Posted on by Fraser Cain

Positron Drive: Fill ‘er Up For Pluto

Computer illustration of a potential antimatter drive. Image credit: Positronics Research LLC. Click to enlarge.
We all played the game as children – “leapfrog” involved one child squatting on all fours while a second placed their hands on the first’s shoulders. Braced against the pull of gravity, the standing child bends at the legs deeply then thrusts up and over the top of the first. The result? The second child now squats and the another froglike leap follows in turn. Not the most efficient way to get to the swing set – but a lot of fun in the right company!

Leapfrogging however is not the same as ‘bootstrapping’. While bootstrapping, a single player bends and grabs the leather loops on the outside of both boots. The player then makes a tremendous exertion upward with the arms. Leapfrogging works – bootstrapping doesn’t, it just can’t be done without hopping – an entirely different thing altogether.

The NASA Institute for Advanced Concepts (NIAC) believes in leapfrogging – no not on the playground but in aerospace. From the institutes own website: “NIAC encourages proposers to think decades into the future in pursuit of concepts that will “leapfrog” the evolution of current aerospace systems.” NIAC is looking for a few good ideas and is willing to support them with six-month-long seed grants to test feasibility before serious research and development funds – available from NASA and elsewhere – are allocated. Hopefully such seeds are allowed to germinate and future investment grows them to maturity.

NIAC wants to separate out leapfrogging from bootstrapping, however. One works and the other makes no sense whatsoever. According to NIAC, the positron drive could lead to a giant leap forward in the way we travel throughout the solar system and beyond. There’s probably no bootstrapping about it.

Consider the positron – mirror twin of the electron – like human twins, a very rare thing. Unlike human twins, a positron is unlikely to survive the birth process. Why? Because positrons and their siblings – electrons – find each other irresistible and quickly annihilate in a burst of soft gamma rays. But that burst, under controlled circumstances, can be converted into any form of ‘work’ you might want to do.

Need light? Mix a positron and an electron then irradiate a gas to incandescence. Need electricity? Mix another pair and irradiate a metal strip. Need thrust? Shoot those gamma rays into a propellant, heat it to outlandishly high temperatures and push the propellant out the back of the rocket. Or, shoot those gamma rays into tungsten plates in a stream of air, heat that air and jettison it out the back of an aircraft.

Imagine having a supply of positrons – what could you do with them? According to Gerald A. Smith, Principle Investigator for Positronics Research, LLC of Sante Fe, New Mexico you could go just about anywhere, “the energy density of antimatter is ten orders of magnitude greater than chemical and three orders of magnitude greater than nuclear fission or fusion energy.”

And what does this mean in terms of propulsion? “Less weight, far, far, far less weight.”

Using chemically based propulsion systems, 55 percent of the weight associated with the Huygens-Cassini probe sent to explore Saturn was found in the probe’s fuel and oxidizer tanks. Meanwhile to hurl the probes 5650 kg of weight beyond the Earth required a launch vehicle weighing some 180 times that of fully-fueled Cassini-Huygens itself (1,032,350 kgs).

Using Dr. Smith’s numbers alone – and only considering the maneuvering thrust required for Cassini-Huygens using positron-electron annihilation, the 3100 kgs of chemical propellant burdening the original 1997 probe could be reduced to a mere 310 micrograms of electrons and positrons – less matter than that found in a single atomized drop of morning mist. And with this reduction in mass the total launch weight from Canaveral to Saturn could easily be reduced by a factor of two.

But positron-electron annihilation is like having plenty of air but absolutely no gasoline ? your car won?t get far on oxygen alone. Electrons are everywhere, while positrons are not naturally available on Earth. In fact where they do occur – near black hole event horizons or for short periods of time after high energy particles enter the Earth’s atmosphere – they soon find one of those ubiquitous electrons and go photonic. For this reason you have to make your own.

Enter the particle accelerator
Companies such as Positronics Research, headed up by Dr. Smith, are working on technologies inherent in the use of particle accelerators – like the Stanford Linear Accelerator (SLAC) located in Menlo Park, California. Particle accelerators create positrons using electron-positron pair-production techniques. This is done by smashing a relativistically accelerated electron beam into a dense tungsten target. The electron beam is then converted into high energy photons which move through the tungsten and turn into matched sets of electrons and positrons. The problem before Dr. Smith and others creating positrons is easier than trapping, storing, transporting, and using them effectively.

Meanwhile during pair-production, all you’ve really done is packed a whole lot of earth-bound energy into extremely small amounts of highly volatile – but extremely light-weight – fuel. That process itself is extremely inefficient and introduces major technical challenges related to accumulating enough anti-particles to power a spacecraft capable of journeying into the Great Beyond at velocities making large space probe – and human spacetravel – possible. How is all this likely to play out?

