Posted on by Fraser Cain

ESO Provides Views of N44 Nebula

Image credit: ESO

The European Southern Observatory has released new images of nebula N44 in the Large Magellanic Cloud. Astronomers used the ESO’s Wide-Field-Imager on the 2.2 metre La Silla Observatory to capture the area with unprecedented clarity. N44 is approximately 1,000 light-years across and contains about 40 bright luminous blue stars. The blue stars live for a very short time and then explode as supernovae – some have already exploded in the area, creating some of the nebula’s visible material.

The two best known satellite galaxies of the Milky Way, the Magellanic Clouds, are located in the southern sky at a distance of about 170,000 light-years. They host many giant nebular complexes with very hot and luminous stars whose intense ultraviolet radiation causes the surrounding interstellar gas to glow.

The intricate and colourful nebulae are produced by ionised gas [1] that shines as electrons and positively charged atomic nuclei recombine, emitting a cascade of photons at well defined wavelengths. Such nebulae are called “H II regions”, signifying ionised hydrogen, i.e. hydrogen atoms that have lost one electron (protons). Their spectra are characterized by emission lines whose relative intensities carry useful information about the composition of the emitting gas, its temperature, as well as the mechanisms that cause the ionisation. Since the wavelengths of these spectral lines correspond to different colours, these alone are already very informative about the physical conditions of the gas.

N44 [2] in the Large Magellanic Cloud is a spectacular example of such a giant H II region. Having observed it in 1999 (see ESO PR Photos 26a-d/99), a team of European astronomers [3] again used the Wide-Field-Imager (WFI) at the MPG/ESO 2.2-m telescope of the La Silla Observatory, pointing this 67-million pixel digital camera to the same sky region in order to provide another striking – and scientifically extremely rich – image of this complex of nebulae. With a size of roughly 1,000 light-years, the peculiar shape of N44 clearly outlines a ring that includes a bright stellar association of about 40 very luminous and bluish stars.

These stars are the origin of powerful “stellar winds” that blow away the surrounding gas, piling it up and creating gigantic interstellar bubbles. Such massive stars end their lives as exploding supernovae that expel their outer layers at high speeds, typically about 10,000 km/sec.

It is quite likely that some supernovae have already exploded in N44 during the past few million years, thereby “sweeping” away the surrounding gas. Smaller bubbles, filaments, bright knots, and other structures in the gas together testify to the extremely complex structures in this region, kept in continuous motion by the fast outflows from the most massive stars in the area.
The new WFI image of N44

The colours reproduced in the new image of N44, shown in PR Photo 31a/03 (with smaller fields in more detail in PR Photos 31b-e/03) sample three strong spectral emission lines. The blue colour is mainly contributed by emission from singly-ionised oxygen atoms (shining at the ultraviolet wavelength 372.7 nm), while the green colour comes from doubly-ionised oxygen atoms (wavelength 500.7 nm). The red colour is due to the H-alpha line of hydrogen (wavelength 656.2 nm), emitted when protons and electrons combine to form hydrogen atoms. The red colour therefore traces the extremely complex distribution of ionised hydrogen within the nebulae while the difference between the blue and the green colour indicates regions of different temperatures: the hotter the gas, the more doubly-ionised oxygen it contains and, hence, the greener the colour is.

The composite photo produced in this way approximates the real colours of the nebula. Most of the region appears with a pinkish colour (a mixture of blue and red) since, under the normal temperature conditions that characterize most of this H II region, the red light emitted in the H-alpha line and the blue light emitted in the line of singly-ionised oxygen are more intense than that emitted in the line of the doubly-ionised oxygen (green).

However, some regions stand out because of their distinctly greener shade and their high brightness. Each of these regions contains at least one extremely hot star with a temperature somewhere between 30,000 and 70,000 degrees. Its intense ultraviolet radiation heats the surrounding gas to a higher temperature, whereby more oxygen atoms are doubly ionised and the emission of green light is correspondingly stronger, cf. PR Photo 31c/03.

Original Source: ESO News Release

Posted on by Fraser Cain

Closest Galaxy Discovered

Image credit: CNRS

An international team of astronomers have discovered a new galaxy colliding with our own Milky Way. This new galaxy, Canis Major, is located only 42,000 light years away from the centre of the Milky Way – it’s our new “closest galaxy”. Canis Major was discovered during an infrared survey of the sky, which allowed the astronomers to peer through the obscuring dust and gas of the Milky Way. Canis Major is quite small (as galaxies go); it only contains about a billion stars.

An international team of astronomers from France, Italy, the UK and Australia has found a previously unknown galaxy colliding with our own Milky Way. This newly-discovered galaxy takes the record for the nearest galaxy to the centre of the Milky Way. Called the Canis Major dwarf galaxy after the constellation in which it lies, it is about 25000 light years away from thesolar system and 42000 light years from the centre of the Milky Way. This i closer than the Sagittarius dwarf galaxy, discovered in 1994, which is also colliding with the Milky Way. The discovery shows that the Milky Way is building up its own disk by absorbing small satellite galaxies. The research is to be published in the Monthly Notices of the Royal Astronomical Society within the next few weeks.

The discovery of the Canis Major dwarf was made possible by a recent survey of the sky in infrared light (the Two-Micron All Sky Survey or “2MASS”), which has allowed astronomers to look beyond the clouds of dust in the disk of the Milky Way. Until now, the dwarf galaxy lay undetected behind the dense disk. “It’s like putting on infrared night-vision goggles,” says team-member Dr Rodrigo Ibata of Strasbourg Observatory. “We are now able to study a part of the Milky Way that has been previously out of sight”.

The new dwarf galaxy was detected by its M-giant stars =AD cool, red stars that shine especially brightly in infrared light. “We have used these rare M-giant stars as beacons to trace out the shape and location of the new galaxy because its numerous other stars are too faint for us to see,” explains Nicolas Martin, also of Strasbourg Observatory. “They are particularly useful stars as we can measure their distances, and so map out the three-dimensional structure of distant regions of the Milky Way disk.” In this way, the astronomers found the main dismembered corpse of the dwarf galaxy in Canis Major and long trails of stars leading back to it. It seems that streams of stars pulled out of the cannibalised Canis Major galaxy not only contribute to the outer reaches of the Milky Way’s disk, but may also pass close to the Sun.

Astronomers currently believe that large galaxies like the Milky Way grew to their present majestic proportions by consuming their smaller galactic neighbours. They have found that cannibalised galaxies add stars to the vast haloes around large galaxies. However, until now, they did not appreciate that even the disks of galaxies can grow in this fashion. Computer simulations show that the Milky Way has been taking stars from the Canis Major dwarf and adding them to its own disk – and will continue to do so.

“On galactic scales, the Canis Major dwarf galaxy is a lightweight of about only one billion Suns,” said Dr. Michele Bellazzini of Bologna Observatory. “This small galaxy is unlikely to hold together much longer. It is being pushed and pulled by the colossal gravity of our Milky Way, which has been progressively stealing its stars and pulling it apart.” Some remnants of the Canis Major dwarf form a ring around the disk of the Milky Way.

“The Canis Major dwarf galaxy may have added up to 1% more mass to our Galaxy,” said Dr Geraint Lewis of the University of Sydney. “This is also an important discovery because it highlights that the Milky Way is not in its middle age – it is still forming.” “Past interactions of the sort we are seeing here could be responsible for some of the exquisite detail we see today in the structure of the Galaxy,” says Dr Michael Irwin of the University of Cambridge.

Original Source: RAS News Release

Posted on by Fraser Cain

ESA Watches Earthquakes Shake the Sky

Image credit: ESA

When a powerful earthquake shook the ground in Alaska a year ago, it also set the Earth’s atmosphere shaking. A team of European scientists used the Global Positioning System to map disturbances in the Earth’s ionosphere after a 7.9 magnitude earthquake struck Denali, Alaska. The ionosphere starts at 75 km and goes up to 1,000 km altitude, and it amplifies any disturbance that happens on the ground beneath it – one millimeter disturbance on the ground could become a 100 metre oscillation at 75 km altitude. This gives scientists a new tool to track earthquakes around the world.

A violent earthquake that cracked highways in Alaska set the sky shaking as well as the land, an ESA-backed study has confirmed.

This fact could help improve earthquake detection techniques in areas lacking seismic networks, including the ocean floor.

A team from the Institut de Physique du Globe de Paris and the California Institute of Technology has successfully used the Global Positioning System (GPS) satellite constellation to map disturbances in the ionosphere following last November?s magnitude 7.9 earthquake in Denali, Alaska.

Their paper has been published in the scientific journal Geophysical Research Letters. The research itself was carried out in support of ESA?s Space Weather Applications Pilot Project, aimed at developing operational monitoring systems for space conditions that can influence life here on Earth.

The ionosphere is an atmospheric region filled with charged particles that blankets the Earth between altitudes of about 75 to 1000 km. It has a notable ability to interfere with radio waves propagating through it.

In the particular case of GPS navigational signals, received on Earth from orbiting satellites, fluctuations in the ionosphere ? known as ‘ionospheric scintillations’ – have the potential to cause signal delays, navigation errors or in extreme cases several hours of service lockouts at particular locations.

But while such interference can be an inconvenience for ordinary GPS users, it represents a boon for scientists. By measuring even much smaller-scale shifts in GPS signal propagation time – caused by variations in local electron density as the signal passes through the ionosphere – researchers have at their fingertips a means of mapping ionospheric fluctuations in near real time.

The French and US team made use of dense networks of hundreds of fixed GPS receivers in place across California. These networks were originally established to measure small ground movements due to geological activity, but they can also be utilised to plot the ionosphere structure across three dimensions and in fine detail.

Then when the Denali earthquake occurred on 3 November 2002, the team had a chance to use this technique to investigate another distinctive property of the ionosphere, its ability to work like a natural amplifier of seismic waves moving across the Earth?s surface.

There are several different types of seismic waves moving the ground during an earthquake, the largest scale and the one that does most of the movement is known as a Rayleigh Wave. This type of wave rolls along the ground up and down and side-to-side, in the same way as a wave rolls along the ocean.

Previous research has established that shock waves from Rayleigh Waves in turn set up large-scale disturbances in the ionosphere. A one millimetre peak-to-peak displacement at ground level can set up oscillations larger than 100 metres at an altitude of 150 km.

What the team were able to do following the Denali quake was detect a distinctive wavefront moving through the ionosphere. “Using the network allowed us to observe the propagation of the waves,” explained co-author Vesna Ducic. “We could also separate the small total electron content signal from the very large total electron content variations related to the daily variation of the ionosphere.”

The team observed a signal two to three times larger than the noise level, arriving about 660 to 670 seconds after the arrival of Rayleigh Waves on the ground. And because around six GPS satellites are visible to every ground receiver they were able to calculate the altitude of maximum perturbation ? around 290 to 300 km up.

The signals were weak and only sampled every 30 seconds, with a maximum resolution of 50 km and the overall noise rate high. But the ionospheric signal observed had a clear pattern consistent with models of seismic behaviour. The hope is that the technique can be improved in future, and used to detect earthquakes in areas without seismic detectors, such as the deep ocean or near islands.

“In the framework of Galileo we plan to develop this research,? said Ducic. “Galileo will double the number of satellites and therefore will allow much more precise maps of the ionosphere. We can also foresee that Europe will develop a dense network of Galileo/GPS stations that will take part in the monitoring of these phenomena.

“ESA, together with the French Ministry of Research and CNES have already decided to fund a pre-operational project called SPECTRE – Service and Products for Ionosphere Electronic Content and Tropospheric Refractive index over Europe from GPS – devoted to the high-resolution mapping of the ionosphere. We will be carrying out mapping above Europe as well as California.

“These investigations will support the French space agency CNES?s DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) microsatellite, to be launched in 2004 and devoted to the detection in the ionosphere of seismic, volcanic and man-made signals. These ESA activities will be performed in the framework of the Space Weather Applications Pilot Project.”

The Space Weather Applications Pilot Project is an ESA initiative which has already begun to develop a wide range of application-oriented services based around space weather monitoring.

The co-funded services under development – of which this project is one – also include forecasting disruption to power and communication systems, and the provision of early warning to spacecraft operators of the hazards presented by increased solar and space weather activities. The hope is that an a seismic detection service based on ionospheric measurements may in future supplement existing resources in Europe and elsewhere.

Original Source: ESA News Release

Posted on by Fraser Cain

NASA Orders Pegasus and Taurus Rockets for Future Launches

Image credit: Orbital

NASA has ordered four launch vehicles from Orbital Sciences Corporation, including two Pegasus and two Taurus rockets, for future missions. The Pegasus rockets will launch NASA’s Space Technology-8 and Small Explorer-10 missions. The Taurus rockets will launch the GLORY satellite and the Orbiting Carbon Observer. NASA has been working with Orbital for 12 years and purchased 25 rockets to launch various missions into space.

Orbital Sciences Corporation (NYSE: ORB) announced today that the National Aeronautics and Space Administration (NASA) has ordered four space launch vehicles, including two Pegasus and two Taurus rockets, for U.S. government scientific satellite missions scheduled to be launched over a two-year period beginning in 2006. The orders were placed under the Small Expendable Launch Vehicles Services (SELVS) contract that was awarded to Orbital by NASA’s Kennedy Space Center in 1998.

The two new Pegasus vehicles will be used to launch the satellites designated for NASA’s Space Technology-8 (ST-8) and Small Explorer-10 (SMEX-10) missions. The two Taurus missions are scheduled to launch NASA satellites that Orbital is currently developing and manufacturing at its Dulles, VA facility. The first of the two new Taurus rockets will launch the GLORY satellite for NASA’s Goddard Space Flight Center. The second Taurus rocket will launch the Orbiting Carbon Observer satellite for the Jet Propulsion Laboratory.

With these new launch vehicle orders, NASA is continuing a 12-year relationship with Orbital for Pegasus and derivative rockets, which began in 1991. During this time, the space agency has purchased 25 Pegasus, Taurus and related launch vehicles for a wide range of Earth and space science and technology demonstration missions. Fourteen of these launches have been carried out to date, while another 11 are planned from 2004 to 2008.

“Orbital is very pleased with NASA’s continued commitment to our space launch vehicle products,” said Mr. David W. Thompson, Orbital’s Chairman and Chief Executive Officer. “We look forward to continuing the excellent working relationship that our launch vehicle team has established with its NASA counterparts. Together, our shared goal is to reliably support the scientific community’s use of small satellites for highly productive Earth and space science investigations.”

About the Pegasus Launch System
Pegasus is the world’s leading launch system for the deployment of small satellites weighing up to 1,000 pounds into low-Earth orbit. Its patented air-launch system, in which the rocket is launched from beneath Orbital’s “Stargazer” L-1011 carrier aircraft over the ocean, reduces cost and provides customers with unparalleled flexibility to operate from virtually anywhere on Earth with minimal ground support requirements.

First launched in 1990, Pegasus is the world’s only small launch vehicle to have earned NASA’s Category-3 certification, which allows the U.S. space agency to launch its most valuable payloads aboard the rocket. A Category-3 certification is achieved through a long-term record of highly reliable launch services, such as the current record of 21 consecutive successful Pegasus missions carried out since 1997.

About the Taurus Launch System
Orbital developed the ground-launched Taurus vehicle to provide a cost-effective, reliable means of launching satellites weighing up to 3,000 pounds into low-Earth orbit. First launched in 1994, Taurus incorporates advanced structural and avionics technology proven on Pegasus and other operational launch systems and is designed for easy transportability, offering customers rapid-response launches from a wide range of locations.

About Orbital
Orbital develops and manufactures small space systems for commercial, civil government and military customers. The company’s primary products are satellites and launch vehicles, including low-orbit, geostationary and planetary spacecraft for communications, remote sensing and scientific missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense boosters that are used as interceptor and target vehicles. Orbital also offers space-related technical services to government agencies and develops and builds satellite-based transportation management systems for public transit agencies and private vehicle fleet operators.

Original Source: Orbital News Release

Posted on by Fraser Cain

China Launches Science Satellite

A Chinese-built science satellite was launched Monday by a Long March 2-D booster from the Jiuquan launch centre in Northwestern China. The FSW-18 satellite was launched into low Earth orbit at 0720 GMT (2:20 am EST). It will stay in orbit for 18 days and perform a series of scientific experiments and then return to Earth. This is China’s third launch in just over two weeks, including their historic launch of astronaut Yang Liwei who orbited the earth 14 times.

Posted on by Fraser Cain

Cassini Listens to a Solar Storm

Image credit: NASA/JPL

The Sun ejected two massive flares towards the Earth last week, and NASA’s Cassini spacecraft listened in on the burst of radio waves that accompanied them. The radio waves took 69 minutes to reach Cassini, moving at the speed of light, and they sound a bit like the whoosh of a jet engine. The blast of radio waves was one of the largest ever recorded – a type 3 event. Cassini is on track to reach Saturn on July 1, 2004.

University of Iowa Professor and Space Physicist Dr. Don Gurnett used NASA’s Cassini spacecraft to record the sound of one of the largest solar flares seen in decades, as it moved outward from the Sun.

The sound can be heard online at: http://www-pw.physics.uiowa.edu/space-audio/.

NASA’s Solar and Heliospheric Observatory (SOHO) spacecraft captured this image of a solar flare, seen in the lower center of the image, as it erupted from the Sun early on Tuesday, October 28, 2003.

The radio wave burst, resembling the clicking of an old-fashioned telegraph machine followed by the rush of a jet engine, was recorded Oct. 28 by Cassini while on its way to a July 1, 2004, encounter with Saturn. Cassini will be the first orbiter to give us a close-up look at the ringed world and its moons. Its piggybacked Huygens probe, contributed by the European Space Agency, will descend through the smoggy atmosphere of Saturn’s moon Titan, impacting on what could be a liquid methane ocean.

Gurnett noted that the radio waves — moving at the speed of light — took just 69 minutes to reach the spacecraft, currently some 1.3 billion kilometers (809 million miles) from Earth.

“This is one of the biggest events of its kind ever seen,” said Gurnett. The event, described as a “type 3” radio burst, was detected using the Cassini radio and plasma wave instrument, largely built at the University of Iowa, and for which Gurnett serves as principal investigator.

“The sound is produced by electrons moving out from the solar flare, beginning at a high frequency before dropping to a lower frequency,” Gurnett said. Scientists monitoring the solar flare said that the massive cloud — composed of billions of tons of electrically charged particles — reached Earth on Oct. 29.

Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of Caltech, manages the mission for NASA’s Office of Space Science, Washington, D.C.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Aurora Reports from Around the World

The aurora reports are in. Universe Today readers from around the world have kept their eyes to the sky over the last few days and seen some of the best auroras in several decades. In the Northern Hemisphere, I’ve heard reports from as far south as Florida and Texas, while people in Australia and New Zealand have been treated to a show as well. It looks like Northern Europe, especially Scotland had some of the best auroras – for two straight evenings.

Here are some emails I received over the last day from people lucky enough to see the auroras. Did you spot them? Send me an email at [email protected] and I’ll post your comments. Send in any pictures in JPEG format.

In Edgecome Maine we had a unique display which was predominately bright red, at times like the sky was painted with red paint. It all came from a very specific point directly over head. The brightest color was between 7:30 and 8pm and lasted until about 9pm or a little later. This was the best I’ve seen them in this area ever. – Caleb, Edgecome, Maine

I was lucky enough to see an aurora on Wednesday night at around 21.30 (gmt) it was along the northern horizon and was pale green in colour.It extended up to about the height of Ursa Major this was the first time i had seen a aurora from this location in England since the 1980s. My observing co-ordinates are 52.560″N 0.109W. – Martin, England

Last night around 7 PM I hopped outside and was awed… very similar to the time I saw the aurora back in 1991. Almost the entire northern horizon was vertical bands of white, slowing moving and changing shape. Moving up away from the horizon, the color changed to red and at some points the very faint bands were actually nearly directly overhead, slowly progressing and fading out. – Mark, Pennsylvania, USA

Well, I discovered today that you don?t have to travel very north to see some Northern Lights. As an Ohioan, I have been waiting my entire life to come across these magnificent light shows, and tonight my wish came true. My fianc? and I have been planning to travel to Alaska or Canada to see these aurora, but we didn?t have to go very far tonight. We were just sitting on the porch passing out candy for the Halloween Trick-or-Treaters here in Elyria, Ohio (near Cleveland) and we saw a beautiful cloud of red in the sky. I gasped and said, ?Look! Do you know what that is???? My fianc? replied, ?No. It?s not an aurora, honey. It?s just some smoke from a fire.? Even though I had never seen one in my life, I knew exactly what it was. The streams of color got brighter and more distinct as it drew higher and higher in the sky. The pattern of lights was moving slowly, and they hung in the atmosphere for quite a while? I?m guessing about 20 minutes. My mother was with us, so she took some pictures while the passers-by looked at me like I was crazy (Imagine a girl dressed as Cleopatra standing motionless in the middle of the driveway staring at the sky). We just have to get the pictures developed; I can?t wait! I?m not expecting much from them, though. We did not have a tripod, and the exposures were fairly long. But the experience was unexplainable. I will never forget this Halloween year! – Lindsey, Ohio

We saw red streams in the sky similar to the shape of an umbrella overhead with a centre core, it appeared wine/red and white colour stripes shifting as we watched. It was an amazing site to see the reddish glow. – Sandra, Prince Edward Island, Canada

I saw green spires below Polaris, and then huge blue/white pillars of light moving in waves directly through Cassiopeia and across into Andromeda. Fantasy clouds of glowing red continued to appear and disappear covering these northeastern constellations. Stretching laterally through Auriga, the pure blue/green “wave” of aurora caught and held. Holding out my shaking hands, I realized this was roughly 20 degrees in length and fluctuated anywhere from 5 to 10 degrees in width. I watched amazed as the ribband seemed to undulate in colors – running anywhere from a pale cyan to a vivid orange. The soft white pillars, like distant searchlights, continued to alternate sky positions from the northeastern horizon up to the zenith. Soft red “clouds” were appearing in patches here and there… But I couldn’t stop staring at the ribband. Sparing a look behind me, I saw that the clouds were fast returning from the southwest and I realized I was on borrowed time. I enjoyed a solid 20 minutes of incredible auroral activity. – Tammy, Ohio

Early Tuesday morning, I saw the red glow in the sky above some clouds that were closer to the horizon. If there was any green below the red, it was obscured by the clouds. I saw it at around 3:15 CST in Imperial, Missouri, just south of St. Louis, Missouri. The coloring was similar to that in your picture (below), but not quite as vivid here. – Theresa, Missouri, USA

We had an awesome display last night (the 29th) in Akron Ohio (app 41 degrees North). We had about a 2 hour clear window until 9:30 or so. Bright red/pink at the horizon with occasional pink/reddish blobs toward the zenith. Rarely there were the typical greenish rays flickering, but that was not a constant sight in our moderately light polluted area. The maximum color was around 7:30-8:00, EST. – Tom, Ohio, USA

I work at the Mills Observatory in Dundee which is the only full time public observatory in the UK and we got a fantastic view of the aurora last night. It was the brightest aurora I have ever seen – Robert, Scotland

I was flying from Toronto to Ottawa last night around 8:30pm and saw them from the aircraft. Luckily I was on the side if the plane that was facing north. They were green, but very, very bright. I could see the wing clearly by the aurora light. I thing the rest of the people on the plane must of thought I was nuts though. I was sitting looking out the window with my jacket hood over my head to block the internal lights… I suspect I was the only person (apart from the pilots) on the plane that saw them. – Andrew, Ontario, Canada

So there I am, thinking “I’ll just take a peek at the night sky before going to bed”. On any other night I would have been out with the telescope but I’d been playing football and wanted to go to bed! Looking to the south I saw Orion, Taurus, and those other wonderful winter constellations letting me know that my serious astronomy for the year was about to begin. Looking north I saw a hazy light that I immediately attributed to hazy cloud. Something rang a bell in my mind though, someone said “What was it that Universe Today article said?”. And so I allowed my eyes to become accustomed to the dark and observed the Northern Lights! Shimmering waves of light like waterfalls glowed gently in the sky, occasionally flaring up and flashing in places as they slowly shifted and danced around Ursa Major, Ursa Minor, Draco and all those so familiar northern constellations. To see them bathed in that wonderful glow, for the first time since I started looking at the sky 20 years ago, made me grateful to Nature (for the terrific show), Science (for the understanding of what I was looking at) and to Universe Today, without which I would have dismissed them as merely hazy cloud without a second thought. – Stefan, York, England

Humungous aurora over central Scotland this evening. First saw it about 19.00 UT and it’s still continuing unabated (23.30 UT). Conditions are far from ideal with a lot of high, thin cloud and a fair bit of thicker cloud here and there. Nevertheless we had everything – pulsing patches; rays; streamers; curtains and several coronas (coronae?). The whole sky was involved, with a lot of the best action being to the South. About 50 people were watching it from the Mills Observatory in Dundee, and were totally bowled over by the experience. Unfortunately, being really busy with visitors we didn’t get the opportunity to take any pics (sigh!) but what a night! This is far and away the best, longest aurora I’ve witnessed in my 50-odd years interest in astronomy. – Bill, Dundee, Scotland

Just thought I would report a wonderful aurora I saw this morning here in Australia,I am at 33degrees south and I was up from 2:30 am to 4:30 am looking south I saw white shafts of bright light extending 90 degrees above my head,these lights changed positions constantly, no red or green colours were seen. – Leon, Australia

After the powerful CME solar event of 29 October 2003, I observed an aurora between 2am-3.30am (local daylight savings time) from Wollongong, New South Wales, Australia on 30 October 2003. It was not very bright, although digital photographs showed an intense red below turning to blue on the higher sections. You could see the red colour faintly with the unaided eye. The aurora consisted of slow moving “searchlight beams” that travelled west to east, over the horizon at the South Celestial Pole in a slow consistent fashion, sometimes fading in and out. There was an overall reddish haze too. Mostly the beams were faint but distinct and quite tall (about 40 degrees in height) reaching as high as the top of Crux, the Southern Cross, apart from a small number of beams that increased in brightness at 3am for 5 minutes. It was still a beautiful sight and 90 minutes is quite a long period to view such an event considering the relatively high latitude of 35 deg. S. – Christian, Wollongong, Australia

Thought I’d drop a line to say that tonight I have seen the Aurora at 8pm(GMT) which was long ribbons of light bands extending East to West but rippling from North to South. Some were coloured greenish but most were mainly white. It looked spectacular against the clear sky, almost like someone waving a searchlight around the sky. – Russ, Dundee, Scotland

Yes, I did see the Aurora Borealis here tonight! Here is the island ?meland in the north of the Netherlands. Between aprox. 22.15hrs. and 23.30hrs.(local time,ofcourse, GMT +1) the sky turned ruby-red with delicate pale-yellow bands and strings.We have seen the Aurora many times ,but we never saw such an intense red.At the end of tonights show the whole of the nothern horizon looked as a midsummer-nightsky,when the sun hardly dissapears. It was great to watch. – Ingrid, The Netherlands

Posted on by Fraser Cain

Storm Compressed the Earth’s Magnetosphere

Image credit: ESA

The European Space Agency’s Cluster spacecraft were perfectly positioned to watch the effect of the recent solar storms on the Earth’s magnetosphere. Normally the magnetosphere bubbles out in front of the Earth by about 64,000 km, but during the storm it was down to only 43,000 km. The speed at which the magnetosphere compressed will help scientists calculate the power of the storm, and make more accurate predictions for what will happen in future storms.

On the 24th of October 2003, the SOHO spacecraft registered a huge Coronal Mass Ejection (CME), emitted by the Sun. Several hours later this eruption reached the Earth and was detected by a number of spacecraft including Cluster.

The ACE spacecraft, situated along the Sun/Earth direction, was situated about 1 500 000 km upstream from the Earth, monitoring the solar wind. At about 14:49 UT, ACE recorded a sharp increase on the proton velocity, which jumped from about 450 kms-1 to more than 600 km-1 . The proton density, which was about 3 to 4 particles cm-3 , increased to more than 20. The proton temperature in the solar wind at this instant was also multiplied by a factor of 8.

The four Cluster spacecraft were in the southern magnetospheric lobe, inbound towards their perigee. Note that the Sun, ACE, Cluster and the Earth were almost aligned when the CME was ejected from the Sun. Cluster was situated close to the inner magnetosphere (near to the ring current region) when it detected the effects of the solar wind pressure on the magnetosphere: The sudden increase of the solar wind pressure registered by ACE arrived at the Earth?s magnetosphere about 40 minutes later. It provoked a huge compression of the dayside magnetosphere. The Cluster spacecraft detected this compression by getting suddenly out of the southern magnetospheric lobe into the Magnetosheath. They thus detected the Magnetopause, moving earthward, at about 15:25 UT. They remained into the Magnetosheath until about 17:00 UT, when they were only at a 6.8 RE (Earth radii) distance from the Earth. The transition between the lobes and the Magnetosheath was characterised by an important ion density increase (from close to 0 in the lobe to more than 160 particles cm-3 in the Magnetosheath) as well as a very clear signature in the velocity components, as measured by the CIS experiment onboard Cluster (P.I: Henri R?me).

This is a very unusual position for the Magnetopause, which on the average is standing ahead of the Earth at about 10 to 11 RE. Such compressions can have dramatic space weather effects, particularly to geostationnary satellites which are orbiting the Earth at a distance of about 6.6 RE. Further analysis of the four spacecraft data will tell us at what speed the magnetopause moved which will give information on the strength of the CME.

Original Source: ESA News Release

Posted on by Fraser Cain

Hubble Sees a Huge Star Forming Region

Image credit: ESA

The Hubble Space Telescope was recently used to peer into a star forming region that’s a million times more active than the Orion Nebula. The Lynx Arc contains a million blue-white stars (the Orion Nebula has four) which are twice as hot as similar stars in our own Milky Way galaxy; but this cluster is located 12 billion light-years away, and seen when the Universe was only 2 billion years old. This discovery will help astronomers understand how some of the first stars formed shortly after the Big Bang.

A mysterious arc of light found behind a distant cluster of galaxies has turned out to be the biggest, brightest and hottest star-forming region ever seen in space.

The so-called Lynx Arc is one million times brighter than the well-known Orion Nebula, a nearby prototypical ?starbirth? region visible with small telescopes. The newly identified super-cluster contains a million blue-white stars that are twice as hot as similar stars in our Milky Way galaxy. It is a rarely glimpsed example of the early days of the Universe where furious firestorms of starbirth blazed across the skies. The spectacular cluster?s opulence is dimmed when seen from Earth only by the fact that it is 12 000 million light years away.

The discovery of this unique and tantalising object was the result of a systematic study of distant clusters of galaxies carried out with major X-ray, optical and infrared telescopes, including the NASA/ESA Hubble Space Telescope, ROSAT and the Keck Telescopes. Bob Fosbury, of the European Space Agency?s Space Telescope-European Coordinating Facility in Germany, and a team of international co-authors report the discovery in the 20 October 2003 issue of the Astrophysical Journal.

The mega-cluster of stars appears as a puzzling red arc behind a distant galaxy cluster 5400 million light-years away in the northern constellation of Lynx. The arc is the stretched and magnified image of a mysterious celestial object about 12 000 million light-years away (at a redshift of 3.36), far beyond the cluster of galaxies. This means that the remote source existed when the Universe was less than 2000 million years old.

