Deceased--Halton C. Arp

"Halton C. Arp, Astronomer Who Challenged Big Bang Theory, Dies at 86"

By: Dennis Overbye, January 6th, 2014, The New York Times: Halton C. Arp, a prodigal son of American astronomy whose dogged insistence that astronomers had misread the distances to quasars cast doubt on the Big Bang theory of the universe and led to his exile from his peers and the telescopes he loved, died on Dec. 28 in Munich. He was 86. The cause was pneumonia, said his daughter Kristana Arp, who said he also had Parkinson’s disease. As a staff astronomer for 29 years at Hale Observatories, which included the Mount Wilson and Palomar Mountain observatories in Southern California, Dr. Arp was part of their most romantic era, when astronomers were peeling back the sky and making discovery after discovery that laid the foundation for the modern understanding of the expansion of the universe. But Dr. Arp, an artist’s son with a swashbuckling air, was no friend of orthodoxy. A skilled observer with regular access to a 200-inch telescope on Palomar Mountain, he sought out unusual galaxies and collected them in “The Atlas of Peculiar Galaxies” (1966), showing them interacting and merging with loops, swirls and streamers that showed the diversity and beauty of nature. But these galaxies also revealed something puzzling and controversial. In the expanding universe, as discovered by Edwin Hubble in 1929, everything is moving away from us. The farther away it is, the faster it is going, as revealed by its redshift, a stretching of light waves — like the changing tone of an ambulance siren as it goes past — known as a Doppler shift. Dr. Arp found that galaxies with radically different redshifts, and thus at vastly different distances from us, often appeared connected by filaments and bridges of gas. This suggested, he said, that redshift was not always an indication of distance but could be caused by other, unknown physics. The biggest redshifts belonged to quasars — brilliant, pointlike objects that are presumably at the edge of the universe. Dr. Arp found, however, that they were often suspiciously close in the sky to relatively nearby spiral galaxies. This suggested to him that quasars were not so far away after all, and that they might have shot out of the nearby galaxies. If he was right, the whole picture of cosmic evolution given by the Big Bang — of a universe that began in a blaze of fire and gas 14 billion years ago and slowly condensed into stars, galaxies and creatures over the eons — would have to go out the window. A vast majority of astronomers dismissed Dr. Arp’s results as coincidences or optical illusions. But his data appealed to a small, articulate band of astronomers who supported a rival theory of the universe called Steady State and had criticized the Big Bang over the decades. Among them were Fred Hoyle, of Cambridge University, who had invented the theory, and Geoffrey Burbidge, a witty and acerbic astrophysicist at the University of California, San Diego. Dr. Arp survived both of them. “When he died, he took a whole cosmology with him,” said Barry F. Madore, a senior research associate at the Carnegie Observatories in Pasadena, Calif. Halton Christian Arp was born on March 21, 1927, in New York City, the only son of August and Anita Arp. His father was an artist and his mother ran institutions for children and adolescents. Halton grew up in Greenwich Village and various art colonies and did not go to school until fifth grade. After bouncing around public schools in New York, he was sent to Tabor Academy, on Buzzards Bay in Massachusetts, a prep school for the United States Naval Academy. After a year in the Navy, he attended Harvard, where he majored in astronomy. He graduated in 1949 and went on to obtain a Ph.D. in 1953 at the California Institute of Technology, which had started an astronomy graduate program to prepare for the advent of the 200-inch telescope. At Harvard, he became one of the best fencers in the United States, ultimately competing in world championship matches in Paris in 1965. Cutting a dashing figure, he would adopt a fencer’s posture when giving talks. “He would strut across the stage and then strut back, as if he were dueling,” Dr. Madore said. Dr. Arp married three times. He is survived by his third wife, Marie-Helene Arp, an astronomer in Munich; four daughters, Kristana, Alissa, Andrice and Delina Arp; and five grandchildren. Dr. Arp became a staff astronomer at the Hale Observatories after stints as a postdoctoral fellow at the Carnegie Institution for Science and Indiana University. His breakthrough occurred, as he recalled, on a rainy night at Palomar in 1966, when he decided to investigate a chance remark by a colleague that a lot of his peculiar galaxies had radio sources near them in the sky. Looking them up in the Palomar library, he realized that many of those radio sources were quasars that could have been shot out of a nearby galaxy, an idea first explored by the Armenian astronomer Victor Ambartsumian a decade earlier. “It is with reluctance that I come to the conclusion that the redshifts of some extragalactic objects are not due entirely to velocity causes,” Dr. Arp wrote in a paper a year later. He combed the sky for more evidence that redshifts were not ironclad indicators of cosmic distance, knowing that he was striking at the heart of modern cosmology. He turned out to be an expert at finding quasars in suspicious places, tucked under the arm of a galaxy or at the end of a tendril of gas. One of the most impressive was a quasarlike object known as Markarian 205, which had a redshift corresponding to a distance of about a billion light years but appeared to be in front of a galaxy only 70 million light years away. The redshift controversy came to a boil in 1972, when Dr. Arp engaged in a debate, arranged by the American Association for the Advancement of Science, with John N. Bahcall, a young physicist at the Institute for Advanced Study. Timothy Ferris described the event in his book “The Red Limit” (1977): “When the debate was over, it was difficult not to be impressed with Arp’s sincerity and his love for the mysterious galaxies he studied, but it was also difficult to feel that his case had suffered anything short of demolition.” As Dr. Arp’s colleagues lost patience with his quest, he was no longer invited to speak at major conferences, and his observing time on the mighty 200-inch telescope began to dry up. Warned in the early 1980s that his research program was unproductive, he refused to change course. Finally, he refused to submit a proposal at all on the grounds that everyone knew what he was doing. He got no time at all. Dr. Arp took early retirement and joined the Max Planck Institute for Astrophysics near Munich, where he continued to promote his theories. He told his own side of the redshift story in a 1989 book, “Quasars, Redshifts and Controversies.”  Halton C. Arp [Wikipedia], Halton C. Arp - The Official Website, Arp Peculiar Galaxy Club Introduction, ATLAS OF PECULIAR GALAXIES, Source: Article

