Universe Today

April 3, 2008December 24, 2015 by Ian O'Neill

There is No Sun-Link with Global Warming

The connection between solar activity and global warming has been a contentious issue for a long time. The idea that cosmic rays create global cloud cover just doesn’t seem to be working out; even the highest estimates of cloud cover variation caused by cosmic ray flux predict the effect to be very small. Now UK scientists have stepped into the debate, producing scientific evidence that there is no link between global warming, cosmic rays and solar activity. Sorry global warming sceptics, we might have to cut back on the emissions after all…

The connection between solar activity and global warming is thought to go like this: The Sun experiences massive changes in energy output throughout the 11-year solar cycle. At its peak (at solar maximum), the Sun’s influence over local space is at its highest. Its massive magnetic field will envelop the Earth and spiral into interplanetary space. As it does so, the immense and large-scale solar wind will deflect high energy cosmic rays. So, counter-intuitively, when the Sun is at its most active, cosmic ray collisions with the atmosphere is at its lowest. It is has been predicted by scientists such as Henrik Svensmark at the Danish National Space Center (DNSC) that these high energy cosmic rays will impact the Earth’s atmosphere, create droplets of water, thus generating cloud cover. So, following this logically, we should have a global decrease in cloud cover during periods of high solar activity (when cosmic rays are not deflected by the solar wind), causing global warming (as there will be less clouds to reflect the solar radiation). Many of the climate problems we are having at the moment can then be attributed to the Sun and not human activity.

But there’s a problem. As previously reported by the Universe Today, research groups will often publish conflicting results about the cosmic ray effect on cloud production. In one of the most definitive results to come out of this area of study has just been announced by UK scientists, and guess what? The Sun/cosmic-ray theory has no measurable effect on the climate change we are currently experiencing.

Dr. Svensmark’s idea was central to the science behind the documentary “The Great Global Warming Swindle” where the human impact on global climate change was brought into question. This theory has been under fire since its conception by highly regarded scientists such as Mike Lockwood from the UK’s Rutherford-Appleton Laboratory. Svensmark stands by his work. So with this in mind, Dr. Terry Sloan from Lancaster University set out to prove Svensmark’s hypothesis. But the results aren’t pretty.

“We tried to corroborate Svensmark’s hypothesis, but we could not […] So we had better carry on trying to cut carbon emissions.” – Dr. Terry Sloan

In a separate study, Giles Harrison from Reading University, also studied the effect of cosmic ray flux on the amount of cloud cover, stating it is an important area of research, “…as it provides an upper limit on the cosmic ray-cloud effect in global satellite cloud data“. Although restricted to the atmosphere above the UK, Harrison’s study also returns the verdict that there is only a very weak cosmic ray effect on cloud production.

The Intergovernmental Panel on Climate Change (IPCC) released a report last year pointing the finger at human activity as the root cause behind global warming. There are very strong correlations between carbon emissions and global warming since the 1970s, so the IPCC has strongly recommended that the international community make radical cuts to their carbon emissions. What’s more the IPCC point out that the contribution from greenhouse gas emissions outweighs the effect of solar variability by a factor of 13 to one.

“…as far as we can see, he has no reason to challenge the IPCC – the IPCC has got it right.” – Dr. Terry Sloan

Source: BBC

April 3, 2008December 24, 2015 by Nancy Atkinson

Using Laser Combs to Find Exoplanets

We’ve run a couple of articles recently about new techniques to find Earth-like extra-solar planets. Here’s one more, but this new technique is really quite exciting. A new device, called a laser comb, uses femto-second (one millionth of one billionth of a second) pulses of laser light coupled with an atomic clock to provide a precise standard for measuring wavelengths of light. Also known as an “astro-comb,” these devices should give astronomers the ability to use the Doppler shift method with incredible precision to measure spectral lines of starlight up to 60 times greater than any current high-tech method, according to a new paper in the journal Nature.

Astronomers have been using the Doppler shift method to find exoplanets for the past 10 years. Current technology can measure spectral lines with a precision of 60 centimeters per second, which works good enough to find a planet 5 times the mass of Earth in a Mercury-like orbit around a Sun-like star. To find an Earth-mass planet in an Earth-like orbit, a precision of less than 5 cm per second is necessary, and the researchers believe they ultimately can achieve 1 cm per second precision.

The combs work by creating regular spikes of laser light that are evenly spaced in wavelength ”like the teeth of a comb” and can be projected onto a spectrograph.

