Posted on by Ian O'Neill

The Pluto Revolt: Leading Astronomers Want the Plutoid to be Reinstated as a Planet

Artist impression of Pluto and Charon (NASA)

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If you thought Pluto was going quietly and giving up its planetary status without a fight, think again. Leading astronomers have spoken out against the International Astronomical Union (IAU) decision to classify the dwarf planet as a “Plutoid,” described by some critics as a “celestial underclass.” The IAU decision was made after it was deemed that Pluto cannot be called a “planet.” Although the spherical rocky body can tick most attributes of being a “planet,” the IAU pointed out that Pluto is too small to be capable of gravitationally clearing its own orbit (plus it periodically crosses the path of Neptune’s orbit); it should therefore be called a “dwarf planet.” Back in June however, the IAU gloriously announced that Pluto should be now be re-classified as a “Plutoid” and any other Pluto-like planets should follow suit. But on Thursday, at a major conference in Maryland, leading astronomers will refute the Plutoid classification saying the IAU re-naming is confusing and unworkable…

It may be the smallest planet in the Solar System a Plutoid, but this little spherical rock is causing a lot of noise down here on Earth. In 2006, the IAU re-classified the definition of a planet to distinguish between the differences between the larger known planets with the smaller rocky bodies (such as the increasing number of observed Kuiper Belt objects). There are three defining characteristics of what a planet should be:

  1. It is in orbit around the Sun.
  2. It has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape.
  3. It has “cleared the neighbourhood” around its orbit.

Pluto fulfils #1 and #2, but fails on #3, it is simply too small to gravitationally clear its own orbit. So Pluto was caught right in the middle of the “planetary classification debate ’06” and incidentally failed on one count. If any object fulfils the first two planetary criteria, but fails on the last, the IAU would classify the celestial body as a “dwarf planet.” To complicate matters, Pluto also travels inside the orbit of the gas giant Neptune periodically, giving it the extra classification of being a Trans-Neptunian Object (TNO). Although Pluto is a “dwarf” by Solar System standards, it is one of the largest Kuiper Belt Objects (KBO) in the outer Solar System; a true King amongst dwarfs.

Pluto has had a hard few months after getting kicked out of the planetary club.
Pluto has had a hard few months after getting kicked out of the planetary club.

So, for two years, Pluto was stuck in no-man’s land. It had been re-classified as a dwarf planet and astronomy teachers had to re-write their teaching material. Websites like NinePlanets.org had to scrub the 9 and replace it with an 8; but also had the foresight to buy “EightPlanets.org.” Times were a little messy for Pluto. Then, in June this year, the IAU seemed to want Pluto to feel a little better. Not only was it the King of the Kuiper Belt, it would have an entire army of Pluto-like dwarf planets named after it. The IAU created the “Plutoid,” and as if to avoid any more confusion, it gave the classification a no-nonsense definition:

Plutoids are celestial bodies in orbit around the Sun at a semi major axis greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighbourhood around their orbit. Satellites of plutoids are not plutoids themselves. – The IAU definition of a Plutoid (June 11th 2008).

Got that? Good. But not everyone was happy, least of all Pluto. T-shirts have even been printed with the quote: “It’s okay Pluto, I’m not a planet either” (and yes, I have one), for anyone wanting to show their support for the struggling rocky body.

So this Thursday, some very prominent astronomers will take their case to the “The Great Planet Debate: Science as Process” conference at The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. To cut a long story short, they want Pluto to be reinstated as a planet, thereby abandoning the term “Plutoid.”

Dr David Morrison, director of the NASA Lunar Science Institute in California, makes the point that if the largest planets in our Solar System can be called Gas “Giants” then it should be fine to call Pluto a “Dwarf” Planet. But in the current IAU classification, Pluto cannot be called a planet.

“It has never before been necessary for any organisation to define a word that has been in common every day use so I see no reason why it was necessary on this occasion. Astronomers use adjectives such as giant and dwarf to describe different subclasses of objects like planets, stars and galaxies, so why could Pluto not remain as a dwarf planet just as Jupiter is a giant planet. Also, around 90 per cent of the planets we know now are outside our solar system, but under the International Astronomical Union’s definition, they cannot be classed as planets.” – Dr David Morrison

So it would seem the classification of “planet” will remain a very exclusive club of eight under the IAU rules; only Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune will have this honour unless the scientists at the Great Planet Debate conference can convince the IAU otherwise. Mark Sykes, from the Planetary Science Institute, argues that only #2 of the IAU planet definition need be applied; it is therefore the shape, or roundness, of the object that defines whether it can be called a planet or not. If this definition were applied, the Solar System would expand to include 12 planets. This worries some traditional thinkers at the IAU. As our observational techniques improve, more planet candidates will be discovered, therefore making the Solar System wildly different than what it is now.

