Mystery ‘dark flow’ extends towards edge of universe

by Marcus Chown

SOMETHING big is out there beyond the visible edge of our universe. That’s the conclusion of the largest analysis to date of over 1000 galaxy clusters streaming in one direction at blistering speeds. Some researchers say this so-called “dark flow” is a sign that other universes nestle next door.

Last year, Sasha Kashlinsky of the Goddard Space Flight Center in Greenbelt, Maryland, and colleagues identified an unusual pattern in the motion of around 800 galaxy clusters. They studied the clusters’ motion in the “afterglow” of the big bang, as measured by the Wilkinson Microwave Anisotropy Probe (WMAP). The photons of this afterglow collide with electrons in galaxy clusters as they travel across space to the Earth, and this subtly changes the afterglow’s temperature.

The team combined the WMAP data with X-ray observations and found the clusters were streaming at up to 1000 kilometres per second towards one particular part of the cosmos (The Astrophysical Journal Letters, vol 686, p L49).

Many researchers argued the dark flow would not turn up in later observations, but now the team claim to have confirmed its existence. Their latest analysis reveals 1400 clusters are part of the flow, and that it continues to around 3 billion light years from Earth, a sizeable fraction of the distance to the edge of the observable universe (arxiv.org/abs/0910.4958). This is twice as far as seen in the previous study.

The dark flow appears to have been caused shortly after the big bang by something no longer in the observable universe. It has no effect today because reaching across this horizon would involve travelling faster than light.

One explanation for the flow would be the gravity of a huge concentration of matter, but this is very unlikely. Within the standard big bang picture, massive cosmic structures were “seeded” by random quantum fluctuations, so overall, matter should be spread evenly.

There could be an exotic explanation. Laura Mersini-Houghton of the University of North Carolina, Chapel Hill, thinks the flow is a sign of a neighbouring universe. If the tiny patch of vacuum that inflated to become our universe was quantum entangled with other pieces of vacuum – other universes – they could have exerted a force from beyond the present-day visible horizon (see “Nosey neighbours”).

Yet despite the new findings, the existence of the dark flow remains disputed. Charles Bennett, principal investigator of WMAP says the cluster analysis is not statistically significant. “There is no evidence for the large-scale dark flow, using all of the best data available.”

Nosey neighbours

Was our universe once entangled with a neighbour? The observation of “dark flow” in galaxy clusters was predicted in 2006 by Laura Mersini-Houghton of the University of North Carolina at Chapel Hill and colleagues. She proposes that the effect occurs because our universe was once influenced by neighbouring domains (arxiv.org/abs/0810.5388).

Mersini-Houghton reasoned that if a force exerted by other universes squeezed ours, it could generate a repulsive effect that would impede the shrinkage of matter into clusters but not leave an imprint on smaller scales. “This skews the distribution of lumps so they are not the same in all directions,” she says. “There is a preferred direction – the dark flow.”

She also predicted in 2006 that there should be two “holes” – regions with fewer galaxies than expected. Sure enough, there does appear to be a hole – the so-called “cold spot” identified by the WMAP probe. The hole is a very large region of space where the afterglow is cooler than average. However, its cause – and even existence – is disputed, and Mersini-Houghton’s hypothesis remains controversial.

http://www.newscientist.com/article/mg20427345.000-mystery-dark-flow-extends-towards-edge-of-universe.html

Rosetta Space Mystery Could Be a Clue to New Laws of the Universe

Scientists are eagerly anticipating the ROSETTA probe’s next pass of Earth, because they know that something they don’t know about might happen.  Probes passing by Earth to pick up a gravitational slingshot have been experiencing unexplained extra accelerations, and the reasons could reveal fundamental facts of existence – if we ever work them out.

The discrepancies are tiny, mere millimeters per second compared to the total value of many thousands of meters a second, but the thing about rocket scientists is they don’t just wave their hand and go “Ah, it’s just off a bit.”  In fact the entire existence of rocket science as more than a field of explosion craters is based on that fact.  These minuscule movement changes have apparently randomly sped or slowed satellites for the last few decades, and some very smart people want to know why.

Don’t dismiss this as some simple error in the calculations or hardware: experts have been picking this phenomena apart for over twenty years, and have discounted all the usual suspects.  Anything at all surviving space implies a mastery of “not forgetting minor details”, and nothing known can explain what’s going on.  More esoteric explanations involve everything from dark matter, the cosmological calculation cure-all, to alterations in our understanding of spacetime.  Or, of course, just missing something.

