Posted on by Tim Reyes

Has the Cosmology Standard Model become a Rube Goldberg Device?

Artists illustration of the expansion of the Universe (Credit: NASA, Goddard Space Flight Center)

This week at the Royal Astronomical Society’s National Astronomy Meeting in the UK, physicists are challenging the evidence for the recent BICEP2 results regarding the inflation period of the Universe, announced just 90 days ago. New research is laying doubt upon the inclusion of inflation theory in the Standard Cosmological Model for understanding the forces of nature, the nature of elementary particles and the present state of the known Universe.

Back on March 17, 2014, it seemed the World was offered a glimpse of an ultimate order from eons ago … actually from the beginning of time. BICEP2, the single purpose machine at the South Pole delivered an image that after analysis, and subtraction of estimated background signal from the Milky Way, lead its researchers to conclude that they had found the earliest remnant from the birth of the Universe, a signature in ancient light that supported the theory of Inflation.

BICEP2 Telescope at twilight at the South Pole, Antartica (Credit: Steffen Richter, Harvard University)
BICEP2 Telescope at twilight at the South Pole, Antarctica (Credit: Steffen Richter, Harvard University)

Thirty years ago, the Inflation theory was conceived by physicists Alan Guth and Andei Linde. Guth, Linde and others realized that a sudden expansion of the Universe at only 1/1000000000000000000000000000000000th of a second after the Big Bang could solve some puzzling mysteries of the Cosmos. Inflation could explain the uniformity of the cosmic background radiation. While images such as from the COBE satellite show a blotchy distribution of radiation, in actuality, these images accentuate extremely small variations in the background radiation, remnants from the Big Bang, variations on the order of 1/100,000th of the background level.

Note that the time of the Universe’s proposed Inflationary period immediately after the Big Bang would today permit light to travel only 1/1000000000000000th of the diameter of the Hydrogen atom. The Universe during this first moment of expansion was encapsulated in a volume far smaller than the a single atom.

Emotions ran very high when the BICEP2 team announced their findings on March 17 of this year. The inflation event that the background radiation data supported is described as a supercooling of the Cosmos however, there were physicists that simply remained cool and remained contrarians to the theory. Noted British Physicist Sir Roger Primrose was one who remained underwhelmed and stated that the incredible circular polarization of light that remained in the processed data from BICEP2 could be explained by the interaction of dust, light and magnetic fields in our own neighborhood, the Milky Way.

Illustration of the ESA Planck Telescope in Earth orbit (Credit: ESA)
Illustration of the ESA Planck Telescope in Earth orbit (Credit: ESA)

Now, new observations from another detector, one on the Planck Satellite orbiting the Earth, is revealing that the contribution of background radiation from local sources, the dust in the Milky Way, is appearing to have been under-estimated by the BICEP2 team. All the evidence is not yet laid out but the researchers are now showing reservations. At the same time, it does not dismiss the Inflation Theory. It means that more observations are needed and probably with greater sensitivity.

So why ask the question, are physicists constructing a Rube Goldberg device?

Our present understanding of the Universe stands upon what is called “the Standard Model” of Cosmology. At the Royal Astronomical Society meeting this week, the discussions underfoot could be revealing a Standard Model possibly in a state of collapse or simply needing new gadgets and mechanisms to remain the best theory of everything.

Also this week, new data further supports the discovery of the Higg’s Boson by the Large Hadron Collider in 2012, the elementary particle whose existence explains the mass of fundamental particles in nature and that supports the existence of the Higgs Field vital to robustness of the Standard Model. However, the Higgs related data is also revealing that if the inflationary period of the Universe did take place, then if taken with the Standard Model, one can conclude that the Universe should have collapsed upon itself and our very existence today would not be possible.

A Rube Goldberg Toothpaste dispenser as also the state of the Standard Model (Credit: R.Goldberg)
A Rube Goldberg Toothpaste dispenser as also the state of the Standard Model (Credit: R.Goldberg)

Dr. Brian Green, a researcher in the field of Super String Theory and M-Theory and others such as Dr. Stephen Hawking, are quick to state that the Standard Model is an intermediary step towards a Grand Unified Theory of everything, the Universe. The contortion of the Standard Model, into a sort of Rube Goldberg device can be explained by the undaunting accumulation of more acute and diverse observations at cosmic and quantum scales.