Read More........→January 08, 2014

NASA's Kepler Provides Insights on Enigmatic Planets

Artist's view of a Earth-size rocky exoplanet. Image credit: NASA/JPL-Caltech

More than three-quarters of the planet candidates discovered by NASA's Kepler spacecraft have sizes ranging from that of Earth to that of Neptune, which is nearly four times as big as Earth. Such planets dominate the galactic census but are not represented in our own solar system. Astronomers don't know how they form or if they are made of rock, water or gas. The Kepler team today reports on four years of ground-based follow-up observations targeting Kepler's exoplanet systems at the American Astronomical Society meeting in Washington. These observations confirm the numerous Kepler discoveries are indeed planets and yield mass measurements of these enigmatic worlds that vary between Earth and Neptune in size. Included in the findings are five new rocky planets ranging in size from 10 to 80 percent larger than Earth. Two of the new rocky worlds, dubbed Kepler-99b and Kepler-406b, are both 40 percent larger in size than Earth and have a density similar to lead. The planets orbit their host stars in less than five and three days respectively, making these worlds too hot for life as we know it. A major component of these follow-up observations was Doppler measurements of the planets' host stars. The team measured the reflex wobble of the host star, caused by the gravitational tug on the star exerted by the orbiting planet. That measured wobble reveals the mass of the planet: the higher the mass of the planet, the greater the gravitational tug on the star and hence the greater the wobble. "This marvelous avalanche of information about the mini-Neptune planets is telling us about their core-envelope structure, not unlike a peach with its pit and fruit," said Geoff Marcy, professor of astronomy at the University of California, Berkeley, who led the summary analysis of the high-precision Doppler study. "We now face daunting questions about how these enigmas formed and why our solar system is devoid of the most populous residents in the galaxy." Using one of the world's largest ground-based telescopes at the W. M. Keck Observatory in Hawaii, scientists confirmed 41 of the exoplanets discovered by Kepler and determined the masses of 16. With the mass and diameter in hand, scientists could immediately determine the density of the planets, characterizing them as rocky or gaseous, or mixtures of the two. The density measurements dictate the possible chemical composition of these strange, but ubiquitous planets. The density measurements suggest that the planets smaller than Neptune -- or mini-Neptunes -- have a rocky core but the proportions of hydrogen, helium and hydrogen-rich molecules in the envelope surrounding that core vary dramatically, with some having no envelope at all. The ground-based observation research validates 38 new planets, six of which are non-transiting planets only seen in

