Posted on by Ian O'Neill

Primordial Stars Frozen Indefinitely by Dark Matter

Dark, cold stars from the young Universe could still be here today (University of Utah)

It is thought that primordial or “Population III” stars were born in dense clouds of dark matter, 100 million years after the Big Bang. During the period between birth and dark matter depletion, these first stars were effectively but into a “deep freeze” where normal star development was prevented. After this period when all the dark matter fuel had been consumed, these stars were allowed to commence normal stellar evolution, dying out within a few hundred thousand years. But say if a Population III star was born in an exceptionally dense cloud of dark matter? How long could “normal stellar evolution” be frozen for? According to new research, dark matter could theoretically freeze the star indefinitely, over timescales longer than the age of the Universe…

This amazing theory comes from research carried out by Gianfranco Bertone and his team at the Paris Institute of Astrophysics in France. The thought that the first stars, born over 14 billion years ago, could possibly inhabit the Universe today is a very impressive idea. These primordial stars are thought to have been seeded inside dense clouds of dark matter, where gravity caused dark matter compression. As the matter became concentrated, non-baryonic particles may have begun annihilating, stopping natural hydrogen fusion (the mechanism commonly associated with star creation). “Normal” stellar evolution was therefore paused and the “dark star” phase began as dark matter annihilation heated the stellar cores.

It has long been the assumption that the “dark star” phase occurred for a short period of time in the early Universe where vast halos of dark matter may have dominated. Once the dark matter fuel ebbed away, primordial stars were left to self-destruct in a flurry of accelerated evolution. Now Bertone and his colleagues believe a few primordial specimens might be alive today, hidden inside particularly dense clouds of dark matter, in galactic centres, keeping some of the Universe’s first stars in a state of suspended animation.

“There could be conditions in the early universe where stars form in big enough reservoirs of dark matter to last until the present day.” – Gianfranco Bertone.

One of the most exciting implications to come from this research is the fact that these ancient relics may be observed, what’s more, we may have already seen some. “A frozen star would appear much bigger and colder than a normal star with the same mass and chemical composition,” says Marco Taoso, co-investigator in the French group. If stars matching the characteristics of these frozen stellar bodies are (or already have been) found, the discovery would have huge consequences for the quantum search for supersymmetry, indicating dark matter was indeed made up of massive “superpartners” to ordinary matter.

If dark matter influenced stars a few hundred thousand years after the Big Bang, can it still influence stellar evolution today? Researchers believe this could be the case. Present-day stars evolving in regions of dark matter clouds may be influenced by non-baryonic particles. White dwarfs are formed after the death of Sun-like stars and it is believed that should the dwarf star encounter a cloud of dark matter, it could be resurrected as a dark matter burner, shining like 30 Suns.

It will be interesting to see if there have already been any observations of these primordial stars, possibly providing more indirect evidence of dark matter in our Universe.

Source: New Scientist

Posted on by Nancy Atkinson

Huge Camera to Observe Dark Energy

Discovering the universe is accelerating and not slowing down made it obvious to astronomers there’s a lot we don’t know about the universe; namely, a big chunk of it is missing from our visible observations. Astronomers determined roughly 4% of the universe is made up of ordinary matter and 27% of Dark Matter (inferred from gravitational affects on visible matter), leaving 68% unaccounted for. Dark energy, while still hypothetical, is what is believed to keep the pedal to the metal, so to speak, on the universe’s expansion. But an international group of astronomers believes that dark energy should be detectable, and they are constructing a huge camera, designed to look for it. The camera will consist of five massive lenses, with the largest at one meter in diameter, making it one of the biggest lenses in the world. A milestone was reached in the construction of this camera, as the pieces of glass for these unique lenses, seen in the image here, are ready to be shaped and polished into their final form.

The Dark Energy Survey (DES) camera will map 300 million galaxies using the Blanco 4-meter telescope – a large telescope with new advanced optics at Chile’s Cerro Tololo Inter-American Observatory. This instrument will consist of an extremely red sensitive 500 Megapixel camera, with a 1 meter diameter, 2.2 degree field of view prime focus corrector, and a data acquisition system fast enough to take images in 17 seconds.

