Posted on by Fraser Cain

Teeny Tiny Solar System

An artist’s concept of the miniature solar system (top) compared to a known solar sytem. Image credit: NASA/JPL Click to enlarge
Scientists using a combination of ground-based and orbiting telescopes have discovered a failed star, less than one-hundredth the mass of the Sun, possibly in the process of forming a solar system. It is the smallest known star-like object to harbor what appears to be a planet-forming disk of rocky and gaseous debris, which one day could evolve into tiny planets and create a solar system in miniature. A team led by Kevin Luhman, assistant professor of astronomy and astrophysics at Penn State University, will discuss this finding in the 10 December 2005 issue of Astrophysical Journal Letters.

The discovered object, called a brown dwarf, is described as a “failed star” because it is not massive enough to sustain nuclear fusion like our Sun. The object is only eight times more massive than Jupiter. The fact that a brown dwarf this small could be in the midst of creating a solar system challenges the very definition of star, planet, moon and solar system.

“Our goal is to determine the smallest ‘sun’ with evidence for planet formation,” said Luhman. “Here we have a sun that is so small it is the size of a planet. The question then becomes, what do we call any little bodies that might be born from this disk: planets or moons?” If this protoplanetary disk does form into planets, the whole system would be a miniaturized version of our solar system — with the central “sun”, the planets, and their orbits all roughly 100 times smaller.

Luhman’s team detected the brown dwarf, called Cha 110913-773444, with NASA’s Spitzer Space Telescope, the Hubble Space Telescope, and two telescopes in the Chilean Andes, the Blanco telescope of the Cerro Tololo Inter-American Observatory and the Gemini South telescope, both international collaborations funded in part by the National Science Foundation. Luhman led a similar observation last year that uncovered a 15-Jupiter-mass brown dwarf with a protoplanetary disk.

Brown dwarfs are born like stars, condensing out of thick clouds of gas and dust. But unlike stars, brown dwarfs do not have enough mass — and therefore do not have enough pressure and temperature in their cores — to sustain nuclear fusion. They remain relatively cool objects visible in lower-energy wavelengths such as infrared. A protoplanetary disk is a flat disk made up of dust and gas that is thought to clump together to form planets. Our solar system was formed from such a disk about five billion years ago. NASA’s Spitzer telescope has found dozens of disk-sporting brown dwarfs so far, several of which show the initial stages of the planet-building process. The material in these disks is beginning to stick together into what may be the “seeds” of planets.

With Spitzer, the science team spotted Cha 110913-773444 about 500 light years away in the constellation Chamaeleon. This brown dwarf is young, only about 2 million years old. The team studied properties of the brown dwarf with infrared instruments on the other observatories. The cool, dim protoplanetary disk was detectable only with Spitzer’s Infrared Array Camera, which was developed at the Harvard-Smithsonian Center for Astrophysics.

In the past decade, advances in astronomy have led to the detection of small brown dwarfs and massive extra-solar planets, which has brought about a quandary in taxonomy. “There are two camps when it comes to defining planets versus brown dwarfs,” said team member Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics. “Some go by size, and others go by how the object formed. For instance, this new object would be called a planet based on its size, but a brown dwarf based on how it formed.” If one were to call the object a planet, Fazio said, then Spitzer may have discovered its first “moon-forming” disk. No matter what the final label may be, one thing is clear: The universe produces some strange solar systems very different from our own. Other members of the discovery team are Lucia Adame and Paola D’Alessio of the National Autonomous University of Mexico and Nuria Calvet and Lee Hartmann of the University of Michigan.

The 4-meter Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile is part of the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) Inc. under a cooperative agreement with the National Science Foundation. The nearby 8-meter Gemini South telescope also is managed by AURA. NASA’s Goddard Space Flight Center, Greenbelt, Md., built Spitzer’s Infrared Array Camera. The instrument’s principal investigator is Giovanni Fazio. The Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer mission for NASA. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena.

Original Source:Penn State University

Posted on by Fraser Cain

Ice Volcanoes on Enceladus

Saturn’s moon Enceladus backlit by the Sun. Image credit: NASA/JPL/SSI Click to enlarge
Recent Cassini images of Saturn’s moon Enceladus backlit by the sun show the fountain-like sources of the fine spray of material that towers over the south polar region. This image was taken looking more or less broadside at the “tiger stripe” fractures observed in earlier Enceladus images. It shows discrete plumes of a variety of apparent sizes above the limb of the moon.

