Nobody is really sure what created Gould's Belt, but many researchers speculate that there was some kind of giant supernova or possibly rogue dark matter that sent out such massive bursts of energy that it created "ripples" spreading outward from the event. The Belt would be the result of those ripples. Here's a map showing some of the Belt's major features.

The image above is the first clear view of one of these features. According to ESA:

Some 700 newly-forming stars are estimated to be crowded into these colourful filaments of dust. The complex is part of a mysterious ring of stars called Gould's Belt.

This image shows a dark cloud 1000 light-years away in the constellation Aquila, the Eagle. It covers an area 65 light-years across and is so shrouded in dust that no previous infrared satellite has been able to see into it. Now, thanks to Herschel's superior sensitivity at the longest wavelengths of infrared, astronomers have their first picture of the interior of this cloud . . .

This cloud is part of Gould's Belt, a giant ring of stars that circles the night sky – the Solar System just happens to lie near the centre of the belt. For more than a hundred years, astronomers have puzzled over the origin of this ring, which is tilted to the Milky Way by 20º. The first to notice this unexpected alignment, in the mid-19th century, was England's John Herschel, the son of William, after whom ESA's Herschel telescope is named. But it was Boston-born Benjamin Gould who brought the ring to wider attention in 1874.

Gould's Belt supplies bright stars to many constellations such as Orion, Scorpius and Crux, and conveniently provides nearby star-forming locations for astronomers to study.

Below, you can see an image of what Gould's Belt would look like from above the Milky Way galactic plane. Our solar system sits right in the middle of that white ring, which represents the Belt.

via ESA Portal and Orbiting Frog

I apologize in advance for the weird racist statue with images # 2 and 3. Images by AFP/Getty.

A18th century Planetarium made by Martin Benjamin is exhibited on October 13, 2009 during the 'Astrum 2009, Astronomy and Instruments' exhibition at The Vatican museum. The exhibition, running from October 16 to January 16, 2010 is organized on occasion of the International year of Astronomy, with the National Institute of Astrophysics (INAF), and is orientated on the history, functioning and evolution of the different instruments created by Man over ten centuries for the observation of the sky, for the location of the stars and celestial bodies. AFP PHOTO / VINCENZO PINTO (Photo credit should read VINCENZO PINTO/AFP/Getty Images)

A view of a celestial and terrestrial Globe designed by Vincenzo Maria Coronelli in 1696 which is exhibited on October 13, 2009 during the 'Astrum 2009, Astronomy and Instruments' exhibition at The Vatican museum. The exhibition, running from October 16 to January 16, 2010 is organized on occasion of the International year of Astronomy, with the National Institute of Astrophysics (INAF), and is orientated on the history, functioning and evolution of the different instruments created by Man over ten centuries for the observation of the sky, for the location of the stars and celestial bodies. AFP PHOTO / VINCENZO PINTO (Photo credit should read VINCENZO PINTO/AFP/Getty Images)

A view of a celestial and terrestrial Globe designed by Vincenzo Maria Coronelli in 1696 which is exhibited on October 13, 2009 during the 'Astrum 2009, Astronomy and Instruments' exhibition at The Vatican museum. The exhibition, running from October 16 to January 16, 2010 is organized on occasion of the International year of Astronomy, with the National Institute of Astrophysics (INAF), and is orientated on the history, functioning and evolution of the different instruments created by Man over ten centuries for the observation of the sky, for the location of the stars and celestial bodies. AFP PHOTO / VINCENZO PINTO (Photo credit should read VINCENZO PINTO/AFP/Getty Images)

A celestial globe by Giovanni Antonio Vanosino in1567, showing the main Ptolemaic constellations in convex representation, is exhibited on October 13, 2009 during the 'Astrum 2009' exhibition at The Vatican museum. The exhibition, running from October 16 to January 16, 2010 is organized on occasion of the International year of Astronomy, with the National Institute of Astrophysics (INAF), and is orientated on the history, functioning and evolution of the different instruments created by Man over ten centuries for the observation of the sky, for the location of the stars and celestial bodies. AFP PHOTO / VINCENZO PINTO (Photo credit should read VINCENZO PINTO/AFP/Getty Images)