What’s more, this is just the sort of experiment to reveal it.  The laurels (and lunatics) around the LHC make many forget that the most important discovers aren’t from multi-billion megasperiments but the identification and analysis of the little niggles and odd phenomena.  The entire science of quantum mechanics comes from one curve which wouldn’t work out, and entire new particles have been isolated from almost-ignorable blips in the data.

It’s awesome that Rosetta can help probe the rest of the universe as a side effect on the way to its real mission, catching a comet and collecting data in 2014.

Luke McKinney

http://esciencenews.com/articles/2009/11/12/esa.spacecraft.may.help.unravel.cosmic.mystery

http://www.dailygalaxy.com/my_weblog/2009/11/rosetta-space-mystery-could-be-clue-to-a-new-physics.html

Earth set for annual Leonid shower

Meteor outlook not bright in Europe or US, though

By Lester Haines

This week sees the annual lightshow that is the Leonid meteors, as debris from comet 55P/Tempel-Tuttle comes to a fiery end in Earth’s atmosphere.

According to New Scientist, the entertainment is due to kick off around 09:00 GMT tomorrow (17 November), with the peak occurring between 21:00 and 22:00 GMT as we pass through “two debris trails left by Tempel-Tuttle in 1466 and 1533″.

The prediction is that “skywatchers in Asia and the easternmost parts of Europe will have the best view of these intense showers, because the sky will be dark and the apparent point of origin of the meteors… will be over the horizon”.

The best time for US spotters to catch the Leonids – so named because they appear to radiate from the constellation Leo – is before dawn tomorrow. Those of us in western Europe should look skywards in the wee hours of 18 November for a chance to catch the post-peak burn-ups.

http://www.theregister.co.uk/2009/11/16/leonid_meteors/

NASA sees “significant quantities” of water on the moon

NASA has decided it’s ready to talk about some of the data obtained when its LCROSS mission slammed two objects into the Moon: the ejected material contained 100kg of water, which created unambiguous signals in the probe’s spectroscopy equipment.

By John Timmer

Shortly after NASA’s LCROSS probe slammed into a crater in the polar region of the Moon, the Agency held a press conference to announce that it had obtained significant amounts of data from the collision. Unfortunately, to the frustration of many present, it wasn’t ready to interpret that data. That reticence ended today, as NASA held a press conference in which it announced that the data contains unambiguous evidence of water, present in what it termed “significant quantities.” But the signal from water isn’t the only one lurking in the data, and NASA is remaining coy about what the other signals indicate.

Back in October, the LCROSS mission sent two objects crashing into the Cabeus crater, which has an interior that is permanently shadowed due to its location in the Moon’s polar region. The first was a heavy booster rocket; its collision was imaged by instruments on the actual LCROSS probe, which followed it into the crater a few minutes later. Its collision was tracked by Earth- and space-based instruments.

Initially, there was a degree of disappointment about the lack of a dramatic plume of debris that accompanied the impact. But NASA reassured everyone that the relevant instruments worked well, and that there was a wealth of data available to analyze. That set off further frustration, as none of the NASA scientists were willing to speculate what that data said about the composition of the material in the crater, since they weren’t confident about their preliminary analysis.

After a few weeks of looking things over, they’re apparently feeling a lot more confident. Both the UV/visible and infrared spectrometers returned detailed data, both in terms of wavelength and time post-impact, and they clearly showed a complex pattern of emission and absorption. The question the scientists had to grapple with is whether any single combination of chemicals could produce that spectrum, or if the spectrum was compatible with a number of scenarios.

According to Anthony Colaprete, LCROSS’ scientific lead, they’ve since eliminated any alternative they can think of—the data contains unambiguous evidence of water. He showed the infrared spectral data, and contrasted that with the null case, blackbody radiation. In at least two areas of the spectrum, a curve produced by modeling blackbody radiation plus water absorption matched the curve nearly exactly. The UV/visible data showed emission lines from hydroxyl bonds, which also suggest water.

Based on the strength of the signal and size of the plume, NASA estimates that about 100kg of water were kicked up in the impact plume, which Colaprete says is enough to indicate that there were actual ice deposits within the crater. In a response to a question, he suggested that this would make it wetter than South America’s Atacama Desert.

Left: The LCROSS spectrum (black bars) diverges significantly from black body radiation. Right: two of these differences, highlighted in yellow can be accounted for by the presence of water.

But Colaprete couldn’t resist a further tease, saying that other features in the spectra hinted at a variety of additional chemicals. “This goes beyond the water,” he said, but declined to discuss any of this additional information, suggesting that it was in the same state as the water findings were shortly after the impact—they still haven’t eliminated enough possible explanations, so they can’t talk about it with any confidence.