But if there are more “planets” out there, why shouldn’t more planets be added to the official eight we currently have? It sounds like the Pluto debate is far from over and it will be interesting to hear what the delegates have to say on Thursday…

Source: Telegraph

Posted on by Ian O'Neill

Constellation Project Parachute Tests: Ares I Success, Orion Failure

An early parachute drop test for the Constellation Project (NASA)

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At the end of last month, the Orion crew module and the Ares I rocket parachute systems underwent a series of drop tests. The “drogue parachute” that will gently slow the descent of the spent first-stage motor of the Ares vehicle appeared to function as expected over the Arizona skies. However, an Orion test failed, “programmer parachute” failing to correct the orientation of the test crew module, allowing the module to drop through the sky upside-down. The programmer parachute is intended to inflate before the main three parachutes are deployed to bring the re-entering Orion astronauts to land safely. This news has come from an internal memo referring to the Orion test drop back on July 31st; the successful Ares I drogue parachute drop was carried out on July 24th. So what went wrong with the Orion test-drop?

NASA engineers are continuing a series of parachute tests on Orion and Ares. The first parachute system to be employed in any given launch will be the Ares parachute recovery system (assuming the emergency jettison motor isn’t fired before then). At approximately 126 seconds into flight and at an altitude of 189,000 feet (58,000 m), the first Ares I stage will separate, letting the spent booster drop through the atmosphere. To ensure the engine can be re-used by subsequent Constellation launches, the booster’s nose cap will be jettisoned at 15,740 feet (4800 m), releasing a small pilot parachute, dragging a larger drogue parachute out to slow down the rapidly falling first stage.

The Ares I components (NASA)
The Ares I components (NASA)

The drogue is smaller than a conventional parachute and it is intended to slow the booster from 402 mph (647 km/hr) to 210 m/hr (338 km/hr), positioning the cylinder vertically. Only when this slowdown is achieved that the main three cluster of parachutes can be deployed to complete the descent and plunge into the Atlantic Ocean for retrieval.

It would appear that the essential drogue testing of the first stage Ares I booster worked flawlessly when tested by NASA at the U.S. Army’s Yuma Proving Ground near Yuma, Arizona on July 24th. The next drogue test is scheduled for October.

However, during the July 31st Orion parachute test-run, there was a slight technical hitch that gave the Parachute Test Vehicle (PTV) a violent spin and then thud into the ground. The “programmer” parachute is intended to “right” the orientation of the re-entering crew module as it descends, an essential task before the drogue parachutes can be deployed to rapidly slow the module (in a similar way to the Ares I system). Unfortunately, during this PTV test-drop, problems arose very quickly. As soon as the programmer parachute was deployed, it failed to inflate and therefore did not cause any drag. This happened as the programmer parachute was being buffeted by the turbulence in the wake of the PTV and stabilization parachutes. The PTV was therefore allowed to fall ungracefully, upside-down.

The Orion crew module (HowStuffWorks.com)
The Orion crew module (HowStuffWorks.com)

Continuing to drop, the programmer and stabilization parachutes were jettisoned (having not done their job very well), and drogue parachutes were deployed. As the PTV was falling out of control, the drogue parachutes were put under immediate strain and wrapped around the PTV, dynamic pressure causing the drogue to be cut away.

Having suffered some major whiplash, the PTV’s main bag retention system was damaged and failed. Continuing to fall, the main parachutes were deployed, two were ripped from the vehicle, forcing the PTV to hit the ground with only one parachute open. There are no details as to what damage was caused by this failed test, but I think we can assume the PTV’s bodywork will be dented (and I wonder if human cadavers were used on this particular drop. If they were, I wouldn’t want to be the first engineer on the scene!).