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 operations center is based at the Space Science Institute in 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 News Release

Posted on by Fraser Cain

Hayabusa Successfully Collects an Asteroid Sample

Hayabusa Muses-C. Image credit: ISAS Click to enlarge
With a maneuver that scientists compared to landing a jumbo jet in a moving Grand Canyon, Japan’s asteroid explorer, Hayabusa, touched down on the surface of the asteroid Itokawa Saturday for the second time in a week and this time it successfully collected a sample of the surface soils, the Japan Aerospace Exploration Agency (JAXA) announced several hours after its bird had flown.

The world’s first mission to attempt to land on an asteroid, collect samples, and return them to Earth has completed what is, arguably, the most difficult challenge on its agenda, and will begin the long journey back to Earth in early December. If all goes as planned, the sample will be returned in a capsule slated to land in the Australian outback in June 2007.

Every command necessary for the sampling was carried out, JAXA announced Saturday evening Japan Standard Time (JST) on its website, and agency officials firmly believe that the mission succeeded in the world’s first collection of samples of surface materials from an asteroid. It is highly probable, according to the agency, that the asteroid explorer has snatched several grams of surface samples from the near Earth asteroid named after the “father” of Japan’s space program, Hideo Itokawa, but the exact volume will not be known until the spacecraft returns safely to Earth.

The spacecraft was on its own once it began to carry out the series of commands for Saturday’s touch-down, because signals take around 17 minutes to get from Earth to Hayabusa. The spacecraft’s autonomous navigation relies on the Optical Navigation Camera and Light Detection and Ranging (ONC/LD&R) instrument that measures the distance to and the shapes of the asteroid surface. Once the data from those and other instruments are fully analyzed, more specific details will be forthcoming.

Hayabusa which means “falcon” in Japanese — flew up and away from the asteroid after snatching its prey, and was subsequently “restored” by its ground team and instructed to return to its home orbit around 7 kilometers away from the asteroid. Japan, meanwhile, is soaring into space exploration history with a flight that has provided a stellar boost for the Japanese space program, and cause for major celebration in the homeland.

“This is a superb achievement, a great moment is space exploration,” said Planetary Society Executive Director Louis D. Friedman. “Automated surface sample return from another world has been done only from the Moon, and only by the Russians. This venture by the Japanese space agency is bold, and Hayabusa has been brilliantly executed mission.”

Hayabusa which was developed at the Institute of Space and Astronautical Science (ISAS), a space science research division of JAXA — launched from Japan’s Kagoshima Space Center on May 9, 2003 and arrived in September of this year despite being rocked on the way by several solar flares, and losing one of its three reaction wheels used to control the spacecraft’s orientation, point instruments, antennas, or subsystems at chosen targets.

Since then it has met with other misfortunes, including the loss of another reaction wheel and the loss of its tiny robot lander, Minerva, which it released at the wrong time. Still, from every mishap, Hayabusa has rebounded. “It’s the little spacecraft that could,” marveled Donald K. Yeomans, senior research scientist at the Jet Propulsion Laboratory (JPL) and the U.S. project scientist for the mission during an interview with The Planetary Society. “And the operations guys are working their tails off around the clock.”

The touch-down landing Saturday was Hayabusa’s second and final attempt to collect a sample from the small asteroid, which, according to the latest Japanese measurements is only 540 meters by 310 meters by 250 meters (about 1800 feet by 1000 feet by 820 feet), and is some 180 million miles from Earth. Although the spacecraft did bounce down twice and even settled on Itokawa’s surface for 30 minutes last weekend — marking a milestone as the first Japanese spacecraft to land on an extraterrestrial body — the sample collection device did not deploy, so that attempt to get a sample failed.

This time around, Hayabusa began its descent around 10:00 p.m., JST, Friday, November 25. By 7:15 a.m., the following morning, it was just 14 meters above Itokawa. At around 8:45 a.m., at least one tantulum pellet was fired through the cylinder in the sample collection device and into the surface at 300 meters per second and the ejecta from that cratering effect was captured and secured in the sample chamber.

The handful of dirt and dust that Hayabusa snatched Saturday may seem a small prize for all the effort, but the knowledge these samples hold about our solar system is by all accounts great. Asteroids preserve in their make-up the pristine materials that went into formation of the solar system, unlike the Moon or other larger planetary bodies that have undergone thermal alterations over the eons.

