Messier 30 is an unusual cluster. It's an ancient cluster, and yet it is filled with blue stars, stars that tend to age and die more quickly than other types of stars. Astronomers have termed these unusually old blue stars "blue stragglers," and they believe that there are two reasons these stars still exist.

Some of the blue stragglers in Messier 30 are vampires; when they get near a more massive star, they are able to siphon off hydrogen from that star, effectively lengthening its life. But more recent studies have found that some of the stars are the results of high-powered collisions. When two older stars collide head-on, it restokes their nuclear fusion, resulting in larger, seemingly younger blue stars than before.

Vampires and collisions rejuvenate stars [Hubble Information Centre via Bad Astronomy]

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

(Thanks, James!)

The above image is an artist's representation of GX 339-4, a "low-mass X-ray binary located about 26,000 light-years away in the constellation Ara." The sun is no bigger than ours, but it orbits a black hole "estimated at 10 solar masses," every 1.7 days. And four times in the past seven years, the sun and its black hole partner have had an explosive meeting.

NASA explains:

Binary systems where a normal star is paired with a black hole often produce large swings in X-ray emission and blast jets of gas at speeds exceeding one-third that of light. What fuels this activity is gas pulled from the normal star, which spirals toward the black hole and piles up in a dense accretion disk.

"When a lot of gas is flowing, the dense disk reaches nearly to the black hole," said John Tomsick at the University of California, Berkeley. "But when the flow is reduced, theory predicts that gas close to the black hole heats up, resulting in evaporation of the innermost part of the disk." Never before have astronomers shown an unambiguous signature of this transformation.

It's a bumpy orbit, but the view is probably spectacular. [NASA]

The US Geological Survey's Astrogeology Science Center revealed the first map of Mercury this week at the American Geophysical Union meeting. The map is a composite of 917 images taken from various Mercury flybys. Photos from Messenger's flybys in January 2008, October 2008, and September 2009 account for 90.90 percent of the mosaic, with the rest provided by the Mariner 10 photos from the 1970s. The map is just shy of complete, covering about 97.72 percent of Mercury, but it's the closest thing we have to a complete map of Mercury.

[USGS Astrogeology via Wired]

Known by the designation GJ1214b, this planet is, according to a paper published yesterday in Nature, one of just two super Earths found recently. It has "a composition of primarily water enshrouded by a hydrogen–helium envelope," and its atmosphere has evolved a great deal over time (much like Earth's). Unlike another super Earth discovered recently, CoRoT-7b, this new super Earth has an atmosphere that can be studied fairly easily due to the size of its star and close proximity.

What's most intriguing is that this super Earth appears to be made up of possibly 75 percent water. Unlike Earth, which has a molten rock and metal core, GJ1214b probably has a core made of water too. (Those of you who read Iain M. Banks' novel The Algebraist are probably grinning right now.) Astronomers aren't entirely certain that the planet is water - this is just an educated guess based the planet's density, which was calculated by observing how much the red dwarf dimmed when this planet passed in front of it.

Given its distance from the dwarf, GJ1214b's surface temperature could be as much as 530 degrees Fahrenheit. On Earth, water at that temperature would boil off into steam. So it's likely that something about GJ1214b's atmosphere is keeping its oceans in an ultrahot liquid state. Basically, we've got a giant boiling ball of water - the perfect place to breed weird new life.

via Nature

According to a news release from NASA's Fermi Gamma Ray Space Telescope:

Astronomers identify the object as 3C 454.3, an active galaxy located 7.2 billion light-years away in the constellation Pegasus. But even among active galaxies, it's exceptional.

"We're looking right down the barrel of a particle jet powered by the galaxy's supermassive black hole," said Gino Tosti at the National Institute of Nuclear Physics in Perugia, Italy. "Some change within that jet — we don't know what — is likely responsible for these flares."

Blazars, like many active galaxies, emit oppositely directed jets of particles traveling near the speed of light when matter falls toward their central supermassive black holes. What makes a blazar so bright in gamma rays is its orientation: One of the jets happens to be aimed straight at us.

Here's the above image, with 3C 454.3 circled:

This first image is the Flame Nebula (NGC 2024), in the consellation of Orion — and that bright blue star towards the right is one of three stars making up Orion's Belt. Normally, you can't see the young stars at the nebula's core with visible light, but VISTA's infrared camera shows them perfectly. [ESO via Universe Today]

Here's the Fornax Cluster of galaxies, one of the closest galaxy clusters beyond our own grouping. "At the lower-right is the elegant barred-spiral galaxy NGC 1365 and to the left the big elliptical NGC 1399, surrounded by a swarm of faint globular clusters."