Although an obvious set-back for the Orion parachute system, the NASA memo highlights that it was a “test technique failure” and not a failure of the technology itself. Regardless, I am sure this issue will be ironed out soon enough as the Constellation Program continues to push ahead with development…

Sources: SpaceRef, Space Travel

Posted on by Nancy Atkinson

From Space to the Olympics

Fireworks at the 2008 Olympics Opening Ceremony. Credit: Clive Rose, Getty Images

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Space and the Olympics might not be synonymous in most people’s minds — although this image of the Opening Ceremony fireworks makes it look like Olympic Stadium is going supernova — but there are a few connections between the two for this year’s Summer Olympics in Beijing, China. Google Earth recently updated the satellite imagery it uses for the Beijing area to provide users with better maps. They also used satellite imagery to create a 3-D tour of all the facilities for the 2008 Olympics (see video below). Other space connections include several space explorers who carried the Olympic torch on its running tour around the world, and NASA space spinoff technology used in some of the clothing and equipment for Olympic use.

Valentina Tereshkova carrying Olympic torch. Credit: Xinhua via CollectSpace

The first woman in space, Russian cosmonaut Valentina Tereshkova, one of 80 Russian runners, carried the Olympic torch during its tour of that country in early April. Sheikh Muszaphar Shukor, the first Malaysian in space, ran with the torch along the top of Kuala Lumpur Tower on April 21, just six months after his visit as a “spaceflight participant” to in International Space Station. Fittingly, several Chinese taikonauts carried the torch: Fei Junlong and Nie Haisheng, the two-man crew from China’s second spaceflight, Shenzou 6 ran with the torch when it arrived in China in May. China’s first space explorer, Yang Liwei who flew solo on Shenzou 5 in 2003, carried the torch when it first arrived in Beijing on August 6.

While no US astronauts carried the torch, NASA astronaut Scott Parazynski was at Base Camp when Chinese climbers carried the torch to the summit of Mt. Everest on May 8.

NASA developed “riblet” technology to aid in the aerodynamic properties of airplanes. Riblets are V-shaped grooves with angles that point in the direction of the air flow. They are no bigger than a scratch, and they look like very tiny ribs. Riblets help reduce “skin-friction” drag. But it also helps reduce friction from water, and riblets have been used in rowing shells in the four-oar-with-coxswain category. Swimsuits with riblets have also been used in competition at the Pan American games.

The shoes from space. Credit: NASA

And of course, everyone is probably familiar with the lore that today’s athletic shoes use the same cushioning technology that was developed for the moon boots used in the Apollo missions to the moon.

News Sources: Collect Space, Kodak Olympic Picture of the Day, NASA Goes to the Olympics

Posted on by Tammy Plotner

2008 Perseid Meteor Shower Peaks On August 12 – But Start Now!

Perseid Against Milky Way

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The Perseids are coming! The Perseids are coming! I’m sure you’re already hearing the cry around the world… But what will be the best place to watch and when will be the best date to see the most “shooting stars”? Follow along and let’s find out…

The Perseid meteor shower has a wonderful and somewhat grisly history. Often referred to as the “Tears of St. Lawrence” this annual shower coincidentally occurs roughly about the same date as the saint’s death is commemorated on August 10. While scientifically we know the appearance of the shooting stars are the by-products of comet Swift-Tuttle, our somewhat more superstitious ancestors viewed them as the tears of a martyred man who was burned for his beliefs. Who couldn’t appreciate a fellow who had the candor to quip “I am already roasted on one side and, if thou wouldst have me well-cooked, it is time to turn me on the other.” while being roasted alive? If nothing else but save for that very quote, I’ll tip a wave to St. Lawrence at the sight of a Perseid!

While the fall rate – the number of meteors seen per hour – of the Perseids has declined in recent years since Swift-Tuttle’s 1992 return, the time to begin your Perseid watch is now. While the peak of activity will not occur until August 12 at approximately 11:00 GMT, this will leave many observers in daylight. For those who wish only to observe during the predicted maximum rate, the place to be is western North America and the time is around 4:00 a.m. However, let’s assume that not all of us can be in that place and be up at that time… So let’s take a more practical look at observing the Perseid Meteor Shower.

For about the last week or so, I’ve noticed random activity has picked up sharply and traceable Perseid activity begins about midnight no matter where you live. Because we are also contending with a Moon which will interfere with fainter meteors, the later you can wait to observe, the better. The general direction to face will be east around midnight and the activity will move overhead as the night continues. While waiting for midnight or later to begin isn’t a pleasant prospect, by then the Moon has gone far west and we are looking more nearly face-on into the direction of the Earth’s motion as it orbits the Sun, and the radiant – the constellation of the meteor shower origin – is also showing well. For those of you who prefer not to stay up late? Try getting up early instead!