Chart of Kepler planet candidates as of January 2014. Image Credit: NASA Ames

the Doppler data. The paper detailing the research is published in the Astrophysical Journal today. A complementary technique used to determine mass, and in turn density of a planet, is by measuring the transit timing variations (TTV). Much like the gravitational force of a planet on its star, neighboring planets can tug on one another, causing one planet to accelerate and another planet to decelerate along its orbit. Ji-Wei Xie of the University of Toronto used TTV to validate 15 pairs of Kepler planets ranging from Earth-sized to a little larger than Neptune. Xie measured masses of the 30 planets, thereby adding to the compendium of planetary characteristics for this new class of planets. The result also was published in the Astrophysical Journal in Dec. 2013. "Kepler's primary objective is to determine the prevalence of planets of varying sizes and orbits. Of particular interest to the search for life is the prevalence of Earth-sized planets in the habitable zone," said Natalie Batalha, Kepler mission scientist at NASA's Ames Research Center in Moffett Field, Calif. "But the question in the back of our minds is: are all planets the size of Earth rocky? Might some be scaled-down

Artist's concept of NASA's Kepler space telescope. Image credit: NASA/JPL-Caltech

versions of icy Neptunes or steamy water worlds? What fraction are recognizable as kin of our rocky, terrestrial globe?" The dynamical mass measurements produced by Doppler and TTV analyses will help to answer these questions. The results hint that a large fraction of planets smaller than 1.5 times the radius of Earth may be comprised of the silicates, iron, nickel and magnesium that are found in the terrestrial planets here in the solar system. Armed with this type of information, scientists will be able to turn the fraction of stars harboring Earth-sizes planets into the fraction of stars harboring bona-fide rocky planets. And that's a step closer to finding a habitable environment beyond the solar system. Ames is responsible for the Kepler mission concept, ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery mission and was funded by the agency's Science Mission Directorate. For more information about the Kepler space telescope, visit: http://www.nasa.gov/kepler . The California Institute of Technology in Pasadena manages JPL for NASA. Images (mentioned), Text, Credits: NASA / J.D. Harrington / JPL / Michele Johnson / Ames Research Center / Michele Johnson. Best regards, Orbiter.ch, Source: Orbiter.ch Space News, Source: Image1-2

Read More........→January 02, 2014

Birth Of Black Hole Kills The Radio Star

Astronomers led by a Curtin University researcher have discovered a new population of exploding stars that “switch off” their radio transmissions before collapsing into a Black Hole. These exploding stars use all of their energy to emit one last strong beam of highly energetic radiation – known as a gamma-ray burst – before they die. Up until now, it was thought all gamma-ray bursts were followed by a radio afterglow – a premise that a team of Australian astronomers of the Centre for All-sky Astrophysics (CAASTRO) at Curtin University and theUniversity of Sydney originally set out to prove correct. “But we were wrong. After studying an ultra-sensitive image of gamma-ray bursts with no afterglow, we can now say the theory was incorrect and our telescopes have not failed us,” lead researcher and Curtin research fellow Dr Paul Hancock said. The technique used to create the ultra-sensitive image was recently published in The Astrophysical Journal. It allowed for the stacking of 200 separate observations on top of each other to re-create the image of a gamma-ray burst in much better quality – yet, no trace of a radio afterglow was found. “In our research paper we argue that there

must be two distinct types of gamma-ray burst, likely linked to differences in the magnetic field of the exploding star,” Dr Hancock said. “Gamma-ray bursts are thought to mark the birth of a Black Hole or Neutron Star – both of which have super-dense cores. But Neutron Stars have such strong magnetic fields (a million times stronger than those of Black Holes) that producing gamma-rays are more difficult. “We think that those stars that collapse to form a Neutron Star have energy left over to produce the radio afterglow whereas those that become Black Holes put all their energy into one final powerful gamma-ray flash.” New work is underway to test the team’s theory and to see if there are other subtle ways in which the two types of bursts differ. “We now have to take a whole new look at gamma-ray bursts – so far this work has shown that being wrong is sometimes more interesting than being right,” Dr Hancock said. Telescope facilities such as the Australia Telescope Compact Array in northern New South Wales and the Karl Jansky Very Large Array in the US both have observing programs to search for gamma-ray burst afterglows and have been recently upgraded to increase their sensitivity. The research report can be found at http://arxiv.org/abs/1308.4766 Contacts and sources: Megan Meates, Curtin University, Source: Article, Image

Read More........→December 27, 2013

Evidence Of Water Vapor Venting Off Jovian Moon

Illustration Credit: NASA, ESA, and L. Roth (Southwest Research Institute and University of Cologne, Germany)

Previous scientific findings from other sources already point to the existence of an ocean located under Europa's icy crust. Researchers are not yet certain whether the detected water vapor is generated by water plumes erupting on the surface, but they are confident this is the most likely explanation. This graphic shows the location of water vapor detected over Europa's south pole that provides the first strongevidence of water plumes erupting off Europa's surface, in observations taken by NASA's Hubble Space Telescope in December 2012. Hubble didn't photograph plumes, but spectroscopically detected auroral emissions from oxygen and hydrogen. The aurora is powered by Jupiter's magnetic field. This is only the second moon in the solar system found ejecting water vapor from the frigid surface. The image of Europa is derived from a global surface map generated from combined NASA Voyager and Galileo space probe observations. Should further observations support the finding, it would make Europa the second moon in the solar systemknown to have water vapor plumes. The findings were published in the Thursday, Dec. 12, online issue of Science Express, and reported at the meeting of the American Geophysical Union in San Francisco. "By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa," said lead author Lorenz Roth of Southwest Research Institute in San Antonio, Texas. "If those plumes are connected with the subsurface water ocean we are confident exists under Europa's crust, then this means that future investigations can directly investigate the chemical makeup of Europa's potentially habitable environment without drilling through layers of ice. And that is tremendously exciting." In 2005, NASA's Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn's moon Enceladus. Although ice and dust particles subsequently have been found in the Enceladus plumes, only water vapor gases have been measured at Europa so far. Hubble's spectroscopic observations provided the evidence for Europa plumes in December 2012. Time sampling of auroral emissions measured by Hubble's imaging spectrograph enabled the researchers to distinguish between features created by Jupiter's magnetospheric particles and local enhancements of gas, and to also rule out more exotic explanations such as serendipitously observing a rare meteorite impact. The imaging spectrograph detected faint ultraviolet light from an aurora, powered by Jupiter's intense magnetic field, near the moon's south pole. Atomic oxygen and hydrogen produce a variable auroral glow and leave a telltale sign that they are products of water molecules being broken apart by electrons along magnetic fieldlines. "We pushed Hubble to its limits to see this very faint emission. These could be stealth plumes, because they might be tenuous and difficult to observe in the visible light," said Joachim Saur of the University of Cologne in Germany. Saur, who is principal investigator of the Hubble observation campaign, co-wrote the paper with Roth. Roth suggested long cracks on Europa's surface, known as lineae, might be venting water vapor into space. Cassini has seen similar fissures that host Enceladus' jets. The Hubble team found that the intensity of Europa's plumes, like that Enceladus's plumes, varies with the moon's orbital position. Active jets have been seen only when Europa is farthest from Jupiter. But the researchers could not detect any sign of venting when Europa is closer to Jupiter. This is an artist's concept of a plume of water vapor thought to be ejected off of the frigid, icy surface of the Jovian moon Europa, located 500 million miles from the Sun. Hubble Space Telescope spectroscopic measurements lead scientists to calculate that the plume rises to an altitude of 125 miles and then probably rains frost back onto the moon's surface. Previous findings already point to a subsurface ocean under Europa's icy crust.