Discussions at the Royal Astronomical Society meeting are laying more doubts upon the inflation theory which just 90 days ago appeared so well supported by BICEP2 – data derived by truly remarkable cutting edge electronics developed by NASA and researchers at the California Institute of Technology. The trials and tribulations of these great theories to explain everything harken back to the period just prior to Einstein’s Miracle Year, 1905. Fragmented theories explaining separately the forces of nature were present but also the accumulation of observational data had reached a flash point.

Today, observations from BICEP2, NASA and ESA great space observatories, sensitive instruments buried miles underground and carefully contrived quantum experiments in laboratories are making the Standard Model more stressed in explaining everything, the same model so well supported by the Higg’s Boson discovery just two years ago. Cosmologists concede that we may never have a complete, proven theory of everything, one that is elegant; however, the challenges upon the Standard Model and inflation will surely embolden younger theorists to double the efforts in other theoretical work.

For further reading:
RAS NAM press release: Should the Higgs Boson Have Caused our Universe To Collapse?
We’ve Discovered Inflation!: Now What?
Cosmologists Cast Doubt on Inflation Evidence
Are the BICEP2 Results Invalid? Probably Not

Posted on by Shannon Hall

First Precise Measurement of Antihydrogen

Hydrogen’s electron and proton have oppositely charged antimatter counterparts in the antihydrogen: the positron and antiproton. Image credit: NSF.

The best science — the questions that capture and compel any human being — is enshrouded in mystery. Here’s an example: scientists expect that matter and antimatter were created in equal quantities shortly after the Big Bang. If this had been the case, the two types of particles would have annihilated each other, leaving a Universe permeated by energy.

As our existence attests, that did not happen. In fact, nature seems to have a one-part in 10 billion preference for matter over antimatter. It’s one of the greatest mysteries in modern physics.

But the Large Hadron Collider is working hard, literally pushing matter to the limit, to solve this captivating mystery. This week, CERN created a beam of antihydrogen atoms, allowing scientists to take precise measurements of this elusive antimatter for the first time.

Antiparticles are identical to matter particles except for the sign of their electric charge. So while hydrogen consists of a positively charged proton orbited by a negatively charged electron, antihydrogen consists of a negatively charged antiproton orbited by a positively charged anti-electron, or a positron

While primordial antimatter has never been observed in the Universe, it’s possible to create antihydrogen in a particle accelerator by mixing positrons and low energy antiprotons.

In 2010, the ALPHA team captured and held atoms of antihydrogen for the first time. Now the team has successfully created a beam of antihydrogen particles. In a paper published this week in Nature Communications, the ALPHA team reports the detection of 80 antihydrogen atoms 2.7 meters downstream from their production.

“This is the first time we have been able to study antihydrogen with some precision,” said ALPHA spokesperson Jeffrey Hangst in a press release. “We are optimistic that ALPHA’s trapping technique will yield many such insights in the future.”

One of the key challenges is keeping antihydrogen away from ordinary matter, so that the two don’t annihilate each other. To do so, most experiments use magnetic fields to trap antihydrogen atoms long enough to study them.

However, the strong magnetic fields degrade the spectroscopic properties of the antihydrogen atoms, so the ALPHA team had to develop an innovative set-up to transfer antihydrogen atoms to a region where they could be studied, far from the strong magnetic field.

To measure the charge of antihydrogen, the ALPHA team studied the trajectories of antihydrogen atoms released from the trap in the presence of an electric field. If the antihydrogen atoms had an electric charge, the field would deflect them, whereas neutral atoms would be undeflected.

The result, based on 386 recorded events, gives a value of the antihydrogen electric charge at -1.3 x 10-8. In other words, its charge is compatible with zero to eight decimal places. Although this result comes as no surprise, since hydrogen atoms are electrically neutral, it is the first time that the charge of an antiatom has been measured to such high precision.

In the future, any detectable difference between matter and antimatter could help solve one of the greatest mysteries in modern physics, opening up a window into a new realm of science.

The paper has been published in Nature Communications.

Posted on by Shannon Hall

Physicists Pave the Way to Turn Light into Matter

This artist's conception shows two photons (in green) colliding. Image Credit: ATLAS / LHC

E = mc². It’s one of the most basic and fundamental equations throughout astrophysics. But it does more than suggest that mass and energy are interconnected, it implies that light can be physically transformed into matter.

