are happening at the same time that the LHC is colliding particles, and may find evidence of dark matter that way.

“It really feels like we’re on the verge of a breakthrough,” Primack said.

Meanwhile, in space, scientists are looking for the signatures of dark matter and dark energy. Riess and colleagues used the Hubble Space Telescope to measure supernovae that are very far away, showing that dark energy must be responsible for how the universe appears to expand faster and faster. This won them the Nobel Prize in 2011.

The James Webb Telescope, costing about $8 billion, will succeed Hubble. The planned telescope will have a 21-foot diameter mirror, six times as big as Hubble’s. Among other things, this telescope is also looking for evidence of dark matter and dark energy.

“There’s a huge synergy there, in astronomers trying to find the influence of dark matter by mapping stars and galaxies and large structures in the universe, and particle physicists trying to discover the source of that influence of dark matter through subatomic particles here on Earth,” said Jason Kalirai, deputy project scientist for the telescope at the Space Telescope Science Institute.

What technology may come

The question remains: What is this all good for?

There’s the pure satisfaction of having greater knowledge of the universe in which we live.

“It’s just one of the things that distinguishes humanity, that we can actually answer questions that are deep and fundamental, make predictions and do science, and that it actually works,” said Lisa Randall, professor of physics at Harvard and author of “Knocking on Heaven’s Door.”

Consider also that all the technology you know can be traced to pure research, initially perceived as esoteric. Electric lights — and, indeed all of electricity — came from fundamental research in the 19th century.

Computers and transistors arose from the understanding of quantum mechanics in the 1920s and 1930s, Incandela said.

Certainly, Einstein didn’t know that his relativity theories would become pertinent to your smartphone’s GPS. The atomic clocks on satellites must be corrected because, in accordance to Einstein’s predictions, moving objects in space are on a different “time” relative to an observer on Earth.

“Technology usually lags pure science by a large amount of time, and I would say, probably now there’s a good chance we’re further ahead of technology than ever before,” Incandela said.

Even the World Wide Web arose out of a proposal from Sir Timothy Berners-Lee, who was a physicist at CERN in the 1980s. Essentially, the reason we have the Internet that we all know and love is that Berners-Lee wanted to enable better communication among physicists there.

It’s likely, Primack said, that useful things will also come from the searches for dark matter and dark energy, and for other particles that the LHC is hunting. No one knows what the uses will be yet — but then again, no one predicted that the World Wide Web would arise at a particle physics lab, either. CERN is, in fact, the same laboratory that houses the LHC.

Nothing is certain, of course, it is at least possible that doing this pure science could help bring into reality the sorts of technologies that right now seem like science fiction.

“If we’re really going to explore the universe, in terms of actually moving through the universe and having the ability to do space exploration that’s what you see in the movies, so to speak, the ‘Star Trek’ type things, in principle, we’re going to need to understand and have the ability to harness the potential of nature at a level that we don’t have now,” Incandela said.

http://www.cnn.com/2013/02/16/tech/innovation/science-exploration/index.html?hpt=hp_c1

Ten things you probably did’nt know about dark energy

Dark energy is the biggest mystery in the cosmos, pervading the vast emptiness of space for billions of light-years. But if you thought you knew everything there was to know about this strange force, think again.

Discovery Space sat down with Michael Turner, a cosmologist at the University of Chicago, to pin down the 10 biggest things you didn’t know about dark energy.

10. Dark Energy’s Discoverer Didn’t Coin the Term

Who came up with the term? “I did,” Turner said. “That’s because when you find something new and weird, you have to name it. It can’t just be ‘the funny stuff that helps the universe speed up.’”

The term is also used to say that it’s different than dark matter, which is yet another weird constituent of the cosmos, and behaves more like energy than anything else that we know of.

9. Albert Einstein First Stumbled on Dark Energy’s Path

Thing is, Einstein didn’t even know it.

The German-born scientist derived an historic ”cosmological constant” to make the universe static — or in other words, prevent gravity from steering the cosmos into a “big crunch” billions of years in the future.

“Instead of counteracting gravity, however, Einstein’s cosmological constant overpowers it and causes the universe to expand at an accelerating pace,” Turner told Discovery Space. “People like to say that even when Einstein thought he made a mistake he was right, but that’s a bit of a stretch.”

If Einstein’s cosmological constant does exist, it’s about four times stronger than he first anticipated.

“We don’t think the universe is static,” he said. “It’s inconsistent with what we see out there.”

8. Dark Energy Could Be Nothing

The “gravity” of dark energy is repulsive, making it a large-scale anti-gravity that acts like an overzealous traffic cop between clusters of galaxies. What’s between those galaxies? Empty space.

“The simplest explanation for dark energy is that it’s associated with something called the ‘quantum vacuum,’” Turner said.

According to quantum mechanics — which explains how the universe works on a small scale — empty space is full of particles living on borrowed time and energy, Turner explained. So it’s not too unreasonable to suggest dark energy might also occupy that “empty” space.

7. Dark Energy Can’t Be Broken into Particles

About 2,500 years ago, Democritus suggested there were four elements in the universe: air, fire, earth and water, later adding “ether.”

“He started on this path that everything is made of indivisible particles called atoms, and that path eventually led us to subatomic particles called quarks today,” Turner said. “But dark energy isn’t made of quarks, or any other particle.”