One of the authors of the paper, Ronald Walsworth from the Harvard-Smithsonian Center for Astrophysics said the group should begin testing its prototype system in June 2008 at the Multi-Mirror Telescope (MMT) Observatory on Mount Hopkins in Arizona. And in 2009 the researchers plan to set up a planet-spotting system at the 4.2-metre William Herschel Telescope on La Palma, in the Canary Islands, in collaboration with the Geneva Observatory.

The inventors of the laser comb, John L. Hall and Theodor W. Hansch shared half of the 2005 Nobel Prize in Physics. This technology has previously been used in chemical sensing and telecommunications. If used with larger telescopes, researchers believe the astro comb could possibly make direct measurements of dark energy.

Original News Sources: Nature, and Nature News

April 2, 2008December 24, 2015 by Ian O'Neill

Source of the Slow Solar Wind Found (Video)

The solar wind comes in two modes: fast and slow. Solar astronomers have a good idea as to where the fast solar wind comes from: polar coronal holes of open magnetic field lines, blasting solar particles at speeds of over 3 million km/hr. But what about the slow solar wind which fires particles into space at a pedestrian 1.5 million km/hr? We know it comes from the streamer belt above equatorial regions of the Sun, but we have never been able to look lower. But now, with the help of the Hinode observatory, stunning high-resolution images and video have been captured showing solar dynamics previously overlooked. The point at which the Sun ejects slow wind particles into space can now be studied in unparalleled detail to help us understand the dynamics of space weather and solar storms.

The Sun is a complex, magnetic body. Its magnetic field is highly dynamic, varying in activity throughout the 11-year solar cycle. We have just witnessed the Sun entering “Solar Cycle 24” (although some old sunspots from the previous cycle have just been seen) and it will gradually build in energy before reaching “solar maximum” in a few years time (looks like the solar storms will be bigger than 2003’s flare excitement).

This time of relative calm (known as “solar minimum”) allows solar physicists to study the less explosive dynamics in the lower corona (the Sun’s atmosphere), chromosphere and photosphere. It is in this region that magnetic field lines (or magnetic flux) are pushed through the photosphere and the plasma from the solar interior is guided by the magnetic flux high into the corona. These hot and bright arcs of magnetism and superheated plasma are known as coronal loops, the scene of rapid reconnection events, sometimes sparking flares and coronal mass ejections (CMEs). But this time the Hinode science team have observed a steady release of solar plasma, venting from the solar interior around a cluster of bright coronal loop footpoints. The location of this steady release of plasma forms the origin of the slow solar wind.

“It is fantastic to finally be able to pinpoint the source of the solar wind – it has been debated for many years and now we have the final piece of the jigsaw. In the future we want to be able to work out how the wind is transported through the solar system.” – Prof. Louise Harra, University College London, Mullard Space Science Laboratory.

See the Hinode video of the region generating solar wind particles…

These dazzling images were captured by the Extreme Ultraviolet Imaging Spectrometer (EIS) on board the Japanese Hinode solar observatory. The observatory, which orbits the Earth, constantly looking at the Sun, has given us unrivaled observations of the Sun in X-ray and EUV wavelengths. Launched by Japan, the project also has collaborators in the UK and US.

These new discoveries are of vast importance to us. The solar wind carries a stream of highly energetic particles from the Sun and into space. The solar wind bathes the Earth in a radioactive stream, carrying the remnants of the solar magnetic field with it. The magnetic field can interact with the Earth’s magnetic field, allowing solar particles to rain down on our Polar Regions, creating vast light displays: the Aurora. However, these particles are also highly dangerous to any unprotected astronaut or sensitive satellite orbiting our planet. It is of paramount importance that as we venture further and further into space that we forecast the characteristics of the solar wind before it hits us. These new observations will aid our understanding of the conditions at the solar wind source and greatly improve our space weather-predicting ability.

Source: ESA

April 2, 2008December 24, 2015 by Ian O'Neill

A Black Hole Observed in the Heart of Mysterious Omega Centauri

Omega Centauri is a strange thing. It’s been classified as a star, then a nebula, then a globular cluster and now it’s thought to be a dwarf galaxy missing its outer stars. Why is it in such a mess? How can this oddball galaxy be explained? New research suggests it has an intermediate-black hole living in its core,Â giving astronomers the best idea yet as to where supermassive black holes come from. Omega Centauri might hold one of the most profound secrets asÂ to how the largest objects in the observable universe are born…

Two thousand years ago, Omega Centauri was classified as a single star by Ptolemy. Edmond Halley studied this “star” but thought it looked a bit diffuse and re-classified it as a nebula in 1677. Then, in the 1830s, John Herschel was the first astronomer to realize this “nebula” was actually a galaxy, a globular cluster galaxy. But now, new observations by the Hubble Space Telescope (HST) reveal that this “globular cluster” isn’t what it seems… it’s actually a dwarf galaxy, stripped of its outer stars, some 17,000 light years away.