How many can you expect to see? A very average and cautiously stated fall rate for this year’s Perseids would be about 30 per hour, but remember – this is a collective estimate. It doesn’t mean that you’ll see one every two minutes, but rather you may see four or five in quick succession with a long period of inactivity in between. You can make your observing sessions far more pleasant by planning for inactive times in advance. Bring a radio along, a thermos of your favorite beverage, and a comfortable place to observe from. The further you can get away from city lights, the better your chances will be.

Will this 2000 year-old meteor shower be a sparkling success or a total dud? You’ll never know unless you go out and try yourself. I’ve enjoyed clear skies here for the last week and without even trying caught at least 15 per hour each night I’ve gone out. One thing we do know is the Perseids are one of the most predictable of all meteor showers and even an hour or so of watching should bring a happy reward!

Wishing you clear skies and good luck…

Posted on by Nancy Atkinson

Evidence for Widespread Water on Early Mars

Mawrth Vallis on Mars. Credit: MRO/NASA/JPL

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Images and data from the Mars Reconnaissance Orbiter (MRO) have revealed layers of clay-rich rock that suggests abundant water was once present on Mars. Scientists from the SETI Institute, the Jet Propulsion Laboratory and several universities have been studying data focused on the Mawrth Vallis area on Mars’ northern highland region. This is a heavily cratered, ancient area of the Red Planet whose surface geology resembles a dried-up, river valley through which water may have flowed. While their findings don’t provide evidence for life, it does suggest widespread and long-term liquid water in Mars’ past.

The researchers used the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard MRO to examine infrared light reflected from clays situated in the many-kilometer wide channel of Mawrth Vallis.

The infrared spectra from CRISM show an extensive swath of phyllosilicate-bearing material. This is a type of iron and magnesium-rich clay that forms in liquid water, and can be found on Earth in oceans and river beds. It is familiar to anyone who’s nearly broken a shovel while trying to plant a tree. There is also evidence in the spectra for hydrated silica, which in its pure, clean form is known as opal.

The researchers combined their data on the composition of soils in this region with topographic information collected by MOLA, the Mars Orbiter Laser Altimeter, on board the Mars Global Surveyor spacecraft. They found layered aluminum clays lying on top of hydrated silica and iron/magnesium clays. These clays were likely formed when water came in contact with basalt – which is the dominant component of the Martian highlands, and probably was produced from volcanic ash, which once blanketed the planet.

CRISM image overlayed with MOLA data of Mawrth Vallis. This covers an area about 10 kilometers (6.2 miles) wide. Fe/Mg-phyllosilicate is shown in red, Al-phyllosilicate is shown in blue, hydrated silica and an Fe2+ phase are shown in yellow/green.
CRISM image overlayed with MOLA data of Mawrth Vallis. This covers an area about 10 kilometers (6.2 miles) wide. Fe/Mg-phyllosilicate is shown in red, Al-phyllosilicate is shown in blue, hydrated silica and an Fe2+ phase are shown in yellow/green.

“We were surprised by the variety of clay minerals in this region,” says Janice Bishop of the SETI Institute. “But what’s interesting is that we find the same ordering of the clay materials everywhere in Mawrth Vallis. It’s like a layer-cake of clays, one on top of another. All these layers are topped with a ‘frosting’ of lava and dust. We can see the clay layers where an impact crater has carved a hole through the surface or where erosion has exposed them.”

Since phyllosilicates have been found in a number of outcrops on Mars in CRISM images, these new data suggest that whatever mechanism formed clays at Mawrth Vallis has probably operated over much greater areas of the Red Planet. Alteration by liquid water may have been widespread on early Mars.

Bishop is careful to note that this work is part of the long-term effort to establish just how widespread, and for what period of time, liquid water may have existed on Mars.

“This is not evidence for life,” she notes. “But it does suggest the long-term and common presence of liquid water – and concomitant active chemistry – on the Red Planet in the distant past.”