6. Dark Energy Is Everywhere

According to Einstein’s famous equation E=MC^2, matter can be converted completely into energy, and the universe can be divided into a “pie” of energy.

“One of the most important things about dark energy is that it makes up most of the stuff in the universe,” Turner told Discovery Space. ” however, locally, we don’t notice it.”

The breakdown of the pie is roughly like this:

• 74 percent is dark energy
• 22 percent is dark matter
• 3.6 percent is nearly invisible gas between stars
• 0.4 percent is stars, planets, moons and everything else. Including you.

5. Dark Energy Is the Most Elastic Substance Ever

“It’d be safe to say it’s more than a zillion times more elastic than anything we know of,” Turner said. “Even NASA’s most stretchy material, whatever it may be.”

If one were to “weigh” the energy of dark energy in a large coffee cup, it would be about 1 x 10^-27 grams (0.000000000000000000000000001 grams) or, in other words, not a whole lot.

If you do the math, Turner explained, contracting a volume of dark energy between here and the sun would create enough juice to power the Earth for about nearly 100,000 years.

4. Dark Energy Shaped the Universe

The Big Bang is thought to have kick-started the universe we live in, but after the event, dark energy began to seize its grip on matter and overcome gravity.

“Our universe was shaped by battle between dark energy and matter,” Turner said. “For the first 8 billion years or so of the universe’s existence, the gravity of matter held sway and clusters of galaxies formed.”

Roughly five billion years after that — or about one billion years ago — dark energy took over, and “put its foot on accelerator,” Turner said. “The expansion of the universe began speeding up and no larger structures were built.”

3. Dark Energy May Not be Energy at All

If it’s not made of particles, and may be nothing, is it really safe to call it energy?

“Not in the least bit,” Turner told Discovery Space. “There may very well be no dark energy at all.”

Instead, Turner suggested that Einstein’s ideas about gravity might need to be replaced.

“Few people think Einstein got the last word on gravity. His story didn’t incorporate the details of the universe at the atomic level,” he said, which is what might hold the key to gravity.”

2. Dark Energy Holds the Destiny of the Cosmos

Until we understand what dark energy is, Turner thinks we won’t really know what the fate of the universe is.

“It could continue to accelerate as it is,” he said. “If it does, then in about 100 billion years the galaxies around us will be speeding away from us too quickly to see.”

Another scenario is that the acceleration of the universe’s expansion may be doubled. And that’s bad news for everyone that might be out there — the cosmos will rip itself to shreds.

“We don’t know if the acceleration we see today is accelerating,” Turner said. “If it is, the ‘big rip’ will occur in roughly 20 billion years.”

One last option is equally as frightening.

“Maybe dark energy’s next trick is to decelerate expansion and lead to the collapse of the universe,” Turner said. “We’ve trapped ourselves time and time again believing in the simplest case, only to correct ourselves. If you want to be squeaky-clean correct, we can’t confidently guess the future of the universe yet.”

1. No One Knows What Dark Energy Is

If you thought you were clueless, even the experts don’t know.

“Welcome to the club,” Turner said. “It’s the most profound mystery in all of science. It ties together the destiny of the universe, mysteries about gravity and quantum nothingness. How’s that for a mystery?”

(via expose-the-light)

SciShow: Dark Matter

Physicists estimate that dark matter accounts for about twenty three percent of the known universe - the only problem is that no one really knows what it is…

(Source: scishow)

electricspacekoolaid:

Dark Matter Could Play a Role in Creating Life in The Universe

First Image : A Hubble Space Telescope image of Dark Matter mapped in a 3d representation.

Second Image: Abel 1689 galaxy cluster.

Dark matter makes up the majority of mass in our universe. However, we cannot directly measure the stuff as it doesn’t interact with electromagnetic radiation (i.e. it doesn’t emit or reflect any light), but we can indirectly observe its presence. In the Hubble Space Telescope image above, the distribution of mostly dark matter has been calculated and mapped. Basically, the location and density of anything with mass has been plotted in a 3D representation of the cosmos.

A 2011 study suggests that mysterious, invisible dark matter could warm millions of starless planets in regions such as Abell 1689 (image below) and make them habitable.

Scientists think the invisible, as-yet-unidentified dark matter which we know exists because of the gravitational effects it has on galaxies, makes up about 85 percent of all matter in the universe.  Current prime candidates for what dark matter might be are massive particles that only rarely interact with normal matter.

These particles could be their own antiparticles, meaning they annihilate each other when they meet, releasing energy. These invisible particles could get captured by a planet’s gravity and unleash energy that could warm that world, according to physicist Dan Hooper and astrophysicist Jason Steffen at the Fermi National Accelerator Laboratory.

Hooper and Steffen’s propose that rocky “super-Earths” in regions with high densities of slow-moving dark matter could be warmed enough to keep liquid water on their surfaces, even in the absence of additional energy from starlight or other sources.The density of dark matter is expected to be hundreds to thousands of times greater in the innermost regions of the Milky Way and in the cores of dwarf spheroidal galaxies than it is in our solar system.

The scientists concluded that on planets in dense “dark-matter” regions, it may be dark matter rather than light that creates the basic elements you need for organic life without a star”