Hayabusa is “the next giant step forward” in understanding the role of near-Earth asteroids in the origin of the solar system, their potential threat to Earth, and the future use of their raw materials to expand human presence beyond Earth, according to Yeomans. “Near Earth asteroids are easier to land on than the Moon itself, some of them, and they’re far more rich in minerals,” he pointed out. “If you’re going to build structures in space, you’re not going to build them on the ground and launch them, you’re going to look for raw materials up there and asteroids provide some ready supplies of minerals, metals, and possibly water.”

Perhaps even more remarkable than Hayabusa’s achievements is the fact that the Japanese have pulled this mission off for a price tag of about $170-million-dollars [about one-third the cost of a NASA Discovery mission], and with a small mission operations team at the helm. “That is extraordinary,” said Yeomans.

Before the mission launched, Yeomans and others at JPL and NASA provided JAXA and ISAS division, with the ephemeris, a table that shows the coordinates of a celestial body at a number of specific times during a given period — essentially “directions” on how to get to the asteroid. NASA is tracking the spacecraft with the Deep Space Network (DSN) and the Americans there are providing some back-up navigation assistance. However, Hayabusa is not relying on NASA for navigation. In Yeomans’ words: “Since the spacecraft arrived at the asteroid it, has been Japan’s show.”

And what a show it’s been.

Original Source: NASA Astrobiology

Posted on by Fraser Cain

Shadows Cast By Venus

Venus at the beach on Nov. 19th. Image credit: Pete Lawrence. Click to enlarge
It’s often said (by astronomers) that Venus is bright enough to cast shadows.

So where are they?

Few people have ever seen a Venus shadow. But they’re there, elusive and delicate?and, if you appreciate rare things, a thrill to witness.

Attention, thrill-seekers: Venus is reaching its peak brightness for 2005 and casting its very best shadows right now.

Amateur astronomer Pete Lawrence of Selsey, UK, photographed the elusive shadow of Venus just two weeks ago. It was a quest that began in the 1960s:

“When I was a young boy,” recalls Lawrence, “I read a book written by Sir Patrick Moore in which he mentioned the fact that there were only three bodies in the sky capable of casting a shadow on Earth. The sun and moon are pretty obvious, but it was the third that fascinated me — Venus.”

Forty years passed.

Then, “quite by chance a couple of months ago,” he continues, “I found myself in Sir Patrick’s home. The conversation turned to things that had never been photographed. He told me that there were few, if any, decent photographs of a shadow caused by the light from Venus. So the challenge was set.”

On Nov. 18th, Lawrence took his own young boys, Richard (age 14) and Douglas (12), to a beach near their home. “There was no ambient lighting, no moon, no manmade lights, only Venus and the stars. It was the perfect venue to make my attempt.” On that night, and again two nights later, they photographed shadows of their camera’s tripod, shadows of patterns cut from cardboard, and shadows of the boy’s hands?all by the light of Venus.

The shadows were very delicate, “the slightest movement destroyed their distinct sharpness. It is difficult,” he adds, “for a cold human being to stand still long enough for the amount of time needed to catch the faint Venusian shadow.”

Difficult, yes, but worth the effort, he says. After all, how many people have seen themselves silhouetted by the light of another planet?

If you’d like to try, this is the week. Your attempt must come before Dec. 3rd. After that, the crescent moon will join Venus in the evening sky, and any shadows you see then will be moon shadows.

Instructions: Find a dark site (very dark) with clear skies and no manmade lights. Be there at sunset. You’ll see Venus glaring in the southern sky: diagram. When the sky fades to black, turn your back on Venus (otherwise it will spoil your night vision). Hold your hand in front of a white screen?e.g., a piece of paper, a portable white board, a white T-shirt stretched over a rock?and let the shadow materialize.

Can’t see it? Venus shadows are elusive. “Young eyes help,” notes Lawrence, whose teenage sons saw the shadows more easily than he did.

Shadows or not, before you go home, be sure to look at Venus directly through binoculars or a small telescope. Like the moon, Venus has phases, and this week it is a lovely crescent. Aside: If Venus is at peak brightness, shouldn’t it be full? No. Venus is full when it is on the opposite side of the sun, fully illuminated yet far from Earth. Venus is much brighter now, as a crescent, because Earth and Venus are on the same side of the sun. Venus is nearby, big and bright.