According to Dr. Smith, “for many years physicists have squeezed positrons out of the tungsten targets by colliding the positrons with matter, slowing them down by a thousand or so to use in high resolution microscopes. This process is horribly inefficient; only one millionth of the positrons survive. For space travel we need to increase the slowing down efficiency by at least a factor of one thousand. After four years of hard work with electromagnetic traps in our labs, we are preparing to capture and cool five trillion positrons per second in the next few years. Our long-range goals are five quad-trillion positrons per second. At this rate we could fuel up for our first positron-fueled flight into space in a matter of hours.”

While it is true that a positron-annihilation engine also requires propellent (typically in the form of compressed hydrogen gas), the amount of propellant itself is reduced to almost 10 percent of that required by a conventional rocket – since no oxidizer is needed to react with the fuel. Meanwhile, future craft may actually be able to scoop propellant up from the solar wind and interstellar medium. This should also lead to a significant reduction in the launch weight of such spacecraft.

Written by Jeff Barbour

Posted on by Fraser Cain

New Method Pinpoints the Age of the Milky Way

One of the meteorites analyzed to help pinpoint the age of Milky Way. Image credit: Nicolas Dauphas, University of Chicago. Click to enlarge.
The University of Chicago?s Nicolas Dauphas has developed a new way to calculate the age of the Milky Way that is free of the unvalidated assumptions that have plagued previous methods. Dauphas? method, which he reports in the June 29 issue of the journal Nature, can now be used to tackle other mysteries of the cosmos that have remained unsolved for decades.

?Age determinations are crucial to a fundamental understanding of the universe,? said Thomas Rauscher, an assistant professor of physics and astronomy at the University of Basel in Switzerland. ?The wide range of implications is what makes Nicolas? work so exciting and important.?

Dauphas, an Assistant Professor in Geophysical Sciences, operates the Origins Laboratory at the University of Chicago. His wide-ranging interests include the origins of Earth?s atmosphere, the oldest rocks that may contain evidence for life on Earth and what meteorites reveal about the formation of the solar system.

In his latest work, Dauphas has honed the accuracy of the cosmic clock by comparing the decay of two long-lived radioactive elements, uranium-238 and thorium-232. According to Dauphas? new method, the age of the Milky Way is approximately 14.5 billion years, plus or minus more than 2 billion years.

That age generally agrees with the estimate of 12.2 billion years?nearly as old as the universe itself? as determined by previously existing methods. Dauphas? finding verifies what was already suspected, despite the drawbacks of existing methods: ?After the big bang, it did not take much time for large structures to form, including our Milky Way galaxy,? he said.

The age of 12 billion years for the galaxy relied on the characteristics of two different sets of stars, globular clusters and white dwarfs. But this estimate depends on assumptions about stellar evolution and nuclear physics that scientists have yet to substantiate to their complete satisfaction.

Globular clusters are clusters of stars that exist on the outskirts of a galaxy. The processes of stellar evolution suggested that most of the stars in globular clusters are nearly as old as the galaxy itself. When the big bang occurred 13.7 billion years ago, the only elements in the universe were hydrogen, helium and a small quantity of lithium. The Milky Way?s globular clusters have to be nearly that old because they contain mostly hydrogen and helium. Younger stars contain heavier elements that were recycled from the remains of older stars, which initially forged these heavier elements in their cores via nuclear fusion.

White dwarf stars, meanwhile, are stars that have used up their fuel and have advanced to the last stage of their lives. ?The white dwarf has no source of energy, so it just cools down. If you look at its temperature and you know how fast it cools, then you can approximate the age of the galaxy, because some of these white dwarfs are about as old as the galaxy,? Dauphas said.

A more direct way to calculate the age of stars and the Milky Way depends on the accuracy of the uranium/thorium clock. Scientists can telescopically detect the optical ?fingerprints? of the chemical elements. Using this capability, they have measured the uranium/thorium ratio in a single old star that resides in the halo of the Milky Way.

Original Source: University of Chicago News Release

Posted on by Fraser Cain

Rosetta Tunes in Tempel 1

Rosetta’s photograph of Comet Tempel 1, it’s down on the lower left. Image credit: ESA. Click to enlarge.
ESA?s Rosetta comet-chaser spacecraft has acquired its first view of the Deep Impact target, Comet 9P/Tempel 1.

This first Rosetta image of the Deep Impact campaign was taken by its Navigation Camera (NAVCAM) between 08:45 and 09:15 CEST on 28 June 2005.

The image shows that the spacecraft now points towards Comet 9P/Tempel 1 in the correct orientation. The NAVCAM is pointing purposely slightly off-target to give the best view to the science instrumentation.

The NAVCAM system on board Rosetta was activated for the first time on 25 July 2004. This system, comprising two separate independent camera units (for back-up), will help to navigate the spacecraft near the nucleus of Comet 67P/Churyumov-Gerasimenko in ten years time.