And here's a look deep into the dusty heart of the Milky Way galaxy, through the constellation of Saggitarius. A million stars are revealed in this image.

The Cassini spacecraft recently sent back images of Saturn's strange hexagon, which was last photographed 30 years ago by Voyager. So what is so unusual about it? In comparing the pictures now from the pictures 30 years ago, scientists have found that the shape of the hexagon has remained unchanged, making it an extremely long-lived weather pattern, perhaps akin to Jupiter's Great Red Spot.

Researchers are trying to determine what causes the weather pattern — which has a diameter more than twice as long as Earth's — how it gets and expels its energy, and how it maintains such a rigid shape. Fortunately, the improved images from Cassini and the fact that Saturn probably has a relatively simple weather model should help the researchers get a better understanding of the hexagon and how weather works on other planets.

Saturn's Mysterious Hexagon Emerges from Winter Darkness [PhysOrg]

Phil Plait over at the Bad Astronomy blog explains further:

They pointed Hubble at a fairly empty region of space, one where very few stars are seen. Then they unleashed the new Wide Field Camera 3 (called WFC3 for short) on it, taking images in infrared wavelengths just outside what the human eye can see… and they let it stare at that spot for a solid 48 hours.

The result? This picture, showing galaxies flippin' everywhere, some seen a mere 600 million years after the Big Bang itself. Because the Universe is expanding, distant galaxies appear to recede from us, and their light gets stretched out. This Doppler Effect - the same thing that makes the sound of a car engine drop in pitch when it passes you at high speed - changes the colors we see from these far-flung galaxies, so their ultraviolet light, for example, gets stretched into visible and even infrared wavelengths. What you are seeing here is actually more energetic light emitted by galaxies that's lost energy traveling across the expanding Universe, so by the time it gets here it's infrared.

So the colors are not "real" in this image; they've been translated into red, green, and blue so we can see them. The reddest objects in the image are most likely the farthest away, and may be as much as 13 billion light years away.

Thirteen billion. With a B.

Plait's deconstruction of this epic photo is worth reading in its entirety... once you're done staring and contemplating the vastness of a cosmos that barely notices the eyeblink of our existence. [Hubblesite via Bad Astronomy Blog]

Download ginormous versions of the image at the link. [Spacetelescope.org via Wired]

Scientists at Caltech think they may have uncovered the reasons for Titan's extremely odd lake arrangement. Data gathered by the Cassini orbiter showed 20 times more area in the Northern extremities were covered by liquid ethane and methane, when compared to the South. The researchers, headed by Oded Aharonson, think that the transport of methane northwards may be due to the elliptical orbit of Saturn, and hence Titan.

Over the course of one Titan year (29.5 Earth years), the Northern hemisphere summer is long and mild, but the Southern hemisphere version is short and intense. That's because in the Southern summer season Titan is around 12% closer to the sun. While this doesn't make a huge difference over the course of a year, it does over a longer time period: It's possible that these uneven seasons result in methane evaporating in the south, drifting northward in the clouds, and then raining prodigiously in the milder north.

Around 32,000 years ago, the situation would have been reversed, with the hydrocarbons traveling Southward instead of North.

This theory is being published in this month's Nature Geoscience. Other possible explanations for the lakes include the idea that there is some (as yet unknown) fundamental difference between the hemispheres. It's also possible the methane transfer happens every season, not gradually.

Check out more of these incredible space pictures over at the photographer's Flickr stream. [s58y on Flickr]

Heart nebula - RGB.

Rosette nebula

Rosette nebula

Barndoor nebula

Elephant trunk nebula

Elephant trunk nebula

Considering hydrogen is the most plentiful element in the universe, astronomers expect to find it pretty much anywhere they look, particularly when stars are involved. And yet the nova in question, classified V445 Puppis, completely lacks the gas. Helium, which is right behind hydrogen as both the second lightest and second most plentiful gas in the universe, has taken hydrogen's place in the composition of V445 Puppis, leading to its designation as a helium nova. Such an object is unique in the history of astronomy, and it might help astronomers better understand how they date the history of the universe.

