What Keeps Time Moving Forward? Blame It On The Big Bang

From Scientific American:

A timely Q&A with physicist Sean Carroll about how our one-way trip from past to future is entangled with entropy and the origin of the universe.

Physicists often describe the fabric of the universe we inhabit as four-dimensional spacetime, comprising three dimensions of space and one of time. But whereas we spend our days passing freely through space in any direction we wish (gravity and solid obstacles permitting), time pushes us along, willingly or not, in a single predetermined direction: toward the future.

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Milky Way's Dark Matter 'Turned On Its Side'

From New Scientist:

The cloud of dark matter that is thought to surround the Milky Way may be shaped like a squashed beach ball. This halo of invisible matter also seems to sit at an unexpected angle – which could be a strike against a theory that challenges Einstein's account of gravity.

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Nature's Most Precise Clocks May Make 'Galactic GPS' Possible: Pulsars Help In Search For Gravitational Waves

Fermi Large Area Telescope first year map of the gamma-ray sky at energies above 100 MeV with the locations of the new millisecond pulsars shown. The symbols are color coded according to the discovery team: red led by Scott Ransom (NRAO) using NRAO's Green Bank Telescope (GBT), cyan led by Mallory Roberts (Eureka Scientific/GMU/NRL) also using the GBT, green led by Fernando Camilo (Columbia University) using Australia's CSIRO Parkes Observatory, white led by Mike Keith (ATNF) also using Parkes, and yellow led by Ismael Cognard (CNRS) using France's Nançay Radio Telescope. (Credit: NASA/DOE/Fermi LAT Collaboration)

From Science Daily:

Science Daily (Jan. 6, 2010) — Radio astronomers have uncovered 17 millisecond pulsars in our galaxy by studying unknown high-energy sources detected by NASA's Fermi Gamma-ray Space Telescope. The astronomers made the discovery in less than three months. Such a jump in the pace of locating these hard-to-find objects holds the promise of using them as a kind of "galactic GPS" to detect gravitational waves passing near Earth.

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Close-Up Photos Of Dying Star Show Our Sun's Fate

Chi Cygni, shown in this artist's conception, is a red giant star nearing the end of its life. As it runs out of fuel, it pulses in and out, beating like a giant heart and ejecting shells of material. Observations by the Infrared Optical Telescope Array found that, at minimum radius, Chi Cygni shows marked inhomogeneities due to roiling "hotspots" on its surface. (Credit: ESO/L. Calçada)

From Science Daily:

Science Daily (Dec. 17, 2009) — About 550 light-years from Earth, a star like our Sun is writhing in its death throes. Chi Cygni has swollen in size to become a red giant star so large that it would swallow every planet out to Mars in our solar system. Moreover, it has begun to pulse dramatically in and out, beating like a giant heart. New close-up photos of the surface of this distant star show its throbbing motions in unprecedented detail.

"This work opens a window onto the fate of our Sun five billion years from now, when it will near the end of its life," said lead author Sylvestre Lacour of the Observatoire de Paris.

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Dying Star Previews Our Own Sun's Fate

Artist's impression of Chi Cygni. As the red giant star runs out of fuel, it pulses in and out, beating like a giant heart and ejecting shells of material. Credit: ESO/L. Calçada

From Cosmos:

CAMBRIDGE: New images of the surface of a distant, dying star offer a preview of the ultimate fate of our own Sun, French scientists say.

"This work opens a window onto the fate of our Sun five billion years from now, when it will near the end of its life," said lead author Sylvestre Lacour of the Observatoire de Paris.

About 550 light-years from Earth, a star like our Sun is writhing in its death throes. Chi Cygni has swollen in size to become a red giant star so large that it would swallow every planet out to Mars in our solar system.

Moreover, it has begun to pulse dramatically in and out, beating like a giant heart.

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Superbright Supernova Is First Of Its Kind

In this schematic illustration of the material ejected from SN 2007bi, the radioactive nickel core (white) decays to cobalt, emitting gamma rays and positrons that excite surrounding layers (textured yellow) rich in heavy elements like iron. The outer layers (dark shadow) are lighter elements such as oxygen and carbon, where any helium must reside, which remain unilluminated and do not contribute to the visible spectrum. (Credit: Image courtesy of DOE/Lawrence Berkeley National Laboratory)

From Science Daily:

Science Daily (Dec. 5, 2009) — An extraordinarily bright, extraordinarily long-lasting supernova named SN 2007bi, snagged in a search by a robotic telescope, turns out to be the first example of the kind of stars that first populated the Universe. The superbright supernova occurred in a nearby dwarf galaxy, a kind of galaxy that's common but has been little studied until now, and the unusual supernova could be the first of many such events soon to be discovered.

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Weird Data Suggests Something Big Beyond The Edge Of The Universe

Something strange appears to be tugging a 'dark flow' of galaxies across the universe. is this evidence that parallel universes really exist?

From Cosmos:

SYDNEY: Astronomers have found the best evidence yet for the weird idea that our universe is one of many in the 'multiverse'. What's more, these parallel universes seem to be exerting a strange force on our own, causing galaxy clusters to stream across space towards the edge of the known universe.