Creating this huge map of the galaxy will enable astronomers to measure the dark energy far more precisely than current observations. Professor Ofer Lahav, who leads the United Kingdom DES Consortium said, “Dark Energy is one of the biggest puzzles in the whole of Physics, going back to a concept proposed by Einstein 90 years ago. The DES observations will tell us if Einstein was right or if we need a major shift in our understanding of the universe.”

The glass for the five lenses was manufactured in the US. In France the lenses will be polished to a smoothness level of one millionth of a centimeter.

After, polishing, the lenses will be sent to the telescope in Chile. Observations are scheduled to begin in 2011, continuing until 2016.

The team’s goals are to extract cosmological information on dark energy from counting galaxy clusters and the spatial distribution of clusters, and measuring the redshift of galaxies and supernovae.

The Science and Technology Facilities Council (STFC) is providing support for the Dark Energy Survey (DES) collaboration, which involves over 100 scientists from the US, UK, Spain and Brazil.

Orignal news sources: Science and Technology Facilities Council, Dark Energy Survey

Posted on by Nicholos Wethington

Homer’s “Odyssey” May Chronicle Ancient Eclipse

It’s likely that sometime in your education career, an English teacher had you enjoy (or suffer through, depending on your tastes) at least part of that classic of classics, Homer’s Odyssey. It tells the story of Odysseus, a Greek general, who embarks on a 10-year journey back home after battling in the fall of Troy. The tale is filled with imagery that is referenced often in contemporary films and books. As old as it is, one would think that we’ve learned pretty much all we can from the book, but a new analysis of celestial events referenced in the Odyssey reveals that Homer may have documented a total solar eclipse.

Here’s a little background on the epic: Odysseus fights in the battle of Troy, which is believed to have occurred in approximately 1200 B.C. After the battle, he must find his way back to Ithaca in Greece, and the journey home is a harrowing one in which he is captured by the nymph Calypso, drifts on a raft at sea, battles a cyclops, resists the temptation of the Sirens and in general has hard luck. While he is away, his wife Penelope is living at his house with 108 suitors who are trying to convince her that she should accept her husband as dead and marry one of them.

Near the end of the story, a seer named Theoclymenus foretells the death of all the suitors, saying:

Poor men, what terror is this that overwhelms you so? Night shrouds your heads, your faces, down to your knees — cries of mourning are bursting into fire — cheeks rivering tears — the walls and the handsome crossbeams dripping dank with blood! Ghosts, look, thronging the entrance, thronging the court, go trooping down to the realm of death and darkness! The sun is blotted out of the sky — look there — a lethal mist spreads all across the Earth.

The reference to the Sun being blotted out of the sky on the day Odysseus returns home to retake his house and slaughter the suitors has been thought for a long time to be a reference to an actual eclipse, and was debated by astronomers, historians and classicists until it was finally decided that there was not enough evidence in the book to pinpoint a specific date for the event.

An analysis of overlooked passages in the book by Marcelo O. Magnasco, who heads the Laboratory of Mathematical Physics at Rockefeller, and Constantino Baikouzis of the Proyecto Observatorio at the Observatorio Astronómico in La Plata, Argentina reveals that there is enough evidence – if their interpretation of the events is correct – to place the eclipse on April 16th of 1178 B.C. Magnasco and Baikouzis reported their findings in this week’s Proceedings of the National Academy of Sciences.

There are four celestial clues in the Odyssey that individually happen rather often, but rarely coincide within a short period of time. As Odysseus is making his way home on a raft, he navigates by the use of the constellations Bootes and the Pleiades, which only appear together in the sky in March and September. The Moon is new when Odyesseus returns home, and on that day Venus rises before dawn, which only happens during one-third of new moons. The most important clue, though, is that Homer refers to the god Hermes flying west to the island of Ogygia about a month earlier. This reference is likely to the planet Mercury, which is low in the sky and experiences retrograde motion – seems to go backward in the sky relative to the stars – every 116 days.