A celestial globe by Giovanni Antonio Vanosino in1567, showing the main Ptolemaic constellations in convex representation, is exhibited on October 13, 2009 during the 'Astrum 2009' exhibition at The Vatican museum. The exhibition, running from October 16 to January 16, 2010 is organized on occasion of the International year of Astronomy, with the National Institute of Astrophysics (INAF), and is orientated on the history, functioning and evolution of the different instruments created by Man over ten centuries for the observation of the sky, for the location of the stars and celestial bodies. AFP PHOTO / VINCENZO PINTO (Photo credit should read VINCENZO PINTO/AFP/Getty Images)

The Arsenius Gualterus' astrolab is exhibited on October 13, 2009 during the 'Astrum 2009, Astronomy and Instruments' exhibition at The Vatican museum. The exhibition, running from October 16 to January 16, 2010 is organized on occasion of the International year of Astronomy, with the National Institute of Astrophysics (INAF), and is orientated on the history, functioning and evolution of the different instruments created by Man over ten centuries for the observation of the sky, for the location of the stars and celestial bodies. AFP PHOTO / VINCENZO PINTO (Photo credit should read VINCENZO PINTO/AFP/Getty Images)

Judges for the Royal Observatory Greenwich combed through over 500 images of moons, planets, nebula, and Earth's own night sky, and chose twenty top photos in each of four categories: Deep Space, Earth and Space, Our Solar System, and Young Photographers — for astronomy buffs 16 and under. Judges were especially wowed by Pugh's image of the oft-photographed Horsehead Nebula. Said Chris Lintott, competition judge and co-presenter of the BBC's The Sky at Night:

I think this is the perfect deep-sky image; perfectly composed, it grabs your attention straight away. When you look closer, the detail is absolutely stunning, whether it's the fine structure in the curtain behind the horse or the subtle details on the edge of the dark nebula itself.

The winning photos will be on display at the Royal Observatory until January 10th, 2010.

[Astronomy Photographer of the Year 2009]

Horsehead Nebula by Martin Pugh — Astronomy Photograph of the Year, Winner Deep Space
Star Trails, Blue Mountains by Ted Dobosz — Winner Earth and Space
Blue Sky Moon by Michael O'Connell — Winner Our Solar System
Occultation of Venus by Paul Smith, aged 14 — Winner Young Astronomy Photographer of the Year
Galaxies M81 and M82 by Edward Henry — Runner Up Deep Space
Venus, Jupiter and Moon trails over the Nepean River by Vincent Miu — Runner Up Earth and Space
3.1 Day-old Moon by Nick Smith — Runner Up Our Solar System
No Dogs on Beach by Sarah Gilligan, aged 11 — Runner Up Young Photographer of the Year
Galactic Dust in Corona Australis by Martin Pugh — Highly Commended Deep Space
Centaurus-A: Ultra-Deep Field by Michael Sidonio — Highly Commended Deep Space
Eta Carina Nebula by Thomas Davis — Highly Commended Deep Space
Milky Way by Nik Szymanek — Highly Commended Earth and Space
Bow of Orion by Karl Johnston — Highly Commended Earth and Space
Death Valley Star Trails by Nikhil Shahi — Highly Commended Earth and Space
Clavius-Moretus Mosaic by Nick Smith — Highly Commended Our Solar System
Comet Holmes by Nick Howes — Highly Commended Our Solar System
Venus by Paul Smith, aged 14 — Highly Commended Young Photographer of the Year
Full Moon by Jathin Premjith, aged 13 — Highly Commended Young Photographer of the Year
Mercury and the crescent moon by Ben Fernando, aged 15 — Highly Commended Young Photographer of the Year

In 2004, the NASA spacecraft Stardust captured particles shed by the Wild 2, an icy comet in our Solar System. Last year, the team examining the Wild 2 sample discovered it contained several amino acids as well as nitrogen-bearing amines. At the time, the team was unable to rule out contamination from Earth as a possible source of the amino acids. But after painstaking tests, they were able to determine that at least one of the amino acids, glycine, came from the comet itself.