But can it really — physically — be done? Scientists proposed the theory more than 80 years ago, but only today have they paved the way to make this transformation routinely on Earth.

The concept calls for a new kind of photon-photon collider. It sounds like science fiction, but it could be turned into reality with existing technology.

“Although the theory is conceptually simple, it has been very difficult to verify experimentally,” said lead researcher Oliver Pike from London’s Imperial College in a press release. “We were able to develop the idea for the collider very quickly, but the experimental design we propose can be carried out with relative ease.”

In 1934, two physicists Gregory Breit and John Wheeler proposed that it should be possible to turn light into matter by smashing together only two photons, the fundamental particles of light, to create an electron and a positron. It was the simplest method of turning light into matter ever predicted, but it has never been observed in the laboratory.

Past experiments have required the addition of massive high-energy particles. We’ve seen from the development of nuclear weapons and fission reactors that a tiny amount of matter can yield a tremendous amount of energy. So it seems Breit and Wheeler’s theory would require the opposite effect: tremendous amounts of energy from photons to yield a tiny amount of matter.

This experiment will be a first in that it doesn’t require the addition of massive high-energy particles. It will be performed purely from photons.

The concept calls for using a high-intensity laser to speed up electrons to just below the speed of light, and then smash them into a slab of gold to create a beam of photons a billion times more energetic than visible light. At the same time, another laser beam would be blasted onto a hohlraum — a small gold container meaning “empty can” in German — that would create a radiation field with photons buzzing inside.

The initial photon beam would be directed into the center of the hohlraum. When the photons from the two sources collide, some would be converted into pairs of electrons and positrons. A detector would then pick up the signatures form the matter and antimatter as they flew out of the container.

Theories describing light and matter interactions. Image Credit: Oliver Pike, Imperial College London
Theories describing light and matter interactions. Image Credit: Oliver Pike, Imperial College London

“Within a few hours of looking for applications of hohlraums outside their traditional role in fusion energy research, we were astonished to find they provided the perfect conditions for creating a photon collider,” Pike said. “The race to carry out and complete the experiment is on!”

The demonstration, if carried out successfully, would be a new type of high-energy physics experiment. It would complete physicists’ list of the fundamental ways in which light and matter interact, and both recreate a process that was important 100 seconds after the Big Bang and a process visible in gamma ray bursts, the most powerful explosions in the cosmos.

The paper has been published in Nature Photonics.

Posted on by Nancy Atkinson

Watch Live Webcast: Secrets of the Universe’s First Light

The BICEP telescope located at the south pole. Image Credit: CfA / Harvard

Just a month ago came the news of the first direct evidence of primordial gravitational waves — ripples in the fabric of spacetime — providing the first direct evidence the Universe underwent a brief but stupendously accelerated expansion immediately following the Big Bang.

This almost unimaginably fast expansion when the Universe was only a trillionth of a trillionth of a trillionth of a second was first theorized more than three decades ago, and the announcement last month was so monumental that some are comparing it to the discovery of the Higgs boson.

On April 18, 20:00 UTC (3 pm EDT, 1:00 pm PDT, two of the scientists who made this groundbreaking discovery will come together for a conversation with two of the pioneering leaders of the field. Together, they will examine the detection of a distinctive, swirling pattern in the universe’s first light, what the swirl tells us about that monumental growth spurt, and the many implications on the way we understand the universe around us.

You can watch below:

The hangout will include members of the BICEP2, which made the discovery, as well as two notable scientists in this field, John Carlstrom and Michael Turner.

Posted on by Brian Koberlein

How CERN’s Discovery of Exotic Particles May Affect Astrophysics

The difference between a neutron star and a quark star (Chandra)

You may have heard that CERN announced the discovery (confirmation, actually. See addendum below.) of a strange particle known as Z(4430).  A paper summarizing the results has been published on the physics arxiv, which is a repository for preprint (not yet peer reviewed) physics papers.  The new particle is about 4 times more massive than a proton, has a negative charge, and appears to be a theoretical particle known as a tetraquark.  The results are still young, but if this discovery holds up it could have implications for our understanding of neutron stars.