Artwork Credit: NASA, ESA, and K. Retherford (Southwest Research Institute)

One explanation for the variability is these lineae experience more stress as gravitational tidal forces push and pull on the moon and open vents at larger distances from Jupiter. The vents are narrowed or closed when the moon is closest to the gas giant planet. "The apparent plume variability supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean," said Kurt Retherford, also of Southwest Research Institute. Europa's and Enceladus' plumes have remarkably similar abundances of water vapor. Because Europa has roughly 12 times more gravitational pull than Enceladus, the vapor, whose temperature is measured at minus 40 degrees Celsius, does not escape into space as it does at Enceladus. Instead, it falls back onto the surface after reaching an altitude of 125 miles, according to the Hubble measurements. This could leave bright surface features near the moon's south polar region, the researchers hypothesize. "If confirmed, this new observation once again shows the power of the Hubble Space Telescope to explore and opens a new chapter in our search for potentially habitable environments in our solar system," said John Grunsfeld, an astronaut who participated in Hubble servicing missions and now serves as NASA's associate administrator for science in Washington, D.C. "The effort and risk we took to upgrade and repair the Hubble becomes all the more worthwhile when we learn about exciting discoveries like this one from Europa." Contacts and sources: Dwayne Brown / J.D. Harrington, NASA Headquarters, Washington, D.C. Joe Fohn, Southwest Research Institute, San Antonio, Texas, Ray Villard, Space Telescope Science Institute, Baltimore, Md. Source: Article

Read More........→December 14, 2013

The Deepest Look Into The Universe Ever

Credit: NASA, ESA, and Z. Levay (STScI/AURA)

NASA's Hubble, Spitzer and Chandra space telescopes are teaming up to look deeper into the universe than ever before. With a boost from natural "zoom lenses" found in space, they should be able to uncover galaxies that are as much as 100 times fainter than what these three great observatories typically can see. In an ambitious collaborative program called The Frontier Fields, astronomers will make observations over the next three years of six massive galaxy clusters, exploiting a natural phenomenon known as gravitational lensing, to learn not only what is inside the clusters but also what is beyond them. The clusters are among the most massive assemblages of matter known, and their gravitational fields can be used to brighten and magnify more distant galaxies so they can be observed. "The Frontier Fields program is exactly what NASA's great observatories were designed to do; working together to unravel the mysteries of the Universe" said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington. "Each observatory collects images using different wavelengths of light with the result that we get a much deeper understanding of the underlying physics of these celestial objects."

MACS J1149.5+2223, Credit: NASA, ESA, and M. Postman (STScI), and the CLASH team

The first object they will view is Abell 2744, commonly known as Pandora's Cluster. The giant galaxy cluster appears to be the result of a simultaneous pile-up of at least four separate, smaller galaxy clusters that took place over a span of 350 million years. Astronomers anticipate these observations will reveal populations of galaxies that existed when the universe was only a few hundred million years old, but have not been seen before. "The idea is to use nature's natural telescopes in combination with the great observatories to look much deeper than before and find the most distant and faint galaxies we can possibly see," said Jennifer Lotz, a principal investigator with the Space Telescope Science Institute (STScI) in Baltimore, Md. Data from the Hubble and Spitzer space telescopes will be combined to measure the galaxies' distances and masses more accurately than either observatory could measure alone, demonstrating their synergy for such studies.

MACS J0717.5+3745, Credit: NASA, ESA, and H. Ebeling (University of Hawaii)

"We want to understand when and how the first stars and galaxies formed in the universe, and each great observatory gives us a different piece of the puzzle," said Peter Capak, the Spitzer principal investigator for the Frontier Fields program. "Hubble tells you which galaxies to look at and how many stars are being born in those systems. Spitzer tells you how old the galaxy is and how many stars have formed." The Chandra X-ray Observatory also will peer deep into the star fields. It will image the clusters at X-ray wavelengths to help determine their mass and measure their gravitational lensing power, and identify background galaxies hosting supermassive black holes. 

MACS J0416.1-2403, Credit: NASA, ESA, and M. Postman (STScI), and the CLASH team

High-resolution Hubble data from the Frontier Fields program will be used to trace the distribution of dark matter within the six massive foreground clusters. Accounting for the bulk of the universe's mass, dark matter is the underlying invisible scaffolding attached to galaxies.

Abell 2744, Credit: NASA, ESA, and R. Dupke (Eureka Scientific, Inc.), et al.

Hubble and Spitzer have studied other deep fields with great success. The Frontier Fields researchers anticipate a challenge because the distortion and magnification caused by the gravitational lensing phenomenon will make it difficult for them to understand the true properties of the background galaxies. Contact and sources" NASA, Hubble Space Telescope, Source: Nano Patents And Innovation

Read More........→October 26, 2013