Although discoveries like this by no means prove that life on Earth originated with a comet bringing amino acids into our atmosphere, the Stardust team is excited by the implications it has for eventually explaining the origins of life on Earth. And, combined with the recent discovery that some comets contain liquid water, it seems possible that comets strikes could bring the building blocks of life to a planet's surface. The next step is to obtain larger samples from comets, and samples from the comet's nucleus instead of its debris. Fortunately, the ESA'a Rosetta spacecraft is scheduled to land on the comet 67P/Churyumov-Gerasimenko in 2014, and will hopefully bring back just the sort of sample the Stardust team is longing for.

[New Scientist]

The Perseid meteor shower occurs every year when the Earth passes into a cloud of debris trailing behind the comet Swift-Tuttle. The shower has already passed its peak for the year, but several quick-fingered photographers have shared their photos of the meteors streaking the sky:

Turn Basin at NASA's Kennedy Space Center: This may actually be an incidental meteor rather than a Perseid, since its path doesn't point back to the shower's radiant. [APOD]
Perseid shooting across star trails by Izzyman1.
Perseid over Mudanya, Turkey by Ugur Ikizler.
Shooting Star Inn & Observatory just outside of Flagstaff, Arizona by Tom Taylor.
Perseid over Malta by stefni082.
Meteor over Halifax, Nova Scotia by Michael Boschat.
Perseid over Laleh-zar, Kerman, Iran by Ehsan Rostamizadeh.
Rooftop view of Perseid in Washington Heights, NYC by meg21210.
Perseid over Glade Park, CO by Thad V'Soske.

In nearly every other observed planetary system, the planets spin around the star the same direction as the star itself is spinning. This is because, scientists believe, both the stars themselves and their planets are formed from the same rotating gas clouds, leaving them all spinning in the same direction as that original cloud.

There are exceptions to this general rule, but those are caused by gravitational interference pushing the planets into orbits at very strange angles. A brush with another planet or large gravity source can cause the aligned orbit to push into a strange angle. And the team that discovered this strange new planet, dubbed WASP-17b, wanted to blame this mechanism again.

But gravitational interference might be a bit of a stretch here: the planet's orbit is 150 degrees opposed, or almost directly opposite, the star's rotation. It'd take a pretty significant gravitational shove to get this much of a difference.

WASP-17b is notable for a couple of other reasons, too, all described in a paper submitted to the Astrophysical Journal. WASP-17b is possibly the largest yet discovered exo-planet, at twice the width of Jupiter. It's also pretty light, at only half of Jupiter's mass. That leaves the planet with a consistency similar to polystyrene, a light, puffed up ball of mostly nothing.The research team thinks this might be an effect of its very close (7 million kilometers), very quick (only 3.7 days) orbit yanking materials around inside the body and deforming it into this weird puffy planet.

The planet is, to say the least, really strange, compared to what scientists have seen before. But such discoveries remind us that we've only seen a very, very small percentage of what exists in the rest of the universe. Maybe what we have deemed to be "normal" isn't normal, but just what we are used to.

Planet found orbiting its star backwards for first time [via NewScientist]
Paper: WASP-17b: an ultra-low density planet in a probable retrograde orbit [arXiv.org]

(Illustration: what such a close-orbiting planet may look like, from ESA/C. Carreau)

As we've mentioned before, once every 15 Earth years, Saturn reaches its equinox, when the ringplane is directly parallel to the sun. This causes the sunlight to hit the thinnest point of the rings, making the ring shadows appear as a thin band against the planet. The Cassini team was able to position the spacecraft in such a way that it was able to capture the illusion, but also captured images of the rings from positions where they were still visible.

[CICLOPS via Universe Today]

Unprocessed image of Saturn just after the equinox.
Unprocessed image of Saturn's rings just after the equinox.
Unprocessed image of Saturn's rings just after the equinox.
Unprocessed image of Saturn's rings at the equinox.