In the meantime though, the cameras can also be used to track other objects, such as Comet Tempel 1, and the two asteroids that Rosetta will be visiting during its long cruise, Steins and Lutetia.

The cameras perform both as star sensors and imaging cameras (but not with the same high resolution as some of its other instruments), and switch functions by means of a refocusing system in front of the first lens.

The magnitude of Comet Tempel 1 is at the detection limit of the camera: it is not as easily visible in the raw image and the image here is a composite of 20 exposures of 30 seconds each.

The comet is the fuzzy object with the tail in the lower left of the image. The faintest stars visible in this image are about 13th magnitude, the bright star in the upper left is about 8th magnitude. The image covers about 0.5 degrees square, and celestial north is to the right.

Original Source: ESA News Release

Posted on by Fraser Cain

Audio: Interview with Story Musgrave

Story Musgrave on the launch pad for the space shuttle Discovery on mission STS-33. Image credit: NASA. Click to enlarge.
Listen to the interview: Interview with Story Musgrave (10 MB)

Or subscribe to the Podcast: universetoday.com/audio.xml

Fraser Cain: We’re just about two weeks away from the next space shuttle going up to return to flight after the Columbia tragedy. How would you feel if you were in the space shuttle?

Story Musgrave: I was never comfortable with the shuttle, of course. The risk is a lot higher than I ever wished to tolerate. I’m not a risk taker. I’ve survived in the aerospace world for 53 years, and I’m a professional who wants to come back and do it again next year. I’ve never been happy with the amount of risk that the shuttle is. But, I think the current mission will probably be one of the safest ever. I think they will have done as much as they can, and they will have looked after the details, so I think this current launch will be as safe as any they’ve ever done.

Fraser: What’s the experience like of launching on board the shuttle? Pretty violent, I guess.

Musgrave: Uh yeah, I’d call it violent. It’s a lot of vibration, a lot of noise, and you’re just hoping that butterfly will just stick to that bullet.

Fraser: There’s been a lot of controversy about the Hubble Space Telescope, about whether to continue the repairs or not. You led the team for the first repair mission. How do you feel about bringing Hubble back to service?

Musgrave: I think we’ll give it one more shot. I think we will go and service it one more time. That’s not over, that game is not over yet, and I expect we’ll service it one more time. It may not be on the books now; what is on the books is don’t preclude it, not to preclude that possibility. I think once we get the shuttle flying again, and certainly the public wants that done. There’s nothing much more important to the public. The public doesn’t understand the space station, they don’t know what’s there, they don’t know what we’re doing, they don’t see anything from it. Once we get the shuttle flying again, and we’ve got an idea about the difficulties there with ice or foam and the thermal protection system, then we’ll get that confidence back. I think we’ll get the confidence to take the shuttle to somewhere other than space station. As you probably know, the only issue is – it’s not a matter of money or anything – the issue is that every time you fly the shuttle until it’s flown out its lifetime, which people are talking 2010; should you take it to the space station every time? You do have a lifeboat, you do have a means of inspection, possibly of repair, and a place for the crew to hang out until rescue if there is a problem. It gets down to the basic question: are you willing to take the risk to fly the shuttle anywhere other than the space station, such as Hubble? You can not make it to Hubble, and then make it to space station. They’re in different planes, and it takes to much fuel to change planes. So you can’t do both. If you go to Hubble, you can’t make it to station.

Fraser: How do you feel about the new Vision for Space Exploration?

Musgrave: A vision of “out there”, I am very happy with, to go beyond Earth orbit. Space station was a terrible strategic error. We’ve not had a solid vision, of course, since the Moon and Skylab. For Skylab, our first space station, I was involved in developing, and as a backup crew member on the first one in 1973. Now the Apollo and the Skylab programs had a vision. We knew where we were going and what we wanted to do, and it was exploration and discovery. It kind of lost the way from that point on, in terms of staying in touch with the public, who wants exploration and discovery, wants a little further out there. The Voyagers, of course, were fantastic successes and this year they’re planning to pull the plug on them just for money purposes when, in fact, the Voyagers are defining the edge of the Solar System. A new vision at least has words “back to the Moon and to Mars”, so it’s a little further out. How that unfolds, of course, no one knows. Where the resources will come from when we transition from the current efforts we’re doing. Until we get out of the current efforts, there’ll be no money for the further out explorations. But they also have to be done right; we can’t leap off and go. We have to lead with the robots. They have to go first to establish habitats and science centres. They need to go first. So then you can do space optimally, low cost option for space. Lead with the robots. We have to do that this time.

Fraser: And do you feel that the US, and maybe the world in general are more interested in space and space exploration then maybe the governments give them credit?