See an observation video zooming into the location of Omega Centauri in the constellation of Centaurus.

So what led to astronomers thinking there was something strange about this cosmic collection of stars? It rotates faster than other globular clusters, it is strangely flat and it contains stars of many generations (globular clusters usually contain stars of one generation). These reasons plus the fact Omega Centauri is ten times bigger than the largest globular clusters have led scientists to believe that this was no ordinary galaxy.

The main theory is that this unlucky galaxy may have crashed into the Milky Way in the distant past, shedding its outermost stars during the collision. This explains the lack of stars in its outer region. But why is it rotating so quickly, especially in the center?

These stunning images were taken by the NASA/ESA Hubble Space Telescope, which continues to do amazing science after 18 years in orbit. Combined with ground-based observations by the Gemini South telescope in Chile, astronomers have been able to deduce that a black hole may be at the root of a lot of the anomalies seen in Omega Centauri.

The research carried out at the Max-Planck Institute for Extraterrestrial Physics (in Garching, Germany), headed by Eva Noyola, shows stars near the center of Omega Centauri orbiting something very fast. In fact, this something is invisible for a reason. Calculating this invisible object’s mass, it is most likely that the group are observing an intermediate-size black hole with the mass of 40,000 solar masses. They have investigated other possibilities, perhaps the fast-orbiting stars could be accelerated by the collective mass of small, weakly radiating bodies such as white dwarves, or the orbiting stars’ have highly elliptical orbits and the point of closest approach is currently being observed, giving the impression they are going faster. However, the intermediate-size black hole theory appears to fit the situation far better.

This is a highly significant discovery, as so far there has been little linking theÂ smaller, stellar black holes with the supermassive ones that sit in the center of large galaxies such as our own. There have been many theories put forward about how these huge black holes may have formed, but to find an intermediate-sized black hole may be the missing link and will help astrophysicists understand how supermassive black holes are “seeded” in the first place.

“This result shows that there is a continuous range of masses for black holes, from supermassive, to intermediate-mass, to small stellar mass types […] We may be on the verge of uncovering one possible mechanism for the formation of supermassive black holes. Intermediate-mass black holes like this could be the seeds of full-sized supermassive black holes.” – Eva Noyola.

Source: SpaceTelescope.org

April 2, 2008December 24, 2015 by Tammy Plotner

Planet Finder Catches a Comet!

Who can forget last October, when astronomers all over the world were astounded by the huge outburst of Comet Holmes? The eruption was the largest for more than a century. (Click on image to animate.) Fortunately for the world, a UK telescope was in the right place and the right time to capture the first images of this once-in-a-lifetime event.

The SuperWASP-North facility on the island of La Palma was built by UK scientists to discover planets around other stars. The 8 cameras that make up the system operate robotically, automatically scanning large areas of the sky each night. By coincidence, at 2339 GMT on the evening of 24 October 2007, it was pointing towards Comet 17P Holmes.

“By the time SuperWASP spotted the comet, it had already brightened by a factor of 1000” explains Dr. Henry Hsieh. “But this was still almost 3 hours before anyone else noticed it.” (The lucky astronomer and the honor belongs to amateur astronomer Juan Antonio Henriquez Santana who saw the eruption from Tenerife. Score a point for those of us who scan the skies!). Over the next 2 hours the comet continued brightening, until SuperWASP could no longer accurately measure it – it was too bright for the cameras.

Orbiting the Sun, comets are mainly composed of frozen gases and microscopic solid particles in a small solid nucleus. As they pass by our solar system’s nearest star, they heat up, releasing gas pockets and other frozen materials. Most of us understand outgassing and the properties of cometary tails, but during this outburst, Comet Holmes released a large amount of its material all at once.

Two days after the eruption began, sunlight reflecting from the ejected material had made the comet one million times brighter than it was originally making it easily visible to observers across the northern hemisphere. Dr. Hsieh comments:

“Over the next few weeks, SuperWASP continued to observe Comet Holmes as the cloud of dust and gas surrounding the 3-km diameter nucleus of the comet steadily expanded. By 31st October, the cloud was already 900,000 km across or more than twice the distance from the Earth to the Moon. Using our SuperWASP observations, we measured the speed of expansion of the outer edge of this cloud to be over 1500 km per hour and by 17 November measured the size of the cloud to be more than 2 million km across – much larger than the Sun.”