At this year's meeting of the General Assembly of the International Astronomical Union, at a panel titled "Solar and Stellar Variability ― impact on Earth and Planets," a multidisciplinary group of experts discussed the evolving research into the types of suns and planets that would be hospitable to the development of life.

Edward Guinan, a professor of astronomy at Villanova University, claims that our sun provided better conditions for the formation of life in its youth. Over four billion years ago, the sun rotated ten times faster than it does today, causing the sun to generate a stronger magnetic field and considerably more radiation than it does today. These conditions have aided the formation of life, but other stars exist that maintain such a rapid rotation for a much longer duration:

The Sun does not seem like the perfect star for a system where life might arise. Although it is hard to argue with the Sun's ‘success' as it so far is the only star known to host a planet with life, our studies indicate that the ideal stars to support planets suitable for life for tens of billions of years may be a smaller slower burning ‘orange dwarf' with a longer lifetime than the Sun ― about 20-40 billion years. These stars, also called K stars, are stable stars with a habitable zone that remains in the same place for tens of billions of years. They are 10 times more numerous than the Sun, and may provide the best potential habitat for life in the long run.

Jean-Mathias Grießmeier of ASTRON's research similarly suggests that the Earth may not be an ideal planet for the formation and development of life. Grießmeier examined planetary magnetic fields, finding that a planet with a stronger magnetic field is less likely to have its atmosphere blown away by cosmic debris and is also better able to shield its surface from cosmic radiation. Guinan suggests that planets larger than Earth might be better able to protect any burgeoning life forms:

On the more speculative side we have also found indications that planets like Earth are also not necessarily the best suited for life to thrive. Planets two to three times more massive than the Earth, with a higher gravity, can retain the atmosphere better. They may have a larger liquid iron core giving a stronger magnetic field that protects against the early onslaught of cosmic rays. Furthermore, a larger planet cools more slowly and maintains its magnetic protection. This kind of planet may be more likely to harbour life.

That K stars are relatively common may offer new hope for the possibility of extraterrestrial life, although astronomers are quick to note they don't fully understand how common or fragile life in the universe may be. But their findings do suggest that, on a cosmological scale, Earth can't support life much longer. Says Guinan:

The Earth's period of habitability is nearly over ― on a cosmological timescale. In a half to one billion years the Sun will start to be too luminous and warm for water to exist in liquid form on Earth, leading to a runaway greenhouse effect in less than 2 billion years.

[Science Daily]

Currently, NASA has been able to detect roughly 83 percent of the estimated 940 Near-Earth asteroids that are at least one kilometer in diameter. If such an asteroid were to enter our atmosphere, it could bring with it sun-blocking dust and radical climate change even before it makes an impact. But astronomers are growing more concerned with the more numerous smaller asteroids, whose impact could flatten trees — as happened in Siberia where many astronomers believe a comet or asteroid exploded in 1908 — shatter cities, and cause unpredictable waves of coastal flooding. Because of their size, these asteroids are difficult to detect, and astronomers fear one could strike the Earth with little or no warning.

In 2005, the United States Congress charged NASA to detect at least 90 percent of these smaller asteroids by 2020, but a report from the US National Research Council reveals that achieving that goal will require far more equipment than is currently allotted to asteroid detection. The report indicates that new facilities need to be built, with equipment capable of detecting fainter asteroids and covering a wider range of the cosmos. A better system will need to be developed for detecting asteroids that are particularly close to Earth, rather than simply creating a catalog of near-Earth asteroids, and a telescope would need to be placed at another vantage point in space to detect asteroids coming from the sun.

The NRC is unsure what the cost of these systems would be, but panel leader Irwin Shapiro of the Harvard-Smithsonian Center for Astrophysics believes it is essential to our continued safety:

"There is no free lunch," Shapiro agrees. But he adds, "We're talking about investing in an insurance policy."

Earth could be blindsided by asteroids, panel warns [New Scientist]

Tonight Saturn will shed its rings — or rather, the rings will hardly be reflecting any sunlight.

