We're not alone, but the universe may be less crowded than we think

 

There may be far fewer galaxies further out in the universe then might be expected, according to a new study led by MSU. Credit: Photo courtesy of NASA/CXC/STSci/DSS/Magellan There may be far fewer galaxies further out in the universe then might be expected, according to a new study led by Michigan State University. Over the years, the Hubble Space Telescope has allowed astronomers to look deep into the universe. The long view stirred theories of untold thousands of distant, faint galaxies. The new research, appearing in the current issue of the Astrophysical Journal Letters, however, offers a theory that reduces the estimated number of the most distant galaxies by 10 to 100 times. "Our work suggests that there are far fewer faint galaxies than we once previously thought," said Brian O'Shea, MSU associate professor of physics and astronomy. "Earlier estimates placed the number of faint galaxies in the early universe to be hundreds or thousands of times larger than the few bright galaxies that we can actually see with the Hubble Space Telescope. We now think that number could be closer to ten times larger. O'Shea and his team used the National Science Foundation's Blue Waters supercomputer to run simulations to examine the formation of galaxies in the early universe. The team simulated thousands of galaxies at a time, including the galaxies' interactions through gravity or radiation. The simulated galaxies were consistent with observed distant galaxies at the bright end of the distribution -- in other words, those that have been discovered and confirmed. The simulations didn't, however, reveal an exponentially growing number of faint galaxies, as has been previously predicted. The number of those at the lower end of the brightness distribution was flat rather than increasing sharply, O'Shea added. These simulations will be tested further when the much-anticipated James Webb Space Telescope comes online in late 2018. The improved technology will afford astronomers even more-detailed views of space than the amazing images that the Hubble has produced in recent years. The Hubble Space Telescope can see the tip of the iceberg of the most-distant galaxies, said Michael Norman, co-author of the paper and director of the San Diego Supercomputer Center at the University of California, San Diego. While the James Webb telescope will improve views of distant galaxies, the telescope has a relatively small field of view. As a result, the observations must take into account cosmic variance -- the statistical variation in the number of galaxies from place to place. That's what makes these simulations pertinent even as improved technology becomes available, O'Shea said. "A deeper understanding based on theory may be necessary to correctly interpret what's being seen, such as high redshift survey results," he said. In addition to O'Shea and Norman, the research team also included John Wise, an assistant professor at the Georgia Institute of Technology, and Hao Xu, a postdoctoral research associate at the University of California, San Diego. The research was funded by the National Science Foundation and NASA. Story Source: The above post is reprinted from materials provided by Michigan State University. Note: Materials may be edited for content and length. Journal Reference: Brian W. O’Shea, John H. Wise, Hao Xu, Michael L. Norman. PROBING THE ULTRAVIOLET LUMINOSITY FUNCTION OF THE EARLIEST GALAXIES WITH THE RENAISSANCE SIMULATIONS. The Astrophysical Journal, 2015; 807 (1): L12 DOI: 10.1088/2041-8205/807/1/L12

Physicists offer a solution to the puzzle of the origin of matter in the universe

UCLA physicists offer a possible solution to the mystery of the origin of matter in the universe. Most of the laws of nature treat particles and antiparticles equally, but stars and planets are made of particles, or matter, and not antiparticles, or antimatter. That asymmetry, which favors matter to a very small degree, has puzzled scientists for many years. New research by UCLA physicists, published in the journal Physical Review Letters, offers a possible solution to the mystery of the origin of matter in the universe. Alexander Kusenko, a professor of physics and astronomy in the UCLA College, and colleagues propose that the matter-antimatter asymmetry could be related to the Higgs boson particle, which was the subject of prominent news coverage when it was discovered at Switzerland's Large Hadron Collider in 2012. Specifically, the UCLA researchers write, the asymmetry may have been produced as a result of the motion of the Higgs field, which is associated with the Higgs boson, and which could have made the masses of particles and antiparticles in the universe temporarily unequal, allowing for a small excess of matter particles over antiparticles. If a particle and an antiparticle meet, they disappear by emitting two photons or a pair of some other particles. In the "primordial soup" that existed after the Big Bang, there were almost equal amounts of particles of antiparticles, except for a tiny asymmetry: one particle per 10 billion. As the universe cooled, the particles and antiparticles annihilated each other in equal numbers, and only a tiny number of particles remained; this tiny amount is all the stars and planets, and gas in today's universe, said Kusenko, who is also a senior scientist with the Kavli Institute for the Physics and Mathematics of the Universe. The research also is highlighted by Physical Review Letters in a commentary in the current issue. The 2012 discovery of the Higgs boson particle was hailed as one of the great scientific accomplishments of recent decades. The Higgs boson was first postulated some 50 years ago as a crucial element of the modern theory of the forces of nature, and is, physicists say, what gives everything in the universe mass. Physicists at the LHC measured the particle's mass and found its value to be peculiar; it is consistent with the possibility that the Higgs field in the first moments of the Big Bang was much larger than its "equilibrium value" observed today. The Higgs field "had to descend to the equilibrium, in a process of 'Higgs relaxation,'" said Kusenko, the lead author of the UCLA research. Two of Kusenko's graduate students, Louis Yang of UCLA and Lauren Pearce of the University of Minnesota, Minneapolis, were co-authors of the study. The research was supported by the U.S. Department of Energy (DE-SC0009937), the World Premier International Research Center Initiative in Japan and the National Science Foundation (PHYS-1066293).

