Posted on by Fraser Cain

Where Does Intelligent Life Come From?

Image credit: Woods Hole Oceanographic
A lot of things had to go well for life to come about. If you go way back, it all begins with a Big Bang universe giving birth to space and time. In that early universe light echoed about, slowed in vibrancy, the primordial elements coalesced then condensed into a first generation of massive breeder stars. After warming to the notion (by gravitational compression), primordial matter began fusing in stellar cores and a lesser form of light moved outward to warm and illuminate a young and potentially ever-expanding Universe.

More time and more space saw many of those early blue stars implode (after living very short lives). Subsequent explosions spewed vast quantities of heavier – non-primordial – atoms into space. Out of this rich cosmic endowment new stars formed – many with planetary attendants. Because such second and third generation suns are less massive than their progenitors, they burn slower, cooler, and much, much longer – something essential to the kind of benignly consistent energy levels needed to make organic life possible.

Although breeder stars formed within a few hundred million years of the Big Bang, life here on Earth took its time. Our Sun – a third generation star of modest mass – formed some nine-billion years later. Life-forms developed a little more than one billion years after that. As this occurred, molecules combined to form organic compounds which – under suitable conditions – joined together as amino acids, proteins, and cells. During all this one layer of complexity was added to another and creatures became ever more perceptive of the world around them. Eventually – after more billions of years – vision developed. And vision – added to an subjective sense of awareness – made it possible for the Universe to look back at itself.

Empirical research into the fundamentals of life shows that a concoction of well-chosen elements (hydrogen, carbon, oxygen, & nitrogen) exposed to non-ionizing ultraviolet radiation forms amino acids. Amino acids themselves have a remarkable capacity to chain together into proteins. And proteins have a rather “protean” ability to give shape and behavior to cells. It is now considered entirely possible that the very first amino acids took form in space1 – shielded from harder forms of radiation within vast clouds comprised of primordial and star-stuff material. For this reason, life may be an ubiquitous phenomenon simply awaiting only certain favorable conditions to take root and grow into a wide variety of forms.

Currently, exobiologists believe that liquid water is essential to the formation and multiplication of organic life. Water is an extraordinary substance. As a mild solvent, water enables other molecules to dissociate and mix. Meanwhile it is very stable and is transparent to visible light – something useful if biotics are to derive energy directly from sunlight. Finally water holds temperature well, carries off excess heat through vaporization, and floats when cooled to solidify as ice.

According to NASA exobiologist Andrew Pohorille, “Water brings organic molecules together and permits organization into structures that ultimately became cells.” In so doing, water acts in an unparalleled matrix enabling organic molecules to form self-organizing structures. Andrew cites one property uniquely associated with water that makes self-organization and growth possible: “The hydrophobic effect is responsible for the fact that water and oil don’t mix, soaps and detergents ‘capture’ oily dirt during washing in water and for a vast number of other phenomena. More generally, hydrophobic effect is responsible for segregating nonpolar (oily) molecules or parts of molecules from water, so they can stick together even though they are not bonded. In biology these are precisely the interactions responsible for the formation of membranous cell walls and for folding proteins into functional structures.”

For water to take the liquid state, it must remain in a relatively narrow range of temperatures and pressures. Because of this only a certain few well-placed planets – and possibly a handful of large moons are favored with the conditions needed to let life live. In many cases it all comes down to a form of celestial real estate – location, location, location…

Early life on Earth was very simple in form and behavior. Though cellular, they lacked a central nucleus (prokaryotic) and other sub-structures (organelles). Lacking a nucleus such cells reproduced asexually. These anaerobes subsisted primarily by creating (anabolizing) methane gas from hydrogen and carbon-dioxide. They liked heat – and there was plenty of it to go around!

The fact that life developed on Earth should not be as surprising as one might think. Life is now considered far more robust than once imagined. Even now hydrothermal vents deep in the ocean eject near-boiling water. Adjacent to such vents life – in the form of giant tube worms and clams – flourishes. Deep under the surface of the Earth mineral-metabolizing anaerobic bacteria are found. Such conditions were thought impossible throughout most of the 20th century. Life seems to spring up under even the harshest of conditions.

As life forms advanced on our world, cells developed organelles – some by incorporating lesser, more specialized cells into their structures. The planet cooled, its atmosphere clarified and sunlight played upon the oceans. Primitive bacteria arose that fixed energy from sunlight as food. Some remained prokaryotic while others developed a nucleus (eukaryotic). These primitive bacteria increased the oxygen content of the Earth’s atmosphere. All this transpired some 2 billion years ago and was essential to support the quality and quantity of life currently populating “the Blue Planet”.

Originally the atmosphere consisted of less than 1% oxygen – but as levels increased, bacteria-eating life-forms adapted to synthesize water from oxygen and hydrogen. This released far more energy than methane metabolism is capable of. The controlled synthesis of water was a huge accomplishment for life. Consider the high school chemistry lab experiments where hydrogen and oxygen gas are combined, heated then explode. Primitive life forms had to learn to handle this very volatile stuff in a far safer manner – putting phosphorus to task in the conversion of ADP to ATP and back again.

Later – roughly 1 billion years ago – the simplest multi-cellular creatures took form. This occurred as cells came together for the common good. But such creatures were simple colonies. Each cell was fully self-contained and took care of its own needs. All they required was constant exposure to the warm broth of the early oceans to acquire nutrients and eliminate wastes.

The next great step in the evolution of life2
came as specialized cell tissue types developed. Muscle, nerve, epidermis and cartilage advanced the development of the many complex life-forms now populating our planet – from flowering plant to budding young astronomer! But that very first organized creature may very well have been a worm (annelid) burrowing through the marine slime of some 700 million years ago. Lacking eyes and a central nervous system it possessed only the capacity to touch and to taste. But now life had the capacity to differentiate and specialize. The creature itself became the ocean…

With the advent of well-organized creatures the pace of life quickened:

By 500 MYA, the first vertebrates evolved. These were probably eel-like creatures lacking in sight but sensitive to chemical – and possibly electrical – changes in their environments.

By 450 MYA, the first animals (insects) joined rooting plants on land.

Some 400 MYA the first vertebrates climbed out of the sea. This may have been an amphibious fish subsisting on insects and plant-life along the shore.

By 350 MYA – the first “iguana-like” reptiles emerged. These possessed strong, hard, jaws in a one-piece skull. As they grew larger, such reptiles lightened their skulls by adding orifices (beyond simple eye sockets). Before dinosaurs dominated the earth, crocodiles, turtles, and pterasaurs (flying reptiles) preceded them.

Primitive mammals go back almost 220MY. Most of these creatures were small and rodent-like. Later versions developed the placenta – but earlier species simply hatched eggs internally. All mammals of course, are warm-blooded and because of this must eat voraciously to maintain body temperature – especially on cold windy nights tracking down faint galaxies along the Eridanus river…

Like mammals, warm-blooded birds require more food than reptiles – but like reptiles – laid eggs. Not a bad idea for a creature of flight! Today celestial birds fly (such as late summer’s Cygnus the Swan and Aquila the Eagle) because real birds took wing some 150 MYA.