According to Astronomy Now:

Equinox is a twice-yearly event when the Sun lies directly above a planet's equator. For Saturn, this occurs every 15 Earth years and sees the Sun pass through the plane containing the giant planet's rings. The unique illumination geometry allows features to be discerned in unprecedented detail. As Saturn marches towards its 11 August equinox, the Sun's angle to the ring plane lowers, causing out-of-plane structures to cast long shadows across the rings' broad expanse, making them easy to detect.

The image above, from Hubble Space Telescope, shows Saturn's axis tilting. Each image is almost a year apart: "starting on the left in 1996, just after the last time the rings were edge-on, and ending on the right in 2000 when the rings had opened up significantly from our point of view."

Iapetus travels in a tidally locked orbit with Saturn, always showing the same face to the planet. When Cassini Regio, the moon's dark hemisphere, faces the Earth, however, it nearly disappears from view, coated entirely in a mysterious black substance that is gradually creeping across the sphere. Astronomers have long speculated on the nature of the substance, which gives the moon an unusually uniform surface, and while many believe that it is composed of the dirt left behind when ice on Iapetus sublimates, they hope that new data from the Cassini spacecraft will offer more concrete clues, as well as help them understand the nature of the equatorial ridge that travels across Cassini Regio, an odd phenomenon in a surface otherwise marked by impact craters.

[APOD]

The blurry areas (including the dark plains) are spots where we have lower-resolution images of the moon's surface. The stripe of sharper images show the surface of the moon beneath its cloud layer, created via special imaging techniques.

According to Universe Today:

The US Geological Survey Astrogeology Science Center announced the first plain or "planitia" given a name will be designated as Chusuk Planitia. Chusuk was a planet from the Dune series, known for its musical instruments. Chusuk Planitia on Titan is located at 5.0S, 23.5W, and in the picture here is the small, dark area next to the "C" of Chusuk

Chusuk is a minor planet in the Dune series, and in an appendix to that novel, Herbert says it is the "fourth planet of Theta Shalish; the so-called 'Music Planet' noted for the quality of its musical instruments." I'm fairly stumped about why Titan cartographers chose Chusuk. Why not just go for Arrakis?

You can see a complete map of Titan, based on survey pictures taken by the Cassini probe, with all its named features labeled, on this PDF.

Star trails reflect the rotation of the Earth, showing how the stars seem to spin in concentric circles around a fixed point in the sky. Photographers who want to capture these trails take several short-exposure pictures over a period of days, weeks, or even months. The resulting pictures are unique, because the camera is able to capture subtle differences in chemical make-up and color that the human eye is unable to discern. Thus, the individual rings are far brighter and more varied than you might expect from simply looking up at the stars yourself.

Star Trails: Secret Paintings of the Night Sky [Environmental Graffiti]

In a paper published in the International Journal of Astrobiology, Chandra Wickramasinghe of the Cardiff Centre for Astrobiology — one of the earliest proponents of the theory of panspermia, that the seeds of life exist throughout the universe — revealed his team's calculation, which indicate that large reserves of water likely existed inside comets in our solar system, that happened to form around the same time as the Earth:

The Cardiff team has calculated the thermal history of comets after they formed from interstellar and interplanetary dust approximately 4.5 billion years ago. The formation of the solar system itself is thought to have been triggered by shock waves that emanated from the explosion of a nearby supernova. The supernova injected radioactive material such as Aluminium-26 into the primordial solar system and some became incorporated in the comets. Professor Chandra Wickramasinghe together with Drs Janaki Wickramasinghe and Max Wallis claim that the heat emitted from radioactivity warms initially frozen material of comets to produce subsurface oceans that persist in a liquid condition for a million years.

Wickramasinghe claims that a "large fraction" of the 100 billion comets in our solar system probably contained liquid interiors, with ideal conditions for the growth of bacteria, which perhaps lends greater credence to Wickramsinghe's theories on the extraterrestrial origins of life.

[Universe Today]

In addition to its main Twitter feed, NASA has just sent its first tweet Asteroid Watch, a Twitter feed to keep you up to date on all the comets, asteroids, and other celestial objects that pose a threat to the Earth. The feed is a companion to the newly-launched Asteroid Watch website, operated by NASA's Jet Propulsion Laboratory.