Look at Venus or look away from it. Either way, it’s a great view.

Original Source: NASA News Release

Posted on by Fraser Cain

A Supernova in Progress

X-ray image of supernova SN 1970G. Image credit: NASA. Click to enlarge
Chandra image in the inset shows X-rays from SN 1970G, a supernova that was observed to occur in the galaxy M101 35 years ago. The bright cloud in the box in the optical image is not related to the supernova, which is located immediately to the upper right (arrow) of the cloud.

Before a massive star explodes as a supernova, it loses gas in a stellar wind that can last tens to hundreds of thousands of years, and creates a circumstellar gas shell around the star. The explosion generates shock waves that rush through this gas and heat it to millions of degrees. The X-rays from SN 1970G are likely due to this process.

By studying the spectrum and intensity of the X-rays from a supernova in the years after the explosion, astronomers can deduce information about the behavior of the star before it exploded. The observations of SN 1970G indicate that the progenitor star created its circumstellar shell by losing about one sun’s worth of gas over a period of about 25,000 years before the explosion.

Astronomers estimate that in another 20 to 60 years the shock waves will have traversed the shell and encountered the interstellar medium. At this time SN 1970G will make the transition to the supernova remnant phase of its evolution.

Original Source: Chandra X-ray Observatory

Posted on by Mark Mortimer

Book Review: Why Explore?

This book shows humans’ natural curiosity, their need to find out what is beyond their limits. Its premise is that exploring is good because it often leads to many new discoveries. This book also shows that when people ask questions, or when you are asking questions yourself, in a way you are exploring. Asking questions is like looking at something and knowing that there is something else to it. Exploring further extends your knowledge. So the next time someone is curious about what you’re doing or they are asking you a million questions, remember they are “exploring” and addressing a natural curiosity.

Each page of this picture book depicts one person questioning another on why they explore. When travelling is involved, the one staying behind argues that everything is O.K. right here so why travel? Fear of the unknown and its dangers keeps them home bound. For the ones leaving, the excitement of going, the fun of experimenting and the opportunity for a fresh start are what give them the impetus. The resonance of the book is that for people, it is natural to crave answers and to explore.

Understanding one’s own body and emotions is one of the greatest undertakings of any human. Whether young or old, they are always learning about themselves. Children, with their knack for asking the obvious, can shed more insight than a hundred doctoral candidates. As well, in helping children understand themselves, we understand ourselves better. This is the viewpoint taken by Lendroth and Moreiro. They show there is no one answer to the question, ‘Why Explore?”. Simply, for some there are many more advantages than in not exploring. The bigger quandary, though unaddressed, is why we keep questioning, why do we continually expect more.

A young child, 5 or 6 years old, would likely really enjoy reading this book with a learned adult. The large format, with reproductions of oil paintings filling every page’s background, makes for a visual treat. The short, rhyming text adds a sense of wonder and pleasure to challenging words like sharecropping and electron scattering. As children tend to be more curious with less patience, the few words and vivid art work would most likely well entertain them.

Picture books can teach children to count or recognize the primary colours. But more demanding books are those that try to broach the subject of emotions. Exploring and curiosity are such emotions and Susan Lendroth and Enrique Moreiro in their book Why Explore? comfortably and clearly let an older person discuss this concept with a younger one. After all, many of us, for whatever reason are not satisfied with the options at hand and are darn sure things could be better.

Review by Mark, Ariana and Lorelei Mortimer

Read more reviews online, or purchase a copy from Amazon.com.

Posted on by Fraser Cain

What’s Up This Week – November 28 – December 4, 2005

M74. Image credit: R. Jay GaBany. Click to enlarge.
Monday, November 28 – Tonight let’s begin by identifying the marker star we will need to make our first galaxy hop – Eta Pisces. The stars of this constellation are rather dim, but try this simple trick: the southernmost star in the “Great Square of Pegasus” is Gamma. You will find Eta about a handspan due east. By centering on Eta, shift east-northeast less than one fingerwidth…

The large spiral galaxy M74 was first observed by Pierre Mechain in 1780. This vague, misty-appearing deep sky object is probably one of the most difficult Messier objects you will ever try to find, but when you do – don’t be disappointed. Even the great John Herschel had trouble correctly identifying it! Even at 11th magnitude, its low surface brightness will make it appear as nothing more than a round, diffuse glow in small scopes, but larger ones will find a condensation towards the nucleus and just a whisper of spiral structure with excellent seeing conditions. Best of luck!