The earliest primates existed even during the time of the extinction of the dinosaurs Strong evidence supports the idea that the dinosaurs themselves passed as a group after an asteroid – or comet – impacted the Yucatan peninsula of the United States of Mexico. After this catastrophic event temperatures fell as a “non-nuclear” winter descended. Under such conditions food was spare, but warm-bloodedness came into its own. It wasn?t long however before one type of a “gigantism” soon replaced another – mammals themselves grew to extraordinary sizes and the largest developed in the womb of the sea and now take the form of the great whales.

The end of the “terrible lizards” was not the first mass-extinction of life – four previous die-offs had preceded it. Today, aware of the potential for other such cataclysmic impacts, some of the world’s astronomers keep an eye on near-earth orbiting chunks of debris left over from the formation of the solar system. The smallest types – meteors for instance – put on harmless celestial light shows. Larger meteors (bolides) occasionally spread “flame” and trail “smoke” as they crash to Earth. Larger bodies have left wakes of natural devastation across miles of forests – without even leaving a trace of their own “party crashing” material behind. But larger intruders have little such modesty. An asteroid or comet one kilometer in diameter would spell absolute calamity for a population center. Bodies ten times that size may account for massive die-offs of the type that spelled the end of the dinosauria.

Human beings first walked upright some 6MYA. This probably occurred as the path diverged between proto-chimpanzees and early hominids. That divergence followed a ten million year period of rapid primate evolution and blended into a six-million year cycle of human evolution. The first stone tools were crafted by human hand roughly 2 million years ago. Fire was harnessed by some enterprising member of the human species a million years later. Technology gained momentum very slowly – hundreds of thousands of years have passed without any significant improvement in the tools used by the tribal societies of long past.

Modern humans originated more than 200,000 years ago. Some 125 thousand years later an event occurred that may have reduced the entire human population of planet Earth to less than 10,000 individuals. That event was not extra-terrestrial in nature – the Earth itself probably belched forth “fire and brimstone” during the eruption of a gas-charged magma chamber (similar to that beneath Yellowstone National Park in the western USA). Another 65,000 years passed and the stone age gave way to the age of agriculture. By 5000 years ago the first city-states coalesced within fertile valleys surrounded by far less hospitable climes. Whole civilizations have come and gone. Each passing a torch of culture and slowly evolving technology to the next. Today it has been only a few short centuries since the first human hand shaped lenses of glass and turned the human eye upon the things of the Night Sky.

Today huge mirrors and space probes allow us to contemplate the vast reaches of the universe. We see a Cosmos dynamic and quite possibly thrilling with life more abundant than anyone could possibly imagine. Like light and matter, life may very well be a fundamental quality of the space-time continuum. Life could be as universal as gravitation – and as personal as an evening alone with a telescope beneath the night sky…

1 In fact, the radio-frequency spectrographic fingerprint of at least one amino acid (glycine) has been found in vast clouds of dust and gas within the interstellar medium (ISM). (See Amino acid found in deep space).

2 That life develops from less sophisticated to more sophisticated forms is a question beyond scientific dispute. Precisely how this process takes place is an issue of deep division in human society. Astronomers – unlike biologists – are not required to hold any particular theory on this issue. Whether chance mutation and natural selection drives the process or some unseen “hand” exists to bring such things about is outside the realm of astronomical inquiry. Astronomers are interested in structures, conditions, and processes in the universe at large. As life becomes more salient to that discussion, astronomy – in particular exobiology – will have more to say about the matter. But the very fact that astronomers can allow nature to speak on such issues as a sudden and instantaneous “creation ex nihilo” in the form of a Big Bang shows just how flexible astronomical thinking is in regard to ultimate origins.

Acknowledgment: My thanks goes out to exobiologist

Andrew Pohorille of NASA who enlightened me as to the great significance of the hydrophobic effect on the formation of self-organizing structures. For more information on exobiology please see NASA’s Exobiology Life Through Space and Time official website through which I had the good fortune of contacting Andrew.

About The Author:
Inspired by the early 1900’s masterpiece: “The Sky Through Three, Four, and Five Inch Telescopes”, Jeff Barbour got a start in astronomy and space science at the age of seven. Currently Jeff devotes much of his time observing the heavens and maintaining the website
Astro.Geekjoy.

Posted on by Fraser Cain

Jupiter Reflects the Sun’s X-Rays

Astronomers using the European Space Agency’s XMM-Newton telescope have discovered that observing the giant planet Jupiter may actually give them an insight in to solar activity on the far side of the Sun! In research reported in the most recent edition of Geophysical Research Letters, they discovered that Jupiter’s x-ray glow is due to x-rays from the Sun being reflected back off the planet’s atmosphere.

Jupiter is an intriguing object when viewed in x-rays; it has dramatic x-ray auroras at the poles and a variable x-ray glow from near the equator. Researchers had theorised that these x-rays from the equatorial regions of Jupiter, called disk x-rays, were controlled by the Sun. In November 2003, during a period of high solar activity, they observed Jupiter.

“We found that Jupiter’s day-to-day disk x-rays were synchronised with the Sun’s emissions,” says Dr Anil Bhardwaj, from NASA Marshall Space Flight Centre and lead author on the paper. “Unfortunately, we missed a relatively large solar flare during the 3.5-days observation due to the perigee passage of the XMM-Newton”. “But, still we were lucky; particularly clear was a signature of a moderate solar flare that went off during the observing period – there was a corresponding brightening of the Jovian disk x-rays”, says Anil Bhardwaj.

In addition to supporting the researchers’ theory, this result has another application – in studying the Sun. The Sun is a very dynamic environment and processes there have an impact on human activities. For example, solar flares (the most powerful explosions in the solar system) can damage satellites or injure astronauts in space, and on Earth they can disrupt radio signals in the atmosphere, so it is important to understand as much as we can about them.

There are several dedicated spacecraft watching the Sun (such as the European Space Agency’s SOHO satellite), as well as ground-based telescopes, but there are gaps in coverage as some areas of the Sun are not visible by any of these means at some times.

“As Jupiter orbits the Sun, we hope to be able to learn more about the active areas of the Sun we can’t see from Earth by watching the Jovian x-ray emissions,” says Dr Graziella Branduardi-Raymont from the University College London’s Mullard Space Science Laboratory. “If a large solar flare occurs on an area of the Sun that is facing Jupiter, we may be able to observe it in light scattered from Jupiter, even if we cannot see that region of the Sun from around the Earth at the time.”

Jupiter’s atmosphere is not a perfect mirror of the Sunlight in X-rays – typically one in a few thousand x-ray photons (packets of light) is reflected back, but the more energetic the photons, the more are reflected into space.

UK participation in this research and the UK subscription to the European Space Agency are funded by the Particle Physics and Astronomy Research Council (PPARC).

Original Source: PPARC News Release

Posted on by Fraser Cain

Saturn’s Twisting Rings

Intriguing features resembling drapes and kinks are visible in this Cassini view of Saturn’s thin F ring. Several distinct ringlets are present, in addition to the bright, knotted core of the ring.

The obvious structure in the ring and its strands has been caused by Prometheus, the inner F ring shepherd moon that recently swept past this region. (Prometheus is about 10 degrees ahead of the F ring material in this image). These types of features were first seen in images taken just after Cassini entered into orbit around Saturn. The gravitational interaction of Prometheus (102 kilometers, or 63 miles across) on the ring pulls material out the ring once every orbit (every 14.7 hours) as the moon gets close to the ring and its strands.