A periodic table of elementary particles. Credit: Wikipedia
A periodic table of elementary particles.
Credit: Wikipedia

The building blocks of matter are made of leptons (such as the electron and neutrinos) and quarks (which make up protons, neutrons, and other particles).  Quarks are very different from other particles in that they have an electric charge that is 1/3 or 2/3 that of the electron and proton.  They also possess a different kind of “charge” known as color.  Just as electric charges interact through an electromagnetic force, color charges interact through the strong nuclear force.  It is the color charge of quarks that works to hold the nuclei of atoms together. Color charge is much more complex than electric charge.  With electric charge there is simply positive (+) and its opposite, negative (-).  With color, there are three types (red, green, and blue) and their opposites (anti-red, anti-green, and anti-blue).

Because of the way the strong force works, we can never observe a free quark.  The strong force requires that quarks always group together to form a particle that is color neutral. For example, a proton consists of three quarks (two up and one down), where each quark is a different color.  With visible light, adding red, green and blue light gives you white light, which is colorless. In the same way, combining a red, green and blue quark gives you a particle which is color neutral.  This similarity to the color properties of light is why quark charge is named after colors.

Combining a quark of each color into groups of three is one way to create a color neutral particle, and these are known as baryons.  Protons and neutrons are the most common baryons.  Another way to combine quarks is to pair a quark of a particular color with a quark of its anti-color.  For example, a green quark and an anti-green quark could combine to form a color neutral particle.  These two-quark particles are known as mesons, and were first discovered in 1947.  For example, the positively charged pion consists of an up quark and an antiparticle down quark.

Under the rules of the strong force, there are other ways quarks could combine to form a neutral particle.  One of these, the tetraquark, combines four quarks, where two particles have a particular color and the other two have the corresponding anti-colors.  Others, such as the pentaquark (3 colors + a color anti-color pair) and the hexaquark (3 colors + 3 anti-colors) have been proposed.  But so far all of these have been hypothetical.  While such particles would be color neutral, it is also possible that they aren’t stable and would simply decay into baryons and mesons.

There has been some experimental hints of tetraquarks, but this latest result is the strongest evidence of 4 quarks forming a color neutral particle.  This means that quarks can combine in much more complex ways than we originally expected, and this has implications for the internal structure of neutron stars.

Very simply, the traditional model of a neutron star is that it is made of neutrons.  Neutrons consist of three quarks (two down and one up), but it is generally thought that particle interactions within a neutron star are interactions between neutrons.  With the existence of tetraquarks, it is possible for neutrons within the core to interact strongly enough to create tetraquarks.  This could even lead to the production of pentaquarks and hexaquarks, or even that quarks could interact individually without being bound into color neutral particles.  This would produce a hypothetical object known as a quark star.

This is all hypothetical at this point, but verified evidence of tetraquarks will force astrophysicists to reexamine some the assumptions we have about the interiors of neutron stars.

Addendum: It has been pointed out that CERN’s results are not an original discovery, but rather a confirmation of earlier results by the Belle Collaboration.  The Belle results can be found in a 2008 paper in Physical Review Letters, as well as a 2013 paper in Physical Review D.  So credit where credit is due.

Posted on by Jason Major

Cosmologists Cast Doubt on Inflation Evidence

Some physicists still have questions on the true origin of the BICEP2 findings...

It was just a week ago that the news blew through the scientific world like a storm: researchers from the BICEP2 project at the South Pole Telescope had detected unambiguous evidence of primordial gravitational waves in the cosmic microwave background, the residual rippling of space and time created by the sudden inflation of the Universe less than a billionth of a billionth of a second after the Big Bang. With whispers of Nobel nominations quickly rising in the science news wings, the team’s findings were hailed as the best direct evidence yet of cosmic inflation, possibly even supporting the existence of a multitude of other universes besides our own.

That is, if they really do indicate what they appear to. Some theorists are advising that we “put the champagne back in the fridge”… at least for now.

Theoretical physicists and cosmologists James Dent, Lawrence Krauss, and Harsh Mathur have submitted a brief paper (arXiv:1403.5166 [astro-ph.CO]) stating that, while groundbreaking, the BICEP2 Collaboration findings have yet to rule out all possible non-inflation sources of the observed B-mode polarization patterns and the “surprisingly large value of r, the ratio of power in tensor modes to scalar density perturbations.”