Hubble finds extremely distant galaxy through cosmic magnifying glass

 

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The heart of the mammoth galaxy cluster Abell 2744, also known as Pandora's Cluster, is shown in this Hubble Space Telescope image. The cluster is so massive that its powerful gravity bends the light from galaxies far behind it, making background objects appear larger and brighter in a phenomenon called gravitational lensing. These powerful lenses allow astronomers to find many dim, distant structures that otherwise might be too faint to see. The small white boxes, labeled "a," "b," and "c," mark multiple images from the same background galaxy, one of the farthest, faintest, and smallest galaxies ever seen. The diminutive object is estimated to be over 13 billion light-years away. Enlarged views of the multiple images are shown in the insets at right.

Peering through a giant cosmic magnifying glass, NASA's Hubble Space Telescope has spotted one of the farthest, faintest, and smallest galaxies ever seen. The diminutive object is estimated to be over 13 billion light-years away.

This new detection is considered one of the most reliable distance measurements of a galaxy that existed in the early universe, said the Hubble researchers. They used two independent methods to estimate its distance.

The galaxy appears as a tiny blob that is only a small fraction of the size of our Milky Way galaxy. But it offers a peek back into a time when the universe was only about 500 million years old, roughly 3 percent of its current age of 13.7 billion years. Astronomers have uncovered about 10 other galaxy candidates at this early era. But this newly found galaxy is significantly smaller and fainter than most of those other remote objects detected to date.

"This object is a unique example of what is suspected to be an abundant, underlying population of extremely small and faint galaxies at about 500 million years after the big bang," explained study leader Adi Zitrin of the California Institute of Technology in Pasadena. "The discovery is telling us that galaxies as faint as this one exist, and we should continue looking for them and even fainter objects so that we can understand how galaxies and the universe have evolved over time."

The galaxy was detected as part of the Frontier Fields program, an ambitious three-year effort, begun in 2013, that teams Hubble with NASA's other Great Observatories -- the Spitzer Space Telescope and the Chandra X-ray Observatory -- to probe the early universe by studying large galaxy clusters. These clusters are so massive that their gravity deflects light passing through them, magnifying, brightening, and distorting background objects in a phenomenon called gravitational lensing. These powerful lenses allow astronomers to find many dim, distant structures that otherwise might be too faint to see.

In this new discovery, the lensing power of the mammoth galaxy cluster Abell 2744, nicknamed Pandora's Cluster, produced three magnified images of the same galaxy. Each magnified image makes the galaxy appear as much as 10 times larger and brighter than it would look without the intervening lens.

An analysis of the distant galaxy shows that it measures merely 850 light-years across, 500 times smaller than the Milky Way, and is estimated to have a mass of only 40 million suns. The galaxy's star formation rate is about one star every three years (one-third the star formation rate in the Milky Way). Although this may seem low, Zitrin said that given its small size and low mass, the tiny galaxy is in fact rapidly evolving and efficiently forming stars.

"Galaxies such as this one are probably small clumps of matter that are starting to form stars and shine light, but they don't have a defined structure yet," Zitrin said. "Therefore, it's possible that we only see one bright clump magnified due to the lensing, and this is one possibility as to why it is smaller than typical field galaxies of that time." Zitrin's team spotted the galaxy's gravitationally multiplied images using near-infrared and visible-light photos of the galaxy cluster taken by Hubble's Wide Field Camera 3 and Advanced Camera for Surveys. But at first they didn't know how far away it was from Earth.

Normally, astronomers use spectroscopy to determine an object's distance. The farther away a galaxy, the more its light has been stretched by the universe's expansion. Astronomers can precisely measure this effect through spectroscopy, which characterizes an object's light.

But the gravitationally lensed galaxy and other objects found at this early epoch are too far away and too dim for astronomers to use spectroscopy. Astronomers instead analyze an object's color to estimate its distance. The universe's expansion reddens an object's color in predictable ways, which scientists can measure.

Members of Zitrin's team not only performed the color-analysis technique, but they also took advantage of the multiple images produced by the gravitational lens to independently confirm their distance estimate. The astronomers measured the angular separation between the three magnified images of the galaxy in the Hubble photos. The greater the angular separation due to lensing, the farther away the object is from Earth. To test this concept, the astronomers compared the three magnified images with the locations of several other multiply imaged objects lensed by Abell 2744 that are not as far behind the cluster. The angular distance between the magnified images of the closer galaxies was smaller.