Magnasco said, “Not only is this corroborative evidence that this date might be something important but if we take it as a given that the death of the suitors happened on this particular eclipse date, then everything else described in The Odyssey happens exactly as is described.”

Baikouzis and Magnasco analyzed all 1,684 new moons between 1250 and 1125 B.C. with commercial astronomy software for any dates that would match this confluence of events and came up with April 16th, 1178 B.C. Given that Homer matched the story to events in reality, this could help historians date the fall of Troy and shows that this great poet may also have had a penchant for astronomy.

Source: EurekAlert, Scientific American

Posted on by Nancy Atkinson

Unusual Galaxies Eat Their Neighbors

Seyfert galaxies appear to be normal spiral galaxies, but they have fluctuating bright centers. And now, their deep-down, hidden nature has been revealed: they are cannibals. While visible-light images didn’t provide much evidence that these galaxies had any interaction with their neighbors, radio-telescope images from the Very Large Array revealed that Seyfert galaxies are snacking on neighboring galaxies, with the “meal” feeding the supermassive black hole at their centers. Astronomers had suspected this was the case, but until now, they didn’t have the evidence to support the idea.

One leading theory said that the fluctuations seen in Seyfert galaxies’ centers were caused by close encounters with neighboring galaxies. The gravitational encounters stirred up gas from the neighboring galaxies and brought it within reach of the black hole. However, when astronomers looked at Seyferts with visible-light telescopes, only a small fraction showed any evidence of such an encounter. Now, new images of hydrogen gas in Seyferts made using the National Science Foundation’s Very Large Array (VLA) radio telescope show the majority of them are, in fact, disturbed by ongoing encounters with neighbor galaxies.

“The VLA lifted the veil on what’s really happening with these galaxies,” said Cheng-Yu Kuo, a graduate student at the University of Virginia. “Looking at the gas in these galaxies clearly showed that they are snacking on their neighbors. This is a dramatic contrast with their appearance in visible starlight,” he added.

The effect of the galactic encounters is to send gas and dust toward the black hole and produce energy as the material ultimately is consumed. Black holes, concentrations of matter so dense that not even light can escape their gravitational pull, reside at the cores of many galaxies. Depending on how rapidly the black hole is eating, the galaxy can show a wide range of energetic activity. Seyfert galaxies have the mildest version of this activity, while quasars and blazars are hundreds of times more powerful.

The astronomers picked a number of relatively nearby Seyfert galaxies that had previously been observed with visible-light telescopes. They then carefully studied the Seyferts with the VLA, specifically looking for radio waves emitted by hydrogen atoms. The VLA images showed the vast majority of the Seyferts were disturbed by encounters with neighbor galaxies.

By comparison, similar VLA images of inactive galaxies showed that very few were disturbed. “This comparison clearly shows a connection between close galactic encounters and the black-hole-powered activity in the cores,” said Ya-Wen Tang, who began this work at the Institute of Astronomy & Astrophysics, Academia Sinica (ASIAA), in Taiwan and now is a graduate student at the National Taiwan University.

“This is the best evidence yet for the fueling of Seyfert galaxies. Other mechanisms have been proposed, but they have shown little if any difference between Seyferts and inactive galaxies,” Tang added.

Original News Source: National Radio Astronomy Observatory

Posted on by Ian O'Neill

ATV Jules Verne Surpasses All Expectations (Videos)

The ATV on approach to the station in April. Mission will end next month (ESA/NASA)

Last week’s record re-boost from ESA’s Automated Transfer Vehicle (ATV) pushed the International Space Station 7 kilometres (4.3 miles) higher to an orbit of 345 kilometres (214 miles) above Earth. This was the second re-boost carried out by the ATV, a mission (dubbed “Jules Verne”) that has surpassed all expectations. In fact, the ATV has not only passed each and every mission objective perfectly, it has gone above and beyond the call of duty…

After 11 weeks attached to the ISS, ATV Jules Verne continues to provide an unexpected service to the ISS crew. Last Thursday it successfully boosted the 300 tonne ISS to a higher orbit (this was the second re-boost, the first was at the end of April) and it has since refuelled the station with 856 kg of propellant. Although these were essential tasks, the ATV has provided an invaluable service to the crew. Not in the design plan of the ATV, the roomy temporary supply vessel has provided a great area for the crew to sleep and wash, plus one of its empty tanks has been used to store 110 litres of condensation water from the ISS. But the best news of all: the ATV’s mission has been extended for a month, allowing the crew to enjoy the ATV for a little while longer. The scheduled undocking and planned burn up on re-entry will now take place in September, not August.

