Artist's impression of how huge cosmic structures deflect photons in the cosmic microwave background (CMB). Credit: ESA and the Planck Collaboration
Leftover radiation from the Big Bang — that expansion that kick-started the universe — can be bent by huge cosmic structures, just like other light that we see in the universe. While the finding seems esoteric at first glance, scientists say the discovery could pave the way for finding a similar kind of signal that indicate the presence of gravitational waves in the moments after the universe was born.
That light is called the cosmic microwave background and is the radiation that was visible when the universe became transparent to radiation, 380,000 years after the Big Bang. A tiny bit of the CMB is polarized. There are two types of polarized light in the CMB: E-modes (first detected in 2002) and B-modes (which were just detected using a telescope in Antarctica and ESA’s Herschel space observatory.
“[B-modes] can arise in two ways,” the European Space Agency wrote in a press release.
“The first involves adding a twist to the light as it crosses the Universe and is deflected by galaxies and dark matter – a phenomenon known as gravitational lensing. The second has its roots buried deep in the mechanics of a very rapid phase of enormous expansion of the Universe, which cosmologists believe happened just a tiny fraction of a second after the Big Bang – ‘inflation’.”
More results are on the way from ESA’s Planck telescope in 2014, at which point scientists hope to see this B-mode of the second type. For now, check out the full study in Physical Review Letters. There is also a preprint version available on Arxiv.
This image, the best map ever of the Universe, shows the oldest light in the universe. This glow, left over from the beginning of the cosmos called the cosmic microwave background, shows tiny changes in temperature represented by color. Credit: ESA and the Planck Collaboration.
Earlier this year, a new map of the Cosmic Microwave Background from the Planck spacecraft revealed our Universe was a bit older and is expanding a tad more slowly that previously thought. Additionally, there are certain large scale features that cosmologists cannot readily explain. In fact, because of this finding — possible because of the Planck satellite — we may need to modify, amend or even fundamentally change our description of the Universe’s first moments.
Today, July 31, at 19:00 UTC (12:00 p.m. PDT, 3:00 pm EDT) the Kavli Foundation is hosting a live Google+ Hangout: “A New Baby Picture of the Universe.” You can watch in the player embedded below. You’ll have the chance to ask your questions to Planck scientists by posting on Twitter with the hashtag #KavliAstro, or by email to [email protected]. Questions can be sent prior and during the live webcast. If you miss it live, you can watch the replay here, as well.
You will hear from three leading members of the Planck research team — George Efstathiou and Anthony Lasenby of the Kavli Institute for Cosmology at the University of Cambridge, and Krzysztof Gorski, Senior Research Scientist at the Jet Propulsion Laboratory in Pasadena, CA and faculty member at the Warsaw University Observatory in Poland — and they’ll answer your questions about what was found and what this means to our understanding of the universe.
The cabinets containing the Grace Hopper Cray XE6 supercomputer. (Credit: LBNL/Dept of Energy).
Behind every modern tale of cosmological discovery is the supercomputer that made it possible. Such was the case with the announcement yesterday from the European Space Agencies’ Planck mission team which raised the age estimate for the universe to 13.82 billion years and tweaked the parameters for the amounts dark matter, dark energy and plain old baryonic matter in the universe.
Planck built upon our understanding of the early universe by providing us the most detailed picture yet of the cosmic microwave background (CMB), the “fossil relic” of the Big Bang first discovered by Penzias & Wilson in 1965. Planck’s discoveries built upon the CMB map of the universe observed by the Wilkinson Microwave Anisotropy Probe (WMAP) and serves to further validate the Big Bang theory of cosmology.
But studying the tiny fluctuations in the faint cosmic microwave background isn’t easy, and that’s where Hopper comes in. From its L2 Lagrange vantage point beyond Earth’s Moon, Planck’s 72 onboard detectors observe the sky at 9 separate frequencies, completing a full scan of the sky every six months. This first release of data is the culmination of 15 months worth of observations representing close to a trillion overall samples. Planck records on average of 10,000 samples every second and scans every point in the sky about 1,000 times.