Two weeks after the outburst, SuperWASP scored again – the faint and delicate tail of Comet Holmes composed of the gas released from the nucleus. As astronomers watched over the next few weeks, this tail gradually faded and moved away from the comet. Although many images were gathered by astronomers around the world, the precise cause of the outburst is still a mystery. All they know right now is that it happened once before – in 1892 – and may well happen again. Keep watching!

April 2, 2008December 24, 2015 by Nancy Atkinson

Jobs Eliminated as Shuttle Program Transitions to Constellation

As the space shuttle program winds down and NASA transitions to the new Constellation program, more than 8,000 NASA contractor jobs in the manned space program could be eliminated after 2010, the U.S. space agency said at a press briefing on April 1, 2008. A NASA report sent to Congress predicts that between 5,700 and 6,400 jobs will be lost at the Kennedy Space Center, where the shuttle processing takes place, before 2012. After that time, a few hundred jobs will be added yearly as the new moon-landing program gets started, with the first Constellation launch tentatively scheduled for 2015. Some NASA managers believe that an update to Tuesday’s report, which is due to Congress in six months, won’t be quite so bleak, but NASA said it could be more than a year before it has more dependable job forecasts.

The most dramatic job cuts will be among private contractors. Bill Gerstenmaier, NASA associate administrator said that the estimates of job losses were preliminary and they do not take into account numerous factors of potential workload. “Don’t overreact to these numbers,” he said.

The report stated “Our (NASAâ€™s) greatest challenge over the next several years will be managing this extremely talented, experienced and geographically dispersed workforce as we transition from operating the space shuttle to utilizing the International Space Station.â€

Nationally, NASA said the number of full-time civil servants in its manned space program would fall to about 4,100 in 2011, a loss of about 600 jobs from this year. Including outside contractors, the number of jobs would fall to an estimated 12,500 to 13,800. About 21,000 are currently employed.

Rick Gilbrech, NASA associate administrator for exploration systems, said that many future contracts for the Constellation program to develop the new moon rockets and spacecraft to replace the shuttle fleet, could improve the local NASA jobs picture.

“There’s a lot of work that’s not folded into these numbers,” he said.

Gilbrech added that the next U.S. president and Congress might not support the Constellation program, which is President Bush’s vision for returning to the moon and going on to Mars.

“We do need stable support and long-term commitment,” he said.

KSC Director Bill Parsons said Tuesday he estimates the center’s 15,000 on payroll will drop to 10,000 people in the next few years before starting to climb slowly. He said, however, that there is hope that layoffs might be rare because up to one-third of KSC workers are eligible to retire before or around the time that the shuttle program ends in 2010. He does not expect workers to abandon their jobs for new careers before then.

“This is not a work force that panics,” he said, referring to the recovery from two shuttle accidents.

Retirement will provide a easier transition for some. However, younger workers may have to redirect their careers into the Constellation program. Those caught in the middle might have to learn new skills or relocate to avoid being laid off. There are also other ripple effects to other non-technical support jobs.

Original News Sources: Space.com, Florida Today

April 2, 2008December 24, 2015 by Tammy Plotner

Meteor Shower… On Mars!

What’s that? Another meteor shower we can’t possibly see? Of course you can. All you need to view this meteor shower is a backyard on Mars! A team of scientists led by Armagh Observatory have, for the first time, detected a storm of shooting stars on Red Planet.

What happens when the orbit of Mars intersects with debris from comet 79P/du Toit-Hartley? Scientists were hard at work making predictions. The detections were then cross-referenced with observations of activity in the Martian ionosphere by NASA’s Mars Global Surveyor (MGS) satellite. Says Dr. Apostolos Christou:

“Just as we can predict meteor outbursts at Earth, such as the Leonids, we can also predict when meteor showers are going to occur at Mars and Venus. We believe that shooting stars should appear at Venus and Mars with a similar brightness to those we see at Earth. However, as we are not in a position to watch them in the Martian sky directly, we have to sift through satellite data to look for evidence of particles burning up in the upper atmosphere.”

We’re all familiar with the cause of most meteor showers. They happen when a planet (and not always ours!) passes through the debris trail left by a comet as it moves along its orbital path. The material lets us glimpse into the age, size and composition of particles ejected from the comet’s nucleus, the speed at which it was thrown off, as well as general information about the structure and history of the comet itself. Oh, to be a comet watcher on Mars! About four times as many comets approach the orbit of Mars than the Earth’s and the greatest majority of these are Jupiter Family Comets.