The image was taken with the Cassini spacecraft narrow-angle camera on Jan. 19, 2005, at a distance of approximately 1.9 million kilometers (1.2 million miles) from Saturn through a filter sensitive to polarized visible light. Resolution in the original image was 11 kilometers (7 miles) per pixel. The image was contrast-enhanced and magnified by a factor of two to aid visibility.

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 . For additional images visit the Cassini imaging team homepage http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Posted on by Fraser Cain

Region Around a Black Hole is Surprisingly Turbulent

Image credit: JHU
For more than 30 years, astrophysicists have believed that black holes can swallow nearby matter and release a tremendous amount of energy as a result. Until recently, however, the mechanisms that bring matter close to black holes have been poorly understood, leaving researchers puzzled about many of the details of the process.

Now, however, computer simulations of black holes developed by researchers, including two at The Johns Hopkins University, are answering some of those questions and challenging many commonly held assumptions about the nature of this enigmatic phenomenon.

“Only recently have members of the research team ? John Hawley and Jean-Pierre De Villiers, both of the University of Virginia ? created a computer program powerful enough to track all the elements of accretion onto black holes, from turbulence and magnetic fields to relativistic gravity,” said Julian Krolik, a professor in the Henry A. Rowland Department of Physics and Astronomy at Johns Hopkins, and co-leader of the research team. “These programs are opening a new window on the complicated story of how matter falls into black holes, revealing for the first time how tangled magnetic fields and Einsteinian gravity combine to squeeze out a last burst of energy from matter doomed to infinite imprisonment in a black hole.”

Close to the black hole’s outer edge, where the Newtonian description of gravity breaks down, ordinary orbits are no longer possible. At that point ? or so it has been imagined for the past three decades ? matter plunges quickly, smoothly and quietly into the black hole. In the end, according to the prevailing picture, the black hole ? except for exerting its gravitational pull ? is a passive recipient of mass donations.

The team’s first realistic calculations of matter falling into black holes has strongly contradicted many of these expectations. They show, for instance, that life in the vicinity of a black hole is anything but calm and quiet. Instead, the relativistic effects that force matter to plunge inward magnify random motions within the fluid to create violent disturbances in density, velocity and magnetic field strength, driving waves of matter and magnetic field to and fro. This violence can have observable consequences, according to research team co- leader Hawley.

“Just like any fluid that has been stirred into turbulence, matter immediately outside the edge of the black hole is heated. This extra heat makes additional light that astronomers on Earth can see,” said Hawley. “One of the hallmarks of black holes is that their light output varies.

Although this has been known for more than 30 years, it has not been possible to study the origins of these variations until now. The violent variations in heating ? now seen to be a natural byproduct of magnetic forces near the black hole ? offer a natural explanation for black holes’ ever-changing brightness.”

One of the most striking properties of a black hole is its ability to expel jets at close to the speed of light. While it has long been expected that magnetic fields are crucial to this process, the latest simulations show for the first time how a field can be expelled from the accreting gas to create such a jet.

Perhaps the most surprising result of the team’s new computer simulations is that the magnetic fields brought near a rotating black hole also couple the hole’s spin to matter orbiting farther out, in the same way that a car’s transmission connects its rotating motor to the axle. Says Krolik, “If a black hole is born spinning extremely rapidly, its ‘drive train’ can be so powerful that its capture of additional mass causes its rotation to slow down. Accretion of mass would then act as a ‘governor,’ enforcing a cosmic speed limit on black hole spins.”

According to Krolik, that “governor” may have strong implications for many of the most striking properties of black holes. It is widely thought, for example, that the strength of a black hole’s jet is related to its spin, so a “spin speed limit” might determine a characteristic strength for the jets, Krolik said.

Funded by the National Science Foundation, this research is being published in a series of four papers in The Astrophysical Journal. ((De Villiers et al 2003, ApJ 599, 1238; Hirose et al. 2004, ApJ 606, 1083; De Villiers et al. ApJ 620, 879; Krolik et al. April 2005 ApJ in press.)) The simulations were performed at the NSF-supported San Diego Supercomputer Center. The research team also included Shigenobu Hirose, also of Johns Hopkins.

Original Source: JHU News Release

Posted on by Fraser Cain

What’s Up This Week – Mar 7 – 13, 2005

Monday, March 7– As we open our week long tour of the “Messier Marathon”, the late rise of the Moon tonight will be on the side of North American observers.

Beginning as soon as the sky darkens enough to find the guidestar Delta Cetus, the M77 spiral galaxy will be your first and the M74 spiral galaxy east of Eta Pisces will be your second mark. Both of these galaxies are telescopic only and will be an extreme challenge at this time of year due to their low position. Even computer-assisted scopes will have some difficulty revealing this pair under less than optimal conditions. Next up is M33 west of Alpha Triangulum. With ideal skies, the “Pinwheel Galaxy” could be seen in binoculars, but skybright will make this huge, low surface brightness spiral difficult for even telescopes at low power. The M31, “Andromeda Galaxy” will, however, be a delightful capture for both binoculars and scopes just west of Nu Andromedae. For the telescope, two more on the list are companions to the M31 – the elliptical M32 on the southeastern edge and M110 to the northwest.

Let’s head Northwest as we take on two open clusters visible to both telescopes and binoculars. You can find the M52 easiest by identifying Alpha and Beta Cassiopeia, drawing a mental line between them and extending it the same distance northwest of Beta. Next just hop north of Delta to pick up our ninth object – the M103 open cluster. Time to head south towards Perseus and go back to the telescope to locate the M76, “Little Dumbbell”, planetary nebula just north of Phi. Binoculars are all that’s needed to see the M34 open cluster also in Perseus, located roughly halfway between the “Demon Star” Algol and lovely double Almach, Gamma Andromeda.

Now that skies are dark and the fastest setting objects are out of the way, we can take a moment to breathe as we view the M45 – the Pleiades. The “Seven Sisters” are easily visible to the unaided eye high in the west and their cool, blue beauty is incomparable in binoculars or telescopes. Our next “hop” is with the “rabbit” Lepus as we go back to the south and identify Beta and Epsilon. Triangulating with this pair to the south is a nearly fifth magnitude star (ADS3954) which will help you locate small globular, M79 to its northeast. At around magnitude 8.5, it is possible to see its very tiny form in binoculars, but the M42 – “Great Orion Nebula” is much easier. The next object, M43, is part of the Orion Nebula, and you will catch it as a small “patch” to the north/northeast. The next two objects, the M78 northeast of Zeta Orionis and the M1 “Crab Nebula” northwest of Zeta Taurii, are both achievable in binoculars with excellent conditions, but are far more interesting to the telescope.

Now we can really relax. Take a few minutes and grab a cup of coffee or hot chocolate and get warmed up. The remaining objects on our observing list for tonight are all very easy, very well positioned for early evening, and all observable in just binoculars. Are you ready? Then let’s go.

The M35 is just as simple as finding the “toe” of Gemini – bright Eta. A short hop to the northwest will capture this fine open cluster. The next stop is Auriga and we’ll go directly between silicon star Theta and southern Beta. About halfway between them and slightly to the east you will find open cluster M37. This time let’s use Theta and Iota to its west. Roughly halfway between them and in the center of Auriga you will find the M38 and a short hop southeast will capture the M36. Now let’s get Sirius and finish this list for tonight. The open cluster M41 in Canis Major is just as quick as drifting south of the brightest star in the sky. The last three for tonight couldn’t be any easier – because we just studied them last week. Go capture the M93, M47 and M46 in Puppis… And give yourself a well-deserved pat on the back.