According to Danny Steeghs, an astrophysicist at the United Kingdom's University of Warwick, V445 Puppis probably came out of a rather unusual kind of binary star system. The star that went nova in 2000 was probably a hydrogen-depleted star that relied on helium to fuel itself and produce light. The other star is likely a white dwarf, the super-dense remnants of a collapsed star that previous went nova. In such systems, the white dwarf sucks in helium from the younger star when it goes nova, which can have one of two possible outcomes.

The first possibility — and the only one observed before V445 Puppis — is that the white dwarf grows in mass and temperature from all the accumulated helium, until it grows beyond what is known as the Chandrasekhar limit, which is about 1.4 times the size of our sun. When this happens, the white dwarf explodes in a special kind of supernova, known as a type Ia supernova.

However, what appears to be happening in the case of V445 Puppis - at least for now - is that the white dwarf is too small to reach the Chandrasekhar limit, and so it will not explode. Instead, the helium radiates out from the binary star system in the bow-tie-like configuration astronomers have observed. Steeghs points out, however, that this may just be a transitional state before V445 Puppis does go supernova, although there's no guarantee that any of us will be around to see such an event.

The subject is of general interest to astronomers because type Ia supernovas are often used to help date different parts of the universe. These supernovas have very consistent luminosities, meaning their brightness is almost entirely determined by their distance from Earth. Thus, type Ia supernovas are hugely useful in determining the distances of their host galaxies, but the supernovas themselves had previously been only poorly understood. Astronomers now hope that, beyond its status as an astronomical curiosity, V445 Puppis will provide a chance to improve our understanding of these supernovas.

[Scientific American]

According to National Geographic:

This new picture of the Crab Nebula combines data from the Chandra X-ray Observatory, the Hubble Space Telescope, and the Spitzer Space Telescope . . . Infrared light caught by Spitzer and visible light seen by Hubble paint the nebula's expanding debris cloud in shades of purple and red. Meanwhile, Chandra's x-ray vision is helping astronomers understand the high-energy particles (seen in blue) coming from the dead star's core, known as a [sic] white dwarf.

I just love that weird tendril of x-rays shooting out of the pulsar. It seems to be emerging from a giant maw in space (which - isn't there a Doctor Who story called Maw In Space? Maybe I'm just on crack).

via National Geographic

The Unidentified Crashing Object colliding with our galaxy is called Smith's Cloud, and is a cloud of hydrogen discovered last year. At the time, scientists believed it had a mass of a million suns, but it's been theorized that it would have to be much larger to have enough gravity to survive the impact. University of Sydney, Australia's Matthew Nichols and Joss Bland-Hawthorn have calculated that Smith's Cloud may, in fact, be up to 100 times larger than originally estimated.

Before you get too worried about the end of all known existence - or, at least, a Crisis On Infinite Earths - take some comfort in the knowledge that, if theories are correct, this has all happened before; according to the trajectory of Smith's Cloud, it would have impacted the Milky Way 70 million years ago. And it's not like anything has changed since then, right? Well, nothing important.

Dark galaxy crashing into the Milky Way [New Scientist]

New Scientist reports that the Japanese Hayabusa asteroid probe is once more on its way back to Earth after scientists worked out a way to use two of the broken engines together to make... one engine:

One engine is still able to spit out positive ions for thrust, but can no longer squirt out negatively charged electrons, a step needed to prevent electric charge buildup on the spacecraft. The team got around this by spewing the required electrons from a second sick engine that retains this ability.

But even with this "frankensteined" engine, scientists at the Japan Aerospace Exploration Agency aren't confident that the probe will reach the Australian outback destination it was supposed to have reached earlier this month; if all goes well, project manager Jun'ichiro Kawaguchi says, it should return in June next year. But, he adds,

This new configuration is very new to us and we are not sure ... how much we can count on [it].

It's like the little probe that can't.

'Frankenstein' fix lets asteroid mission cheat death [New Scientist]

According to NASA:

After forming as a tropical storm over the Southern Indian Ocean on November 14, 2009, Anja strengthened to a cyclone one day later. By November 16, 2009, Anja was a Category 3 cyclone, with maximum sustained winds of 105 knots (195 kilometers per hour), and gusts up to 130 knots (240 kilometers per hour). Anja was located near 14.7 degrees South and 68.3 degrees East.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this true-color image on November 16, 2009. Far away from any major landmasses, Anja sprawls over the Southern Indian Ocean, her long arms spiraling outward, and her eye easily detectable.

via SpaceGadget