"These measurements imply that, given the large angular separation between the three images of our background galaxy, the object must lie very far away," Zitrin explained. "It also matches the distance estimate we calculated, based on the color-analysis technique. So we are about 95 percent confident that this object is at a remote distance, at redshift 10 (a measure of the stretching of space since the big bang). The lensing takes away any doubt that this might be a heavily reddened, nearby object masquerading as a far more distant object."

Astronomers have long debated whether such early galaxies could have provided enough radiation to warm the hydrogen that cooled soon after the big bang. This process, called "reionization," is thought to have occurred 200 million to 1 billion years after the birth of the universe. Reionization made the universe transparent to light, allowing astronomers to look far back into time without running into a "fog" of cold hydrogen.

"We tend to assume that galaxies ionized the universe with their ultraviolet light," Zitrin said. "But we do not see enough galaxies or light that could do that. So we need to look at fainter and fainter galaxies, and the Frontier Fields and galaxy cluster lensing can help us achieve this goal."

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Story Source:

The above story is based on materials provided by Space Telescope Science Institute (STScI). Note: Materials may be edited for content and length.

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Journal Reference:

1. Adi Zitrin, Wei Zheng, Tom Broadhurst, John Moustakas, Daniel Lam, Xinwen Shu, Xingxing Huang, Jose M. Diego, Holland Ford, Jeremy Lim, Franz E. Bauer, Leopoldo Infante, Daniel D. Kelson, Alberto Molino. A GEOMETRICALLY SUPPORTEDz∼ 10 CANDIDATE MULTIPLY IMAGED BY THE HUBBLE FRONTIER FIELDS CLUSTER A2744. The Astrophysical Journal, 2014; 793 (1): L12 DOI: 10.1088/2041-8205/793/1/L12

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In a "Rainbow" Universe Time May Have No Beginning

 

If different wavelengths of light experience spacetime differently, the big bang may never have happened

 

 

Our Origins

 

Q: How did the universe form?

For thousands of years, humans have looked to the night sky and created myths to explain the origins of the planets and stars. The real answer could soon come from the elegant computer simulations conducted by Tom Abel, an associate professor of physics at Stanford.

Cosmologists face an ironic conundrum. By studying the current universe, we have gained a tremendous understanding of what occurred in the fractions of a second after the Big Bang, and how the first 400,000 years created the ingredients – gases, energy, etc. – that would eventually become the stars, planets and everything else. But we still don’t know what happened after those early years to create what we see in the night sky.

“It’s the perfect problem for a physicist, because we know the initial conditions very well,” says Abel, who is also director of the Kavli Institute for Particle Astrophysics and Cosmology at SLAC. “If you know the laws of physics correctly, you should be able to exactly calculate what will happen next.”

Easier said than done. Abel’s calculations must incorporate the laws of chemistry, atomic physics, gravity, how atoms and molecules radiate, gas and fluid dynamics and interactions, the forces associated with dark matter and so on. Those processes must then be simulated out over the course of hundreds of millions, and eventually billions, of years. Further complicating matters, a single galaxy holds one billion moving stars, and the simulation needs to consider their interactions in order to create an accurate prediction of how the universe came to be.

“Any of the advances we make will come from writing smarter algorithms,” Abel says. “The key point of the new facility is it will allow for rapid turnaround, which will allow us to constantly develop and refine and validate new algorithms. And this will help us understand how the very first things were formed in the universe.” —Bjorn Carey //

Q: How did we evolve?

The human genome is essentially a gigantic data set. Deep within each person’s six billion data points are minute variations that tell the story of human evolution, and provide clues to how scientists can combat modern-day diseases.

To better understand the causes and consequences of these genetic variations, Jonathan Pritchard, a professor of genetics and of biology, writes computer programs that can investigate those links. “Genetic variation affects how cells work, both in healthy variation and in response to disease,” Pritchard says. How that variation displays itself – in appearance or how cells work – and whether natural selection favors those changes within a population drives evolution.

Consider, for example, variation in the gene that codes for lactase, an enzyme that allows mammals to digest milk. Most mammals turn off the lactase gene after they’ve been weaned from their mother’s milk. In populations that have historically revolved around dairy farming, however, Pritchard’s algorithms have helped to elucidate signals of strong selection since the advent of agriculture to enable people to process milk active throughout life. There has been similarly strong selection on skin pigmentation in non-Africans that allow better synthesis of vitamin D in regions where people are exposed to less sunlight.

The algorithms and machine learning methods Pritchard used have the potential to yield powerful medical insights. Studying variations in how genes are regulated within a population could reveal how and where particular proteins bind to DNA, or which genes are turned on in different cell types­ – information that could help design novel therapies. These inquiries can generate hundreds of thousands of data sets and can only be parsed with up to tens of thousands of hours of computer work.