You’ve just conquered 24 Messiers.

Tuesday, March 8 – Ready for tonight’s challenge? Then nap away the very early evening hours and let’s head out well before bedtime to work on the next section of our week-long “marathon”.

First up will be four binocular targets, the incredibly colorful open cluster M50 is roughly a third of the way in a line drawn between Sirius and Procyon – use binoculars. Hydra is a difficult constellation, but try dropping south/southeast of the most eastern star in Monoceros – Zeta – about half a fist’s width to discover relatively dim open cluster M48. Far brighter and usually unaided eye is the M44, better known as the “Beehive Cluster”, just a scant few degrees north/northwest of Delta Cancri. From Delta, go south and identify Alpha because the M67 is just to its west. It will appear as a “fine haze” to binoculars, but telescopes will find a spectacular “cloud” of similar magnitude resolvable stars.

Now we really do have to use the telescopes again because we’re going “lion taming” by hunting galaxies in Leo. Let’s trade one Alpha for another as we head west to Regulus. Roughly about a fist width east of this major star you will see two dim stars that may require the use of the finderscope – 52 to the north and 53 to the south. We’re heading right between them. About a degree and a half south of 52, you will discover ninth magnitude elliptical M105. Larger scopes will also show two additional faint galaxies, NGC 3384 and NGC 3389 to M105’s west. Continuing about a degree south towards star 53 you will spot the silver-gray beauty of M96 in a relatively starless field. Enjoy its bright nucleus and wispy arms. About another degree west will bring you to the M95, which is neither as bright nor as large as its Messier “neighbor”. Small scopes should show a brightening towards its center and large ones should begin to resolve out the arms of this awesome barred spiral. Our next destination is the southwestern star of the three that mark Leo’s “hips”, Theta Leonis – or more commonly called Chort. South of it you will see faint star 73 and right around one degree to its east/southeast you will locate a pair. In small scopes at low power, the M65 and M66 are same field. The western M65 and eastern M66 are both beautiful spirals.

Now let’s head north for another “same field pair” of galaxies and hunt down the M81 and M82 in Ursa Major. Many folks have trouble “star hopping” to these galaxies, but a very simple way of finding them is to draw a mental line between Phecda (Gamma) and Dubhe (Alpha). By extending that line beyond Dubhe almost the same distance, you’ll locate our next two “marathon” objects. At low power with a smaller scope, the southern-most and most pronounced of the two is the stunning M81 with its bright core. To the north is broken, spindle-shaped peculiar galaxy M82. Viewable in binoculars, we’ll study more about this pair later on as we head for Mirak (Beta) and our next galaxy. About a degree and a half southeast you will see a 10th magnitude “scratch” of light. This great edge-on galaxy – M108 – should show at least four brighter “patches” to the small scope and a nice dark dust-lane to larger ones. Continuing about another half degree southeast will bring you to planetary nebula, M97. Also known as the “Owl”, this 12th magnitude beauty is roughly the same diameter as Jupiter and can be spotted under optimal conditions with binoculars – but requires a large scope at high power to begin to discern its features. Let’s continue south to Phecda and less than half a degree to the east you will locate M109. In the field with Gamma, the M109 will show its faded central bar and prominent nucleus to the small scope, but requires large aperture and high magnification to make out structure. The last in Ursa Major is an error on Messier’s part. Labeled as the M40, this object is actually double star WNC4 located in the same eyepiece field as 70 Ursa Major to the northeast.

Now let’s move into Canes Venatici and round up a few more. This is an area of dimmer stars, but the two major stars, Alpha (it is called Cor Caroli and it is a wonderful double star) and Beta are easily recognizable to the east of the last star in the “handle” of the “Big Dipper” (Eta). The northernmost is Beta and you will find the soft-spoken spiral galaxy – M106 – almost directly midway between it and Phecda less than 2 degrees south of star 3. The M94 is a much brighter, compact galaxy and is found by forming an isosceles triangle with Alpha and Beta Canum with the imaginary apex towards Eta Ursae Majoris. The M63 is a very pretty, bright galaxy (often known as “the Sunflower”) that approaches magnitude 10 and is found about one-third the distance between Cor Caroli and Eta Ursae Majoris (Alkaid). Still heading towards Alkaid (Eta UM), the incomparable M51 comes next. Near Eta you will see an unmistakable visual star called 24 CnV, the “Whirlpool” is the same basic distance to the southwest. Now that we’re back into “big bear country” again, we might as well head on to the M101 “Pinwheel” galaxy which is found by following the same trajectory and distance to the other side of Alkaid. Before we head on, let’s continue north and clean up… ummm… another “messy mistake”. The accepted designation for the M102 is lenticular galaxy NGC 5866, located in Draco south east of Iota.

Now let’s finish up – it’s getting late. Our next stop will be to identify the three primary stars of Coma Berenices now high in the east above Arcturus. You will find small globular cluster M53 northeast of Alpha. One of the coolest galaxies around is the M64 (known as the “Blackeye”) just a degree east/northeast of 35 Comae, which is about one third the distance between Alpha Comae and Alkaid. The last, and most outstanding for the night, is a globular cluster that can be seen in binoculars – M3. As strange as this may sound, you can find M3 easily by drawing a line between Cor Caroli and Arcturus. Starting at Arcturus, move up about one third the way until you see Beta Comae to the west of your “line”… Poof. There it is.

Awesome job. We’ve just completed another 24 objects and we’ve claimed 48 on the Messier list before bedtime in two days.

Wednesday, March 9 – We have one more day until New Moon, but the challenge will not be so much avoiding Luna, nor the visibility of the next objects – but the “window of opportunity” in which we’ll be able to see them. Am I going to ask you to stay up past your bedtime? Darn right…

These next targets will be best viewed after midnight when the constellations of Coma Berenices and Virgo have well risen, providing us with the darkest sky and best position. For the large telescope, we are going to be walking into an incredibly rich galaxy field that we will touch on only briefly because they will become the object of future studies. Just keep in mind that our Messier objects are by far the brightest of the many you will see in the field. For the smaller scope? Don’t despair. These are quite easy enough for you to see as well and probably far less confusing because there won’t be so many of them visible. Now let’s identify the easternmost star in Leo – Denebola – and head about a fist width due East…

Our first will be the M98, just west of star 6 Comae. It will be a nice edge-on spiral galaxy in Coma Berenices. Next return to 6 Comae and go one degree southeast to capture the M99, a face-on spiral known as the “Pinwheel” that can be seen in apertures as small as 4″. Return to 6 Comae and head two degrees northeast. You will pass two fifth magnitude stars that point the way to the M100 – the largest appearing galaxy in the Coma/Virgo cluster. To the average scope, it will look like a dim globular cluster with a stellar nucleus. Now let’s continue on two degrees north where you will see bright yellow 11 Comae. One degree northeast is all it takes to catch the ninth magnitude, round M85. (ignore that barred spiral. let’s keep moving…) Now, let’s try a “trick of the trade” to locate two more. Going back to 6 Comae, relocate the M99 and turn off your drive. If you are accurately aligned to the equator, you may now take a break for 14 minutes. When you return the elongated form and near stellar nucleus of the M88 has now “drifted” into view. Wait another two to three minutes and the faint barred spiral, M91 will have joined the show in a one degree field of view.. (pretty fun, huh? 😉