News Source: SETI Institute

Posted on by Tammy Plotner

Weekend SkyWatcher’s Forecast – August 8-10, 2008

Shevill Mathers

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Greetings, fellow SkyWatchers! Are you ready for another weekend? As the seasons slowly begin to change for both hemispheres and the Moon grows more full, look for an optical phenomena known as a “nimbus” – or halo around the Moon. While it’s nothing more than a thin layer of ice crystals in the upper troposphere, it is a wonderfully inspiring sight and was once used as a means of weather forecasting. If you see a nimbus, try counting the number of stars visible inside the halo and see if it matches the number of days before bad weather arrives! In the meantime, follow me as we head out on our next weekend journey into the night…

Hipparchus
Hipparchus
Friday, August 8, 2008 – Our first order of business for the weekend will be to pick up a Lunar Club challenge we haven’t noted so far this year – Hipparchus. Located just slightly south of the central point of the Moon and very near the terminator, this is not truly a crater – but a hexagonal mountain-walled plain. Spanning about 150 kilometers in diameter with walls around 3320 meters high, it is bordered just inside its northern wall by crater Horrocks. This deep appearing “well” is 30 kilometers in diameter, and its rugged interior drops down an additional 2980 meters below the floor. To the south and just outside the edge of the plain is crater Halley. Slightly larger at 36 kilometers in diameter, this crater named for Sir Edmund Halley is a little shallower at 2510 meters – but it has a very smooth floor. To the east you’ll see a series of three small craters – the largest of which is Hind.

On this date in 2001, the Genesis Solar Particle Sample Return mission was launched on its way toward the Sun. On September 8, 2004, it returned with its sample of solar wind particles – unfortunately a parachute failed to deploy, causing the sample capsule to plunge unchecked into the Utah soil. Although some of the specimens were contaminated, many did survive the mishap. So what is “star stuff?” Mostly highly charged particles generated from a star’s upper atmosphere flowing out in a state of matter known as plasma.

Despite tonight’s Moon, let’s study one of the grandest of all solar winds as we seek out an area about three fingerwidths above the Sagittarius teapot’s spout as we have a look at the magnificent M8.

Visible to the unaided eye as a hazy spot in the Milky Way, fantastic in binoculars, and an area truly worth study in any size scope, this 5200 light-year diameter area of emission, reflection, and dark nebulae has a rich history. Its involved star cluster – NGC 6530 – was discovered by Flamsteed around 1680, and the nebula by Le Gentil in 1747. Cataloged by Lacaille as III.14 about 12 years before Messier listed it as number 8, its brightest region was recorded by John Herschel, and dark nebulae were discovered within it by Barnard.

Tremendous areas of starbirth are taking place in this region, while young, hot stars excite the gas in a region known as the “Hourglass” around the stars Herschel 36 and 9 Sagittarii. Look closely around cluster NGC 6530 for Barnard Dark Nebulae B 89 and B 296 at the nebula’s southern edge…and try again on a darker night. No matter how long you choose to swim in the “Lagoon” you will surely find more and more things to delight both the mind and the eye!

Archimedes
Archimedes
Saturday, August 9, 2008 – Today in 1976, the Luna 24 mission was launched on a return mission of its own – not to retrieve solar wind samples, but lunar soil! When we begin our observations tonight, we’ll start by having a look at another great study crater – Archimedes. You’ll find it located in the Imbrium plain north of the Apennine Mountains and west of Autolycus.

Under this lighting, the bright ring of this class V walled plain extends 83 kilometers in diameter. Even though it looks to be quite shallow, it still has impressive 2150 meter high walls. To its south is a feature not often recognized – the Montes Archimedes. Though this relatively short range is heavily eroded, it still shows across 140 kilometers of lunar topography. Look for a shallow rima that extends southeast across Palus Putredinus toward the Apennines. Mark your challenge notes!

Now let’s go have a look at a star buried in one of the spiral arms of our own galaxy – W Sagittarii…

Located less than a fingerwidth north of the tip of the teapot spout (Gamma), W Sagittarii (RA 18 05 01 Dec -29 34 48) is a Cepheid variable that’s worth keeping an eye on. While its brightness only varies by less than a magnitude, it does so in less than eight days! Normally holding close to magnitude 4, nearby field stars will help you correctly assess when minimum and maximum occur. While it’s difficult for a beginner to see such changes, watch it over a period of time. At maximum, it will be only slightly fainter than Gamma to the south. At minimum, it will be only slightly brighter than the stars to its northeast and southwest.

While you watch W go through its changes – think on this. Not only is W a Cepheid variable (a standard for the cosmic distance scale), but it is also one that periodically changes its shape. Not enough? Then think twice… Because W is also a Cepheid binary. Still not enough? Then you might like to know that recent research points toward the W Sagittarii system having a third member as well!