Ultimately, that data may tell us very significant things about the status and behavior of the water. Papers that argued for lunar water had suggested different explanations for the origin of that water, such as cometary delivery and capture of the solar wind. They also hinted that there might be an active cycling of the water, driven by the changes in light that accompany the long solar day. The new data, should they contain chemicals typical of comets, could help inform the debate over what’s happening on the moon.

In any case, it’s important to emphasize the mental U-turn the scientific community has to make here. For decades following the Apollo missions, scientists were operating based on the evidence returned from the Moon, which suggested a completely dry environment. The three papers that first suggested a revision to those conclusions were only published in September, and LCROSS data was only obtained in October. It will undoubtedly take a while for the full implications of these findings to sink in.

Further reading:

NASA’s LCROSS mission page.

http://arstechnica.com/science/news/2009/11/nasa-announces-significant-quantities-of-water-on-the-moon.ars

To Find New Planets, Look for the Lithium?

John Roach
for National Geographic News

November 11, 2009

Sunlike stars that harbor planets are low on lithium, according to a recent study that may offer a new tool in the hunt for planets beyond our solar system.

(See what could be the first picture of a planet orbiting a sunlike star.)

Stars are made almost entirely of hydrogen and helium. A small percentage of a star’s mass comes from heavier elements, which astronomers refer to as metals.

Young, yellow stars like our sun usually have more metals than older, redder stars, although the exact mix of those metals can vary.

But astronomers have been unable to explain why otherwise similar sunlike stars have widely different lithium levels.

The new study suggests that the answer lies with the presence of planets.

“There’re stars with and without planets, and the scatter of lithium abundance is very large,” noted lead study author Garik Israelian, of the Instituto de Astrofísica de Canarias on Tenerife, one of the Spanish-run Canary Islands.

“But for planet-host stars, we find that they all have low abundances of lithium.”

Mixed-up Stars

It’s been a puzzle for decades why our sun has significantly less lithium on its surface than other stars of the same age, mass, and metal abundance.

For the new study, Israelian and colleagues monitored 451 sunlike stars, 70 of which were already known to harbor planets.

(Related: “32 New Planets Found Outside Our Solar System.”)

Observations made over several years revealed that all the known planetary hosts had similarly low lithium levels.

By contrast, stars that have been scrutinized for years, without any planets having been found, had almost ten times more lithium than stars with known planets.

Why, exactly, planets would cause lithium depletion remains unknown.

One possibility is that, early in a star’s life, gravitational motion from orbiting planets or a planet-forming disk stirs up the star’s elements. This mixing causes surface materials such as lithium to get shuttled into the star’s interior and burned away.

More research is required, Israelian said, “but at least we have a clear signature that planets do change [a star's] surface abundance of lithium.”

Israelian cautions that low lithium does not guarantee the presence of planets around a particular star. Astronomers would have to follow up with existing methods for planet detection.

But, he said, “if we have ten planet-host candidates, those ones with very low lithium will be the best ones to [check for] planets.”

Findings appear in this week’s issue of the journal Nature.

http://news.nationalgeographic.com/news/2009/11/091111-new-planets-stars-lithium.html

The Surprising Contents of Titan’s Lakes

The lakes on Titan have some surprising chemical contents, according to the latest data from the Cassini spacecraft.

One of the exotic attractions of Saturn’s moon Titan is the possibility that it has oceans and lakes, with waves and breakers not unlike those on Earth. In the 1990s, astronomers ruled out the possibility of a global ocean using radar measurements taken from Earth but the possibility of lakes remained. And sure enough, in 2005, the Cassini spacecraft spotted a large lake-like feature called Ontario Lacus near the south pole and has since spotted numerous smaller ones.

So what are these lakes made of? The conventional thinking is that the lakes must be made of a mixture of liquid ethane, methane and nitrogen. However, the amount of methane in the atmosphere makes it difficult to see in liquid form at ground level and only liquid ethane has been directly spotted in Ontario Lacus.

The only other way to infer the composition of the lakes is by creating a thermodynamic model of the atmosphere using spacecraft and laboratory data and theoretical calculations. And of course, data from Cassini is revolutionising these calculations.

Today, Daniel Cordier from the Ecole Nationale Superieure de Chimie de Rennes, France, et amis, present the latest take on the data. Their number crunching reveals that:

“the main constituents of the lakes are ethane ( 76-79%), propane (7-8%), methane (5-10%), hydrogen cyanide (2-3%), butene (1%), butane (1%) and acetylene (1%).”