Now let’s shift guidestars by locating bright Vindemiatrix (Epsilon Virginis) almost due east of Denebola. Let’s hop four and a half degrees west and a shade north of Epsilon to locate one of the largest elliptical galaxies presently known – the M60. At a little brighter than magnitude 9, this galaxy could be spotted with binoculars. In the same telescopic low power field you will also note faint NGC 4647 which only appears to be interacting with M60. Also in the field is our next Messier, bright cored elliptical M59 to the west. (yes. there’s more – but not tonight.) Moving a degree west of this group will bring you to our “galactic twin”, fainter M58. Moving about a degree north will call up face-on spiral M89, which will show a nice core region in most scopes. One half degree northeast is where you will find the delightful 9.5 magnitude M90 – whose dark dust lanes will show to larger scopes. Continue on one and a half degrees southwest for the M87, one of the first radio sources discovered. This particular galaxy has shown evidence of containing a black hole and its elliptical form is surrounded by more than 4,000 globular clusters.

Just slightly more than a degree northwest is a same field pair, the M84 and M86. Although large aperture scopes will see many more in the field, concentrate on the two bright cored ellipticals which are almost identical. M84 will drift out of the field first to the west and M86 is east. Next we will select a new guidestar by going 31 Virginis to identify splendid variable R about a degree to its west. We then move two degrees northwest of R to gather in the evenly lighted oval of M49. Now shifting about three degrees southwest, you will see handsome yellow double – 17 Virginis. Only one-half degree south is the large face-on spiral, M61. Larger scopes will see arms and dust lanes in this one. Last for tonight is to head for the bright blue beauty of Spica and go just slightly more than a fist width (11 degrees) due west. The M104 – “Sombrero” galaxy will be your reward for a job well done.

Congratulations. You’ve just seen 17 of the finest galaxies in the Coma/Virgo region and our “Marathon” total for three days has now reached 65. We’re over halfway home…

Thursday, March 10 – Hey… It’s New Moon. While tonight would be the “perfect choice” for completing a Messier Marathon from start to finish, there are no iron-clad guarantees that the sky will cooperate on this date. Even worse? Many of us have to work the next day. So what’s an astronomer to do, eh? How about if we try an “early to bed and early to rise” attitude and conquer these next objects well ahead of the dawn? Set your alarm for 3:00 am, dress warm and let’s dance.

With Corvus relatively high to the south, the drop is about five degrees to the south/south east of Beta Corvii. Just visible to the unaided eye will be the marker star – double A8612. Eighth magnitude M68 is a bright, compact globular cluster in Hydra that will appear as a “fuzzy star” to binoculars and a treat to the telescope. Our next is tough for far-northern observers, for the “Southern Pinwheel” – M83 – is close to ten degrees southeast of Gamma Hydrae. (this is why it is imperative to get up early enough to catch this constellation at its highest.)

Now we’re going to make a wide move across the sky and head southeast of brilliant Arcturus for Alpha Serpentis. About 8 degrees southwest you will find outstanding globular cluster M5 sharing the field with 5 Serpens. Now locate the “keystone” shape of Hercules and identify Eta in its northwest corner. About one-third of the way between it and Zeta to the south is the fantastic M13, also known as the “Great Hercules Globular Cluster”. A little more difficult to find is the small M92 because there are no stars to guide you. Try this trick – Using the two northernmost stars in the “keystone”, form an equilateral triangle in your mind with its imaginary apex to the north. Point your scope there. At sixth magnitude, this compact globular cluster has a distinct nucleus. Now we’re off to enjoy summer favourites and previous studies. The M57, “Ring Nebula”, is located about halfway between Sheilak and Sulafat. You’ll find the small globular M56 residing conveniently about midpoint between Sulafat and Alberio. About 2 degrees south of Gamma Cygni is the bright open cluster M29 and equally bright M39 lay about a little less than a fist width to the northeast of Deneb. If you remember our hop north of Gamma Sagitta, you’ll easily find the M27 “Dumbbell Nebula” and the loose globular, M71, just southwest of Gamma. All of the objects in this last paragraph are viewable with binoculars (albeit some are quite small) and all are spectacular in the telescope.

And now we’ve made it to 76 on our “Messier Hit List”.

Friday, March 11 – So, are you having fun yet?. Now we’re moving into early morning skies and looking at our own galactic halo as we track down some great globular clusters. What time of day, do you ask? Roughly two hours before dawn…

Ophiuchus is a sprawling constellation and its many stars can sometimes be hard to identify. Let’s start first with Beta Scorpii (Graffias) and head about a fist’s width to the northeast. That’s Zeta and the marker you will need to locate the M107. About one quarter the way back towards Graffias, you will see a line of three stars in the finder. Aim at the center one and you’ll find this globular in the same field. Now go back to Zeta and you will see a pair of similar magnitude dim stars higher to the northeast. The southernmost is star 30 and you will find the M10 globular cluster about one degree to its west. The M12 is only about three degrees further along to the northeast. Both are wonderfully large and bright enough to be seen in binoculars.

Now we need to identify Alpha in Ophiuchus. Head toward Hercules. South of the “keystone” you will see bright Beta Hercules with Alpha Hercules to the southeast. The next bright star along the line is Alpha Ophiuchi and globular cluster M14 is approximately 16 degrees south and pretty much due east of M10. Now let’s head for bright Eta Ophiuchi (Sabik) directly between Scorpius and Sagittarius The next globular, M9 is about three and a half degrees southeast.

Now let’s move on to an easier one. All you need to know is Antares to find the globular cluster, M4 in Scorpius. All you have to do is aim your binoculars there, for this diffuse giant is just a little over one degree to the west. Go back to Antares and shift about four degrees to the northwest and you’ll find compact, bright globular M80. It will be very small in binoculars, but it’s quite bright. Going back to the scope is best for the M19, although it’s easy to find around seven degrees due east of Antares. The last for this morning is the M62 about a half a fist’s width to the south.

Hey, you’re doing terrific. Some of these are tough to find unless you’ve had practice… But now we’re up to a total of 85.

Saturday, March 12 – Ready to get up early again? I know it’s hard, but what we’re after this morning is truly worth it. These are some of the most beautiful objects in the sky.

The lower curve of Scorpius is quite distinctive and the unaided eye pair you see at the “stinger” is beautiful double Shaula (Lambda) and its slightly less bright neighbor Upsilon. Aim your binoculars there and head towards the northeast and you cannot miss the M6 “Butterfly Cluster”. Below it and slightly east is a hazy patch, aim there and you will find another spectacular open cluster M7 often known as “Ptolemy’s Cluster”. Now go north and identify Lambda Aquilae and you will find the M11 “Wild Duck” open cluster just to the west. About the same distance away to the south/southwest you will spot the M26, another open cluster. These are all great binocular targets, but it will take an exceptionally dark, clear sky to see the “Eagle Nebula” associated with the M16 easy open cluster about a fist’s width away to the southwest. Far easier to see is the “Nike Swoosh” of the M17 just a little further south. Many of you know this as the “Omega” or “Swan” nebula. Keeping moving south and you will see the a very small collection of stars known as the M18 and a bit more south will bring up a huge cloud of stars labeled M24. This patch of Milky Way “stuff” will show a wonderful open cluster – NGC 6603 – to average telescopes and some great Barnard darks to the larger ones.