Tuesday, November 29 – Tonight let’s start with Mira and hop about three fingerwidths northeast to Delta Ceti. About one degree to the southeast you will discover our next galaxy – M77.

At magnitude 10, this bright, compact spiral galaxy can even be spotted with larger binoculars as a faint glow and is unmistakable as a galaxy in smaller scopes. Its small bright nucleus shows well in mid-sized scopes, while larger ones will resolve out three distinctive spiral arms. But this “Seyfert” galaxy isn’t alone… If you are using a larger scope, be sure to look for 11th magnitude edge-on companion NGC 1055 about half a degree to the north-northeast, and fainter NGC 1087 and NGC 1090 about a degree to the east-southeast. All are part of a small group of galaxies associated with the 60 million light-year distant M77.

Wednesday, November 30 – Tonight let’s go north for a mid-size scope challenge about two fingerwidths east-northeast of the beautiful double star Gamma Andromeda.

The 12th magnitude NGC 891 is a perfect example of a spiral galaxy seen edge-on. To the mid-sized scope, it will appear as a pencil-slim scratch of light, but larger telescopes will be able to make out a fine, dark dust lane upon aversion. Discovered by Caroline Herschel in 1783, NGC 891 contained a magnitude 14 supernova event recorded on August 21, 1986. Often considered a “missed Messier,” you can add this one to your Caldwell list as number 23!

Thursday, December 1 – Born today in 1811 was Benjamin (Don Benito) Wilson. He was the namesake of Mt. Wilson, California.

Tonight is New Moon and time for big scopes to get serious. Return to NGC 891 and head another degree or so to the southeast to take on the Abell 347 Galaxy Cluster. Here you will find a grouping of at least a dozen galaxies that can be fitted into a wide field view. Let’s tour a few…

The brightest and largest is NGC 910 – a round elliptical with a concentrated nucleus. To the northwest you can catch faint, edge-on NGC 898. NGC 912 is northeast of NGC 910, and you’ll find it quite faint and very small. NGC 911 to the north is slightly brighter, rounder, and has a substantial core region. NGC 909 further north is fainter, yet similar in appearance. Fainter yet is more northern NGC 906 and shows as nothing more than a round contrast change. Northeast is NGC 914, which appears almost as a stellar point with a very small haze around it. To the southeast is NGC 923 which is just barely visible with wide aversion as a round contrast change. Enjoy this Abell quest!

Friday, December 2 – Today in 1934, the largest mirror in telescope history began its life when the blank for the 200-inch telescope was cast in Corning, New York. But, tonight you won’t need aperture that large as we seek out two more sky gems – one for the north and one for the south.

Located in western Perseus just slightly less than one degree north-northwest of Phi, M76 is often referred to as “The Little Dumbbell.” Originally discovered by Messier’s assistant M?chain in September of 1780, Charles didn’t get around to cataloging it for another six weeks. What a shame it took him so long to view this fine planetary nebula! Its central star is one of the hottest known, but its resemblance to M27 is what makes it so fascinating. Looking very much like a miniaturization of the much larger M27, M76 is rather faint at magnitude 11, but is quite achievable in scopes of 114mm in aperture or larger. It is small, but its irregular shape makes this planetary nebula a real treat.

For our Southern Hemisphere friends, get thee out there and view Eta Carinae! First recorded by Halley in 1677, this nebular variable star left even the great Sir John Herschel at a loss to describe its true beauty and complexity This “slow nova” is filled with all the wonders the we “northerners” can only dream about…

Saturday, December 3 – Today in 1971, Soviet Mars 3 became the first spacecraft to make a soft landing on the red planet, and two years later on this same date the Pioneer 10 mission became the first spacecraft to fly by Jupiter. One year later on this same date? Pioneer 11 did the same thing!

Although we can’t land on Mars, we can certainly make the journey with our eyes as the planet is now very well placed in the early evening hours for viewing. Be sure to look for the deep, dark triangle of Syrtis Major highlighted by Hellas Basin. Perhaps at your viewing time it might be the long expanse of Amazonis Planitia or the “fingers” of Mare Erythraeum. Even if you don’t use a telescope, just seeing Mars shining so brightly is worth the trip outside! And Jupiter?