Pritchard is bracing for an even bigger explosion of data; as genome sequencing technologies become less expensive, he expects the number of individually sequenced genomes to jump by as much as a hundredfold in the next few years. “Storing and analyzing vast amounts of data is a fundamental challenge that all genomics groups are dealing with,” says Pritchard, who is a member of Stanford Bio-X. “Having access to SRCC will make our inquiries go easier and more quickly, and we can move on faster to making the next discovery.” —Bjorn Carey //

Is All the Universe from Nothing?

 

By Richard Yonck | May 22, 2014 |  

The views expressed are those of the author and are not necessarily those of Scientific American.

 

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In March, a team of researchers based in Antarctica announced they’d detected gravitational waves, faint echoes from the first moments of the Big Bang. This discovery has enormous implications for cosmology, the world of physics and even our understanding of the future of our universe. My recent blog post about the BICEP2 project explored some of these, as does my upcoming article about cosmic inflation in the July-August issue of The Futurist.

The expansion of the universe. (Source: NASA)

These writings gave me a lot to think about regarding the origins of our universe. Invariably, when explaining the early evolution of the cosmos, one particular question always comes up: where did the singularity that started the Big Bang come from? For some time, many physicists and cosmologists have said it could be possible for our universe to have actually started from nothing – as wild and counterintuitive as that sounds. But without proof this seems like a statement of faith, impossible to prove or disprove and therefore outside the purview of true scientific discussion. Ever since Popper, we’ve said that falsifiability is the demarcation between what is scientific and what is not. It felt like this might be the point where the scientific method would have to give way to the origin stories of myth.

Or perhaps not.

Last month saw the publication of a paper that may be as important to our understanding of the Big Bang as was the detection of gravitational waves. A team from the Wuhan Institute of Physics and Mathematics in China has made the first rigorous mathematical proof that the Big Bang could have spontaneously generated from nothing. The Wuhan team, led by Qing-yu Cai, developed new solutions to the Wheeler-DeWitt equation, which sought to combine quantum mechanics and general relativity in the mid-20^th century.

A map of cosmic microwave background radiation. (Source: NASA)

According to Heisenberg’s uncertainty principle, quantum fluctuations in the metastable false vacuum – a state absent of space, time or matter – can give rise to virtual particle pairs. Ordinarily these pairs self-annihilate almost instantly, but if these virtual particles separate immediately, they can avoid annihilation, creating a true vacuum bubble. The Wuhan team’s equations show that such a bubble has the potential to expand exponentially, causing a new universe to appear. All of this begins from quantum behavior and leads to the creation of a tremendous amount of matter and energy during the inflation stage. (Note that as stated in this paper, the metastable false vacuum has “neither matter nor space or time,” but is a form of wavefunction referred to as “quantum potential.” While most of us wouldn’t be inclined to call this “nothing,” physicists do refer to it as such.)

This description of exponential growth of a true vacuum bubble corresponds directly to the period of cosmic inflation resulting from the Big Bang. According to this proof, the bubble even stops expanding – or else it may continue to expand at a constant velocity – once it reaches a certain size. Nevertheless, this is a very different version of inflation than those proposed by Guth, Linde and others, in that it doesn’t rely on scalar fields, only quantum effects. Still, this work dovetails well with that of the BICEP2 team, both discoveries having significant implications for our understanding of the universe and our future should they stand up to further inquiry.

A map of cosmic microwave background radiation. (Source: European Space Agency)

Given the quantum behavior of virtual particles in a vacuum as put forth in this paper, it’s reasonable to assume this hasn’t happened only this once, but rather many or potentially even an infinite number of times. The idea of a multitude of multiverses being generated by processes similar to those that gave rise to our own universe is not new. But this is the first time we’ve actually identified the mechanisms that may have been involved. In discussing this with one of the authors, Qing-yu Cai said he thinks their work “supports the multiverse concept.” Whether this process would result in the exact same physical laws that we see in our own universe remains to be determined, since according to these equations only limited conditions could result in an exponentially expanding true vacuum bubble.

Another idea that’s been discussed in the past is whether or not we could ever create new universes ourselves, perhaps using something like the Large Hadron Collider (LHC). However, as Qing-yu Cai observed, “space-time of our universe is a whole, it cannot be divided into small parts arbitrarily, even at LHC.” Therefore, “it seems impossible to create new universes ourselves.”

Ultimately, this mathematical proof needs to be checked out by others and ideally put to some yet-to-be-determined tests. In the end, the work may or may not be accepted. That is, after all, how the scientific method operates. But if this proof should stand up to scrutiny, it will most certainly give us considerable new insights into the mechanisms that gave birth to our cosmos. The news of this past month demonstrates that the field of cosmology remains vibrant, with new ideas and discoveries regularly being made. Our universe and the physics at its foundation are incredibly complex and will continue to yield new knowledge about our past, present and future for a long time to come. Perhaps until the end of time.