That’s a challenge to analyze, even for a supercomputer. Hopper is a Cray XE6 supercomputer based at the Department of Energy’s National Energy Research Scientific Computing center (NERSC) at the Lawrence Berkeley National Laboratory in California. Named after computer scientist and pioneer Grace Hopper, the supercomputer has a whopping 217 terabytes of memory running across 153,216 computer cores with a peak performance of 1.28 petaflops a second. Hopper placed number five on a November 2010 list of the world’s top supercomputers. (The Tianhe-1A supercomputer at the National Supercomputing Center in Tianjin China was number one at a peak performance of 4.7 petaflops per second).
One of the main challenges for the team sifting through the flood of CMB data generated by Planck was to filter out the “noise” and bias from the detectors themselves.
“It’s like more than just bugs on a windshield that we want to remove to see the light, but a storm of bugs all around us in every direction,” said Planck project scientist Charles Lawrence. To overcome this, Hopper runs simulations of how the sky would appear to Planck under different conditions and compares these simulations against observations to tease out data.
“By scaling up to tens of thousands of processors, we’ve reduced the time it takes to run these calculations from an impossible 1,000 years to a few weeks,” said Berkeley lab and Planck scientist Ted Kisner.
But the Planck mission isn’t the only data that Hopper is involved with. Hopper and NERSC were also involved with last year’s discovery of the final neutrino mixing angle. Hopper is also currently involved with studying wave-plasma interactions, fusion plasmas and more. You can see the projects that NERSC computers are tasked with currently on their site along with CPU core hours used in real time. Maybe a future descendant of Hopper could give Deep Thought of Hitchhiker’s Guide to the Galaxy fame competition in solving the answer to Life, the Universe, and Everything.
Also, a big congrats to Planck and NERSC researchers. Yesterday was a great day to be a cosmologist. At very least, perhaps folks won’t continue to confuse the field with cosmetology… trust us, you don’t want a cosmologist styling your hair!
Like archaeologists sifting through the dust of ancient civilizations, scientists with the ESA Planck mission today showed a map of the oldest light in the Universe. The first cosmology results of the mission suggest our Universe is slightly older and expanding more slowly than previously thought.
Planck’s new estimate for the age of the Universe is 13.82 billion years.
The map also appears to show more matter and dark matter and less dark energy, a hypothetical force that is causing an expansion of the Universe.
“We are measuring the oldest light in the Universe, the cosmic microwave background,” says Paul Hertz, director of astrophysics with NASA. “It is the most sensitive and detailed map ever. It’s like going from standard television to a new high definition screen. The new details have become crystal clear.”
Overall, the cosmic background radiation, the afterglow of the Universe’s birth, is smooth and uniform. The map, however, provides a glimpse of the tiny temperature fluctuations that were imprinted on the sky when the Universe was just 370,000 years old. Scientists believe the map reveals a fossil, an imprint, of the state of the Universe just 10 nano-nano-nano-nano seconds after the Big Bang; just a tiny fraction of the time it took to read that sentence. The splotches in the Planck map represent the seeds from which the stars and galaxies formed.
The colors in the map represent different temperatures; red for warmer, blue for cooler. The temperature differences being only 1/100 millionth of a degree. “The contrast on the map has been turned way up,” says Charles Lawrence, the US project scientist for Planck at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
Planck, launched in 2009 from the Guiana Space Center in French Guiana, is a European Space Agency mission with significant contribution from NASA. The two-ton spacecraft gathers the ancient glow of the Universe’s beginning from a vantage more than 1 million miles from Earth.
This graphic shows the evolution of satellites designed to measure the light left over from the Big Bang that created our Universe about 13.8 billion years ago. Called the cosmic background radiation, the light reveals information about the early Universe. The three panels show the same 10-square-degree patch of sky as seen by NASA’s Cosmic Background Explorer, or COBE, NASA’s Wilkinson Microwave Anisotropy Probe, or WMAP, and Planck. Planck has a resolution about 2.5 times greater than WMAP. Credit: NASA/JPL-Caltech/ESA
This is not the first map produced by Planck. In 2010, Planck produced an all-sky radiation map. Scientists, using supercomputers, have removed not only the bright emissions from foreground sources, like the Milky Way, but also stray light from the satellite itself.
As the light travels, matter scattered throughout the Universe with its associated gravity subtly bends and absorbs the light, “making it wiggle to and fro,” said Martin White, a Planck project scientist with the University of California, Berkeley and the Lawrence Berkeley National Laboratory.