You’ll find it just before dawn…

Sunday, December 4 – Today in 1978, the Pioneer Venus Orbiter became the first spacecraft to orbit Venus. Is Venus still around? You bet. Just have a look right after sunset… You’ll find both it and the tender crescent Moon very close together…

Now wait until the Moon sets and let’s take on one more galaxy quest before we return to lunar studies. What shall we chose? Let’s try a very large and elusive galaxy that can be spotted with binoculars, and even unaided, from a very dark observing site – M33.

The “Triangulum Galaxy” is very misty, vague and also a totally wonderful galaxy for study. Just west of Alpha Triangulum, this galaxy is about the size of the full Moon, but it is so diffuse it’s sometimes hard to locate. Cataloged by Charles Messier in August 1764, M33 is often known as the “Pinwheel.” because of its distinguishable arm structure. As a part of our local galaxy group, M33 (NGC 598) is quite prized by amateurs for its ability to resolve. It has a distinct concentration toward the nucleus area plus a northern and southern “arm” that are within a small telescope’s capabilities. Telescopes ranging from 12.5″ to 16″ and larger will find a wealth of NGC and IC objects hiding within this fantastic galaxy, allowing us to study star clusters and nebulae almost 750,000 light-years away. It’s out there tonight!

My many thanks go to Ken and to all of you nice folks who take the time to write! Wishing you all clear, dark skies and may all of your journeys be at light speed… ~Tammy Plotner

Posted on by Fraser Cain

SOHO Celebrates 10 Years

SOHO is celebrating ten years in space on 2nd December. Image credit: SOHO Click to enlarge
The world’s flagship solar probe, the Solar and Heliospheric Observatory (SOHO), is celebrating ten years in space on 2nd December. Scientists are gathering at CCLRC Rutherford Appleton Laboratory on the anniversary of the launch to celebrate the achievements of SOHO which has revolutionised our understanding of our star, the Sun, and its impacts on the Earth.

The 12 instruments on board SOHO probe the Sun’s every detail. One, the Coronal Diagnostic Spectrometer (CDS), is led from the UK, another was partly built in the UK, and UK scientists are involved in the operations and research of all instruments. SOHO’s instruments are monitoring the complex, violent solar atmosphere, the charged gases that the Sun expels into space and examining the solar interior.

“Never before have we had such a detailed view of a star. All life on Earth is dependent on the Sun’s energy, and when the Sun ejects clouds into space which engulf the Earth it can have severe consequences for satellite systems, navigation, communication and power distribution systems. We need to understand how the Sun works and how to predict how its activity impacts on the Earth”, said Professor Richard Harrison, from the CDS team.

“SOHO has provided us with a comprehensive, detailed examination of a star over an extended period, and has operated superbly during that time. The advances generated by this mission are incredible”, commented Professor Len Culhane of the UCL Mullard Space Science Laboratory.

The mission has revealed the true nature of the Sun’s violent atmosphere as it flings clouds into space and as huge magnetic loops tie themselves in knots to generate solar flare explosions. Scientists have discovered that the solar atmosphere is riddled with Earth-sized explosions and occasional tornadoes and the mission has also revealed how the interior of the Sun rotates. SOHO has even discovered over 1000 comets as they pass close to the Sun – a world record. Sophisticated observations have allowed scientists to monitor the far-side of the Sun and instruments have enabled weather maps of the Sun’s atmosphere – probing temperatures, densities, solar wind speeds and even what the Sun is made of, from a distance of 150 million km.

Professor Keith Mason, Chief Executive Officer of the Particle Physics and Astronomy Research Council, the main funder of the UK involvement in the mission, said “SOHO continues to be a stunning success and over its extended lifetime has provided the scientific community and the public with a wealth of data about the Sun. Its success is testimony to the expertise of the scientists and industrialists, in the US and Europe, including the UK, that have worked on its design and operation.”