Musgrave: Oh yeah, the people are. The people are usually interested in exploration and discovery; they’re very interested in what kind of Universe they’ve got; what’s their place in it. They’re interested in the big questions. So, that’s what they’re after. That’s what’s exciting about space. Not the spinoffs, not the technical spinoffs, not just the technology. They’re interested in discovering their Universe. They want some answers to their existential questions. What’s life mean here? What’s the meaning of hope? What am I doing here? So things like Hubble tend to bridge those gaps between cosmology and theology, philosophy and astronomy. And that’s why Hubble has always meant so much to people. That’s why for that kind of exploration and discovery, you can do it in a microscope as well. You could do it with really cutting edge science, all those things are exciting to people. But space, going out to beyond Earth, whether you do it with telescopes or other robots or eventually humans, that’s why people are excited about space.

Fraser: Astronomy and the search for life on Mars and so on has a chance to really put things in perspective here in the Universe.

Musgrave: You’ll never know. You can’t know what happened here until you find one other. Of course, contact, you know with linear time and linear distances is going to be very difficult, but no way will we understand how creation, evolution and intelligent beings and the information age all came to pass on this planet. We’ll never understand that until we see how that happened on some other body. And so that is critical, very critical. We’re dealing, as scientists, we’re dealing with a sample of one; how it happened and why it happened. With a sample of one, usually you can’t make conclusions from one. So all those things are highly important. But we can take small steps before we make contact. You can make steps in that the human species accepts the other long before you get the proof of contact. That’s part of our growth, part of our Copernican growth; do we accept other living creatures, and accept other intelligent creatures. It’s all part of the Copernican thing – the Universe does not go around the Earth. It’s part of the Darwinian thing about evolution, it’s part of Freud, of the subconscious, which is very important to human behaviour even though you can’t get at it. It’s Einstein’s Relativity, the Heisenberg uncertainty. Those kinds of things, they are part of our species’ growth. And so I think that long before we get to physical proof of it, that part of our growth will be universal among the species acceptance of the other.

Fraser: Do you think that humans are emotionally ready to make contact with other alien species?

Musgrave: No, they’re not. They’re not, and it won’t happen. Anything that is so advanced as to be doing interstellar travel, and you know with the trillions of planets out there that could support life, there is interstellar travel going on. They wouldn’t come here, we’re not ready. We’re not ready because we are not ready to meet members of our own species. I mean, there are 60 wars this week on planet Earth. So, if we’re not ready to meet – to embrace – members of our own species, let alone other creatures or a sustainable behaviour with Earth, we are not advanced enough in our globalization and in our moving further out until we think of ourselves as galactic creatures on the journey together. No, we’re not ready to meet them, and we would not welcome them – we’d send the guns first. It would be a national defense. It would be a national security issue, as opposed to a communications issue. I’m not a cynic, and I’m not being skeptical, I’m pointing at the facts… the pure facts. But it also points out that humans have got to get it together. They’ve simply got to get the will, the desire, to get it together. And that has not become more important than protecting the tribalism and protecting our provincial interests. You know, globalization of the species, where we become global creatures, and then solar system, and then galactic kinds of creatures which would live at a different transcendent level. That’s obtainable to us today if we only have the desire.

Fraser: Do you think that the universities and the schools and even the popular culture are doing a good job of popularizing space and astronomy and science right now?

Musgrave: Yes, I think they do a good job. That’s not the problem: what do we give them? What are we handing them? For example, let me come back to you and ask you a question, what are we giving them today?

Fraser: On the news, people are interested in Michael Jackson’s trial more than the things being discovered in space.

Musgrave: I absolutely agree that the Michael Jacksons to Britney Spears and the Donald Trumps are running the world. There’s no question about that, and I’m serious, they really are. If you look at the internet, if you look at the explosion of information with 100 television channels, and the massive number of books, magazines, print and the satellite communications, the internet, all the rest of that; if you look upon that as we’re almost forming a global brain here, or we have already – it may even be conscious. That’s a stretch, but how are we to know? You know, a single brain cell doesn’t know it’s part of a brain; it can’t see that great big picture. But the gate guarders, the people who run the media and the like. There are people who, when they sneeze, the entire system reverberates; they kick off huge waves that go through this massive global brain that we have. And it’s not the scientists, and it’s not the scientific information. That’s not necessarily just a problem with the space program, that’s a cultural problem. You want to build the people; you want to make the people so that when they sneeze, the whole brain shivers. You make them, and then you mine money from them. But that’s a process where we really do need to get our priorities and get beyond that.

Fraser: I see a few glimmers of hope, with shows like CSI where the scientists and geeks are the heroes. Back in the 60s and 70s, the astronauts were seen as heroes and as rock stars in that world, so it’s definitely possible. It’s almost as if, this is what’s currently in focus, so that’s all people care about.