Studying Martian meteor showers can definitely improve our understanding of meteor showers and the Jupiter Family Comets as well. JFC are short period comets with an orbital period of less than 20 years. Their orbits are controlled by Jupiter and many are believed to originate from the Edgeworth-Kuiper Belt, a vast population of small icy bodies that orbit just beyond Neptune. Famous JFCs include Comet 81P/Wild 2, which was encountered by the Stardust spacecraft in January 2004 and Comet Shoemaker-Levy 9, which broke up and collided with Jupiter in July 1994.

When meteor particles burn up in a planet’s atmosphere, metals contained within them are ionised to form a layer of plasma. On Earth, this layer has an altitude of approximately 95-100 kilometres and on Mars the layer is predicted to be around 80-95 kilometres above the Martian surface. Meteor showers leave a narrow layer of plasma superimposed on top of the main plasma layer, caused by meteors that are general debris from the Solar System. Dr. Christou and his colleagues developed a model to predict meteor showers caused by the intersection of Mars with dust trails from comet 79P/du Toit-Hartley. From the model, the team identified six predicted meteor showers since the MGS satellite entered into orbit around Mars in 1997. Although the metallic ions cannot be observed directly by MGS instruments, evidence for the plasma layer can be inferred by monitoring electron density in the Martian atmosphere using the spacecraft’s radio communication system.

Just like earthly meteor showers, we can predict all we want – but sometimes we draw a blank. In this instance only one of the six predictions came true. In the April 2003 data, the team found that an ionospheric disturbance appeared at the exact time of the predicted meteor outburst. The height of the disturbance corresponded with the predicted altitude for the formation of the metallic ion layer and its width and multi-peaked shape were similar to structures observed in the Earth’s ionosphere linked to the Perseid meteor shower.

For the 2005 data, no features were observed near or immediately after the predicted meteor shower. Dr Christou says, “We speculate that we don’t see anything in the 2005 data because the meteors burned up deeper in the atmosphere where their ionisation is less efficient. If we are going to get a clear picture of what is going on, we need more optical and ionospheric observations of meteor showers at both the Earth and Mars so we can establish a definitive link between cause and effect. Equally importantly, we need further observations of Martian meteor showers, either from orbit or from the planet’s surface, to confirm our predictions. Finally, we need to improve our prediction model by tracking more comets that might cause meteor showers on Mars.”

Dr Christou is now investigating the possibilities of making observations with Europe’s ExoMars mission, which is due to land on Mars in 2015.

April 2, 2008December 24, 2015 by Ian O'Neill

Lumpy Neutron Stars can Generate Gravitational Waves

A new simulation of neutron stars suggest they may not be as smooth as predicted. The rapidly spinning exotic bodies may have significant topological features like mountains. These “lumps” on the star’s surface may cause fluctuations in space-time as the variation of the huge gravitational field varies on each spin. This fluctuation may generate gravitational waves, propagating into the cosmos, and could be detected here on Earth…

Neutron stars are the remnants of massive stars after they have exploded as supernovae. The dense core remains behind, spinning fast and composed of only neutrons. They have immense gravitational fields and thought to have as much mass as our Sun, but measuring only 20 kilometres across. As they conserve the angular momentum of their massive sun predecessor, as they are so small, they are expected to spin hundreds of times per second.

But how can these strange objects be detected? Well, for one, they may be seen as highly radiating pulsars (or, possibly, “magnetars“), flashing a beam of radiation past the Earth asÂ they spinÂ like a lighthouse, beams of high energy photons emitted from the neutron star’s poles. But what about the effect they have on space-time? Can these massive bodies create gravitational waves? (Note: A gravitational wave is a totally different creature from an atmospheric “gravity wave“.)

To picture the scene: Imagine spinning a perfectly spherical ball in a swimming pool. If the ball is perfectly stationary (not bobbing up and down and not drifting), only spinning on its axis, no ripples in the pool will be seen. Therefore, any instrument measuring ripples in the pool will not detect the presence of the spinning ball. Now spin an object not spherical (like a rugby ball, or an American football) in the pool. As this object spins, the irregularities on the surface (i.e. the pointed ends) will produce a wave on each revolution of the irregular object. The ripple instrument will detect the presence of the ball in the pool.