Sunday, August 10, 2008 – Today in 1966 Lunar Orbiter 1 was successfully launched on its mission to survey the Moon. In the days ahead, we’ll take a look at what this mission sent back! Tonight keep a very close watch on Selene as Antares is less than a degree away. Check for an occultation event!

Walter
Walter
Our lunar mission for tonight is to move south, past the crater rings of Ptolemaeus, Alphonsus, Arzachel and Purbach, until we end up at the spectacular crater Walter. Named for Dutch astronomer Bernhard Walter, this 132 by 140 kilometer wide lunar feature offers up amazing details at high power. It is perhaps most fascinating to take the time to study the differing levels, which drop to a maximum of 4130 meters below the surface. Multiple interior strikes abound, but the most fascinating of all is the wall crater Nonius. Spanning 70 kilometers, Nonius would also appear to have a double strike of its own – one that’s 2990 meters deep!

Eta Sgr
Eta Sgr
Although it will be tough to locate with the unaided eye thanks to the Moon, let’s take a closer look at one of the most unsung stars in this region of sky – Eta Sagittarii (RA 18 17 37 Dec -36 45 42). This M-class giant star will display a wonderful color contrast in binoculars or scopes, showing up as slightly more orange than stars in the surrounding field. Located 149 light-years away, this irregular variable is a source of infrared radiation and is a little larger than our own Sun – yet is 585 times brighter. At around three billion years old, Eta has either expended its helium core or just began to use it to fuse carbon and oxygen – creating an unstable star capable of changing its luminosity by about 4%. But have a closer look…for Eta is also a binary system with an 8th magnitude companion.

Keep an eye out for the beginnings of the Perseid meteor shower and a futher report! Wishing you clear skies and a great weekend…

This week’s awesome images are: Nimbus – Credit: Shevill Mathers, Hipparchus: Credit: Tammy, M8 – Credit: NOAO/AURA/NSF, Archimedes – Credit: Wes Higgins, Walter – Credit: West Higgins and Eta Sagittarii – Credit: Palomar Observatory courtesy of Caltech. Thank you for sharing!

Posted on by Ian O'Neill

Could Jupiter and Saturn Contain Liquid Metal Helium?

Rendering of a blue liquid metal... could this be what metallic helium looks like? Source: http://tinyurl.com/6lffol (waxellis)

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The interiors of the two gas giants, Jupiter and Saturn, are pretty extreme places. With atmospheric pressures of around 70 million Earth atmospheres, the phases of material become a bit difficult to understand. Usually when we think of a liquid metal, we have thoughts about liquid mercury at room temperature (or the reassembling liquid metal T-1000 played by Robert Patrick in the film Terminator 2), rarely do we consider two of the most abundant elements in the Universe to be a liquid metal in certain conditions. And yet, this is what a team of physicists from UC Berkley are claiming; helium and hydrogen can mix together, forced by the massive pressures near the cores of Jupiter and Saturn, forming a liquid metal alloy, possibly changing our perception of what lies beneath those Jovian storms…

Usually planetary physicists and chemists focus most of their attention on the characteristics of the most abundant element in the Universe: hydrogen. Indeed, over 90% of both Jupiter and Saturn is hydrogen too. But within these gas giant’s atmospheres is not the simple hydrogen atom, it is the surprisingly complex diatomic hydrogen gas (i.e. molecular hydrogen, H2). So, to understand the dynamics and nature of the insides of the most massive planets in our Solar System, researchers from UC Berkley and London are looking into a far simpler element; the second most abundant gas in the Universe: helium.

Raymond Jeanloz, a professor at UC Berkeley, and his team have uncovered an interesting characteristic of helium at the extreme pressures that can be exerted near the cores of Jupiter and Saturn. Helium will form a metallic liquid alloy when mixed with hydrogen. This state of matter was thought to be rare, but these new findings suggest liquid metal helium alloys may be more common than we previously thought.

“This is a breakthrough in terms of our understanding of materials, and that’s important because in order to understand the long-term evolution of planets, we need to know more about their properties deep down. The finding is also interesting from the point of view of understanding why materials are the way they are, and what determines their stability and their physical and chemical properties.” – Raymond Jeanloz.

Jupiter for example exerts an enormous pressure on the gases in its atmosphere. Due to it’s large mass, one can expect pressures up to 70 million Earth atmospheres (no, that isn’t enough to kick-start fusion…), creating core temperatures of between 10,000 to 20,000 K (that’s 2-4 times hotter than the Sun’s photosphere!). So helium was chosen as the element to study under these extreme conditions, a gas that makes up 5-10% of the Universe’s observable matter.