The new evidence comes from studies of 'bumps and wiggles' in the temperature of the cosmic background radiation (CMB), the leftover afterglow of the Big Bang.

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ESA Spacecraft May Help Unravel Cosmic Mystery

Cassini-Huygens swings by Earth and accelerates towards Saturn. (Credit: ESA)

From Science Daily:

Science Daily (Nov. 13, 2009) — When Europe's comet chaser Rosetta swings by Earth on Nov. 13 for a critical gravity assist, tracking data will be collected to precisely measure the satellite's change in orbital energy. The results could help unravel a cosmic mystery that has stumped scientists for two decades.

Since 1990, scientists and mission controllers at ESA and NASA have noticed that their spacecraft sometimes experience a strange variation in the amount of orbital energy they exchange with Earth during planetary swingbys. The unexplained variation is noticed as a tiny difference in speed gained or lost during the swingby when comparing that predicted by fundamental physics and that actually measured after the event.

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Tweak Gravity: What If There Is No Dark Matter?

INVISIBLE OR NONEXISTENT? A composite image of the galaxy cluster Abell 520 shows the inferred presence of matter, primarily dark matter, in blue. X-ray: NASA/CXC/UVic./A.Mahdavi et al.; Optical/Lensing: CFHT/UVic./A.Mahdavi et al.

From Scientific American:

Modifications to the theory of gravity could account for observational discrepancies, but not without introducing other complications.

Theorists and observational astronomers are hot on the trail of dark matter, the invisible material thought to account for puzzling mass disparities in large-scale astronomical structures. For instance, galaxies and galactic clusters behave as if they were far more massive than would be expected if they comprised only atoms and molecules, spinning faster than their observable mass would explain. What is more, the very presence of assemblages such as our Milky Way Galaxy speaks to the influence of more mass than we can see. If the mass of the universe were confined to atoms, the clumping of matter that allowed galaxies to take shape would never have transpired.

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Dark Matter And Dark Energy Make Up 95 Percent Of Universe, Detailed Measurements Reveal

The QUaD collaboration uses the 2.6-meter telescope shown here to view the temperature and polarization of the cosmic microwave background, a faintly glowing relic of the hot, dense, young universe. (Credit: Image courtesy of Nicolle Rager Fuller, NSF)

From Science Daily:

Science Daily (Nov. 3, 2009) — A detailed picture of the seeds of structures in the universe has been unveiled by an international team co-led by Sarah Church of the Kavli Institute for Particle Astrophysics and Cosmology, jointly located at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University, and by Walter Gear, of Cardiff University in the United Kingdom. These measurements of the cosmic microwave background -- a faintly glowing relic of the hot, dense, young universe -- put limits on proposed alternatives to the standard model of cosmology and provide further support for the standard cosmological model, confirming that dark matter and dark energy make up 95% of everything in existence, while ordinary matter makes up just 5%.

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Universe's Quantum 'Speed Bumps' No Obstacle For Light

Different wavelengths of light from a distant gamma-ray burst travel at the same speed, down to quantum scales (Illustration: NASA/SkyWorks Digital)

From New Scientist:

A hint that quantum fluctuations in the fabric of the universe slow the speed of light has not been borne out in observations by NASA's Fermi telescope. The measurements contradict a 2005 result that supported the idea that space and time are not smooth.

Einstein's theory of special relativity says that all electromagnetic radiation travels through a vacuum at the speed of light. This speed is predicted to be constant, regardless of the energy of the radiation.

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Monster Supernovae May Explain Galaxy's Mystery Haze

The mysterious WMAP haze (Image: WMAP)

From New Scientist:

WHAT is causing a mysterious "haze" of radiation at the centre of the Milky Way? It may be a load of monster supernovae kicking out radiation which is then amplified by magnetic stellar winds and turbulence near the galaxy's core.

In 2003, the Wilkinson Microwave Anisotropy Probe found a patch of particularly energetic microwave radiation in the centre of our galaxy - dubbed the "WMAP haze". It was proposed that this could be caused by collisions of a new type of dark-matter particle.

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Is Unknown Force In Universe Acting On Dark Matter?

M63: The Sunflower Galaxy. (Credit: Satoshi Miyazaki (NAOJ), Suprime-Cam, Subaru Telescope, NOAJ)

From Science Daily:

Science Daily (Oct. 23, 2009) — An international team of astronomers have found an unexpected link between mysterious 'dark matter' and the visible stars and gas in galaxies that could revolutionise our current understanding of gravity.

One of the astronomers, Dr Hongsheng Zhao of the SUPA Centre of Gravity, University of St. Andrews, suggests that an unknown force is acting on dark matter. The findings are published this week in the scientific journal Nature.

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What Does A Star Sound Like?

The Big Bang A supernova like this would sound like 10 octillion two-megaton nuclear bombs exploding. Nasa/CXC/M. Weiss

From Popular Science:

Observing a star up close (putting aside for a moment how you’d get there or withstand its heat) is probably like sitting beside an enormous silent fire. Sounds—which are simply pressure variations in a medium such as air or water—can’t propagate in the vacuum of space, so the roiling surface of a star would make an impression on the eyes, but not the ears.