“The Planck map shows the impact of all matter back to the edge of the Universe,” says White. “It’s not just a pretty picture. Our theories on how matter forms and how the Universe formed match spectacularly to this new data.”
“This is a treasury of scientific data,” said Krzysztof Gorski, a member of the Planck team with JPL. “We are very excited with the results. We find an early Universe that is considerably less rigged and more random than other, more complex models. We think they’ll be facing a dead-end.”
An artists animation depicting the “life” of a photon, or a particle light, as it travels across space and time from the beginning of the Universe to the detectors of the Planck telescope. Credit: NASA
Planck scientists believe the new data should help scientists refine many of the theories proposed by cosmologists that the Universe underwent a sudden and rapid inflation.
An “bridge” of hot gas stretches between galaxy clusters Abell 401 and Abell 399
It may not be good practice to burn bridges but this is one super-heated bridge that astronomers were happy to find: an enormous swath of hot gas connecting two galaxy clusters 10 million light-years apart, and nearly a billion light-years away.
Using ESA’s Planck space telescope, astronomers have identified leftover light from the Big Bang interacting with a filament of hot gas stretching between Abell 401 and Abell 399, two galactic clusters each containing hundreds of individual galaxies.
Launched in May 2009, Planck is designed to study the Cosmic Microwave Background (CMB) — the leftover light from the Big Bang. When this radiation interacts with large-scale cosmic structures, like the hot gas bridging clusters of galaxies, its energy is modified in a specific way. This is referred to as the Sunyaev–Zel’dovich Effect (SZE), and Planck is specifically attuned to finding it.
This, however, is Planck’s first discovery of inter-cluster gas found using the SZ technique.
The temperature of the gas is estimated to be around 80 million degrees C, similar to the temperature of the gas found within the clusters themselves. It’s thought that the gas may be a combination of cosmic web filaments left over from the early Universe mixed with gas from the clusters.
The image above shows the clusters Abell 401 and Abell 399 as seen at optical wavelengths with ground-based telescopes overlaid with the SZE from Planck. The entire bridge spans a distance about the size of two full Moons in the sky.
Top image: Sunyaev–Zel’dovich effect: ESA Planck Collaboration; optical image: STScI Digitized Sky Survey. Inset image: Artist’s impression of Planck against the CMB. (ESA and the HFI Consortium, IRAS)
Artist's impression of the Planck spacecraft. Credit: ESA
[/caption]
After two and a half years of observing the Cosmic Microwave Background, the ESA Planck spacecraft’s High Frequency Instrument ran out of its on-board coolant gases over this past weekend, reaching the end of its very successful mission. But that doesn’t mean the end for Planck observations. The Low Frequency Instrument, which does not need to be super-cold (but is still at a bone-chilling -255 C), will continue taking data.
“The Low Frequency Instrument will now continue operating for another year,” said Richard Davis, of the University of Manchester in the UK. “During that time it will provide unprecedented sensitivity at the lower frequencies.”
From its location at the Earth/Sun’s L2 Lagrangian point, Planck was designed to ‘see’ the microwaves from the CMB and detects them by measuring temperature. The expansion of the Universe means that the CMB is brightest when seen in microwave light, with wavelengths between 100 and 10,000 times longer than visible light. To measure such long wavelengths Planck’s detectors have to be cooled to very low temperatures. The colder the spacecraft, the lower the temperatures the spacecraft can detect.
The High Frequency Instrument (HFI) was cooled to as close to 2.7K (about –270°C, near absolute zero) as possible.
Planck worked perfectly for 30 months, about twice the span originally required, and completed five full-sky surveys with both instruments.
“Planck has been a wonderful mission; spacecraft and instruments have been performing outstandingly well, creating a treasure trove of scientific data for us to work with,” said Jan Tauber, ESA’s Planck Project Scientist.
While it was the combination of both instruments that made Planck so powerful, there is still work for the LFI to do.