Using quantum mechanics to calculate the behaviour of helium under different extreme pressures and temperatures, the researchers found that helium will turn into a liquid metal at very high pressure. Usually, helium is thought of as a colourless and transparent gas. In Earth-atmosphere conditions this is true. However, it turns into an entirely different creature at 70 million Earth atmospheres. Rather than being an insulating gas, it turns into a conducting liquid metal substance, more like mercury, “only less reflective,” Jeanloz added.

This result comes as a surprise as it has always been thought that massive pressures make it more difficult for elements like hydrogen and helium to become metal-like. This is because the high temperatures in locations like Jupiter’s core cause increased vibrations in atoms, thus deflecting the paths of electrons trying to flow in the material. If there is no electron flow, the material becomes an insulator and cannot be called a “metal.”

However, these new findings suggest that atomic vibrations under these kinds of pressures actually have the counter-intuitive effect of creating new paths for the electrons to flow. Suddenly the liquid helium becomes conductive, meaning it is a metal.

In another twist, it is thought that the helium liquid metal could easily mix with hydrogen. Planetary physics tells us that this isn’t possible, hydrogen and helium separate like oil and water inside the gas giant bodies. But Jeanloz’s team has found that the two elements could actually mix, creating a liquid metal alloy. If this is to be the case, some serious re-thinking of planetary evolution needs to be done.

Both Jupiter and Saturn release more energy than the Sun provides meaning both planets are generating their own energy. The accepted mechanism for this is condensing helium droplets that fall from the planets’ upper atmospheres and to the core, releasing gravitational potential as the helium falls as “rain.” However, if this research is proven to be the case, the gas giant interior is likely to be a lot more homogenous than previously thought meaning there can be no helium droplets.

So the next task for Jeanloz and his team is to find an alternate power source generating heat in the cores of Jupiter and Saturn (so don’t go re-writing the textbooks quite yet…)

Source: UC Berkeley

Posted on by Ian O'Neill

Next Generation Magnetoplasma Rocket Could be Tested on Space Station

The Vasimir experiment (Ad Astra Rocket Corporation)

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NASA Administrator Michael Griffin has announced his intentions to send an advanced spaceship propulsion prototype to the International Space Station for advanced testing. The Variable Specific Impulse Magnetoplasma Rocket (Vasimir) is currently in an experimental phase, but Griffin hopes that a scale model will be ready for one of the remaining Shuttle-ISS missions before 2010. The Vasimir concept bridges the gap between conventional (fuel hungry, high thrust) rockets and economical (fuel efficient, low-thrust) ion engines. Vasimir achieves this by using an ingenious method of ionizing and heating a neutral gas fuel…

It sounds like an idea from the “let’s do something useful with the Space Station” department in response to recent criticism about the quality of science that is being carried out on the $100 billion orbiting outpost. Michael Griffin, attended the July 29th AirVenture show in Oshkosh and was asked about the status of NASA’s advanced space propulsion research. In response he outlined plans to begin testing the Vasimir on board the ISS within the coming years. This possibly means that Vasimir will undergo vacuum testing on the outside of the station. (NOTE: This is not a propulsion device for the Space Station itself, it will remain in Earth orbit for the rest of its years, regardless of the optimistic idea that it could become an interplanetary space vehicle.)

Vasimir on the test-bed (Ad Astra Rocket Corporation)
Vasimir on the test-bed (Ad Astra Rocket Corporation)

The Vasimir uses a gas, like hydrogen, as a fuel. When injected, the engine turns the hydrogen into a plasma (a highly ionized state of matter). Through the use of intense radio signals emitted from powerful superconducting magnets, the engine is able to produce this plasma and energize it. The hot plasma is then focused and directed by a magnetic nozzle which creates thrust. The Vasimir turns out to be a very efficient way to get optimal thrust from minimal fuel (a quantity in rocket science known as “specific impulse”) through ionizing a fuel and accelerating it with a magnetic field. Such a technology is far more efficient than conventional rockets (as it uses less fuel) and provides more thrust than ion engines.

At the moment, the Vasimir looks as if it is in a “test-bed” phase of development, resembling something too large and unwieldy to be put into space, but Griffin is hoping a scale model may me taken to the ISS, possibly by one of the remaining Shuttle flights before 2010.