Original Source: PPARC News Release

Posted on by Fraser Cain

Upcoming Solutions for Near Earth Objects

Artist’s impression of ESA’s Hildalgo spacecraft. Image credit: ESA.Click to enlarge
Telescope facilities across the world are watching the skies for rocky remnants from outer space on a collision course with planet Earth. Currently one or two of these so called ‘Near Earth Objects’ [NEOs] are being recorded each day but fortunately for humankind the vast majority are the size of a human fist and pose no threat. Nevertheless, the presence of large impact craters on Earth provides dramatic evidence of past collisions, some of which have been catastrophic for the planet’s species, as was the case with the dinosaurs. This week, experts from across Europe and the US met in London to consider current and future efforts to monitor NEOs in order to better predict those with Earth impacting trajectories, since it is inevitable that a catastrophic collision will happen again in the future.

Professor Monica Grady, a leading expert on meteorites from the Open University explains, “It’s simply a question of when, not if, a NEO collides with the Earth. Many of the smaller objects break up when they reach Earth’s atmosphere and have no impact. However, a NEO larger than 1 km will collide with Earth every few hundred thousand years and an NEO larger than 6 km, which could cause a mass extinction, will collide with Earth every hundred million years. And we are overdue for a big one!”

NEO’s, remnants from the formation of the inner planets, range in size from 10 metre objects to those in excess of 1 km. It is estimated that 100 fist sized meteorites, fragments of NEO’s, fall to Earth on a daily basis but larger objects impact with Earth on a much less regular basis.

Professor Alan Fitzsimmons from Queens University Belfast is a UK astronomer (supported by the Particle Physics and Astronomy Research Council) involved in the study of NEO’s, using telescope facilities such as the European Southern Observatory’s Very Large telescope in Chile, the Isaac Newton Telescope in La Palma and the Faulkes Telescope in Hawaii. He said, “By the end of the decade as new dedicated facilities, such as the Pan-STARR project in Hawaii, come on line there will be a quantum leap in the discovery of NEO’s – with rates anticipated to increase to hundreds per day. This will provide us with a greater ability to determine which ones are on a potential Earth colliding trajectory.”

Studies of one such asteroid (Apophis), which was discovered in June2004, have shown that there is a low probability that this object will impact the Earth in 2036. This has raised a whole series of issues about the prospect of deflecting the asteroid before a very close approach in 2029. Government’s across the world are looking at the issue and in particular at the technologies and methods required to carry out an asteroid deflection manoeuvre in space.

The European Space Agency’s NEO Mission Advisory Panel (NEOMAP), of which Professor Fitzsimmons is a member, has selected “Don Quixote” as their preferred option for an asteroid deflecting test mission. Don Quixote would comprise two spacecraft – one of them (Hildalgo) would impact the asteroid at a very high relative speed while the second spacecraft (Sancho) would arrive earlier to monitor the effect of the impact to measure the variation of the asteroid’s orbital parameters. This attempt to deflect an incoming NEO would act as a precursor mission with the primary objective of modifying the trajectory of a “non-threatening” asteroid.

Richard Tremayne-Smith, from the British National Space Centre, heads up the coordination of UK NEO activity and helps provide an international lead on NEO efforts on the issue. He said, “NEO collisions are the only known natural disaster that can be avoided by applying appropriate technology – and so it is the interest of Governments across the World to take interest in this global issue. Here in the UK we take the matter very seriously and progress is being made in taking forward the recommendations of the UK NEO Task Force Report in an international arena.”

The current method of studying NEOs is achieved through a combination of 3 different methods:- the study of meteorites to understand their structure and composition; earth based astronomical observations of asteroids; and space based observations and encounters with asteroids.

Much can be understood about the nature of asteroids from the study of meteorites which are fragments of asteroids that have broken up and fallen to Earth. Professor Grady explains how the ground based study of meteorites is crucial to future plans for dealing with asteroids.

“In order to define successful strategies for deflecting asteroids that might collide with Earth, it is essential to understand the material properties such as the composition, strength and porosity of asteroids. By putting together such information with data from both ground based and space based studies we can begin to build an accurate picture of these diverse phenomena.”

UK scientists are involved in a number of other missions which will also be investigating the properties of asteroids and comets. This includes NASA’s Stardust mission which collected samples from Comet Wild 2 in January 2004. These samples are set to return to Earth in January 2006 and scientists from the Open University will be involved in their analysis. The European Space Agency’s Rosetta mission which is currently on route to Comet Churyumov-Gerasimenko will pass by two asteroids, Steins and Lutetia, before reaching its target in 2014, gathering data about their properties as it flies past.

Original Source: PPARC News Release