Watch the ESA video montage of the crew working (and playing) inside the spacious ATV »

Ever since Jules Verne docked at the ISS on April 3rd, the ISS astronauts have had access to the roomy 48 m3 vessel and they have made it a centre for daily life onboard the station. The ATV mission control gave the crew special permission to use the spaceship for a variety of everyday needs. For starters, the astronauts and cosmonauts have been using the ATV as an improved “Crew Hygiene Station” where they have been able to wash their laundry. They have also been able to use the space to wash their hair with an alcohol-free rinse less shampoo (I’d love to know how that stuff works!). This additional space also has the effect of keeping the station’s air humidity low.

Watch an animated version of last week’s re-boost operation »

Crewmembers have also used the ATV as alternative sleeping quarters. Apparently, the ATV is a quieter environment to the rest of the station as the sound levels of the ventilator fans and air circulation is fairly low. The station’s sleeping arrangements are fairly strict, two crewmembers must sleep in the small ISS crew cabins, but the third can sleep anywhere in the station. It turns out the ATV has proven to be the location of choice for the third crewmember.

For further detail about the huge array of ATV successes, check out the ESA news release. For now, the crew have a little more time to enjoy the ATV before it ends its mission in September only to be dropped into the atmosphere where it will burn to a cinder, leaving any mass left to drop to the bottom of the Pacific Ocean. How sad.

Sources: ESA [1], [2]

Posted on by Ian O'Neill

US Senator: NASA Job Losses Could Generate Jobs for Russian Space Program

Could the Shuttle launch after 2010? (NASA)

It’s not good news, but it could be worse. On Monday, NASA announced that it anticipates shedding 3,000-4,000 jobs in two years once the Space Shuttle fleet is retired to make way for the Constellation Program. This is obviously terrible news for the staff, scientists and engineers and their families, but it is in improvement on previous estimates that up to 8,000 personnel could have lost their livelihoods. NASA Administrator Michael Griffin confirmed that about 3,000 jobs would be saved by filling positions in the new space program that will build spaceships to supply the International Space Station and eventually take man to the Moon and Mars. However, the early Shuttle retirement and late Constellation completion will increase the dependence on Russia to provide access to space…

In April, Nancy reported that NASA could cut 8,000 jobs mainly around the Kennedy Space Center where the Shuttle launches are administered. Although job losses were to be expected during the Shuttle-Constellation handover, this high figure will have come as a shock, not only to NASA’s workforce, but the whole space exploration community. Today’s announcement will come as a relief as although 6,000-7,000 Kennedy Space Center employees will be lost, around 3,000 will be relocated to the new exploration program, most likely based at Cape Canaveral.

This news has surfaced from a two-hour hearing at Port Canaveral, on the doorstep of the space center where officials, residents and protesters attended. About 1,000 people had gathered earlier in the day for an outdoor rally before the morning meeting.

“America – one small step, one giant voice”
“America the place for space”
– Slogans written on rally protester’s banners this morning.

Protesters this morning (Canaveral Port Authority)

U.S. Sen. Bill Nelson, chairman of the space subcommittee and ex-astronaut who flew on Columbia in 1986, organized the hearing so concerned employees could have direct communication with NASA officials. Although the news was still tough to swallow, Nelson was upbeat about Griffin’s announcement. “I can’t say it’s good news, but it’s certainly news that’s a step in the right direction,” he said. The Senator also suggested that the forthcoming presidential elections may be fruitful when trying to find a change in policy for space exploration funding.