 

That’s a rich and somewhat unexpected mix. But it’s also useful because it allows more detailed calculations about the role of liquid on the surface of Titan. “Our results provide the chemical data needed to compute the amount of deposition of various hydrocarbons and nitriles in fluvial valleys in the Titan’s midlatitudes,” says the team.

And that should allow planetary geologists to build and test a new generation of models that show how rivers and streams have carved the surface of Titan. Geologists will be waiting with baited breath. The differences as well as the similarities with the processes that occur on Earth should make fascinating reading.

Ref: http://arxiv.org/abs/0911.1860: An Estimate of the Chemical Composition of Titan’s Lakes

http://www.technologyreview.com/blog/arxiv/24395/

SPACE PHOTOS THIS WEEK: Sun Storm, Galactic Core, More

Magnetic loops create a bright white flurry over an active region of the sun’s surface in a colorized video still from one of NASA’s twin STEREO spacecraft.

The video, captured from November 2 to 3, showed where particles from the sun were tracing active magnetic field lines, which elongated and sent out a small solar storm.

—Photograph courtesy SOHO/NASA

More photos – http://news.nationalgeographic.com/news/2009/11/photogalleries/week-in-space-pictures-68/index.html

MESSENGER Spacecraft Reveals More Hidden Territory On Mercury

This enhanced-color view was created with a statistical technique that highlights subtle color variations seen in the 11 filters of MESSENGER’s wide-angle camera that are often related to composition. Merged with images from the higher-resolution narrow-angle camera, the two sets of observations tell the story of the geology of the area and the compositional differences of the features observed. This region, viewed in detail for the first time during the third flyby, appears to have experienced a high level of volcanic activity. (Credit: Image courtesy of NASA)

A NASA spacecraft gliding over the battered surface of Mercury for the second time this year has revealed more previously unseen real estate on the innermost planet. The probe also has produced several science firsts and is returning hundreds of new photos and measurements of the planet’s surface, atmosphere and magnetic field.

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging, or MESSENGER, spacecraft flew by Mercury shortly after 4:40 a.m. EDT, on Oct. 6. It completed a critical gravity assist to keep it on course to orbit Mercury in 2011 and unveiled 30 percent of Mercury’s surface never before seen by a spacecraft.

“The region of Mercury’s surface that we viewed at close range for the first time this month is bigger than the land area of South America,” said Sean Solomon, principal investigator and director of the Department of Terrestrial Magnetism at the Carnegie Institution of Washington. “When combined with data from our first flyby and from Mariner 10, our latest coverage means that we have now seen about 95 percent of the planet.”

The spacecraft’s science instruments operated throughout the flyby. Cameras snapped more than 1,200 pictures of the surface, while topography beneath the spacecraft was profiled with a laser altimeter. The comparison of magnetosphere observations from the spacecraft’s first flyby in January with data from the probe’s second pass has provided key new insight into the nature of Mercury’s internal magnetic field and revealed new features of its magnetosphere. The magnetosphere is the volume surrounding Mercury that is controlled by the planet’s magnetic field.

“The previous flybys by MESSENGER and Mariner 10 provided data only about Mercury’s eastern hemisphere,” explains Brian Anderson of the Johns Hopkins University Applied Physics Laboratory, known as APL, in Laurel, Md. “The most recent flyby gave us our first measurements on Mercury’s western hemisphere, and with them we discovered that the planet’s magnetic field is highly symmetric.”

The probe’s Mercury Laser Altimeter, or MLA, measured the planet’s topography, allowing scientists, for the first time, to correlate high-resolution topography measurements with high-resolution images.

“The MLA collected altimetry in regions where images from MESSENGER and Mariner 10 data are available, and new images were obtained of the region sampled by the altimeter in January,” said Maria Zuber, co-investigator and head of the Department of Earth, Atmospheric, and Planetary Sciences at the Massachusetts Institute of Technology. “These topographic measurements now improve considerably the ability to interpret surface geology.”

The Mercury Atmospheric and Surface Composition Spectrometer observed Mercury’s thin atmosphere, known as an exosphere. The instrument searched for emissions from sodium, calcium, magnesium, and hydrogen atoms. Observations of magnesium are the first detection of this chemical in Mercury’s exosphere. Preliminary analysis suggests that the spatial distributions of sodium, calcium, and magnesium are different. Simultaneous observations of these spatial distributions, also a first for the spacecraft, have opened an unprecedented window into the interaction of Mercury’s surface and exosphere.

Spacecraft images also are revealing for the first time vast geologic differences on the surface.

“Now that MESSENGER’s cameras have imaged more than 80 percent of Mercury, it is clear that, unlike the moon and Mars, Mercury’s surface is more homogeneously ancient and heavily cratered, with large extents of younger volcanic plains lying within and between giant impact basins,” said co-investigator Mark Robinson of Arizona State University in Tempe.

The project is the seventh in NASA’s Discovery Program of lower-cost, scientifically focused missions. APL designed, built and operates the spacecraft and manages the mission for NASA’s Science Mission Directorate in Washington. Science instruments were built by APL; NASA’s Goddard Space Flight Center in Greenbelt, Md.; the University of Michigan, Ann Arbor; and the University of Colorado, Boulder. GenCorp Aerojet of Sacramento, Calif., and Composite Optics Inc. of San Diego, provided the propulsion system and composite structure.

For more information about the Mercury mission, visit: www.nasa.gov/messenger

---

Adapted from materials provided by NASA.

http://www.sciencedaily.com/releases/2009/11/091108215449.htm

“BioFingerprints” -New Tech in the Search for Earth’s Twin

“Detecting Earth in reflected light is like searching for a firefly from a searchlight that is 2,400 miles distant,” according to a panel of astronomers describing the challenges facing the search for other planets in the universe.

With a dramatic new advance, however, astronomers have confirmed an effective way to search the atmospheres of planets for signs of life, vastly improving our chances of finding alien life outside our solar system. Think of it as the method to discover the Earth’s “fingerprint” -information about the chemical composition of the Earth’s atmosphere from sunlight that has passed through it.

A team from the Instituto de Astrofisica de Canarias used the William Herschel Telescope on La Palma  and the Nordic Optical Telescope  to take the first transmission spectrum of the Earth.

When a planet passes in front of its parent star, part of the starlight passes through the planet’s atmosphere and contains information about the constituents of the atmosphere. Even though astronomers can’t use exactly the same method to look at the Earth’s atmosphere, the team was able for the first time ever to gain a spectrum of our planet by observing light reflected from the Moon towards the Earth during a lunar eclipse.

The spectrum not only contained signs of life but these signs were unmistakably strong. It also contained unexpected molecular bands and the signature of the earth ionosphere.

“Now we know what the transmission spectrum of a inhabited planet looks like, we have a much better idea of how to find and recognize Earth like planets outside our solar system where life may be thriving,” said Enric Palle, of the Instituto de Astrofisica de Canarias. “The information in this spectrum shows us that this is a very effective way to gather information about the biological processes that may be taking place on a planet.”

“Many discoveries of Earth-size planets are expected in the next decades and some will orbit in the habitable zone of their parent stars. Obtaining their atmospheric properties will be highly challenging; the greatest reward will happen when one of those planets shows a spectrum like that of our Earth,” added Pilar Montañes-Rodriguez, of the Instituto de Astrofisica de Canarias.

Posted by Casey Kazan.

http://www.scitech.ac.uk/PMC/PRel/STFC/transmissionspectrum.aspx

http://www.dailygalaxy.com/my_weblog/2009/11/biofingerprints-the-search-for-earths-twin-.html

Not Science Fiction: Solar Power to be Zapped From Space By Lasers

Japan’s government has picked companies and researchers to turn the multi-billion dollar dream of unlimited clean energy into reality by 2030.

The Space Solar Power System involves an array of photovoltaic dishes reaching across several square miles that hover in geostationary orbit outside the Earth’s atmosphere.

“Since solar power is a clean and inexhaustible energy source, we believe that this system will be able to help solve the problems of energy shortage and global warming,” Mitsubishi Heavy Industries, one of the project participants, said.

The solar cells would capture the sun’s energy, which is at least five times stronger in space than on Earth, and beam it down to the ground through clusters of lasers or microwaves.

Article continues: http://news.sky.com/skynews/Home/World-News/Japan-Space-Solar-Power-Zapped-To-Earth-By-Laser-Suns-Energy-From-Station-By-2030-Japanese-Hope/Article/200911215445545?lpos=World_News_First_Strange_News__Article_Teaser_Region__3&lid=ARTICLE_15445545_Japan%3A_Space_Solar_Power_Zapped_To_Earth_By_Laser%3A_Suns_Energy_From_Station_By_2030%2C_Japanese_Hope

PHOTO CREDIT: USEF

http://www.enn.com/energy/article/40682