“However, while there is little doubt that inflation at the Grand Unified Scale is the best motivated source of such primordial waves, it is important to demonstrate that other possible sources cannot account for the current BICEP2 data before definitely claiming Inflation has been proved. “

– Dent, Krauss, and Mathur (arXiv:1403.5166 [astro-ph.CO])

The history of the universe starting the with the Big Bang. Image credit: grandunificationtheory.com
The history of the universe starting the with the Big Bang. Image credit: grandunificationtheory.com

Inflation may very well be the cause — and Dent and company state right off the bat that “there is little doubt that inflation at the Grand Unified Scale is the best motivated source of such primordial waves” —  but there’s also a possibility, however remote, that some other, later cosmic event is responsible for at least some if not all of the BICEP2 measurements. (Hence the name of the paper: “Killing the Straw Man: Does BICEP Prove Inflation?”)

Not intending to entirely rain out the celebration, Dent, Krauss, and Mathur do laud the BICEP2 findings as invaluable to physics, stating that they “will be very important for constraining physics beyond the standard model, whether or not inflation is responsible for the entire BICEP2 signal, even though existing data from cosmology is strongly suggestive that it does.”

Read more: We’ve Discovered Inflation! Now What?

Now I’m no physicist, cosmologist, or astronomer. Actually I barely passed high school algebra (and I have the transcripts to prove it) so if you want to get into the finer details of this particular argument I invite you to read the team’s paper for yourself here and check out a complementary article on The Physics arXiv Blog.

And so, for better or worse (just kidding — it’s definitely better) this is how science works and how science is supposed to work. A claim is presented, and, regardless of how attractive its implications may be, it must stand up to any other possibilities before deemed the decisive winner. It’s not a popularity contest, it’s not a beauty contest, and it’s not up for vote. What it is up for is scrutiny, and this is just an example of scientists behaving as they should.

Still, I’d  keep that champagne nicely chilled.

Source: The Physics arXiv Blog

_________

Want to read more about the BICEP2 findings from actual physicists? Read more in an article by Peter Coles, see what Matthew Francis has to say in his article on arstechnica here, and watch a video by Sean Carroll on PBS News Hour.

Posted on by Jason Major

Twin NASA Probes Find “Zebra Stripes” in Earth’s Radiation Belt

Illustration of the twin Van Allen Probes (formerly Radiation Belt Storm Probes) in orbit (JHUAPL/NASA)

Earth’s inner radiation belt displays a curiously zebra-esque striped pattern, according to the latest findings from NASA’s twin Van Allen Probes. What’s more, the cause of the striping seems to be the rotation of the Earth itself — something that was previously thought to be impossible.

“…it is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties.”

– Aleksandr Ukhorskiy, Johns Hopkins University Applied Physics Laboratory

Our planet is surrounded by two large doughnut-shaped regions of radiation called the Van Allen belts, after astrophysicist James Van Allen who discovered their presence in 1958. (Van Allen died at the age of 91 in 2006.) The inner Van Allen belt, extending from about 800 to 13,000 km (500 to 8,000 miles) above the Earth, contains high-energy electrons and protons and poses a risk to both spacecraft and humans, should either happen to spend any substantial amount of time inside it.

Read more: Surprising Third Radiation Belt Found Around Earth

The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) is a time-of-flight versus energy spectrometer (JHUAPL)
The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) is a time-of-flight versus energy spectrometer (JHUAPL)

Launched aboard an Atlas V rocket from Cape Canaveral AFS on the morning of Aug. 30, 2012, the Van Allen Probes (originally the Radiation Belt Storm Probes) are on a two-year mission to investigate the belts and find out how they behave and evolve over time.

One of the instruments aboard the twin probes, the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE), has detected a persistent striped pattern in the particles within the inner belt. While it was once thought that any structures within the belts were the result of solar activity, thanks to RBSPICE it’s now been determined that Earth’s rotation and tilted magnetic axis are the cause.

“It is because of the unprecedented high energy and temporal resolution of our energetic particle experiment, RBSPICE, that we now understand that the inner belt electrons are, in fact, always organized in zebra patterns,” said Aleksandr Ukhorskiy of the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Md., co-investigator on RBSPICE and lead author of the paper. “Furthermore, our modeling clearly identifies Earth’s rotation as the mechanism creating these patterns. It is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties.”

The model of the formation of the striped patterns is likened to the pulling of taffy.