The engine itself is being developed by the Ad Astra Rocket Corporation and NASA signed a co-operation agreement with the company in 2006 in the hope of working on large-scale testing of rocket products. Naturally, Vasimir testing on board the Space Station would be of tremendous value in the research of this technology (but there is no mention that the Vasimir could be used as an ISS propulsion device, shame really).

Source: Flight Global

Posted on by Nancy Atkinson

Where In The Universe Challenge #15

Betcha thought I forgot about this week’s “Where In the Universe” challenge. Sorry its late, but summer is the time for vacations and partaking in hobbies like rock hunting and late night stargazing. Here’s an image that might provide the opportunity for both. That’s just a little hint for this week’s challenge. Your mission, should you choose to accept, is to name the location in the universe this image was taken, or maybe in this instance, what this is an image of. Give yourself extra points if you can name the spacecraft responsible for the image (that might be the easy part this week). No peeking below until you make your guess. And to be honest, I should say that this image is part of a larger image, which can be seen below.

image credit: Hubble Space Telescope
image credit: Hubble Space Telescope

In this unusual image, the Hubble Space Telescope captures a rare view of the celestial equivalent of a geode — a gas cavity carved by the stellar wind and intense ultraviolet radiation from a hot young star. The object, called N44F, is being inflated by a torrent of fast-moving particles –a stellar wind –from an exceptionally hot star once buried inside a cold dense cloud. N44F is located about 160,000 light-years in our neighboring dwarf galaxy the Large Magellanic Cloud, in the direction of the southern constellation Dorado.

Real geodes are baseball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these geodes are split in half by a geologist, do we get a chance to appreciate the inside of the rock cavity that is lined with crystals. In the case of Hubble’s 35 light-year diameter “celestial geode” the transparency of its bubble-like cavity of interstellar gas and dust reveals the treasures of its interior.

Compared with our Sun, the central star in N44F is ejecting more than a 100 million times more mass per second. The hurricane of particles moves much faster at about 4 million miles per hour (7 million kilometers per hour), as opposed to about 0.9 million miles per hour (1.5 million kilometers per hour) for our Sun. Because the bright central star does not exist in empty space but is surrounded by an envelope of gas, the stellar wind collides with this gas, pushing it out, like a snowplow. This forms a bubble, whose striking structure is clearly visible in the crisp Hubble image.

How’d everyone do?

Find the original image here.

Posted on by Ian O'Neill

Get Ready for September 10th: CERN Announces LHC Switch-On

A series of problems forced LHC shutdown (CERN/LHC)

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It’s official, the Large Hadron Collider (LHC) will begin operations in a little over a month. On September 10th, the most sophisticated particle accelerator will go online, injecting the first circulation of accelerated particles. Actual experiments involving collisions will occur once scientists are satisfied the LHC is fully optimized and calibration is complete. The LHC has been undergoing “cool-down” for some time, ensuring the LHC’s eight sectors are approaching the 1.9K (-271°C) operational temperature (that is 1.9 degrees above absolute zero). All going well, on September 10th, the first beam will be accelerated to an energy of 450 GeV (0.45 TeV), the preliminary step on the path to attaining particle energies of 5 TeV, a record breaking target… awesome.

Earlier today, CERN announced that the LHC will be ready by September 10th to attempt to circulate a beam of particles. This news comes as the “cool-down” phase of LHC commissioning reaches a successful conclusion, cooling all eight sectors to 1.9 degrees above absolute zero. To manage temperatures this extreme has been a long and painstaking task, referred to as a “marathon” by the project leader:

“We’re finishing a marathon with a sprint. It’s been a long haul, and we’re all eager to get the LHC research programme underway.” – LHC project leader Lyn Evans.

Now scientists and engineers must synchronize the LHC with the Super Proton Synchrotron (SPS) accelerator, which is the last component in the LHC’s particle injector chain. For the system to work, the LHC and SPS must be synchronized to within a fraction of a nanosecond. This task is expected to begin on August 9th (Saturday). These calibration tasks are expected to continue through August and into the beginning of September, preparing the LHC for its first particle injection on the 10th.

The LHC will accelerate particles to relativistic velocities, accessing energies previously unimaginable. Once the LHC reaches its optimum design specification (possibly by 2010), it will generate beams seven-times more energetic and 30-times more intense than any other particle accelerator on the planet. The accelerator ring lies below the Swiss countryside with a circumference of 27 km (17 miles).

Source: CERN