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Astrophysicists Puzzle Over Planet That's Too Close To Its Sun

From L.A. Times:

Completing an orbit in less than an Earth day, planet Wasp-18b should have burned up, according to accepted theory.

Scientists have discovered a planet that shouldn't exist. The finding, they say, could alter our understanding of orbital dynamics, a field considered pretty well settled since the time of astronomer Johannes Kepler 400 years ago.

The planet is known as a "hot Jupiter," a gas giant orbiting the star Wasp-18, about 330 light-years from Earth. The planet, Wasp-18b, is so close to the star that it completes a full orbit (its "year") in less than an Earth day, according to the research, which was published in the journal Nature.

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Star-Birth Myth 'Busted'

False-colour images of two galaxies, NGC 1566 (left) and NGC 6902 (right), showing their different proportions of very massive stars. Regions with massive O stars show up as white or pink, while less massive B stars appear in blue. NGC 1566 is much richer in O stars than is NGC 6902. The images combine observations of UV emission by NASA's Galaxy Evolution Explorer spacecraft and H-alpha observations made with the Cerro Tololo Inter-American Observatory (CTIO) telescope in Chile. NGC 1566 is 68 million light years away in the southern constellation of Dorado. NGC 6902 is about 33 million light years away in the constellation Sagittarius. (Credit: NASA/JPL-Caltech/JHU)

From Science Daily:

ScienceDaily (Aug. 30, 2009) — An international team of researchers has debunked one of astronomy's long held beliefs about how stars are formed, using a set of galaxies found with CSIRO’s Parkes radio telescope.

When a cloud of interstellar gas collapses to form stars, the stars range from massive to minute.

Since the 1950s astronomers have thought that in a family of new-born stars the ratio of massive stars to lighter ones was always pretty much the same — for instance, that for every star 20 times more massive than the Sun or larger, you’d get 500 stars the mass of the Sun or less.

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A Look Into The Hellish Cradles Of Suns And Solar Systems

The dense star cluster RCW 38 glistens about 5500 light years away in the direction of the constellation Vela (the Sails). RCW 38 is an "embedded" cluster, in that the nascent cloud of dust and gas still envelops its stars. (Credit: Image courtesy of ESO)

From Science Daily:

ScienceDaily (Aug. 20, 2009) — New images released today by ESO delve into the heart of a cosmic cloud, called RCW 38, crowded with budding stars and planetary systems. There, young stars bombard fledgling suns and planets with powerful winds and blazing light, helped in their task by short-lived, massive stars that explode as supernovae. In some cases, this onslaught cooks away the matter that may eventually form new solar systems. Scientists think that our own Solar System emerged from such an environment.

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What Came Before The Big Bang?

Mehau Kulyk / Science Photo Library / Corbis

From Time Magazine:

Even as a boy watching the first moon landing on TV, Brian Clegg remembers wondering, "How did it all begin?" In his latest book, Before the Big Bang, the Cambridge-educated writer examines the theories that physicists and philosophers alike have put forth to explain how we got here. TIME spoke with Clegg about science as a social network, thinking outside of the box without losing his mind, and using Buffy the Vampire Slayer to explain Einstein.

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Integral Disproves Dark Matter Origin For Mystery Radiation

Combining more than 4 years of observations, the inner Galaxy has been mapped in the 511 keV positron annihilation line with unprecedented detail as shown above using the SPI spectrometer. For the first time, positron annihilation is found to be asymmetric in the inner Galactic disk. Consistent with earlier findings, the annihilation emission is brightest around the Galactic centre. In the sky maps, the Galactic centre is at the origin and the Galactic disk runs along the equator. (Credit: ESA/ INTEGRAL/ MPE (G. Weidenspointner et al.))

From Space Daily:

ScienceDaily (Aug. 2, 2009) — A team of researchers working with data from ESA’s Integral gamma-ray observatory has disproved theories that some form of dark matter explains mysterious radiation in the Milky Way.

That this radiation exists has been known since the 1970s, and several theories have been proposed to explain it. Integral’s unprecedented spectral and spatial resolution showed that it strongly peaks towards the centre of the Galaxy, with an asymmetry along the Galactic disc.

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Phantom Menace To Dark Matter Theory

Image: The answer to the riddle of dark matter could be found in our own solar system (Image: NASA)

From New Scientist:

A SUBTLE anomaly in the orbit of the planets in our solar system could prove a controversial idea that goes beyond Einstein.

The orbit of the innermost planet, Mercury, departs from what it should be under Newton's laws. A century ago, when Einstein explained this anomaly, it confirmed his theory of gravity - the general theory of relativity.

Now an Israeli physicist predicts that a similar but far more subtle anomaly in the orbits of the planets, if detected, might prove his own theory, known as modified Newtonian dynamics, or MOND. This provides an alternative theory to dark matter to explain why stars orbiting at the edge of spiral galaxies are not flung out into space. These stars are travelling at speeds too fast for conventional gravity from the mass at the heart of a spiral galaxy to hold them in their orbits, so something else must be keeping them on track.

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