Now we’re going to shift to the southeast just a shade and pick up the M25 open cluster and head due west about a fist’s width to capture the next open cluster – M23. From there, we are dropping south again and the M21 will be your reward. Head back for your scope and remember your area, because the M20 “Triffid Nebula” is just a shade to the southwest. Small scopes will pick up on the little glowing ball, but anything from about 4″ up can see those dark dust lanes that make this nebula so special. You can go back to the binoculars again, because the M8 “Lagoon Nebula” is south again and very easy to see.

This particular star hop is very fun. Sagittarius has long been my favourite constellation. If you have children who would like to see some of these riches, point out the primary stars and show them how it looks like a dot-to-dot “tea kettle”. From the kettle’s “spout” pours the “steam” of the Milky Way. If you start there, all you will need to do is follow the “steam” trail up the sky and you can see the majority of these with ease. Our Messier total has now risen to 98…

Sunday, March 13 – OK, folks… It’s “crunch time” and the first few on this list will be fairly easy around 5:00 am, but you won’t have long before the dawn steals the last few from the sky.

At the top of the “tea kettle” is Lambda. This is our marker for two easy binocular objects. The small M28 globular cluster is quite easily found just a breath to the north/northwest. The larger, brighter and quite wonderful globular cluster M22 is also very easily found to Lambda’s northeast. Now we’re roaming into “binocular possible” but better with the telescope objects. The southeastern corner of the “tea kettle” is Zeta, and we’re going to hop across the bottom to the west. Starting at Zeta, slide southwest to capture globular cluster M54. Keep heading another three degrees southwest and you will see the fuzzy ball of the M70. Just around two degrees more to the west is another globular that looks like the M70’s twin. Say good morning to the M69.

Now it’s really going to get tough. The small globular M55 is out there in “No Man’s Land” about a fist’s width away east/south east of Zeta and the dawn is coming. It’s going to be even harder to find the equally small globular M75, but if you can see Beta Capricorn it will be about a fist’s width southwest. Look for a “V” pattern of stars in the finder and go to the northeastern star of this trio. You should be able to put it in the same low power field. Without the “square” of Pegasus to guide us, look low to the east and identify Enif by its reddish color. (Delphinus above it should help you.) Power punch globular M15 is to Enif’s northwest and you should be able to see the star on its border in the finderscope. Let’s be thankful that the M2 is such a fine, large globular cluster. The hop is two thirds of the way between Enif and Beta Aquarius, or just a little less than a fist’s width due west of Alpha. Let’s hope that Beta is still shining bright, because we’ll need to head about a fist’s width away again to the southwest to snag what will now be two very dim ones – the M72 globular cluster and M73 open cluster just west of Nu Aquarius. We’re now running just ahead of the light of dawn and the M30 globular cluster is our last object. Hang on Delta Capricornus and show us the way south/southwest to star 41. If you can find that? You’ve got the very last one…

We’ve done the Messier Catalog of all 110 objects in just one week.

Is this a perfect list with perfect instructions? No way. Just like the sky, things aren’t always perfect. This is just a general guideline to helping you find the Messier objects for yourself. Unless you are using a computer-guided scope, it truly takes a lot of practice to find all the Messiers with ease, so don’t be discouraged if they just don’t fall from the sky. You might find all of these in one year or one week – and you just might find all of them in one good night. Regardless of how long it takes you – or when the skies cooperate – the beauty, joy and reward is the peace and pleasure it brings.

Until next week? May all of your journeys be at light speed. ….~Tammy Plotner

Posted on by Fraser Cain

Detector Ready to Receive Beam of Neutrinos

Particle physicists from around the World are poised to unravel the secrets of the ethereal neutrino. Operational from this afternoon, March 4th, the Main Injector Neutrino Oscillation Search (MINOS) will produce a beam of neutrinos and fire them through the earth. By comparing neutrinos at the start with those that at the finish, some 735 km away, the scientists hope to understand many of their properties, including their most mysterious behaviour; how neutrinos can morph between three different types!

“This strange property of neutrinos was only recently discovered experimentally, because neutrinos interact with the their surroundings very rarely – in fact millions are passing through air, earth and even people unnoticed at any given time. Even a specially built detector like the MINOS Far detector is only expected to see 1,500 neutrinos in a year – billions more will pass straight through!” says UK project spokesperson, Dr Geoff Pearce of the CCLRC Rutherford Appleton Laboratory.

The MINOS experiment will use a neutrino beam produced just outside Chicago, USA at Fermilab’s Main Injector accelerator to probe the secrets of these elusive subatomic particles: where do they come from, what are their masses and how do they change from one kind to another? There are three types or ‘flavours’ of neutrino: electron, muon and tau, each with different properties. The neutrino beam will be projected straight through the earth from Fermilab to the Soudan Mine in Northern Minnesota – a distance of 735 kilometres. No tunnel is needed because neutrinos interact so rarely with matter that they can pass straight through the earth virtually unhindered. In a ceremony this afternoon, the Speaker of the US House of Representatives, the Honourable J. Dennis Hastert Jr. will activate the neutrino beam, sending the first particles on their journey to the detector in the Soudan mine.

Dr Alfons Weber, University of Oxford explains “This is an exciting time for us. The beam we now generate at Fermilab will contain only one type of neutrino – muon neutrinos. When it arrives at the Far Detector in the Soudan Mine fractions of a second later, some of the muon neutrinos will have changed into the other types – tau and electron neutrinos. We want to understand how they do this.”

Two massive neutrino detectors have been built by MINOS, both of which are complete and ready for the beam. The 1000 ton ‘near’ detector will sample the beam as it leaves Fermilab and provide the control measurements. The 5,500 ton ‘far’ detector, half a mile underground in the Soudan Mine, will measure the neutrinos when they arrive, just 2.5 milliseconds later. The detectors have to be a long distance apart to allow the neutrinos, which travel at close to the speed of light, time to oscillate. “By comparing these two measurements we will be able to study how the neutrinos have oscillated and provide the world’s most precise measurement of this effect with muon-type neutrinos” explains Dr Geoff Pearce.

Prof. Ian Halliday, CEO of the Particle Physics and Astronomy Research Council which funds UK work on this project, anticipated the revelations from the experiment’s precision measurements.

“The mysteries of the elusive neutrino are about to be unveiled,” Halliday said. “For the very first time we will be able to investigate the changing state of this bizarre particle to an unprecedented accuracy of a few percent in a controlled beam of neutrinos created in the laboratory. I’m extremely proud that UK scientists have played a key role in bringing this experiment to fruition and, in collaboration with their international colleagues, will be amongst the first in the world to study its unique characteristics.”

“Physicists from around the world are trying to understand what these mysterious neutrinos are telling us,” said Fermilab director Michael Witherell. “Today, we are embarking on a journey of exploration using the most powerful neutrino facility in the world. I am extremely proud of what the people of Fermilab have accomplished in completing the NuMI project. I would like to thank the American people and the federal government for making the necessary commitment to support great science.”

Original Source: PPARC News Release

Posted on by Fraser Cain

Dawn Will Show How Different Two Asteroids Can Be

Although they’re both enormous asteroids, protoplanets really, and lie within the asteroid belt between Mars and Jupiter, Vesta and Ceres couldn’t be more different.

Vesta formed closer to the Sun, and probably shares many features of the inner planets. Scientists believe it formed in a hot, dry environment and will probably have layers of volcanic flows and a solid metallic core. But even the best photos from Hubble show a blurry gray world, bringing more questions than answers. It’s the brightest asteroid in the Solar System, measuring 530 km (329 miles) across. You can even see it with the unaided eye; in fact, it’s the only main belt asteroid you can see. Traveling to Vesta could be a little dangerous. “We know very little about Vesta’s internal structure,” explained Chief Engineer Dr. Marc Rayman, “it
has an unpredictable and possibly very irregular gravity field.”

Just a little further out – across an invisible line that separates the inner rocky planets from the outer planets – is Ceres; the largest asteroid in the Solar System, measuring 957 km (595 miles) across. Unlike Vesta, Ceres is believed to have formed in a cool, wet environment, and in the presence of water. This water is probably still there, in the form of ice caps, a thin water vapour atmosphere, or even as a liquid underneath the surface.

While most of the objects in the asteroid belt are pulverized chunks of rock, accumulations of material from different bodies, Vesta and Ceres remain largely unchanged from when they first formed 4.6 billion years ago. Revelations about the early history of the Solar System could be written on their surfaces.

The $370 million US spacecraft is scheduled for liftoff in June, 2006. After 4 or 5 years of travel time (depending on whether or not it’ll be making a flyby of Mars first) Dawn will arrive at Vesta in 2010 or 2011, studying it for almost a year before flying off to rendezvous with Ceres three years later. It has a suite of scientific instruments on board to study the two asteroids in great detail: their mass, volume, spin rate, chemical and elemental composition, and gravity. Oh, and it’ll be taking pretty pictures too.

Dawn will be the first spacecraft ever to orbit two separate objects in the solar system (and no, orbiting the Earth doesn’t count here). A feat that wouldn’t even be possible without its ion engine. A very similar engine helped Deep Space 1 set speed and duration records, and served as a model for Dawn’s development. It uses solar electricity to ionize xenon atoms and then hurl them out the back of the spacecraft. The thrust is tiny but fuel efficient, and the engine can keep running for months or even years providing a tremendous velocity.

And an ion engine gives controllers flexibility. “It gives us a very long launch window. We’re launching in June 2006 because that’s when the spacecraft will be ready. But we could still make it in November or even after that,” said Dr. Rayman. So far, though, the project is right on schedule. The completed spacecraft shipped this week from NASA’s Jet Propulsion Laboratory to Orbital Sciences for the next stage of assembly and testing.

If you’re interested in finding out more about this mission, stay tuned. Dr. Rayman is planning on keeping the world well informed, through the Internet. He learned how important this can be while working on Deep Space 1, taking the unusual step – at the time – of maintaining a web log to describe his experiences working with the spacecraft. “I was in the airport when I realized that we needed to get the word out. I dictated my first entry over the phone,” recalled Dr. Rayman. Rayman continued maintaining his popular DS1 blog, giving armchair mission controllers a unique insight into the day-to-day challenges and decisions that go into managing a spacecraft half a solar system away.

Expect more of the same with Dawn. “These missions belong to more than just NASA, or the United States. They’re humanity’s emissaries to the cosmos, and we want everyone to come along for the ride,” explained Rayman. But this time, he’ll get started earlier, bringing an Internet audience into the development stages as well as post-launch.

Official Dawn Mission Page

Written by Fraser Cain

Posted on by Fraser Cain

Rosetta Photographs the Earth on Flyby

The European Space Agency’s Rosetta spacecraft yesterday performed ESA’s closest-ever Earth fly-by, gaining an essential gravity boost in its ten-year, 7.1 billion kilometre flight to Comet 67P/Churyumov-Gerasimenko.

At closest approach, at 22:09:14 GMT, Rosetta passed above the Pacific Ocean just west of Mexico at an altitude of 1954.74 km and a velocity relative to the Earth of 38 000 kph.

The passage through the Earth-Moon system allowed ground controllers to test Rosetta’s ‘asteroid fly-by mode’ (AFM) using the Moon as a ‘fake’ asteroid, rehearsing the fly-bys of asteroids Steins and Lutetia due in 2008 and 2010 respectively. The AFM test started at 23:01 GMT and ran for nine minutes during which the two onboard navigation cameras successfully tracked the Moon, allowing Rosetta’s attitude to be automatically adjusted.

Before and after closest approach, the navigation cameras also acquired a series of images of the Moon and Earth; these data will be downloaded early today for ground processing and are expected to be available by 8 March.

In addition, other onboard instruments were switched on, including ALICE (ultraviolet imaging spectrometer), VIRTIS (visible and infrared mapping spectrometer) and MIRO (microwave instrument for the Rosetta orbiter), for calibration and general testing using the Earth and Moon as targets.

The fly-by manoeuvre swung the three-tonne spacecraft around our planet and out towards Mars, where it will make a fly-by on 26 February 2007. Rosetta will return to Earth again in a series of four planet fly-bys (three times with Earth, once with Mars) before reaching Comet 67P/Churyumov-Gerasimenko in 2014, when it will enter orbit and deliver a lander, Philae, onto the surface.

The fly-bys are necessary to accelerate the spacecraft so as to eventually match the velocity of the target comet. They are a fuel-saving way to boost speed using planetary gravity.

Yesterday’s fly-by came one year and two days after launch and highlights the valuable opportunities for instrument calibration and data gathering available during the mission’s multi-year voyage.

In just three months, on 4 July, Rosetta will be in a good position to observe and gather data during NASA’s spectacular Deep Impact event, when the Deep Impact probe will hurl a 380 kg projectile into Comet Tempel 1, revealing data on the comet’s internal structure. Certain of Rosetta?s unique instruments, such as its ultraviolet light instrument ALICE, should be able to make critical contributions to the American mission.

About Rosetta
Rosetta is the first mission designed to both orbit and land on a comet, and consists of an orbiter and a lander. The spacecraft carries 11 scientific experiments and will be the first mission to undertake long-term exploration of a comet at close quarters. After entering orbit around Comet 67P/Churyumov-Gerasimenko in 2014, the spacecraft will release a small lander onto the icy nucleus. Rosetta will orbit the comet for about a year as it heads towards the Sun, remaining in orbit for another half-year past perihelion (closest approach to the Sun).

Comets hold essential information about the origin of our Solar System because they are the most primitive objects in the Solar System and their chemical composition has changed little since their formation. By orbiting and landing on Comet 67P/Churyumov-Gerasimenko, Rosetta will help us reconstruct the history of our own neighbourhood in space.

Original Source: ESA News Release

Posted on by Fraser Cain

New Kind of Object Discovered?

Image credit: NRAO/AUI/NSF
Astronomers at Sweet Briar College and the Naval Research Laboratory (NRL) have detected a powerful new bursting radio source whose unique properties suggest the discovery of a new class of astronomical objects. The researchers have monitored the center of the Milky Way Galaxy for several years and reveal their findings in the March 3, 2005 edition of the journal, “Nature”.

Principal investigator, Dr. Scott Hyman, professor of physics at Sweet Briar College, said the discovery came after analyzing some additional observations from 2002 provided by researchers at Northwestern University. “”We hit the jackpot!” Hyman said referring to the observations. “An image of the Galactic center, made by collecting radio waves of about 1-meter in wavelength, revealed multiple bursts from the source during a seven-hour period from Sept. 30 to Oct. 1, 2002 ? five bursts in fact, and repeating at remarkably constant intervals.”

Hyman, four Sweet Briar students, and his NRL collaborators, Drs. Namir Kassim and Joseph Lazio, happened upon transient emission from two radio sources while studying the Galactic center in 1998. This prompted the team to propose an ongoing monitoring program using the National Science Foundation?s Very Large Array (VLA) radio telescope in New Mexico. The National Radio Astronomy Observatory, which operates the VLA, approved the program. The data collected, laid the groundwork for the detection of the new radio source.

“Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths,” NRL astronomer Dr. Joseph Lazio pointed out, “very little has been done to look for radio bursts, which are often easier for astronomical objects to produce.”

The team has monitored the Galactic center for new transient sources and for variability in approximately 250 known sources, but the five bursts from the new radio source, named GCRT J1745-3009, were by far the most powerful seen. The five bursts were of equal brightness, with each lasting about 10 minutes, and occurring every 77 minutes.

The source of the bursts is transient Hyman noted. “It has not been detected since 2002 nor is it present on earlier images.”

Although the exact nature of the object remains a mystery, the team members currently believe that GCRT J1745-3009 is either the first member of a new class of objects or an unknown mode of activity of a known source class.

One important clue to understanding the origin of the radio bursts is that the emission appears to be “coherent,” Hyman said. “There are very few classes of coherent emitters in the universe. Natural astronomical masers ? the analog of laser emission at microwave wavelengths ? are one class of coherent sources, but these emit in specific wavelengths. In contrast, the new transient?s bursts were detected over a relatively large bandwidth.”

“In addition to these intriguing properties, NRL astronomer Dr. Paul Ray and colleague, Dr. Craig Markwardt of NASA?s Goddard Space Flight Center, have searched the source for X-ray emission but have not found any convincing evidence. “The non-detection of X-ray emission is intriguing,” Ray said. “Many sources that emit transient X-ray flares, such as black hole binary star systems, also have associated radio emission. If upon further observations, X-ray emission is definitively detected or ruled out, this will be a significant help in understanding the nature of this remarkable source.”

“Needless to say, the discovery of these transients has been very exciting for our students,” Hyman added. Participating in this research program has inspired at least two of Hyman’s students ? Jennifer Neureuther and Mariana Lazarova ? to pursue graduate studies in astronomy.

This project was supported at Sweet Briar College by funding from Research Corporation and the Jeffress Foundation. Basic research in radio astronomy at NRL is supported by the Office of Naval Research.

Hyman and his NRL colleagues plan to continue monitoring the Galactic center and search for the source again with the VLA and other X-ray and radio telescopes. They are also developing (with Dr. Kent Wood of NRL) a model that attempts to account for the radio bursts as a new type of outburst from a class of sources known as “magnetars.”

NRL is also contributing to an effort to build the world?s largest and most sensitive low-frequency telescope, called the Long Wavelength Array (LWA), which may revolutionize future searches for other radio transient sources. Current plans call for the LWA, which is being developed by the University of New Mexico-led Southwest Consortium, to be sited in New Mexico, not far from the VLA.

“One of the key advantages of observing at long radio wavelengths,” explained NRL astronomer, Dr. Namir Kassim, “is that the field-of-view is so large that a single observation can efficiently detect transient phenomena over a large region.”

“When completed, the LWA may uncover hundreds of previously unknown radio transients, some of which may be examples of Jupiter-like planets orbiting other stars,” Kassim added. Jupiter is the most famous example of a nearby radio transient.

Original Source: NRAO News Release

Posted on by Fraser Cain

Did Clouds in Space Cause Snowball Earth?

Image credit: NASA
Eons ago, giant clouds in space may have led to global extinctions, according to two recent technical papers supported by NASA’s Astrobiology Institute.

One paper outlines a rare scenario in which Earth iced over during snowball glaciations, after the solar system passed through dense space clouds. In a more likely scenario, less dense giant molecular clouds may have enabled charged particles to enter Earth’s atmosphere, leading to destruction of much of the planet’s protective ozone layer. This resulted in global extinctions, according to the second paper. Both recently appeared in the Geophysical Research Letters.

“Computer models show dramatic climate change can be caused by interstellar dust accumulating in Earth’s atmosphere during the solar system’s immersion into a dense space cloud,” said Alex Pavlov, principal author of the two papers. He is a scientist at the University of Colorado, Boulder. The resulting dust layer hovering over the Earth would absorb and scatter solar radiation, yet allow heat to escape from the planet into space, causing runaway ice buildup and snowball glaciations.

“There are indications from 600 to 800 million years ago that at least two of four glaciations were snowball glaciations. The big mystery revolves around how they are triggered,” Pavlov said. He concluded the snowball glaciations covered the entire Earth. His work is supported by the NASA Astrobiology Institute, which has offices at NASA Ames Research Center, located in California’s Silicon Valley.

Pavlov said this hypothesis has to be tested by geologists. They would look at Earth’s rocks to find layers that relate to the snowball glaciations to assess whether uranium 235 is present in higher amounts. It cannot be produced naturally on Earth or in the solar system, but it is constantly produced in space clouds by exploding stars called supernovae.

Sudden, small changes in the uranium 235/238-ratio in rock layers would be proof interstellar material is present that originated from supernovae. Collisions of the solar system with dense space clouds are rare, but according to Pavlov’s research, more frequent solar system collisions, with moderately dense space clouds, can be devastating. He outlined a complex series of events that would result in loss of much of Earth’s protective ozone layer, if the solar system collided with a moderately dense space cloud.

The research outlined a scenario that begins as Earth passes through a moderately dense space cloud that cannot compress the outer edge of the sun’s heliosphere into a region within the Earth’s orbit. The heliosphere is the expanse that begins at the sun’s surface and usually reaches far past the orbits of the planets. Because it remains beyond Earth’s orbit, the heliosphere continues to deflect dust particles away from the planet.

However, because of the large flow of hydrogen from space clouds into the sun’s heliosphere, the sun greatly increases its production of electrically charged cosmic rays from the hydrogen particles. This also increases the flow of cosmic rays towards Earth. Normally, Earth’s magnetic field and ozone layer protect life from cosmic rays and the sun’s dangerous ultraviolet radiation.

Moderately dense space clouds are huge, and the solar system could take as long as 500,000 years to cross one of them. Once in such a cloud, the Earth would be expected to undergo at least one magnetic reversal. During a reversal, electrically charged cosmic rays can enter Earth’s atmosphere instead of being deflected by the planet’s magnetic field.

Cosmic rays can fly into the atmosphere and break up nitrogen molecules to form nitrogen oxides. Nitrogen oxide catalysts would set off the destruction of as much as 40 percent of the protective ozone in the planet’s upper atmosphere across the globe and destruction of about 80 percent of the ozone over the polar regions according to Pavlov.

Original Source: NASA News Release