Musgrave: I guess it boils down to a sense of values. What are our values? What are our species, what are our cultural, what are our national, what are our values in terms of what do we value?

Fraser: I wanted to go a bit into the recent CD that we reviewed here on Universe Today a little way back. Can you give me some background on what went into doing this CD, and the people that you worked with?

Musgrave: Well, it was mostly my son who was instrumental in that. And we have some other musicians which I adore: Jonn Serrie writes a lot about space music. Harry Roberts, we discovered him. He was just living across the street from Todd in Austin. Brian Eno, I’ve always adored his stuff, the Apollo track, and that. It’s basically a montage of things we recorded some of my poems in the studio, and then Harry added some music to them. It kind of evolved in that way to be a space themed audio.

Fraser: And having finished Cosmic Fireflies, do you think you’ll do another CD?

Musgrave: Yes, I think we will. I think it may focus a little more heavily. The poetry I wrote were mostly class assignments. One poem, the longer poem about orbit about the Earth I wrote for National Geographic magazine. But if I’d had it in mind ahead of time, that we’d put the poems to music, then I would maybe do some different things. But I didn’t know that’s where those things would end up, when I wrote them, or when I recorded them. So it’s possible that with the specificity in mind, it’s possible that I could do a better job although, there’s nothing much like spontaneity. I think a live audience is very nice too, so you might do a live poetry reading. And I do live programs to record on DVDs. I’m just wrapping up one now on Australia from space. I’m going down to Sydney in two weeks and probably put the wraps on that. We’ve been in post production here for a year.

Fraser: One question I get a lot from readers, is how do they become astronauts. One suggestion I’ve heard is to save up $20 million and pay for a trip to space. Do you have any advice for the next generation of astronauts out there?

Musgrave: I disagree with money, I disagree, I think that’s the wrong thing to do. Money, just like we were talking about earlier, who runs the world, with celebrity running the world with celebrity money and power, they all go together of course. I disagree with the idea that money should go into space. The artists, the poets and scientists and other teachers and stuff, they don’t get to go because they don’t have money. So I disagree with that grab for resources. We had a wonderful communicator in space program, teacher in space program, but of course, Christa McAuliffe died on Challenger and we haven’t had the courage to reinstitute that program. We took her backup, Barbara Morgan, we took her on as a regular astronaut so that we would eventually get a teacher into space. The wider range of people you put in space, the more richly you’re going to communicate what space is about. I’ve always been highly in favour of flying a diversity of people in space. Money should not be the deciding factor. Your ability to have the experience and bring it home for others should be the deciding factor. Now, new things are happening; there’s SpaceShipOne, and the Ansari X-Prize. So new things are happening, but it’s not going to open a huge door right away. Space is so critical, you have to do it right. You can’t just do it, you know. You can’t just do it to pull it off. So you have to do more deeper engineering, and backup systems, and safety systems, and escape systems, and you have to get more into those kinds of things. Tourism in space by private enterprise will be a little slower to happen than maybe we perceive now, as we see private ventures getting into it. It’s very important to have those innovative kinds of things happening. It’s exceedingly important because NASA’s not doing it.

Posted on by Fraser Cain

Universe Today Podcast in iTunes

Apple has released their latest version of iTunes, 4.9, with support for podcasting. The Universe Today podcast is located in their directory, currently it’s the 63rd most popular podcast… woohoo! So, if you’re using iTunes for music, you might want to download the latest version and transfer your subscriptions into iTunes. Just do a search for Universe Today in the podcast directory, and then click on the “subscribe” button. You don’t actually need to own an iPod to listen to these shows, just a computer that can play music/sound.

Thanks for all your support, I’d better hurry and do some more interviews.

Fraser Cain
Publisher, Universe Today

Posted on by Fraser Cain

Planets Can Survive a Red Giant

The white dwarf star Gliese 86B is the tiny dot to the left of the bright star. Image credit: ESO. Click to enlarge.
The team has found that a star known as Gliese 86 – part of the southern constellation Erinadus, and just visible to the unaided eye – has another companion in addition to the gas giant planet that was found in a tight orbit around it seven years ago. However, this more distant companion is not another planet, but a white dwarf star that is about as far from Gliese 86 as is Uranus from the sun. The discovery marks the first time a planet has been found in the vicinity of a white dwarf, and could have implications for our own solar system – which will itself be centered around a white dwarf in a few billion years.

“This is the first observational evidence that planets can survive the white dwarf formation process of a star several astronomical units away,” said researcher team member Markus Mugrauer, a doctoral student at the Astrophysical Institute and University Observatory, University of Jena, Germany. “In theory, nearby planets should not survive the formation process, but this finding is evidence that, if they are sufficiently distant, they can. This is of interest because most stars in the galaxy, including our own, will eventually evolve into white dwarfs.”