For now, workers at the site will have to wait until 2009 until a clearer picture emerges. In 2010, NASA has been instructed by the government to wind up Shuttle operations so a new focus can be set on Moon launches.

Nelson voiced concerns that these cutbacks at NASA will have the effect of “generating jobs in Russia to accomplish the same mission,” as once the Shuttle is retired there will be a dependence on the Russian space agency for access to space. Griffin responded by saying the situation was “unseemly in the extreme” but ultimately unavoidable. More NASA funding would be required to bring the new Constellation program into operation to fill the 5-year gap (from 2010 to 2015) in US launches to the space station. Nelson has also voiced his concern that the area could be economically damaged during this time through job lay-offs, identical to the situation in the 1970’s when Apollo was decommissioned and the Shuttle made its first flight in 1981.

Sources: Link to Launch, Associated Press

Posted on by Nancy Atkinson

Rare Binary Pulsars Provide High Energy Physics Lab

For the first time, a spacecraft has detected signals from both stars of a binary pulsar system in X-rays. XMM-Newton is watching both stars radiate pulsating X-rays, providing scientist with the perfect laboratory for high energy physics and a never-ending source of intriguing physical problems. The binary pulsar PSR J0737-3039 was first spotted by astronomers in 2003 in radio wavelengths, but now X-rays can be used to investigate this system in greater detail.

Binary pulsars are extremely rare. Each star of the closely-packed system is a dense neutron star, spinning extremely fast, radiating X-rays in pulses. One pulsar (B) rotates slowly, what scientists call a ‘lazy’ neutron star, while orbiting a faster and more energetic companion (pulsar A).

Each pulsar or neutron star once existed as a massive star. “These stars are so dense that one cup of neutron star-stuff would outweigh Mt. Everest,” says Alberto Pellizzoni, who has been studying this system. “Add to that the fact that the two stars are orbiting really close to each other, separated by only 3 light-seconds, about three times the distance between Earth and the Moon.”

Pellizzoni added, “One cup of neutron star-stuff would outweigh Mt. Everest. Add to that the fact that they’re orbiting really close, separated by only about three times the distance between Earth and the Moon.”

Pulsar B is an oddity, in that it is very different from a ‘normal’ pulsar. Additionally, the amount of X-rays coming from the system is greater that the scientists predicted. But how the two pulsars work together is still not understood.

“One possible solution for the mystery could be mutual interaction between the two stars, where the lazy star derives energy from the other,” says Pellizzoni.

Watch video of how the two pulsars may interact

The fundamental physical processes involved in these extreme interactions are a matter of debate among theoretical physicists. But now, with XMM-Newton’s observations, scientists have gained new insight, providing a new experimental setting for them. In X-rays, it will be possible to study the subsurface and magnetospheres of the stars as well as the interaction between the two in that close, heated environment.

This system also provides the study of strong-field gravity, given how close and dense the two stars are. Future tests of general relativity by radio observations of this system will supersede the best Solar System tests available. It is also a unique laboratory for studies in several other fields, ranging from the equation of state of super-dense matter to magneto-hydro dynamics.

Original News Source: ESA

Posted on by Astronomy Cast

Podcast: Humans to Mars, Part 1 – Scientists

Mars Explorer. Image credit: NASA

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We’re learned about the failed missions to Mars in the past, and the current spacecraft, rovers and landers currently exploring the Red Planet. But the real prize will come when the first human sets foot on Mars. Robots are cheaper, but nothing beats having a real human being on the scene, to search for evidence of water and life.

Click here to download the episode

Humans to Mars, Part 1 – Scientists – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Posted on by Tammy Plotner

NGC 6302 by Don Goldman

NGC 6302 by Don Goldman

Over the weeks we’ve looked at a lot of curious objects and today is no exception. NGC 6302 is often called the “Bug Nebula”, but its resemblance to an insect isn’t what makes it unique – it’s the complex structure. Deep inside this bipolar planetary nebula lay an unseen star… One of the hottest objects in the galaxy.

Residing about 4,000 light years away in the constellation of Scorpius, NGC 6302 is the end remains of an enormous dying star. With a surface temperature of an estimated 200,000 K, its central star exceeds our own Sun’s mean temperature output by nearly 35 times – yet has never been observed. Why? Because it is shielded from view at all wavelengths by an impossibly dense equatorial disc composed of gas and dust… One that may have restricted the star’s outflow into the unusual bipolar structure we can see.

But the hidden central star isn’t what’s bugging scientists, it’s the chemical composition!

Filled with ionization walls, edges and lobes, this dust is both oxygen and carbon-rich – a dual chemistry which means it has undergone recent changes and alternate formation processes in its 10,000 year life. Studies done by the European Space Agency’s Infrared Space Observatory (ISO) have shown that the dusty torus contains hydrocarbons, carbonates such as calcite, as well as water ice and iron. If the word carbonates made you raise an eyebrow, it should because carbonates form when carbon dioxide dissolves in liquid water and forms sediments.

Says Albert Zijlstra from UMIST: “What caught our interest in NGC 6302 was the mixture of minerals and crystalline ice – hailstones frozen onto small dust grains. Very few objects have such a mixed composition.”

Yet NGC 6302 is even more complex, displaying evidence that a second pair of lobes may have formed during a previous phase of the star’s mass loss. The visible northwest lobe is believed to have been created some 1,900 years ago and shows some signs that it may have once collided with pre-existing globules of gas which changed its outflow. According to studies done by Groves, Doptia, Williams and Hua; “We find that for NGC 6302, the visible to IR extinction law is indistinguishable from `standard’ interstellar reddening, but that the UV extinction curve is much steeper than normal, suggesting that more small dust grains had been ejected into the nebula by the PN central star.”

Kinematical studies done by Minkowski and Johnson suggest that NGC 6302 originated in some type of explosive event. It exhibits a rich spectrum of lines, indicating rich deposits of helium and nitrogen – far more than an ordinary planetary nebula. What the Bug Nebula seems to lack in its diet, however, is iron and calcium – two elements which may very well be tied up as solid grains.

So what’s next for this extreme, high-excitation planetary nebula? According to Wright, Barlow, Ercolano and Rauch; “We use the 3D photoionisation code to model the emission from the gas and dust. We have produced a good fit to the optical emission-line spectrum, from which we derived a density distribution for the nebula. A fit to the infrared coronal lines places strong constraints on the properties of the unseen ionising source. We find the best fit comes from using a 220,000 K hydrogen-deficient central star model atmosphere, indicating that the central star of this PN may have undergone a late thermal pulse.”

ngc 6302 mapBut don’t you be late observing the Bug Nebula yourself! NGC 6302 is located in Scorpius (RA 17 13 44 Dec -37 06 15). At around magnitude 9, this surprisingly bright planetary is well within the reach of a mid-size telescope and a treat to larger aperture. NGC 6302 was discovered by James Dunlop in 1826 with a handmade reflecting telescope he had constructed himself and the earliest known study of NGC 6302 is Edward Emerson Barnard who, in 1907, drew and described it.

Seek it out… And enjoy!

This week’s awesome image was taken by Don Goldman from Macedon Ranges Observatory.

Posted on by Ian O'Neill

Paranormal Radio’s “2012 Just Another Day” Show Now Available!

Paranormal Radio banner

On June 10th, I was invited on Captain Jack’s Paranormal Radio show to chat about the various 2012 Doomsday scenarios. We had a great time for three hours talking about everything from the Mayan calendar and Planet X to the Phoenix Mars Mission and Saturn. The show has just been made available as an MP3 that should be easy to listen to on your podcast-grabbing equipment, or your favorite media player on your computer.

Download the Paranormal Radio “2012 Just Another Day” show with Captain Jack and myself (hosted at Astroengine.com) »

Enjoy!

And in case you missed it, the first radio show I did with Colin Knight on Terra Chat (dated June 8th) is still online.

I’ve been invited back to both Paranormal Radio and Terra Chat for future shows, so I’ll post any news as I get it.

Cheers! Ian