Fosbury and colleagues first tried to identify the arc by analysing the light from the object, but the team was not able to recognise the pattern of colours in the spectral signature of the remote object. While looking for matches with the colour spectrum, Fosbury realised that the light was related to that of the nearby Orion Nebula, a star-forming region in our own Milky Way. However where the Orion Nebula is powered by only four hot and bright blue stars, the Lynx Arc must contain around a million such stars!

Furthermore, the spectrum shows that the stars in the Lynx Arc are more than twice as hot as the Orion Nebula?s central stars, with surface temperatures up to 80 000?C. Though there are much bigger and brighter star-forming regions than the Orion Nebula in our local Universe, none are as bright as the Lynx Arc, nor do they contain such large numbers of hot stars.

Even the most massive, normal nearby stars are no hotter than around 40 000?C. However, stars forming from the original, pristine gas in the early Universe can be more massive and consequently much hotter – perhaps up to 120 000?C. The earliest stars may have been as much as several hundred solar masses, but the chemical make-up of the Universe today prevents stars from forming beyond about 100 solar masses. Such ?primordial? super-hot stars are thought to be the first luminous objects to condense after the Big Bang cooled. Astronomers believe that these first ?monster? stars formed considerably earlier than the Lynx Arc ? up to 1800 million years earlier. ?This remarkable object is the closest we have come so far to seeing what such primordial objects might look like when our telescopes become powerful enough to see them,? says Fosbury. The desire to find and study the first luminous objects in the Universe is the main scientific drive behind the construction of the NASA/ESA/CSA James Webb Space Telescope, scheduled for launch in 2011.

Original Source: ESA News Release

Posted on by Fraser Cain

Solar Storm Buffets the Earth

Image credit: SOHO

It started as the largest flare ever seen by the SOHO spacecraft, and only 19 hours later, the associated solar storm reached the Earth. The storm arrived as a G-5, the largest they get on the NOAA space weather scale. There was little disruption on Earth, however, with only some communications disrupted, and it appears that the Japanese might have lost contact with one of their satellites. Beautiful auroras were visible from many parts of the world, as far south in North America as Texas and Florida. People in Scotland reported that the aurora had already started when the Sun went down, and it was still going past midnight.

Forecasters at the NOAA Space Environment Center in Boulder, Colo., said that a powerful geomagnetic storm emitted from the sun sped though space at 5 million mph and reached Earth Wednesday 1:13 a.m. EST. NOAA space weather forecaster Larry Combs said, ?It took the geomagnetic storm just 19 hours to reach Earth after it occurred on the sun. That?s one of the fastest traveling solar storms this cycle.? The storm came in as a G-5 or extreme geomagnetic storm on the NOAA space weather scales, which run 1 to 5. (Click here to view larger image from the SOHO spacecraft of the intense solar activity on the sun taken Oct. 28, 2003, at 5:24 p.m. EDT. Click here to view high resolution version, which is a large file. Click here to view latest images. Please credit ?SOHO.?)

The solar flare caused an S-4 radiation event, which is the fourth largest in history since NOAA began keeping records in 1976. It?s also the second largest radiation event during this cycle of the sun.

Combs said, ?The geomagnetic storm is expected affect the Earth for the next 12 to 24 hours, but NOAA is forecasting that further major eruptions in these active regions of the sun will continue for the next week.?

Reports received by NOAA indicate that power grids in the northern United States and Canada are feeling the effects of the extreme geomagnetic storm. Utilities are experiencing power surges and are closely monitoring their systems. NOAA received a report that the Aurora Borealis, or northern lights, were visible as far south as El Paso, Texas.

?The NOAA Space Environment Center is home to the nation?s early warning system for solar activities that directly affect people and equipment?, explained retired Navy Vice Admiral Conrad Lautenbacher, undersecretary of commerce for oceans and atmosphere and NOAA administrator. ?Big solar storms like the current one can create brilliant northern lights but can also threaten with increased exposure to X-rays, damage and disrupt communications, energy delivery systems and aviation operations. SEC?s 24 hour-a-day, 7 day-a-week operations are critical to protecting space and ground-based assets.?

Through the NOAA Space Environment Center, NOAA and the U.S. Air Force jointly operate the space weather operations center that continuously monitors, analyzes and forecasts the environment between the sun and Earth. In addition to the data gathered from NOAA and NASA satellites, the center receives real-time solar and geophysical information from ground based-observatories around the world. The NOAA space weather forecasters use the data to predict solar and geomagnetic activity and issue worldwide alerts of extreme events.

The NOAA Space Environment Center plays a leadership role in the space weather community and helps foster a space weather services industry.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation?s coastal and marine resources. NOAA is part of the U.S. Department of Commerce.

Original Source: NOAA