The study, which Mugrauer conducted with Dr. Ralph Neuhaeuser, director of observations at the university’s astrophysics institute, were published as a letter in the May issue of “Monthly Notices of the Royal Astronomical Society.”

The planet itself was discovered in late 1998 at Switzerland’s La Silla observatory, and was the first exoplanet to be found using a telescope at La Silla that had been fitted with a spectrograph for the express purpose of searching for planets around other stars. Further analysis of Gliese 86’s movements indicated that the star also had a faint stellar companion that had not yet been observed, possibly a brown dwarf — an object with insufficient mass to sustain fusion in its core.

“No one was sure what it was, however,” Mugrauer said. “Just as the planet itself had been found by its influence on Gliese 86 but had not actually been ‘seen,’ the companion was tugging on the star but it was difficult to separate from background light.”

To resolve Gliese 86’s companion, the pair used high contrast observations using the 8m Very Large Telescope at La Silla together with a new simultaneous differential imaging device.

“With these instruments, we can resolve objects about 150,000 times fainter than the central star, but which are still very close to them,” Mugrauer said. “This allows us to search for close and very faint companions of our target stars.”

After filtering out the background noise, they found Gliese’s companion orbiting at a distance of about 21 AU, but were surprised to find it hotter than expected — at least 3700 Kelvin, too warm to be a brown dwarf. Judging by its velocity and distance from Gliese 86, they also found that the white dwarf has about 55 percent the mass of our sun, making it smaller than Gliese 86, which has 70 percent of our sun’s mass.

“But since a star loses a good deal of its mass as it evolves into a white dwarf, this companion was once much larger than Gliese 86, perhaps as large as our own sun or even larger,” Mugrauer said. “It was much closer to Gliese 86 before it became a white dwarf, perhaps 15 AU, or a distance about halfway between the orbits of Saturn and Uranus in our own system. It migrated outward after it lost mass during its evolution into a white dwarf.”

Because of the planet’s size and distance from the red giant, Mugrauer said, the companion’s evolution wouldn’t have dramatically affected the planet’s size.

“The planet’s gravity is simply too strong to lose mass because of the impacting material and due to its large separation,” he said. “However, during the red giant phase, the companion would have swollen up and become 10,000 more luminous. It would also have become the dominant heat source of the planet, heating it 1000K or more.”

Nowadays, he said, the companion would probably appear as a very bright star in the planet’s night sky, but would provide it with very little additional heat in comparison with Gliese 86, which the giant planet circles at about a tenth the distance of the Earth to the sun.

“We expect that distant planets — those farther than Jupiter is from our sun — can survive the evolution of a star from red giant to white dwarf. These observations tend to confirm that expectation,” Mugrauer said. “In the Gliese 86 system in particular, the separation between the white dwarf and the exoplanet is large enough that it seems very possible that a planet can survive the red giant phase of a G dwarf such as our sun.”

But Mugrauer said that he and Neuhaeuser would continue to search for companion stars in this and other exoplanetary systems because, despite the number of planets that have been found circling other stars, little is known about the properties of planets in binary systems. Planets in close binaries, like Gliese 86, are rare. “Gliese 86 is one of the closest binary systems hosting a planet,” Mugrauer said.

“These systems provide important information about the planet formation process and how the multiplicity of the host star may effect it,” he said. “Gliese 86 is only about 35 light years from earth, so it was near the top of our list of stars to explore. But we are on our way to checking out a lot more.”

Written by Chad Boutin

Posted on by Fraser Cain

Mars Organic Analyzer Passes the Test

Graduate student Alison Skelley in the Atacama desert in Chile. Image credit: Richard Mathies lab/UC Berkeley. Click to enlarge.
The dry, dusty, treeless expanse of Chile’s Atacama Desert is the most lifeless spot on the face of the Earth, and that’s why Alison Skelley and Richard Mathies joined a team of NASA scientists there earlier this month.

The University of California, Berkeley, scientists knew that if the Mars Organic Analyzer (MOA) they’d built could detect life in that crusty, arid land, then it would have a good chance some day of detecting life on the planet Mars.
Collecting samples in the Atacama Desert

In a place that hadn’t seen a blade of grass or a bug for ages, and contending with dust and temperature extremes that left her either freezing or sweating, Skelley ran 340 tests that proved the instrument could unambiguously detect amino acids, the building blocks of proteins. More importantly, she and Mathies were able to detect the preference of Earth’s amino acids for left-handedness over right-handedness. This “homochirality” is a hallmark of life that Mathies thinks is a critical test that must be done on Mars.

“We feel that measuring homochirality – a prevalence of one type of handedness over another – would be absolute proof of life,” said Mathies, professor of chemistry at UC Berkeley and Skelley’s research advisor. “We’ve shown on Earth, in the most Mars-like environment available, that this instrument is a thousand times better at detecting biomarkers than any instrument put on Mars before.”