The current sole tweet assures us that all is well in the solar system:

We're going live today, July 29,2009. It's a beautiful day in the near-Earth neighborhood!

But if you're looking for recent near-misses, you can also check out Tom Taylor's lowflyingrocks feed, which pulls data from NASA on objects that have passed within 0.2AU of Earth.

The Real Twitpocalypse: Asteroid Alerts Come to Twitter [Wired]

Most geologists believe that Devil's Tower in the Black Hills of Wyoming was formed by a hardened plume of lava that never broke through to the surface. Unlike most national monuments, visitors are allowed to climb Devil's Tower and get an extraordinary view of the night sky. In this view of the Milky Way, we can see strands of the Pipe Nebula:

As well as the red glow of the Lagoon Nebula to the right of the Tower:

[Astronomy Picture of the Day]

Levin, who has also written a beautiful, fascinating book about physics called How the Universe Got Its Spots, gives a technical explanation of her periodic table of black hole orbits:

Understanding the dynamics around rotating black holes is imperative to the success of the future gravitational wave observatories. Although integrable in principle, test particle orbits in the Kerr spacetime can also be elaborate, and while they have been studied extensively, classifying their general properties has been a challenge. This is the first in a series of papers that adopts a dynamical systems approach to the study of Kerr orbits, beginning with equatorial orbits. We define a taxonomy of orbits that hinges on a correspondence between periodic orbits and rational numbers. The taxonomy defines the entire dynamics, including aperiodic motion, since every orbit is in or near the periodic set. A remarkable implication of this periodic orbit taxonomy is that the simple precessing ellipse familiar from planetary orbits is not allowed in the strong-field regime. Instead, eccentric orbits trace out precessions of multi-leaf clovers in the final stages of inspiral. Furthermore, for any black hole, there is some point in the strong-field regime past which zoom-whirl behavior becomes unavoidable. Finally, we sketch the potential application of the taxonomy to problems of astrophysical interest, in particular its utility for computationally intensive gravitational wave calculations.

Kerr black holes are black holes that rotate, and that affects the gravity waves they generate. I love these charts of the many possible ways that objects might approach, orbit, and eventually get swallowed by a black hole. If you want to delve into the math Levin used to create these images, check out the whole paper. It's free online.

"A Periodic Table for Black Hole Orbits" via arXiv

Many of us who grew up learning about the nine planets took Pluto's reclassification hard, championing it as a celestial underdog. Meanwhile, astronomers were left to grapple with the question of what defines a planet as such. Mark Sykes of the Planetary Science Institute in Tucson, Arizona, suggests that Pluto's demotion by the International Astronomical Union (IAU) stems from a misconception that full-fledged planets are somehow unusual:

"We are [now] in the midst of a conceptual revolution," he says. "We are shaking off the last vestiges of the mythological view of planets as special objects in the sky - and the idea that there has to be a small number of them because they're special."

As we learn more about Pluto and about objects outside our solar system, astronomers may well learn that the other eight solar planets have much more in common with Pluto than with other celestial bodies that exceed it in size:

Sykes believes that missions currently en route to Pluto and the asteroid Ceres, which orbits the sun between Mars and Jupiter, will reveal these dwarf planets as active and intricate worlds. Meanwhile, astronomers may find distant objects as large as Earth which the IAU would not define as planets.

This leaves many astronomers clamoring for the view that any planet large enough to be pulled into a sphere by its own gravity should be considered a planet. By this definition, not only would Pluto be a planet, so would Ceres, Haumea, Makemake, and Eris, all currently considered dwarfs.

Although the International Astronomical Union, which classifies celestial bodies, convenes this year for the first time since Pluto's demotion, its chief does not expect any challenges to Pluto's status. But in 2015, NASA's New Horizons missions will reach Pluto, giving us our first up-close look at the sphere, and perhaps making Pluto the little planet that could.

Is Pluto a planet after all? [New Scientist]