Now and Then. This single all-sky image simultaneously captured two snapshots that straddle virtually the entire 13.7 billion year history of the universe. One of them is ‘now’ – our galaxy and its structures seen as they are over the most recent tens of thousands of years (the thin strip extending across the image is the edge-on plane of our galaxy – the Milky Way). The other is ‘then’ – the red afterglow of the Big Bang seen as it was just 380,000 years after the Big Bang (top and bottom of image). The time between these two snapshots therefore covers about 99.997% of the 13.7 billion year age of the universe. The image was obtained by the Planck spacecraft. Credit: ESA
The scientists involved in Planck have been busy understanding and analyzing the data since Planck launched in May 2009. Initial results from Planck were announced last year, and with Planck data, scientists have created a map of the CMB identifying which bits of the map are showing light from the early Universe, and which parts are due to much closer objects, such as gas and dust in our galaxy, or light from other galaxies. The scientists have also produced a catalog of galaxy clusters in the distant Universe — many of which had not been seen before — and included some gigantic ‘superclusters,’ which are probably merging clusters.
The scientists expect to release data about star formation later next month, and reveal cosmological findings from the Big Bang and the very early Universe in 2013.
“The fact that Planck has worked so perfectly means that we have an incredible amount of data,” said George Efstathiou, a Planck Survey Scientist from the University of Cambridge. “Analyzing it takes very high-performance computers, sophisticated software, and several years of careful study to ensure that the results are correct.”
Six areas of the sky in which distant galaxies can be seen by Planck, overlaid on the Planck’s first all-sky image. The emission from our own Galaxy, seen in blue and white, has to be removed before the distant population of galaxies can be seen. Each square inset image is around the same size as the Full Moon. Image credit: ESA / Planck Collaboration.
[/caption]
The mission began on 13th August 2009 with a goal to image the echo’s of the birth of the Universe, the cosmic background radiation. But scientists working on the European Space Agency’s (ESA) Planck mission got more than they bargained for making ground breaking discoveries and shedding light on old mysteries. By studying light from the far reaches of the Universe, Planck has to look through the rest of the Universe first and it was during this, that the incredible discoveries were made.
The crazy thing about looking at the far reaches of the Universe is that we actually look back in time as it takes billions of years for the light to reach us here on Earth. This enables astronomers to look back in time and study the evolution of the Universe almost back to the Big Bang itself. Amongst the discoveries was evidence for an otherwise invisible population of galaxies that seem to be shrouded in dust billions of years in the past. Star formation rates in these galaxies seem to be happening at an incredible pace, some 10-1000 times higher than we see in our own Milky Way galaxy today. Joanna Dunkley, of Oxford University, said “Planck’s measurements of these distant galaxies are shedding new light on when and where ancient stars formed in the early universe”.
One of the challenges of getting a clear view of these galaxies though has been removing the so called ‘anomalous microwave emission’ (AME) foreground haze. This annoying and poorly understood interference, which is thought to originate in our own Galaxy, has only just been pierced through with Planck’s instruments. But in doing so, clues to its nature have been unveiled. It seems that the AME is coming from dust grains in our Galaxy spinning several tens of billions of times per second, perhaps from collisions with incoming faster-moving atoms or from ultra-violet radiation. Planck was able to ‘remove’ the foreground microwave haze, leaving the distant galaxies in perfect view and the cosmic background radiation untouched.
Its also the ideal instrument to detect very cold matter in the form of dust in our Galaxy and beyond, thanks to its broad wavelength coverage. During its study, it detected over 900 clumps of cold dark dust clouds which are thought to represent the first stages of star birth. By studying a number of nearby galaxies within a few billion light years, the study shows that some of them contain much more cold dust than previously thought. Dr David Clements from Imperial College London says “Planck will help us to build a ladder connecting our Milky Way to the faint, distant galaxies and uncovering the evolution of dusty, star forming galaxies throughout cosmic history.”
These results make Planck a roaring success but it doesn’t stop there. Other results just published include data on galaxy clusters revealing them silhouetted against the cosmic microwave background. These clusters contain thousands of individual galaxies gravitational bound together into gigantic strings and loops.
The Planck mission, which was in development for 15 years is already providing some ground breaking science in its first few years of operation and its exciting to wonder what we will see from it in the years that lie ahead.
A newly discovered supercluster of galaxies detected by Planck and XMM-Newton. This is the first supercluster to be discovered through its Sunyaev-Zel'dovich Effect. Copyright: Planck image: ESA/LFI & HFI Consortia; XMM-Newton image: ESA
[/caption]
Scanning the sky in microwaves, the Planck mission has obtained its very first images of galaxy clusters, and found a previously unknown supercluster which is among one of the largest objects in the Universe. The supercluster is having an effect on the Cosmic Microwave Background, and the observed distortions of the CMB spectrum are used to detect the density perturbations of the universe, using what is called the Sunyaev–Zel’dovich effect (SZE). This is the first time that a supercluster has been discovered using the SZE. In a collaborative effort, the XMM Newton spacecraft has confirmed the find in X-rays.
Sunyaev-Zel’dovich Effect (SZE) effect describes the change of energy experienced by CMB photons when they encounter a galaxy cluster as they travel towards us, in the process imprinting a distinctive signature on the CMB itself. The SZE represents a unique tool to detect galaxy clusters, even at high redshift. Planck is able to look across nine different microwave frequencies (from 30 to 857 GHz) to remove all sources of contamination from the CMB, and over time, will provide what is hoped to be the sharpest image of the early Universe ever.
“As the fossil photons from the Big Bang cross the Universe, they interact with the matter that they encounter: when travelling through a galaxy cluster, for example, the CMB photons scatter off free electrons present in the hot gas that fills the cluster,” said Nabila Aghanim of the Institut d’Astrophysique Spatiale in Orsay, France, a leading member of the group of Planck scientists investigating SZE clusters and secondary anisotropies. “These collisions redistribute the frequencies of photons in a particular way that enables us to isolate the intervening cluster from the CMB signal.”
Since the hot electrons in the cluster are much more energetic than the CMB photons, interactions between the two typically result in the photons being scattered to higher energies. This means that, when looking at the CMB in the direction of a galaxy cluster, a deficit of low-energy photons and a surplus of more energetic ones is observed.
The SZE signal from the newly discovered supercluster arises from the sum of the signal from the three individual clusters, with a possible additional contribution from an inter-cluster filamentary structure. This provides important clues about the distribution of gas on very large scales which is, in turn, crucial also for tracing the underlying distribution of dark matter.
These images of the Coma cluster (also known as Abell 1656), a very hot and nearby cluster of galaxies, show how it appears through the Sunyaev-Zel'dovich Effect (top left) and X-ray emission (top right). Copyright: Planck image: ESA/ LFI & HFI Consortia; ROSAT image: Max-Planck-Institut für extraterrestrische Physik; DSS image: NASA, ESA, and the Digitized Sky Survey 2. Acknowledgment: Davide De Martin (ESA/Hubble)
“The XMM-Newton observations have shown that one of the candidate clusters is in fact a supercluster composed of at least three individual, massive clusters of galaxies, which Planck alone could not have resolved,” said Monique Arnaud, who leads the Planck group following up sources with XMM-Newton.
“This is the first time that a supercluster has been discovered via the SZE,” said Aghanim. “This important discovery opens a brand new window on superclusters, one which complements the observations of the individual galaxies therein.”
Superclusters are large assemblies of galaxy groups and clusters, located at the intersections of sheets and filaments in the wispy cosmic web. As clusters and superclusters trace the distribution of both luminous and dark matter throughout the Universe, their observation is crucial to probe how cosmic structures formed and evolved.
The first Planck all-sky survey began in mid-August 2009 and was completed in June 2010. Planck will continue to gather data until the end of 2011, during which time it will complete over four all-sky scans.
The Planck team is currently analyzing the data from the first all-sky survey to identify both known and new galaxy clusters for the early Sunyaev-Zel’dovich catalogue, which will be released in January of 2011.
Labelled version of the Planck space observatory's all-sky survey. Credit: ESA.
[/caption]
Remember how you could once pick up a book about the first three minutes after the Big Bang and be amazed by the level of detail that observation and theory could provide regarding those early moments of the universe. These days the focus is more on what happened between 1×10-36 and 1×10-32 of the first second as we try to marry theory with more detailed observations of the cosmic microwave background.
About 380,000 years after the Big Bang, the early universe became cool and diffuse enough for light to move unimpeded, which it proceeded to do – carrying with it information about the ‘surface of last scattering’. Before this time photons were being continually absorbed and re-emitted (i.e. scattered) by the hot dense plasma of the earlier universe – and never really got going anywhere as light rays.
But quite suddenly, the universe got a lot less crowded when it cooled enough for electrons to combine with nuclei to form the first atoms. So this first burst of light, as the universe became suddenly transparent to radiation, contained photons emitted in that fairly singular moment – since the circumstances to enable such a universal burst of energy only happened once.
With the expansion of the universe over a further 13.6 and a bit billion years, lots of these photons probably crashed into something long ago, but enough are still left over to fill the sky with a signature energy burst that might have once been powerful gamma rays but has now been stretched right out into microwave. Nonetheless, it still contains that same ‘surface of last scattering’ information.
Observations tell us that, at a certain level, the cosmic microwave background is remarkably isotropic. This led to the cosmic inflation theory, where we think there was a very early exponential expansion of the microscopic universe at around 1×10-36 of the first second – which explains why everything appears so evenly spread out.
Really, the most remarkable thing about the CMB is its large scale isotropy and finding some fine grain anisotropies is perhaps not that surprising. However, it is data and it gives theorists something from which to build mathematical models about the contents of the early universe.
The apparent quadrupole moment anomalies in the cosmic microwave background might result from irregularities in the early universe - including density fluctuations, dynamic movement (vorticity) or even gravity waves. However, a degree of uncertainty and 'noise' from foreground light sources is apparent in the data, making firm conclusions difficult to draw. Credit: University of Chicago.
Some theorists speak of CMB quadrupole moment anomalies. The quadrupole idea is essentially an expression of energy density distribution within a spherical volume – which might scatter light up-down or back-forward (or variations from those four ‘polar’ directions). A degree of variable deflection from the surface of last scattering then hints at anisotropies in the spherical volume that represents the early universe.
For example, say it was filled with mini black holes (MBHs)? Scardigli et al (see below) mathematically investigated three scenarios, where just prior to cosmic inflation at 1×10-36 seconds: 1) the tiny primeval universe was filled with a collection of MBHs; 2) the same MBHs immediately evaporated, creating multiple point sources of Hawking radiation; or 3) there were no MBHs, in accordance with conventional theory.
When they ran the math, scenario 1 best fits with WMAP observations of anomalous quadrupole anisotropies. So, hey – why not? A tiny proto-universe filled with mini black holes. It’s another option to test when some higher resolution CMB data comes in from Planck or other future missions to come. And in the meantime, it’s material for an astronomy writer desperate for a story.
A multi-color all-sky image of the microwave sky. Credit: ESA, HFI and LFI consortia
[/caption]
After a year of observations, the Planck observatory team released an all-sky microwave image, and what a gorgeous image it is! The Planck satellite looks at the entire sky in the microwave region of the electromagnetic spectrum, (30 to 857 GHz) with the main goal of tracking down the echoes of the Big Bang, the Cosmic Microwave Background (CMB.) This new image reveals the cosmic signal is literally hidden behind a fog of foreground emission, arising mostly from the interstellar medium (ISM), the diffuse mixture of gas and dust filling our Galaxy.
At the top and bottom of the image in the red and yellow marbled region is where the CMB is visible.
“By contrast, a good part of the sky is dominated by the Milky Way contribution, shining strongly along the Galactic Plane but also extending well above and below it, albeit at a very much lower intensity,” said Jan Tauber, Planck Project Scientist.
To produce this image, the Planck team combined data from the full frequency range of Planck. The main disc of our Galaxy runs across the center of the image, with streamers of cold dust reaching above and below the Milky Way. This galactic web is where new stars are being formed, and Planck has found many locations where individual stars are edging toward birth or just beginning their cycle of development.
To get your bearings of where everything is locatated, here is an annotated version.
Annotated version of the Planck all-sky image. Credit: ESA, HFI and LFI consortia.
“Planck has ‘painted’ us its first spectacular picture of the Universe,” said Dr. David Parker, Director of Space Science and Exploration for the UKSpace Agency. “This single image captures both our own cosmic backyard — the Milky Way galaxy that we live in — but also the subtle imprint of the Big Bang from which the whole Universe emerged. We’re proud to be supporting this great new discovery machine and look forward to our scientists unraveling the deeper meaning behind the beauty of this first image.”
And this is just the beginning of beautiful things from Planck!
Here’s another annotated version:
Planck all-sky annotated image. Credit: ESA, HFI and LFI consortia.
(Thanks to IVAN3MAN for suggesting to add this image.)