The instrument has been chosen to fly aboard the European Space Agency’s ExoMars mission, now scheduled to launch in 2011. The MOA will be integrated with the Mars Organic Detector, which is being assembled by scientists directed by Frank Grunthaner at the Jet Propulsion Laboratory (JPL) in Pasadena together with Jeff Bada’s group at UC San Diego’s Scripps Institution of Oceanography.

Skelley, a graduate student who has been working on amino acid detection with Mathies for five years and on the portable MOA analyzer for the past two years, is hoping to remain with the project as it goes through miniaturization and improvements at JPL over the next seven years in preparation for its long-range mission. In fact, she and Mathies hope she’s the one looking at MOA data when it’s finally radioed back from the Red Planet.

“When I first started this project, I had seen photos of the Martian surface and possible signs of water, but the existence of liquid water was speculative, and people thought I was crazy to be working on an experiment to detect life on Mars,” Skelley said. “I feel vindicated now, thanks to the work of NASA and others that shows there used to be running liquid water on the surface of Mars.”

“The connection between water and life has been made very strongly, and we think there is a good chance there is or was some life form on Mars,” Mathies said. “Thanks to Alison’s work, we’re now in the right position at the right time to do the right experiment to find life on Mars.”

Mathies said that his experiment is the only one proposed for ExoMars or the United States’ own Mars mission – NASA’s roving, robotic Mars Science Laboratory mission – that could unambiguously find signs of life. The experiment uses state-of-the-art capillary electrophoresis arrays, novel micro-valve systems and portable instrument designs pioneered in Mathies’ lab to look for homochirality in amino acids. These microarrays with microfluidic channels are 100 to 1,000 times more sensitive for amino acid detection than the original life detection instrument flown on the Viking Landers in the 1970s.

The Atacama Desert was selected by NASA scientists as one of the key spots to test instruments destined for Mars, primarily because of its oxidizing, acidic soil, which is similar to the rusty red oxidized iron surface of Mars. Skelley and colleagues Pascale Ehrenfreund, professor of astrochemistry at Leiden University in The Netherlands, and JPL scientist Frank Grunthaner visited the desert last year, but were not able to test the complete, integrated analyzer.

This year, Skelley, Mathies and other team members carried the complete analyzers in three large cases to Chile by plane – in itself a test of the ruggedness of the equipment – and trucked them to the barren Yunguy field station, essentially a ramshackle building at a deserted crossroads. With a noisy Honda generator providing power, they set up their experiments and, with six other colleagues, tested the integrated subcritical water extractor together with the MOA on samples from popular test sites such as the “Rock Garden” and the “Soil Pit.”

One thing they learned is that with low environmental levels of organic compounds, as is likely to be the case on Mars, the microfluidic channels in the capillary disks don’t get clogged as readily as they do when used to test samples in Berkeley with its high bioorganic levels. That means they’ll need fewer channels on the instrument that travels to Mars, and the scanner used to read out the data needn’t be as elaborate. This translates into a cheaper and easier way to build instruments, but more importantly, an instrument that is smaller and uses less power.

With the success of this crucial field test, Skelley and Mathies are eager to get to work on a prototype of their instrument that would fit in the allowed space within the ExoMars spacecraft.

“I’m much more optimistic that we could detect life on Mars, if it’s there,” Mathies said.

Original Source: UC Berkeley News Release

Posted on by Fraser Cain

Deep Impact Sees a Burst from Tempel 1

Artist illustration of Deep Impact with Comet Tempel 1. Image credit: NASA/JPL. Click to enlarge.
NASA’s Deep Impact spacecraft observed a massive, short-lived outburst of ice or other particles from comet Tempel 1 that temporarily expanded the size and reflectivity of the cloud of dust and gas (coma) that surrounds the comet nucleus.

The outburst was detected as a dramatic brightening of the comet on June 22. It is the second of two such events observed in the past two weeks. A smaller outburst also was seen on June 14 by Deep Impact, the Hubble Space Telescope and by ground based observers.

“This most recent outburst was six times larger than the one observed on June 14, but the ejected material dissipated almost entirely within about a half day,” said University of Maryland College Park astronomer Michael A’Hearn, principal investigator for the Deep Impact mission. A’Hearn noted that data from the spectrometer aboard the spacecraft showed that during the June 22 outburst the amount of water vapor in the coma doubled, while the amount of other gases, including carbon dioxide, increased even more.

A movie of the cometary outburst is available on the Internet at http://www.nasa.gov/deepimpact .

“Outbursts such as this may be a very common phenomenon on many comets, but they are rarely observed in sufficient detail to understand them because it is normally so difficult to obtain enough time on telescopes to discover such phenomena,” A’Hearn said. “We likely would have missed this exciting event, except that we are now getting almost continuous coverage of the comet with the spacecraft’s imaging and spectroscopy instruments.”