Sources and Further Reading:

Spontaneous creation of the universe from nothing. Dongshan He, Dongfeng Gao, Qing-yu Cai. Apr 4, 2014.

A Window on the Universe’s Distant Past and Future. Yonck, Richard. Mar 17, 2014.

The Origin of the Universe (text). Hawking, Stephen. Berkley lecture, Mar 13, 2007.

Inflation in Cosmology. Wikipedia.

Twin Earth May Be Better Than Earth for Life

 

By Michael Moyer | April 17, 2014 |  

Artist's vision of Kepler-186f

Pseudo-Earths are out there. That’s the message of today’s exciting announcement that a planet about the same size as Earth lives in its star’s habitable zone—the temperate region around a star where liquid water might flow. “For me, the impact is to prove that such planets really do exist,” said David Charbonneau, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, to Nature.

It’s an article of faith that the planets most likely to harbor life are the planets most like Earth. Our home is, after all, the only known place in the universe that gives life shelter. From our sample of size of one we peer out into the cosmos for places that might mirror back the essential features that make our planet so fertile.

Unfortunately, discovering distant planets is so difficult that we can only discern the barest information about any potential neighbor. In the case of Kepler-186f, the newly discovered Earth-like exoplanet, astronomers know its size (about 1.11 times the radius of Earth), the length of its year (130 Earth days), and how much solar radiation it receives (about 32 percent of what the Earth gets from the Sun). Other questions—what is it made of? does it have an atmosphere? how hot is its surface?—we can only answer indirectly, if at all. There’s no way to tell, in other words, if the surface of Kepler-186f supports swimmable temperatures between zero and 100 degrees Celsius.

But we can flip the question of habitability around. Instead of assuming that the most life-friendly planets are Earth-sized orbs circling a Sun-like star, we can ask what characteristics a planet might have if we were to build it from scratch with the express purpose of setting the stage for the genesis of life and evolutionary success. What simple beginnings would best brew life’s endless forms most beautiful?

The answer, it turns out, isn’t an exact copy of Earth. Astronomers have recently begun to ponder the possibility of a “superhabitable” planet—one that has all the life-giving features of Earth, but more so. What are the characteristic signatures of such a world?  As the astronomers René Heller and John Armstrong describe in a recent paper, these planets will be slightly larger than Earth—up to about two or three times Earth’s radius. These chubby Earths would presumably have more magnetic shielding from solar radiation; greater tectonic activity, which means more volcanoes to belch carbon dioxide into the atmosphere; a thicker atmosphere, held in by the greater surface gravity, and simply more surface area for life to roam.

A moon wouldn’t hurt either. As Lee Billings described in our January story “The Search for Life on Faraway Moons,” a moon surrounding a distant planet could create a tidal heating effect—the orbit of the moon stretching and contracting the planet enough to generate frictional heating forces that would make a planet habitable even if it orbited outside of its star’s habitable zone. Discovering a moon is much trickier than finding a planet itself, however. (A few intrepid astronomers are on the case.) For now, the only special planetary attributes we can reliably search for are those that a spacecraft like Kepler can discern: size and distance from star. And, of course, what the star itself looks like.

In this, the planet Kepler-186f may be a winner. The star it orbits—Kepler 186—is a dwarf star, dimmer and smaller than our Sun. These stars burn a little less vigorously than our Sun does, which means their nuclear fuel can last for billions of years longer—additional billions of years for evolution to do its work.

With a radius 11 percent larger than Earth’s and an orbit around an extremely long-lived dwarf star, Kepler 186f may be undersold as a twin of Earth. It could be our first example of a superhabitable world.

Image courtesy NASA Ames/SETI Institute/JPL-Caltech

First Earth-Size Planet that Could Support Life Found

 

NASA's Kepler space telescope has identified a planet that is both similar in size to Earth and within the habitable zone of its sun

This artist illustration shows the planet Kepler-186f, the first Earth-size alien planet discovered in the habitable zone of its star NASA Ames/SETI Institute/JPL-CalTech

For the first time, scientists have discovered an Earth-size alien planet in the habitable zone of its host star, an "Earth cousin" that just might have liquid water and the right conditions for life.

The newfound planet, called Kepler-186f, was first spotted by NASA's Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth. While the host star is dimmer than Earth's sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say. You can learn more about the amazing alien planet find in a video produced by Space.com.

"One of the things we've been looking for is maybe an Earth twin, which is an Earth-size planet in the habitable zone of a sunlike star," Tom Barclay, Kepler scientist and co-author of the new exoplanet research, told Space.com. "This [Kepler-186f] is an Earth-size planet in the habitable zone of a cooler star. So, while it's not an Earth twin, it is perhaps an Earth cousin. It has similar characteristics, but a different parent." [10 Exoplanets That Could Host Alien Life]

Potentially habitable planet

Scientists think that Kepler-186f — the outermost of five planets found to be orbiting the star Kepler-186 — orbits at a distance of 32.5 million miles (52.4 million kilometers), theoretically within the habitable zone for a red dwarf.

Earth orbits the sun from an average distance of about 93 million miles (150 million km), but the sun is larger and brighter than the Kepler-186 star, meaning that the sun's habitable zone begins farther out from the star by comparison to Kepler-186.

"This is the first definitive Earth-sized planet found in the habitable zone around another star," Elisa Quintana, of the SETI Institute and NASA's Ames Research Center and the lead author of a new study detailing the findings, said in a statement.

Other planets of various sizes have been found in the habitable zones of their stars. However, Kepler-186f is the first alien planet this close to Earth in size found orbiting in that potentially life-supporting area of an extrasolar system, according to exoplanet scientists.

'An historic discovery'

"This is an historic discovery of the first truly Earth-size planet found in the habitable zone around its star," Geoff Marcy, an astronomer at the University of California, Berkeley, who is unaffiliated with the research, told Space.com via email. "This is the best case for a habitable planet yet found. The results are absolutely rock-solid. The planet itself may not be, but I'd bet my house on it. In any case, it's a gem."

The newly discovered planet measures about 1.1 Earth radii, making it slightly larger than Earth, but researchers still think the alien world may be rocky like Earth. Researchers still aren't sure what Kepler-186f's atmosphere is made of, a key element that could help scientists understand if the planet is hospitable to life. [Kepler-186f: Earth-Size World Could Support Oceans, Maybe Life (Infographic)]

"What we've learned, just over the past few years, is that there is a definite transition which occurs around about 1.5 Earth radii," Quintana said in a statement. "What happens there is that for radii between 1.5 and 2 Earth radii, the planet becomes massive enough that it starts to accumulate a very thick hydrogen and helium atmosphere, so it starts to resemble the gas giants of our solar system rather than anything else that we see as terrestrial."

The edge of habitability

Kepler-186f actually lies at the edge of the Kepler-186 star's habitable zone, meaning that liquid water on the planet's surface could freeze, according to study co-author Stephen Kane of San Francisco State University.

Because of its position in the outer part of the habitable zone, the planet's larger size could actually help keep its water liquid, Kane said in a statement. Since it is slightly bigger than Earth, Kepler-186f could have a thicker atmosphere, which would insulate the planet and potentially keep its water in liquid form, Kane added.

"It [Kepler-186f] goes around its star over 130 days, but because its star is a lower mass than our sun, the planet orbits slightly inner of where Mercury orbits in our own solar system," Barclay said. "It's on the cooler edge of the habitable zone. It's still well within it, but it receives less energy than Earth receives. So, if you're on this planet [Kepler-186f], the star would appear dimmer."

Exoplanet hunting in the future

Kepler-186f could be too dim for follow-up studies that would probe the planet's atmosphere. NASA's James Webb Space Telescope — Hubble's successor, expected to launch to space in 2018 — is designed to image planets around relatively nearby stars; however, the Kepler-186 system might be too far off for the powerful telescope to investigate, Barclay said.

Scientists using the Kepler telescope discovered Kepler-186f using the transit method: When the planet moved across the face of its star from the telescope's perspective, Kepler recorded a slight dip in the star's brightness, allowing researchers to learn more about the planet itself. Kepler suffered a major malfunction last year and is no longer working in the same fashion, but scientists are still going through the spacecraft's trove of data searching for new alien worlds.

NASA Technology Views Birth of the Universe

 

Astronomers are announcing today that they have acquired the first direct evidence that gravitational waves rippled through our infant universe during an explosive period of growth called inflation. This is the strongest confirmation yet of cosmic inflation theories, which say the universe expanded by 100 trillion trillion times, in less than the blink of an eye.

The findings were made with the help of NASA-developed detector technology on the BICEP2 telescope at the South Pole, in collaboration with the National Science Foundation.

"Operating the latest detectors in ground-based and balloon-borne experiments allows us to mature these technologies for space missions and, in the process, make discoveries about the universe," said Paul Hertz, NASA's Astrophysics Division director in Washington.

Our universe burst into existence in an event known as the Big Bang 13.8 billion years ago. Moments later, space itself ripped apart, expanding exponentially in an episode known as inflation. Telltale signs of this early chapter in our universe's history are imprinted in the skies, in a relic glow called the cosmic microwave background. Recently, this basic theory of the universe was again confirmed by the Planck satellite, a European Space Agency mission for which NASA provided detector and cooler technology.

But researchers had long sought more direct evidence for inflation in the form of gravitational waves, which squeeze and stretch space.

"Small, quantum fluctuations were amplified to enormous sizes by the inflationary expansion of the universe. We know this produces another type of waves called density waves, but we wanted to test if gravitational waves are also produced," said project co-leader Jamie Bock of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., which developed the BICEP2 detector technology. Bock has a joint appointment with the California Institute of Technology, also in Pasadena.

The gravitational waves produced a characteristic swirly pattern in polarized light, called "B-mode" polarization. Light can become polarized by scattering off surfaces, such as a car or pond. Polarized sunglasses reject polarized light to reduce glare. In the case of the cosmic microwave background, light scattered off particles called electrons to become slightly polarized.

The BICEP2 team took on the challenge to detect B-mode polarization by pulling together top experts in the field, developing revolutionary technology and traveling to the best observing site on Earth at the South Pole. The collaboration includes major contributions from Caltech; JPL; Stanford University, Stanford, Calif.; Harvard University, Cambridge, Mass.; and the University of Minnesota, Minneapolis.

As a result of experiments conducted since 2006, the team has been able to produce compelling evidence for the B-mode signal, and with it, the strongest support yet for cosmic inflation. The key to their success was the use of novel superconducting detectors. Superconductors are materials that, when chilled, allow electrical current to flow freely, with zero resistance.

"Our technology combines the properties of superconductivity with tiny structures that can only be seen with a microscope. These devices are manufactured using the same micro-machining process as the sensors in cellphones and Wii controllers," said Anthony Turner, who makes these devices using specialized fabrication equipment at JPL's Microdevices Laboratory.

The B-mode signal is extremely faint. In order to gain the necessary sensitivity to detect the polarization signal, Bock and Turner developed a unique array of multiple detectors, akin to the pixels in modern digital cameras but with the added ability to detect polarization. The whole detector system operates at a frosty 0.25 Kelvin, just 0.45 degrees Fahrenheit above the lowest temperature achievable, absolute zero.

"This extremely challenging measurement required an entirely new architecture," said Bock. "Our approach is like taking a camera and building it on a printed circuit board."

The BICEP2 experiment used 512 detectors, which sped up observations of the cosmic microwave background by 10 times over the team's previous measurements. Their new experiment, already making observations, uses 2,560 detectors.

These and future experiments not only help confirm that the universe inflated dramatically, but are providing theorists with the first clues about the exotic forces that drove space and time apart.

The results of this study have been submitted to the journal Nature.

JPL is managed by the California Institute of Technology in Pasadena for NASA.

 

 

This Is What We Don’t Know About The Universe

 

By Caleb A. Scharf | March 12, 2014 |  

 

You may experience some temporary disillusionment

In recent days I’ve had some interesting conversations. There’s a giddiness going around, related to an outpouring of science love – the kind you get from President Obama introducing TV science shows, the kind that has wonderful visuals, but is, well, a wee bit simplistic (a sin that none of us could ever, ever be accused of, naturally). It’s all very positive, commendable, and perfectly reasonable. But it leaves me feeling a little askew. You see, the thing is, it’s relatively easy to focus on what we know, yet to me the wonder of the cosmos, the awesomeness, is never greater than when we contemplate all that we don’t know.

It’s true that when we take note of the impossibly brief sliver of time that our entire species has inhabited compared to the billions of years before, and the untold billions ahead, one can feel refreshingly small. Or, if we contemplate the billions of trillions of other worlds that must exist across the observable universe, we can grasp momentarily at just how tiny our daily existence is. But for me nothing compares to the perspective, the shock, or the excitement, of being reminded of what we don’t know.

We don’t know why the universe exists: This is really quite unfair, and could be grounds for doubting that the cosmos knows what its doing. But in terms of physics, although there are some really very appealing, very promising, theoretical frameworks that begin to answer the question, the simple truth is that we’re not sure which might be right. It may be that the universe springs from an inherently unstable ‘nothingness’. The most void-like void, prone to spontaneous generation of matter and energy in proportions that always balance out to zero (yep, really, read Lawrence Krauss’s great book on this). Furthermore, this may not be the only universe (a terrible linguistic fail, I know), but rather one of a vast array, part of a multiverse of more than 10 to the power of 10 to the power of 16 distinguishable realities. But a big piece of the problem is that we’re still waiting for the next generation of cosmic measurements to chip away at the models, and we’re still waiting for theories that provide more readily testable hypotheses, not just mathematical elegance. So we don’t know why the heck all of this exists. Sorry.

We don’t know what dark matter, or dark energy, is: Big problem, honking big problem. Normal matter, the stuff of you, the stuff of me, planets, stars, and cheese sandwiches, amounts to only about 4.9% of the total matter and energy content of the universe. 26.8% of matter is ‘dark’, we know it’s there because on large, cosmic, scales stuff moves around faster than it should and because the way that galaxies strew themselves across space is consistent with the existence of vast amounts of slow-moving gravitating ‘stuff’ that never turns into stars or planets or anything, just stays as diffuse, invisible, incredibly antisocial particles. Except we really have no idea what these particles truly are – a situation beautifully summarized recently by Mario Livio and Joe Silk. That’s nasty, but perhaps nastier is dark energy. Something is causing the expansion of the universe to accelerate. It didn’t used to. Until about 5 or 6 billion years ago the stretching of space following the Big Bang was in decline, but then something started to counter that, another unseen component, perhaps a type of vacuum energy density that fills up space as space itself grows. What exactly is it? We do not know. We have lots of ideas though, which is great, always good to have ideas about 68.3% of the universe.

We don’t know whether life exists anywhere else: This one is close to my heart. Here we are, sentient beings on a planet seething with life (although perhaps not as seething as it could be) that’s been busy sculpting and re-sculpting the physical and chemical environment for much of the past 5 billion years. And now we’re confident that there are lots of planets out there, and that many of them could have an equal shot at playing host to life. But we still don’t know whether or not we’re alone. No clue. That’s quite a problem. Don’t get me wrong, it’s a good problem, a juicy problem, one of the best. But even when the President of the United States introduces a lovely glossy TV series all about science, science that addresses the question of life in the universe, that doesn’t mean that governments or industry give a fig about paying to solve the problem. As Lee Billings writes in his recent, wonderful, book, the lack of a sense of urgency is a little bewildering. So we continue to bumble along in splendid isolation, with only our towels for comfort.

We probably haven’t really figured out the quantum world: What!? While it’s true that our present mathematical framework of quantum mechanics can do wonders, from describing atoms and molecules to the bizarre nature of entanglement and qubits, that doesn’t mean that we’ve nailed the case shut. Quite the contrary. One need only cast a look over the literature to see that the most fundamental aspects of the quantum nature of the universe are still causing headaches and disagreements. People are still reformulating the ways in which we cope with the quantum nature of reality (yes, they are) so it’s clearly too soon to call this fully understood. Not only that, but the possibility of pure quantum effects reaching into the realm of soft, wet, and warm biology has also raised its head (although admittedly it depends on who’s talking) – a rather unnerving notion. . Oh, and don’t get me started on black holes and quantum firewalls…

We don’t understand our own biology: It’s not too radical to say this, after all, if we did understand every detail of how we worked we’d presumably be able to eliminate disease (assuming that’s actually better for us, which it clearly is individually, but perhaps not as a species). We’d also be able to customize ourselves by reaching into to those 3 billion or so nucleic acids in our DNA and doing a spot of molecular engineering, getting those purple earlobes we’ve always wanted. But we’re not close to doing this any better than we can come up with ‘engineered’ crops -  lots of misses and a few hits. Want a good example of our pitiful lack of knowledge? It’s the microbiome. Our ten trillion human cells are augmented, exploited, nurtured, by a hundred trillion microbial cells – a couple of pounds of bacteria and archaea that we all carry around and can’t live without. They’re in our guts, our lungs, up our noses and in every other dank corner. We’re just cruise ships for the ultimate microbial Club-Med, and we simply don’t know what that all means.

We don’t know how the Earth works: Let’s lurch back to a grander scale. No human, or robot, has ever physically traveled deeper than a few miles into the Earth’s crust, everything else is extrapolation and interpolation from ‘remote sensing’ and clever physical analyses. It took us a ridiculously long time to figure out that the outer planetary skin is moving and sliding around; plate tectonics was not generally accepted until the mid-20th century! We’re still not sure exactly how the inner dynamo works, how rolls of convecting, conducting material in the outer core generate our planetary magnetic field. There’s also so much mess after 4.5 billion years of geophysics that some of our best information about the planet’s origins come from meteorites and the cratering of other worlds – outsourced. Speaking of other worlds, we’re not even sure we understand where the Moon came from, maybe it was a giant impact, maybe not. For an allegedly clever species on a small rocky planet this is a bit of an epic fail.

We can’t prove or solve many of our own mathematical conjectures and problems: Ouch. Lest mathematics thinks it can escape this festival of ignorance, just remind yourself that there’s a long list of unproven, unsolved problems and unproven conjectures. Here, take a look. All in all, best kept firmly brushed under the carpet. Another glass of sherry professor?

We don’t know how to make an artificial intelligence: I’m putting this here because it’s a perennial problem, and one that speaks to both our desire to understand ourselves (if you can make an artificial being you may find the secret sauce behind your own intelligence, even if ultimately it’s just an emergent phenomenon) as well as to understand what might be ‘out there’ in the vastness of the cosmos, wrought by billions of years of alien evolution, and really quite depressed by it all. Although we’ve come a long way with our machines, it’s not clear that predictive text or automated suggestions for shopping and movie streaming are really assembling information in any way that resembles how our minds generate ideas. This is truly a frontier.

The conclusion? There’s an awful lot we don’t know (far more than just the examples here). But the point is not to get despondent, because this ignorance is a beautiful thing. It’s what ultimately drives science, and it’s what makes the universe truly awe-inspiring. After the hundreds of thousands of years that Homo sapiens has loped around, the cosmos can still elude our fidgety, inquisitive minds, easily outracing our considerable imaginations. How wonderful.