RBSPICE data of stripes within the inner Van Allen belt (Click for animation) Credit: A. Ukhorskiy/JHUAPL
RBSPICE data of stripes within the inner Van Allen belt (Click for animation) Credit: A. Ukhorskiy/JHUAPL

“If the inner belt electron populations are viewed as a viscous fluid,” Ukhorskiy said, “these global oscillations slowly stretch and fold that fluid, much like taffy is stretched and folded in a candy store machine.”

“This finding tells us something new and important about how the universe operates,” said Barry Mauk, a project scientist at APL and co-author of the paper. “The new results reveal a new large-scale physical mechanism that can be important for planetary radiation belts throughout the solar system. An instrument similar to RBSPICE is now on its way to Jupiter on NASA’s Juno mission, and we will be looking for the existence of zebra stripe-like patterns in Jupiter’s radiation belts.”

Jupiter’s Van Allen belts are similar to Earth’s except much larger; Jupiter’s magnetic field is ten times stronger than Earth’s and the radiation in its belts is a million times more powerful (source). Juno will arrive at Jupiter in July 2016 and spend about a year in orbit, investigating its atmosphere, interior, and magnetosphere.

Thanks to the Van Allen Probes. Juno now has one more feature to look for in Jupiter’s radiation belts.

“It is amazing how Earth’s space environment, including the radiation belts, continue to surprise us even after we have studied them for over 50 years. Our understanding of the complex structures of the belts, and the processes behind the belts’ behaviors, continues to grow, all of which contribute to the eventual goal of providing accurate space weather modeling.”

– Louis Lanzerotti, physics professor at the New Jersey Institute of Technology and principal investigator for RBSPICE

The team’s findings have been published in the March 20 issue of the journal Nature.

The Van Allen Probes are the second mission in NASA’s Living With a Star program, managed by NASA’s Goddard Space Flight Center in Greenbelt, MD. The program explores aspects of the connected sun-Earth system that directly affect life and society.

Source: Van Allen Probes news release

Posted on by Nancy Atkinson

That Moment When the “Father of Inflation” Learns of the Detection of Gravitational Waves

Polarization patterns imprinted in the CMB. Image Credit: CfA

Andrei Linde, a professor in the Department of Physics at Stanford University, is one of the main authors of the inflationary universe theory, that the universe underwent a brief but remarkably accelerated expansion immediately following the Big Bang.

Today, scientists announced that they’ve found direct evidence of primordial gravitational waves, which would provide a “smoking gun” for inflation, and also tell us when inflation took place and how powerful the process was.

Above is a scientifically heartwarming video of Linde being told of the gravitational wave discovery by Chao-Lin Kuo, also from Stanford University, the designer of the BICEP2 detector that made the discovery.

Read our full article about the discovery here.

Posted on by Shannon Hall

Rumors Flying Nearly as Fast as Their Subject: Have Gravitational Waves Been Detected?

This detailed map of the cosmic microwave background is created from seven years worth of data. It shows the "seed" structures of galaxies in the infant Universe. Image Credit: NASA
This detailed map of the cosmic microwave background is created from seven years worth of data. It shows the "seed" structures of galaxies in the infant Universe. Image Credit: NASA

Last week the Harvard-Smithsonian Center for Astrophysics (CfA) stated rather nonchalantly that they will be hosting a press conference on Monday, March 17th, to announce a “major discovery.” Without a potential topic for journalists to muse on, this was as melodramatic as it got.

But then the Guardian posted an article on the subject and the rumors went into overdrive. The speculation is this: a U.S. team is on the verge of confirming they have detected primordial gravitational waves — ripples in the fabric of spacetime that carry echoes of the big bang nearly 14 billion years ago.

If there is evidence for gravitational waves, it will be a landmark discovery, ultimately changing the face of physics.

Not only are gravitational waves the last untested prediction of Albert Einstein’s General Theory of Relativity, but primordial gravitational waves will allow astronomers to glimpse the universe in its infancy.

“It’s been called the Holy Grail of cosmology,” Hiranya Peiris, a cosmologist from University College London, told the Guardian. “It would be a real major, major, major discovery.” Any convincing evidence would almost certainly lead to a Nobel prize.

The signal is rumored to have been found by a telescope known as BICEP (Background Imaging of Cosmic Extragalactic Polarization), which scans the sky from the south pole, looking for a subtle effect in the cosmic microwave background (CMB): the radiation released 380,000 years after the big bang when space became transparent to light and photons were allowed to travel freely across the universe.