Deep Impact co-investigator Jessica Sunshine, with Science Applications International Corporation, Chantilly, Va., agreed that observing such activity twice in two weeks suggests outbursts are fairly common. “We must now consider them as a significant part of the processing that occur on comets as they heat up when approaching the sun,” she said.

Comet Tempel 1 is near perihelion, or the point in its orbit at which it is closest to the Sun.

“This adds to the level of excitement as we come down to the final days before encounter,” said Rick Grammier, Deep Impact project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “But this comet outburst will require no modification to mission plan and in no way affects spacecraft safety.”

Deep Impact consists of a sub-compact-car-sized flyby spacecraft and an impactor spacecraft about the size of a washing machine. The dual spacecraft carries three imaging instruments, two on the flyby spacecraft and one on the impactor. A spectrometer on the flyby spacecraft uses the same telescope as the flyby’s high- resolution imager.

The final prelude to impact will begin early on July 3, 24 hours before the 1:52 a.m. EDT July 4th impact, when the flyby spacecraft releases the impactor into the path of the comet. Like a copper penny pitched up into the air just in front of a speeding tractor-trailer truck, the 820-pound impactor will be run down by the comet, colliding with the nucleus at a closing speed of 23,000 miles per hour. Scientists expect the impact to create a crater several hundred feet in size; ejecting ice, dust and gas from the crater and revealing pristine material beneath. The impact will have no significant affect on the orbit of Tempel 1, which poses no threat to Earth.

Nearby, Deep Impact’s “flyby” spacecraft will use its medium and high resolution imagers and infrared spectrometer to collect and send to Earth pictures and spectra of the event. The Hubble and Spitzer Space Telescopes, the Chandra X-ray Observatory, and large and small telescopes on Earth also will observe the impact and its aftermath.

The University of Maryland, College Park, conducts overall mission science for Deep Impact that is a Discovery class NASA program. NASA’s Jet Propulsion Laboratory handles project management and mission operations. The spacecraft was built for NASA by Ball Aerospace and Technologies Corporation, Boulder, Colo.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Is This a Lake on Titan?

An unusual feature on the surface of Titan that could be a hydrocarbon lake. Image credit: NASA/JPL/SSI. Click to enlarge.
This view of Titan?s south polar region reveals an intriguing dark feature that may be the site of a past or present lake of liquid hydrocarbons.

The true nature of this feature, seen here at left of center, is not yet known, but the shore-like smoothness of its perimeter and its presence in an area where frequent convective storm clouds have been observed by Cassini and Earth-based astronomers make it the best candidate thus far for an open body of liquid on Titan.

If this interpretation is correct, then other very dark but smaller features seen in the south polar region, some of which are captured in this image, may also be the sites of liquid hydrocarbon reservoirs.

In addition to the notion that the dark feature is or was a lake filled with liquid hydrocarbons, scientists have speculated about other possibilities. For instance, it is plausible that the ‘lake’ is simply a broad depression filled by dark, solid hydrocarbons falling from the atmosphere onto Titan?s surface. In this case, the smoothed outline might be the result of a process unrelated to rainfall, such as a sinkhole or a volcanic caldera.

A red cross below center in the scene marks the pole. The brightest features seen here are methane clouds. A movie sequence showing the evolution of bright clouds in the region during the same flyby is also available (see PIA06241).

This view is a composite of three narrow angle camera images, taken over several minutes during Cassini’s distant June 6, 2005 flyby. The images were combined to produce a sharper view of Titan?s surface. The images were taken using a combination of spectral filters sensitive to wavelengths of polarized infrared light. The images were acquired from approximately 450,000 kilometers (279,000 miles) from Titan. Resolution in the scene is approximately 3 kilometers (2 miles) per pixel. The view has been contrast enhanced to improve the overall visibility of surface features.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Posted on by Fraser Cain

Spotty Janus

Close up view of Saturn’s moon Janus. Image credit: NASA/JPL/SSI. Click to enlarge.
This close-up look at Saturn’s moon Janus reveals spots on the moon’s surface which may be dark material exposed by impacts. If the dark markings within bright terrain are indeed impact features, then Janus’ surface represents a contrast with that of Saturn’s moon Phoebe, where impacts have uncovered bright material beneath a darker overlying layer. Janus is 181 kilometers (113 miles) across.

Janus may be a porous body, composed mostly of water ice.

This image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2005, at a distance of approximately 357,000 kilometers (222,000 miles) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 6 degrees. Resolution in the original image was 2 kilometers (1 mile) per pixel. The view was magnified by a factor of two and contrast-enhanced to aid visibility of the moon’s surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI