Posted on by Fraser Cain

Deep Space Alcohol

The cloud, where OH maser filament are red and extended methanol filaments are green. Image credit: JIVE Click to enlarge
Astronomers have located a gigantic cloud of methyl alcohol surrounding a stellar nursery. The cloud measures half a trillion km across (300 billion miles), and could help astronomers understand how some of the most massive stars in the Universe are formed. It’s methanol, not ethanol, so you wouldn’t want to drink it if you could reach it.

Astronomers based at Jodrell Bank Observatory have discovered a giant bridge of methyl alcohol, spanning approximately 288 billion miles, wrapped around a stellar nursery. The gas cloud could help our understanding of how the most massive stars in our galaxy are formed.

The new observations were taken with the UK’s MERLIN radio telescopes, which have recently been upgraded. The team studied an area called W3(OH), a region in our galaxy where stars are being formed by the gravitational collapse of a cloud of gas and dust. The observations have revealed giant filaments of gas that are emitting as ‘masers’ (molecules in the gas are amplifying and emitting beams of microwave radiation in much the same way as a laser emits beams of light).

The filaments of masing gas form giant bridges between maser ‘spots’ in W3(OH) that had been observed previously. The largest of these maser filaments is 288 billion miles (463 billion km) long. Observations show that the entire gas cloud appears to be rotating as a disc around a central star, in a similar manner to the accretion discs in which planets form around young stars. The maser filaments occur at shock boundaries where large regions of gas are colliding.

“Our discovery is very interesting because it challenges some long-accepted views held in astronomical maser research. Until we found these filaments, we thought of masers as point-like objects or very small bright hotspots surrounded by halos of fainter emission,” said Dr Lisa Harvey-Smith, who is the Principal Investigator for the study and is presenting results at the Royal Astronomical Society’s National Astronomy Meeting on 4th April.

Since the upgrade of the UK’s MERLIN telescope network, astronomers have been able to image methanol masers with a much higher sensitivity and, for the first time, get a complete picture of all the radiation surrounding maser sources. In the new study, the Jodrell Bank team looked at the motion of the W3(OH) star forming region in 3-dimensions and also measured physical properties of the gas such as temperature, pressure and the strength and direction of the magnetic fields. This information is vital when testing theories about how stars are born from the primordial gas in stellar nurseries.

Dr Harvey-Smith said, “There are still many unanswered questions about the birth of massive stars because the formation centres are shrouded by dust. The only radiation that can escape is at radio wavelengths and the upgraded MERLIN network is now giving us the first opportunity to look deep into these star forming regions and see what’s really going on.”

The many different types of interactions between molecules in star forming regions lead to emissions in many different wavelengths. Future observations of masers at other frequencies are planned to complete the complex jigsaw puzzle that has now been revealed.

Dr Harvey-Smith adds, “Although it is exciting to discover a cloud of alcohol almost 300 billion miles across, unfortunately methanol, unlike its chemical cousin ethanol, is not suitable for human consumption!”

Original Source: RAS News Release

Posted on by Fraser Cain

Galaxies Trapped in the Universe’s Web

Galaxies are not randomly distributed. Image credit: IAC Click to enlarge
Although the galaxies we see in the night sky seem randomly strewn across the heavens, they’re actually organized into large scale structures that look like cosmic filaments. These filaments and walls surround huge bubble-like voids that lack any large structures at all. European astronomers measured the orientation of thousands of galaxies, and found that many are oriented in the direction of these linear filaments.

Astronomers from the University of Nottingham, UK, and the Instituto de Astrofisica de Canarias (Spain), have found the first observational evidence that galaxies are not randomly oriented.

Instead, they are aligned following a characteristic pattern dictated by the large-scale structure of the invisible dark matter that surrounds them.

This discovery confirms one of the fundamental aspects of galaxy formation theory and implies a direct link between the global properties of the Universe and the individual properties of galaxies.

Galaxy formation theories predicted such an effect, but its empirical verification has remained elusive until now. The results of this work were published the 1 April issue of Astrophysical Journal Letters.

Nowadays, matter is not distributed uniformly throughout space but is instead arranged in an intricate “cosmic web” of filaments and walls surrounding bubble-like voids. Regions with high galaxy concentrations are known as galaxy clusters whereas low density regions are termed voids.

This inhomogeneous distribution of matter is called the “Large-scale distribution of the Universe.” When the Universe is considered as whole, this distribution has a similar appearance to a spider’s web or the neural network of the brain. But it was not always like this.

After the Big Bang, when the Universe was much younger, matter was distributed homogeneously. As the Universe was evolving, gravitational pulls began to compress the matter in certain regions of space, forming the large-scale structure that we currently observe.

According to these models and theories a direct consequence of this process is that galaxies should be preferentially oriented perpendicularly to the direction of the linear filaments.

Several observational studies have looked for a preferential spatial orientation (or alignment) of galaxy rotation axes with respect to their surrounding large-scale structures. However, none of them have been successful, due to the difficulties associated with trying to characterise the filaments.

The research conducted by the astrophysical group formed by Ignacio Trujillo (University of Nottingham, UK), Conrado Carretero and Santiago G. Patiri, (both from the Instituto de Astrofisica de Canarias, Spain) has been able to measure this effect, confirming theoretical predictions.

To achieve this goal, they used a new technique based on the analysis of the huge voids that are found in the large-scale structure of the Universe. These voids have been detected by searching for large regions of space depleted of bright galaxies.

In addition, they took advantage of information provided by the two largest sky surveys yet undertaken: the Sloan Digital Sky Survey and the Two Degree Field Survey. These surveys contain positional information for more than half a million galaxies located within a distance of one billion light-years of the Earth.

Other parameters provided by the surveys, such as the position angle and the ellipticity of the objects, were used to estimate the orientation of the disk galaxies.

“We found that there is an excess of disk galaxies that are highly inclined relative to the plane defined by the large-scale structure surrounding them,” explained Dr. Trujillo. “Their rotation axes are mainly oriented in the direction of the filaments.

“Our work provides important confirmation of the tidal torque theory which explains how galaxies have acquired their current spin,” said Trujillo.

“The spin of the galaxies is believed to be intrinsically linked to their morphological shapes. So, this work is a step forward on our understanding of how galaxies have reached their current shapes.”

Dr. Ignacio Trujillo has a research assistant position, funded by PPARC, in the School of Physics and Astronomy at the University of Nottingham.

An abstract of the paper is available on the web at:
http://xxx.lanl.gov/abs/astro-ph/0511680

Original Source: RAS News Release

Posted on by Fraser Cain

Deep Impact Caused a Great Gush of Water Vapour

Deep Impact. Image credit: NASA. Click to enlarge
When Deep Impact collided with Tempel 1, it released an amazing amount of water vapour from the comet – as much as 250,000 tonnes were blasted into space. These measurements were made by NASA’s Swift satellite, which normally locates and observes gamma ray bursts. Swift, like almost every other telescope on Earth and in space was pointed at Comet Tempel 1 when Deep Impact smashed into it last July. Swift monitored the X-ray emissions before and after the collision, and used that to measure the amount of water vapour ejected.

Over the weekend of 9-10 July 2005 a team of UK and US scientists, led by Dr. Dick Willingale of the University of Leicester, used NASA’s Swift satellite to observe the collision of NASA’s Deep Impact spacecraft with comet Tempel 1. Reporting today (Tuesday) at the UK 2006 National Astronomy Meeting in Leicester, Dr. Willingale revealed that the Swift observations show that the comet grew brighter and brighter in X-ray light after the impact, with the X-ray outburst lasting a total of 12 days.

“The Swift observations reveal that far more water was liberated and over a longer period than previously claimed,” said Dick Willingale.

Swift spends most of its time studying objects in the distant Universe, but its agility allows it to observe many objects per orbit. Dr. Willingale used Swift to monitor the X-ray emission from comet Tempel 1 before and after the collision with the Deep Impact probe.

The X-rays provide a direct measurement of how much material was kicked up after the impact. This is because the X-rays were created by the newly liberated water as it was lifted into the comet’s thin atmosphere and illuminated by the high-energy solar wind from the Sun.

“The more material liberated, the more X-rays are produced,” explained Dr. Paul O’Brien, also from the University of Leicester.

The X-ray power output depends on both the water production rate from the comet and the flux of subatomic particles streaming out of the Sun as the solar wind. Using data from the ACE satellite, which constantly monitors the solar wind, the Swift team managed to calculate the solar wind flux at the comet during the X-ray outburst. This enabled them to disentangle the two components responsible for the X-ray emission.

Tempel 1 is usually a rather dim, weak comet with a water production rate of 16,000 tonnes per day. However, after the Deep Impact probe hit the comet this rate increased to 40,000 tonnes per day over the period 5-10 days after impact. Over the duration of the outburst, the total mass of water released by the impact was 250,000 tonnes.

One objective of the Deep Impact mission was to determine what causes cometary outbursts. A simple theory suggests that such outbursts are caused by the impact of meteorites on the comet nucleus. If this is the case, Deep Impact should have initiated an outburst.

Although the impact was observed across the electromagnetic spectrum, most of what was seen was directly attributable to the impact explosion. After 5 days, optical observations showed that the comet was indistinguishable from its state prior to the collision. This was in stark contrast to the X-ray observations.

The analysis of the X-ray behaviour by the Swift team indicates that the collision produced an extended X-ray outburst largely because the amount of water produced by the comet had increased.

“A collision such as Deep Impact can cause an outburst, but apparently something rather different from the norm can also happen,” said Dr. Willingale. “Most of the water seen in X-rays came out slowly, possibly in the form of ice-covered dust grains.”

Original Source: RAS News Release

Posted on by Mark Mortimer

Book Review: Columbia – Final Voyage


Tragedies bring on sad times. People reflect and think of what’s changed or lost. No one wants unfortunate events, but great rewards only come with great risks. Philip Chien in his book Columbia Final Voyage brings a comprehensive, personal view of the most recent shuttle disaster. He shows that it was just one more risky attempt to further understand the complexities and dangers of space.

The Columbia space shuttle destructed during its re-entry in February 2003. The accident investigation board traced the fault to a chunk of foam that came loose at launch. The foam hit the shuttle’s forward wing edge and pierced the heat resistant shielding. Thus, on re-entry, the shuttle burned up. The seven astronauts onboard all perished, yet many results from their 16 days of research were saved and used. Due to an unprecedented number of delays prior to launch, the seven came to learn more about the background of their onboard experiments as well as each other. Their camaraderie and willingness to face risks for potential scientific rewards show the strong sense of compassion and desire held by everyone.

Chien was at the landing site in Florida waiting hopelessly for Columbia to return. Prior to this, he had witnessed the launch and had many opportunities to talk with the crew during their years of training. With this viewpoint, he relives Columbia’s final voyage, not as a vindicator trying to lay blame, but as a concerned participant wanting to express his own thoughts and feelings. He does this by providing a short biography of each of the seven astronauts, a review of their experiments and a description of the activities while the mission was underway. A brief but encompassing perception of the aftermath completes his review of the last flight of NASA’s first space shuttle.

In the biographies, Chein puts a face to a name and a person to the face. He includes how the astronauts came to join the NASA fold, a bit of their personalities and some words on significant others in their lives. Certainly the 8 to 10 pages for each isn’t exhaustive, but it does add that human element.

Chien next tackles the task of the mission. This was for microgravity research. Though maligned as a series of high-school experiments, Chien shows that a lot of serious science kept the astronauts busy for the full duration of their 16 day mission. Some even volunteered to work during their scheduled rest periods to get malcontent equipment to cooperate. To relive mission, Chien allocates a chapter for each day of the flight. He describes the main activities regarding the research as well as off-hand human touches. For example, there’s the menu items, wake up songs and many capcom dialogues. Also, as some images survived the burn-up, he includes photographs of the astronauts going about the tasks. Even were this mission not a tragedy, Chien’s review provides plenty of interest.

Apart from a look at the science, Chien provides a great overview of a typical shuttle research mission. Included are the experiments, with the identities and expectations of the principal investigators. As the mission progresses, he shows the research progressing, building on results from the previous day. The uninitiated reader can quickly appreciate the shuttle’s capabilities and operations. Though Chien’s perspective is of one who?s never flown, he does include many first hand accounts from those who have.

Chien’s overall objective is to establish a synopsis of Columbia’s mission, and he succeeds. His is a fair and honest book about the people and the mission. He points few fingers, he maligns the conspiracy theorists, and he does refute those who thought the mission unworthy. His own involvement with the shuttle operations comes through as he provides information regarding systems, structures and procedures, though not so much as to overload the reader. In total, he’s produced a warm memorial both for the people and the mission.

However, though Chien provides a warm memorial, he doesn’t add any new information. Further, his presentation, though logically and chronologically laid out, can get stilted. He has a particularly disturbing habit of referring to a related web link. This makes the book seem to be support material for the web site rather than a stand alone source. Further, though the many quotes lend authenticity, they interrupt the text. His drive for detail doesn’t always mesh with the warm personal anecdotes from the astronauts lives. Nevertheless, the book is an excellent source for someone wanting to relive this mission or to reflect on the nature of the people involved or on people in general.

The Columbia mission ended in tragedy. But this is no reason to end research in space. Philip Chien in his book, Columbia Final Voyage shows the dedication and drive of the seven astronauts who lost their lives. His thoughtful and sombre tribute to the astronauts is a pleasing dedication to them and their mission.

Review by Mark Mortimer

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

Posted on by Fraser Cain

Simulating the Early Universe

Spiral galaxy NGC 1300. Image credit: Hubble. Click to enlarge
Researchers have harnessed the power one of the world’s fastest supercomputers – the Earth Simulator – to model the growth of galaxies in the early Universe. The team simulated the process right from the beginning, shortly after the Big Bang, when clumps of gas came together to form stars which then merged into larger and larger collections, and finally became galaxies. They found that galaxies like the Milky Way probably have the same composition now as they did only a billion years after the Big Bang.

Two astronomers have performed one of the world’s largest astrophysics simulations to date in order to model the growth of galaxies. Using the “Earth Simulator” supercomputer in Japan, which is also used for climate modelling and simulating seismic activity, Masao Mori of the University of California at Los Angeles and Masayuki Umemura at the University of Tsukuba have calculated how galaxies evolved from just 300 million years after the Big bang to the present day. The results show that galaxies may have evolved much faster than currently believed (Nature 440 644).

According to the “hierarchical” model, galaxies are formed via a bottom-up process that starts with the formation of small clumps of gas and stars that then merge into bigger systems. Mori and Umemura simulated this process using a powerful 3D hydrodynamic code combined with a “spectral synthesis” code for an astrophysical plasma in order to take into account the dynamical and chemical evolution of a primordial galaxy. The Earth-Simulator simulation was performed with an ultra-high resolution based on 1024 “grid points”, making it one of the biggest calculations ever performed in astrophysics.

Mori and Masayuki set up the initial conditions in their simulation based on a cold dark matter universe, the parameters of which are determined by measurements of the cosmic microwave background. These observations, first made in 2003, show that we are living in a flat universe comprising just 4% ordinary matter, 22% dark matter and 74% dark energy – in agreement with the standard model of cosmology. The researchers then directly compared their numerical results with observations of primitive galaxies called Lyman-alpha emitters and “Lyman break” galaxies, which astronomers find in the most distant and therefore oldest parts of the universe.

The results show that the primordial bubbles of gas that formed in the early universe just 300 millions years after the Big Bang do indeed look like Lyman-alpha emitters. After about 1 billion years, the simulations show that these galaxies mutate into Lyman break galaxies. Finally, after 10 billion years of evolution, the structures resemble present-day elliptical galaxies.

The simulation also predicts the mixture of chemical elements in the galaxy at each stage of its evolution, and suggests that our Milky Way has roughly the same composition today as it did when it was just 1 billion years old. Until now, galaxies were thought to have evolved gradually and become enriched in heavier elements beyond hydrogen and helium over a period of 10 billion years by repeated star formation and supernova explosions.

“Our finding shows that galaxy formation proceeded much faster and that a large amount of heavy elements were produced in galaxies in just 1 billion years,” says Mori.

Original Source: Institute of Physics

Posted on by Fraser Cain

The Strongest Magnetic Fields in the Universe

NASA’s first look at a lonely neutron star. Image credit: NASA/HST Click to enlarge
The most powerful explosions in the Universe are the mysterious gamma ray bursts, which astronomers now think are collisions between neutron stars. A new simulation has calculated that in the moments after a collision, the explosion generates a magnetic field 1000 million million times more powerful than the Earth’s magnetic field – the strongest magnetic fields in the Universe. The simulation took weeks on a supercomputer to calculate just a few milliseconds of a collision between neutron stars.

Scientists from The University of Exeter and the International University, Bremen have discovered what is thought to be the strongest magnetic field in the Universe. In a paper in the journal Science, Dr Daniel Price and Professor Stephan Rosswog show that violent collisions between neutron stars in the outer reaches of space create this field, which is 1000 million million times larger than our earth’s own magnetic field. It’s thought that these collisions could be behind some of the brightest explosions in the Universe since the Big Bang, so-called short Gamma-ray bursts.

Dr Daniel Price, of the School of Physics at The University of Exeter, said: “We have managed to simulate, for the first time, what happens to the magnetic field when neutron stars collide, and it seems possible that the magnetic field produced could be sufficient to spark the creation of Gamma-ray bursts. Gamma-ray bursts are the most powerful explosions we can detect but until recently little to nothing has been known about how they are generated. It’s thought that strong magnetic fields are essential in producing them, but until now no one has shown how fields of the required intensity could be created.”

He continues: “What really surprised us was just how fast these tremendous fields are generated – within one or two milliseconds after the stars hit each other.”

Prof Stephan Rosswog, of the International University, Bremen, Germany, adds: “Even more incredible is that the magnetic field strengths reached in the simulations are just lower limits on the strengths that may be actually be produced in nature. It has taken us months of nearly day and night programming to get this project running – just to calculate a few milliseconds of a single collision takes several weeks on a supercomputer.”

The remnants of supernovae, neutron stars are formed when massive stars run out of nuclear fuel and explode, shedding their outer layers and leaving behind a small but extremely dense core. When two neutron stars are left orbiting each other, they will spiral slowly together, resulting in these massive collisions.

Original Source: University of Exeter

Posted on by Fraser Cain

Don Quijote Will Reach Out and Impact an Asteroid

Impacts with very large asteroids are uncommon. Image credit: ESA Click to enlarge
Asteroids don’t hit the Earth often, but when they do, the results can be catastrophic. The European Space Agency is working on several approaches to minimize the chances we’ll make a close encounter with an asteroid. A new mission, called Don Quijote, will launch in 2011 and slam an impactor probe into an asteroid to see what happens. An orbiter spacecraft will remain in orbit around the asteroid and continue to study the aftereffects of the impact. There are now three European teams working on preliminary studies for the potential mission.

If a large asteroid such as the recently identified 2004 VD17 – about 500 m in diameter with a mass of nearly 1000 million tonnes – collides with the Earth it could spell disaster for much of our planet. As part of ESA’s Near-Earth Object deflecting mission Don Quijote, three teams of European industries are now carrying out studies on how to prevent this.

ESA has been addressing the problem of how to prevent large Near-Earth Objects (NEOs) from colliding with the Earth for some time. In 1996 the Council of Europe called for the Agency to take action as part of a “long-term global strategy for remedies against possible impacts”. Recommendations from other international organisations, including the UN and the Organisation for Economic Cooperation and Development (OECD), soon followed.

In response to these and other calls, ESA commissioned a number of threat evaluation and mission studies through its General Studies Programme (GSP). In July 2004 the preliminary phase was completed when a panel of experts appointed by ESA recommended giving the Don Quijote asteroid-deflecting mission concept maximum priority for implementation.

Now it is time for industry to put forward their best design solutions for the mission. Following an invitation to tender and the subsequent evaluation process, three industrial teams have been awarded a contract to carry out the mission phase-A studies. :

– a team with Alcatel Alenia Space as prime contractor includes subcontractors and consultants from across Europe and Canada; Alcatel Alenia Space developed the Huygens Titan probe and is currently working on the ExoMars mission

– a consortium led by EADS Astrium, which includes Deimos Space from Spain and consultants from several European countries, brings their experience of working on the design of many successful ESA interplanetary missions such as Rosetta, Mars and Venus Express

– a team led by QinetiQ (UK), which includes companies and partners in Sweden and Belgium, draws on their expertise in mini and micro satellites including ESA’s SMART-1 and Proba projects

This month the three teams began work and a critical milestone will take place in October when the studies will be reviewed by ESA with the support of an international panel of experts. The results of this phase will be available next year.

The risk is still small however, and may decrease even further when new observations are carried out. Still, if this or any other similar-sized object, such as 99942 Apophis, an asteroid that will come close enough to the Earth in 2029 to be visible to the naked eye, collided with our planet the energy released could be equivalent to a significant fraction of the world’s nuclear arsenal, resulting in devastation across national borders.

Luckily, impacts with very large asteroids are uncommon, although impacts with smaller asteroids are less unlikely and remote in time. In 1908 an asteroid that exploded over Siberia devastated an unpopulated forest area of more than 2000 km2; had it arrived just a few hours later, Saint Petersburg or London could have been hit instead.

Asteroids are a part of our planet’s history. As anyone visiting the Barringer Meteor Crater in Arizona, USA or aiming a small telescope at the Moon can tell, there is plenty of evidence that the Earth and its cosmic neighbourhood passed through a period of heavy asteroid bombardment. On the Earth alone the remains of more than 160 impacts have been identified, some as notorious as the Chicxulub crater located in Mexico?s Yucatan peninsula, believed to be a trace of the asteroid that caused the extinction of the dinosaurs 65 million years ago.

Collisions have shaped the history of our Solar System. Because asteroids and comets are remnants of the turbulent period in which the planets were formed, they are in fact similar to ‘time capsules’ and carry a pristine record of those early days. By studying these objects it is possible to learn more about the evolution of our Solar System as well as ‘hints’ about the origins of life on Earth.

Comet 67P/Churyumov-Gerasimenko is one of these primitive building blocks and will be visited by ESA’s Rosetta spacecraft in 2014, as a part of a very ambitious mission – the first ever to land on a comet. Rosetta will also visit two main belt asteroids (Steins and Lutetia) on its way to comet 67P/Churyumov-Gerasimenko. The mission will help us to understand if life on Earth began with the help of materials such as water and organisms brought to our planet by ‘comet seeding’.

ESA’s Science programme is already looking at future challenges, and its Cosmic Vision 2015-2025 plan has identified an asteroid surface sample return as one of the key developments needed to further our understanding of the history and composition of our Solar System.

Asteroids and comets are fascinating objects that can give or take life on a planetary scale. Experts around the world are putting all their energy and enthusiasm into deciphering the mysteries they carry within them.

With an early launch provisionally scheduled for 2011, Don Quijote will serve as a ‘technological scout’ not only to mitigate the chance of the Earth being hit by a large NEO but also for the ambitious journeys to explore our solar system that ESA will continue to embark upon. The studies now being carried out by European industry will bring the Don Quijote test mission one step nearer.

Original Source: ESA Portal

Posted on by Fraser Cain

Astrophoto: Abell 34 by Jim Misti

Abell 34 by Jim Misti
Most stars do not end their existence in a cataclysmic supernova explosion. For example, our Sun is more typical and someday, in the remote future, the location of our local star will look something like this picture of a distant planetary nebula.

Suns are born from vast clouds of dust and gas that gather in the dark places between the stars. Gravity causes these interstellar vapors to collapse inward until the pressure causes high enough temperatures at its center to fuse hydrogen, the universe’s basic building block, into helium – an event that also releases gamma-ray photons. These photons can take a million years to travel outward through the overlying matter until they reach the surface and escape into space as visible light. The push of the photon’s rush to make an exit also stops the cloud’s collapse and thus what began as thin gas and dust becomes a shining star illuminating the heavens. For billions of years stars, similar to our sun, shine predictably until the hydrogen starts to give out. Then through a series of steps, helium is fused into a succession of elements and the star expands enormously; eventually throwing off its outer surface like a spherical shell. This ends the star’s previous life and marks its passing with a ghostly shroud known as a planetary nebula.

George Abell was a professor at UCLA and an admired research astronomer who began is career as a tour guide at the Griffith Observatory in Los Angeles. As an astronomer, he was best known for his work at Mt. Palomar with the first photographic sky survey conducted in the 1950’s. He cataloged galaxy clusters and contributed to our understanding of their formation and evolution. He also compiled a catalog of 86 faint planetary nebulas discovered as he studied the sky plates taken with Palomar’s 48 inch Oschin Schmidt Telescope.

This planetary nebula is number 34 in Abell’s listing and is located in the constellation of Hydra. It is very faint and has a low surface brightness thus making it very hard to see or photograph, even with a large telescope.

Astronomer Jim Misti produced this exceptional image over three nights in February 2006 using his personal 32-inch telescope located in a dark remote spot in Arizona. The light grasp of Jim’s instrument is several thousand times greater than the unaided eye yet the faintness of this nebula still required over four hours of accumulated exposure time to take this full color picture. Notice, also, the small galaxies located much farther in the distance.

Do you have photos you’d like to share? Post them to the Universe Today astrophotography forum or email them, and we might feature one in Universe Today.

Written by R. Jay GaBany

Posted on by Fraser Cain

What’s Up This Week – April 3 – April 9, 2006

What's Up 2006

Download our free “What’s Up 2006” ebook, with entries like this for every day of the year.

Craters Steinheil and Watt. Image credit: Tammy Plotner. Click to enlarge.
Greetings, fellow SkyWatchers! We’ll take a journey to the Moon this week as we explore some outstanding features that make our “neighbor” such a fascinating target. ‘Tis also the season for aurora and we’ll find out why. Be sure to be on watch for meteors and get out the scope to play, because….

Here’s what’s up!

Monday, April 3 – Today marks the 40th anniversary of the launch of the first lunar orbiter – Luna 10. That makes another good reason to view the Moon tonight!

Just a short distance north of the southern cusp, look for a twin pair of craters on the terminator tonight. These are Steinheil and Watt. The two are nearly identical in size an overlap each other. Steinheil, named for mathematician, physicist, optician, and astronomer Karl August von Steinheil is just bit deeper and to the north. Watt, named for my great gandfather James Watt, Scottish engineer and first man to patent the use of a telescope for surveying, will show a wee bit more detail on its floor.

Right now Earth’s magnetosphere and magnetopause are positioned correctly to interact with the Sun’s influencing interplanetary magnetic field (IMF) – and the plasma stream which flows past us as solar winds. During this time after equinox, this phenomenon leaves the door wide open for one of the most awesome signs of spring – aurora! Visit the Geophysical Institute to sign up for aurora alerts and use their tools to help locate the position of the Earth’s auroral oval.

Tuesday, April 4 – Tonight through binoculars or a telescope, let’s head toward the Moon’s southern quadrant and view Theophilus. Located on the terminator and bordered on the northern edge by Mare Nectaris and to the south by Mare Tranquillitatis, Theophilus has an average diameter of 105 km and contains a wonderful multiple-peaked center. This particular crater is unusual because the floor is parabolic. The interior may be dark, but you should see the Sun catching the summit of its huge central peak.

After the Moon sets, keep the watch for the Kappa Serpentid meteor shower. Its radiant lies near the “Northern Crown” – Corona Borealis. The fall rate is low, with an average 4 or 5 per hour.

Tonight will be the last chance for deep sky studies before the Moon dominates, so let’s take advantage. Did you know that there is a galaxy in Cancer? OK – so you did… But, did you know that the galaxy NGC 2775 has been home to 5 supernovae in the last 30 years, or that it’s one of the most unusual but otherwise perfect spiral shapes in the heavens? Then, get a scope out and start by locating Alpha Cancri and head not quite a fist’s width southeast and in line with Zeta Hydrae. NGC 2775 is a 10.3 magnitude oval of luminosity within a low power field.

Wednesday, April 5 – There’s plenty of Moon to explore tonight, so why not try locating an area where many lunar missions left their mark? Binoculars easily reveal the fully disclosed mares of Serenitatis and Tranquillitatis. Set your sites where these two vast lava plains converge. Telescopically you will see a bright “peninsula” where they meet in the west. Look for bright and small crater Pliny to the east of this point.

It is near this rather inconspicuous feature that the remains of Ranger 6 lay forever preserved after “crash-landing” on February 2nd, 1964. Unfortunately, technical errors prevented Ranger 6 from transmitting lunar pictures. Not so Ranger 8! On a very successful mission to the same basic area, NASA received 7137 “postcards from the near side of the Moon” for 23 minutes before a very hard landing. On the “softer side,” Surveyor 5 touched down near this area safely after two days of malfunctions on September 10, 1967. Incredibly, the tiny Surveyor 5 endured temperatures of up to 283 degrees F, but still spectrographically analyzed the area’s soil and also managed to televise over 18,000 frames of “home movies” from its distant lunar location.

Tonight let’s “see double.” At magnitude 2.5, Gamma Leonis – or Algieba – is second brightest member of the Leo “question mark.” Now we have a question for you. Did you know that Algieba is among the most lovely pairs in the night sky? See for yourself! Separated by less than 5 arc seconds, the primary appears ivory, while the secondary is golden. Those with smaller scopes will enjoy the beauty of the “airy disks” displayed by this pair.

Thursday, April 6 – Tonight let’s return to a now familiar lunar feature, Albategnius. A fine challenge for binoculars will be to see if you can make out its bright central peak from the darker lava-covered floor. Power up with a telescope for another challenge. Can you spot the small craters Vogel and Burnham on its southeast edge? Or Ritchey just outside its eastern wall? Look for craters Halley and Hind just between Albategnius and Hipparchus to the north. Hipparchus also holds a very detailed small crater named Horrocks on its northern wall. Shallow crater Saunder is just to its east.

Ready for another challenge? Then let’s head for Iota Leonis – just south of the triangle that makes up eastern Leo. At magnitude 4, it will be difficult to see its close 7th magnitude companion. This is known as a disparate double – a pair unevenly matched in brightness. One of the most difficult double stars in the heavens!

Friday, April 7 – Today in 1991, the Compton Gamma Ray Observatory (GRO) was deployed. Part of NASA’s Great Observatories program, the CGRO was named to honor Dr. Arthur Holly Compton – a Nobel Prize winning physicist. CGRO scanned six decades of electromagnetic radiation at energy ranges well beyond anything the eye can see. Such energies often happen in bursts as extraordinary and cataclysmic events occur in the cosmos.

Be sure to take your telescope out and have a look at the Moon tonight. One of the most sought-after and unusual features will be visible in the southern half of the Moon near the terminator – Rupes Recta! Also known as “The Straight Wall,” this 130 km (75 mile) long, 366 meter (1200 ft) high feature slopes upward with the steepest angle on the lunar surface (41 degrees). It will be a challenge under these lighting conditions, but look for triple ring of craters Ptolemy, Alphonsus, and Arzachel to guide you. The “Straight Wall” appears as a very thin line stretching across the edge of Mare Nubium.

Be on the lookout for bright streaks from the Delta Draconid meteor shower. Its radiant lies near the border with Cepheus to the east. The fall rate is quite low – around 5 meteors per hour.

Even with the Moon, let’s try for a scattered open cluster toward the west in Auriga. At magnitude 5.4, NGC 2281 should be visible as a nebulous mist in binoculars on a dark night, but you’ll need a scope and high power to darken the sky enough to see the bright members found near its core. NGC 2281 is around 1500 light years distant and 50 million years old. It can best be found by extending a line from Capella to Beta Aurigae an equal distance east to a pair of 5th magnitude stars separated by a finger width. NGC 2281 lies less than one degree southeast of the eastern member of this pair (58 Aurigae.)

Saturday, April 8 – Start your evening by revisiting crater Copernicus as it becomes visible to even the most modest of optical aids. Small binoculars will see Copernicus as a bright “ring” about midway along the lunar dividing line of light and dark called the “terminator.” Telescopes will reveal its 97 km (60 mile) expanse and 120 meter (1200 ft.) central peak to perfection. Copernicus holds special appeal as the aftermath of a huge meteoric impact! At 3800 meters deep, its walls are 22 km thick. Over the next few days, the impact ray system extending from this tremendous crater will become wonderfully apparent.

Tonight we’ll use Copernicus as a guide and look north-northwest to survey the Carpathian Mountains. The Carpathians ring the southern edge of Mare Imbrium beginning well east of the terminator. But let’s look on the dark side. Extending some 40 km beyond into the Moon’s own shadow, you can continue to see bright peaks – some reaching 2000 meters high! Tomorrow, when this area is fully revealed, you will see the Carpathians begin to disappear into the lava flow forming them. Continuing onward to Plato – on the northern shore of Mare Imbrium – look for the singular peak of Pico. Between Plato and Mons Pico you will find the many scattered peaks of the Teneriffe Mountains. It is possible that these are the remnants of much taller summits of a once precipitous range. Now the peaks rise less than 2000 meters above the surface. Time to power up! West of the Teneriffes, and very near the terminator, you will see a narrow line of mountains, very similar in size to the Alpine Valley. This is known as the Straight Range and some of its peaks reach as high as 2000 meters. Although this doesn’t sound particularly impressive, that’s over twice as tall as the Vosges Mountains in west central Europe and on average, comparable to the Appalachian Mountains of the eastern United States.

Sunday, April 9 – Tonight let’s continue our lunar mountain climbing expedition and revisit the “big picture” on the lunar surface. Tonight all of Mare Imbrium is bathed in sunlight and we can see its complete shape. Appearing as a featureless ellipse bordered by mountain ranges, let’s identify them all again. Starting at Plato and moving east to south to west you will find the Alps, the Caucasus, the Apennine and the Carpathians mountains. Look at the form closely=85doesn’t it look like it’s possible that an enormous impact created the entire area? Compare it to the younger Sinus Iridium ringed by the Juras Mountains. It may have also been formed by a much later and very similar massive impact event.

In the mood for a double star? Then let’s head west and away from the Moon. Begin your search right after skydark with El Nath – Beta Tauri. From Beta shift about two finger-widths east-northeast to identify very dim 26 Aurigae. At low power, look for an 8th magnitude companion due west of the 5.5 magnitude primary. The brighter star should give a warm yellow appearance while the fainter appears slightly more blue. This pair shares space with a third member (magnitude 11.5) – some three times further out from the primary than the closer, brighter secondary. Thanks to lunacy, small instruments will have difficulty distinguishing the C star in such bright skies.

May all your journeys be at light speed… ~Tammy Plotner. (contributing writer: Jeff Barbour).

Posted on by Fraser Cain

Mars Aerobraking Begins

Image showing the heat being emitted from the day and night side of Mars. Image credit: NASA Click to enlarge
Now firmly in orbit around the Red Planet, NASA’s Mars Reconnaissance Orbiter has begun a series of maneuvers through the atmosphere to slow itself down even further. The process is called aerobraking, and each successive pass slows it down a little bit, lowering its orbit. After 6 months of aerobraking, sweeping through the atmosphere 550 times, the spacecraft will be in its final science orbit.

NASA’s Mars Reconnaissance Orbiter yesterday began a crucial six-month campaign to gradually shrink its orbit into the best geometry for the mission’s science work.

Three weeks after successfully entering orbit around Mars, the spacecraft is in a phase called “aerobraking.” This process uses friction with the tenuous upper atmosphere to transform a very elongated 35-hour orbit to the nearly circular two-hour orbit needed for the mission’s science observations.

The orbiter has been flying about 426 kilometers (265 miles) above Mars’ surface at the nearest point of each loop since March 10, then swinging more than 43,000 kilometers (27,000 miles) away before heading in again. While preparing for aerobraking, the flight team tested several instruments, obtaining the orbiter’s first Mars pictures and demonstrating the ability of its Mars Climate Sounder instrument to track the atmosphere’s dust, water vapor and temperatures.

On Thursday, Mars Reconnaissance Orbiter fired its intermediate thrusters for 58 seconds at the far point of the orbit. That maneuver lowered its altitude to 333 kilometers (207 miles) when the spacecraft next passed the near point of its orbit, at 6:46 a.m. Pacific time today (9:46 a.m. Eastern Time).

“We’re not low enough to touch Mars’ atmosphere yet, but we’ll get to that point next week,” said Dr. Daniel Kubitschek of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., deputy leader for the aerobraking phase of the mission.

The phase includes about 550 dips into the atmosphere, each carefully planned for the desired amount of braking. At first, the dips will be more than 30 hours apart. By August, there will be four per day.

“We have to be sure we don’t dive too deep, because that could overheat parts of the orbiter,” Kubitschek said. “The biggest challenge is the variability of the atmosphere.”

Readings from accelerometers during the passes through the atmosphere are one way the spacecraft can provide information about upward swelling of the atmosphere due to heating.

The Mars Climate Sounder instrument also has the capability to monitor changes in temperature that would affect the atmosphere’s thickness. “We demonstrated that we’re ready to support aerobraking, should we be needed,” JPL’s Dr. Daniel McCleese, principal investigator for the Mars Climate Sounder, said of new test observations.

Infrared-sensing instruments and cameras on two other Mars orbiters are expected to be the main sources of information to the advisory team of atmospheric scientists providing day-to-day assistance to the aerobraking navigators and engineers. “There is risk every time we enter the atmosphere, and we are fortunate to have Mars Global Surveyor and Mars Odyssey with their daily global coverage helping us watch for changes that could increase the risk,” said JPL’s Jim Graf, project manager for the Mars Reconnaissance Orbiter.

Using aerobraking to get the spacecraft’s orbit to the desired shape, instead of doing the whole job with thruster firings, reduces how much fuel a spacecraft needs to carry when launched from Earth. “It allows you to fly more science payload to Mars instead of more fuel,” Kubitschek said.

Once in its science orbit, Mars Reconnaissance Orbiter will return more data about the planet than all previous Mars missions combined. The data will help researchers decipher the processes of change on the planet. It will also aid future missions to the surface of Mars by examining potential landing sites and providing a high-data-rate communications relay.

Test observations from the Mars Climate Sounder, other images and additional information about Mars Reconnaissance Orbiter are available online at http://www.nasa.gov/mro and at http://marsprogram.jpl.nasa.gov/mro .

For information about NASA and agency programs on the Web, visit http://www.nasa.gov .

Original Source: NASA News Release