The South Pole Telescope (left) and BICEP (right). Image Credit: Dana Hrubes
The South Pole Telescope (left) and BICEP (right). Image Credit: Dana Hrubes

While the CMB has been mapped in exquisite detail, astronomers think that hidden within the map is a second fingerprint, which would reveal gravitational waves. Its radiation was scattered toward us from the universe’s earliest atoms, similar to the way blue light is scattered toward us from the atoms in the sky. And just as the sky is slightly polarized — the waves have a preferred orientation — so is the CMB (on the level of a few percent).

Cosmologists are digging through the data, searching for a subtle twist in the polarized light, known as B-modes. If a gravitational wave moves through the fabric of spacetime, it will squeeze spacetime in one direction (the universe will look a little hotter) and stretch it in another (the universe will look a little cooler). The photons will scatter with a preferred direction, leaving a slightly polarized imprint on the CMB, due to the passing gravitational wave.

Not only will detecting this slight polarization pattern in the CMB allow astronomers to uncover evidence of primordial gravitational waves but they will provide proof that immediately after the big bang the universe expanded exponentially — inflated — by at least a factor of 1025. While the theory of inflation is a pillar of big bang cosmology and helps explain key features of the observable universe today (i.e. why the universe is outstandingly uniform on such massive scales), many physicists don’t buy it. It remains a theoretical framework because we can’t explain what physical mechanism would have driven such a massive expansion, let alone stop it.

Inflation is the only mechanism with the ability to amplify gravitational waves, born from quantum fluctuations in gravity itself, into a detectable signal.

“If a detection has been made, it is extraordinarily exciting,” Andrew Jaffe, a cosmologist from Imperial College, London, told the Guardian. “This is the real big tick-box that we have been waiting for. It will tell us something incredibly fundamental about what was happening when the universe was only 10-34 seconds old.”

But even if the rumors prove true, it’s crucial to remain skeptical. Extracting the signal is extremely tricky. The CMB’s temperature varies by a few parts in 100,000. In comparison, B-modes account for just one part in 10 million in the CMB temperature distribution.

The microwaves also travel across the entire observable universe first. Only last year the signal was detected in the CMB for the first time using the South Pole Telescope, but it was in fact distorted by intervening clusters of galaxies and not intrinsic to the CMB itself.

The announcement will be made on Monday at noon EST.

Posted on by Nancy Atkinson

Happy Pi Day: 5 Ways NASA Uses Pi

The Cassini spacecraft uses a Pi Transfer to navigate its path around Saturn. Credit: NASA.

Got circles on the brain today? It’s Pi Day — (3/14 for those of us on the west side of the pond) and a celebration of math and science – as well as the infinite and irrational! It is also Albert Einstein’s birthday. What’s Pi? Π is the 16th letter in the Greek alphabet and is used to represent a mathematical constant, the ratio of a circle’s circumference to its diameter, approximately equal to 3.1415…

In basic mathematics, Pi is used to find area and circumference of a circle. You might not use it yourself every day, but Pi is used in most calculations for building and construction, quantum physics, communications, music theory, medical procedures, air travel, and space flight, to name a few.

You might imagine that NASA regularly uses Π to calculate trajectories of spacecraft. Above is a visible documentation of a technique called a “pi transfer” used by the Cassini spacecraft to complete a maneuver to fly by Saturn’s moon Titan flyby.

NASA explains:

A pi transfer uses the gravity of Saturn’s largest moon, Titan, to alter the orbit of the Cassini spacecraft so it can gain different perspectives on Saturn and achieve a wide variety of science objectives. During a pi transfer, Cassini flies by Titan at opposite sides of its orbit about Saturn (i.e., Titan’s orbital position differs by pi radians between the two flybys) and uses Titan’s gravity to change its orbital perspective on the ringed planet.

This image was taken on January 19, 2007, showing the perspective the spacecraft had of Saturn and its rings during the pi transfer.

Other ways NASA uses Pi is to determine the size of craters and extrasolar planets, figuring out how much propellent a spacecraft has, and learning what an asteroid is made of. Mike Seibert from the Mars Exploration Rover team explained on Twitter today how they use Pi every day to talk to the Opportunity rover:

Here’s an infographic of ways NASA uses Π

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And here’s a great song about Pi to help you celebrate the day:

Get ready to celebrate with extra gusto next year — it will be 3/14/15.