This is the issue facing scientists trying to detect gravitational waves from neutron stars. If they are smooth objects (perhaps spherical, or slightly flattened due to the spin), they cannot produce ripples in space-time and therefore cannot be detected. If, on the other hand, they are irregularly-shaped spinning bodies, with inhomogeneities (lumps or “mountains”) on the surface, gravitational waves may be generated. The lump will sweep out a fluctuation in space-time on each rotation. This is fine, but are neutron stars lumpy?

Well, the outlook isn’t very good. The space-time “ripple” detectors set out to observe gravitational waves have so far not detected any sign of these rapidly spinning neutron stars. This could either mean that the technology we are using is not sensitive enough to detect gravitational waves or that neutron stars are naturally smooth and cannot produce gravitational waves in the first place.

Matthias Vigelius and Andrew Melatos, researchers from University of Melbourne in Australia, think they have new hope that some types of neutron star might be detected as they are naturally lumpy. Using a new computer modelling technique, the pair believes that even a small variation in the neutron star surface will produce detectable gravitational waves. But how do these lumps form? Often, stars evolve as part of a binary system (i.e. two stars orbiting a common centre of gravity), should one die as a supernova, leaving a neutron star behind, the intense gravitational field will strip its companion star of its gases. As the gas is funnelled into the neutron star, the intense magnetic field will give structural support to the incoming gas, creating an electron-proton mix of superheated plasma sitting on top of the neutron star surface. The lumps formed at the neutron star’s magnetic poles will be a long-living feature, sweeping around the star each time it rotates. Vigelius and Melatos think that detectors such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) may be able to detect this characteristic signature of an irregularly shaped neutron star…. in time.

As yet, these “lumpy” neutron stars have not been detected, but through continued observation (exposure time), it is hoped that Earth-based gravitational wave observatories may eventually receive the signal.

Source: RAS, New Scientist

April 2, 2008December 24, 2015 by Tammy Plotner

Venus’ Variable Evolution

For every backyard astronomer, we know 4.5 billion years ago, both Venus and Earth were formed with nearly the same radius, mass, density and chemical composition. Venus is like Earth’s evil twin, but why is the climate on both worlds so widely varied? Scientists analysing the data from the orbiting European Venus Express spacecraft are finally putting the pieces of the geological and climatological puzzle together as they take a closer look at Venusian evolution.

Today, Professor Fred Taylor of Oxford University presented the scenario in a talk at the Royal Astronomical Society National Astronomy Meeting in Belfast. According to the studies, Venus appeared to have evolved very rapidly compared to the Earth during the early formation of the solar system. Thanks to data obtained from the Venus Express, it would appear our wicked sister planet once had significant volume of water covering the surface… Oceans which were lost in a very short geological timescale. As the water disappeared, the geological evolution of the surface of Venus slowed quickly – unable to develop plate tectonics like the Earth. Biological evolution could never happen. If, at one time, Venus mirrored Earth in climate and habitability terms, then it evolved too quickly at first, then too slowly.

‘They may have started out looking very much the same,’ said Professor Taylor, ‘but increasingly we have evidence that Venus lost most of its water and Earth lost most of its atmospheric carbon dioxide.’

Here on Earth, carbon dioxide is captive plant life, minerals and the crust itself. Not to harp on global warming, but the release CO2 back into the atmosphere is a source of climatic change. On Venus, the majority of the carbon dioxide resides it its atmosphere, leaving the surface temperature at a searing 450 degrees Celsius. This slows or stops geological as well as biological evolution.

‘The interesting thing is that the physics is the same in both cases’ said Prof Taylor. ‘The great achievement of Venus Express is that it is putting the climatic behaviour of both planets into a common framework of understanding.’

But, we haven’t heard the last from Venus Express just yet. Due to operate until May 2009, scientists involved in the project are already busy applying for an extension until 2011.

‘We have plans for joint operations with the Japanese spacecraft called Venus Climate Orbiter that will arrive in December 2010’, said Taylor. ‘Together, we can do things neither could do alone to crack some of the remaining puzzles about Venus.’

April 2, 2008December 24, 2015 by Tammy Plotner

The Sun’s Magnetic Fountains

For you solar observing fans, enjoy the beauty. Over the years both the public and astronomers alike have witnessed the Sun’s volatile and ever-changing atmosphere. Before our eyes huge geysers of hot gas spew into the solar corona at tens of thousands of km per hour. Every few minutes they erupt and reach dynamic proportions. Now a team of scientists have used the Hinode spacecraft to find the origin and progenitor of these fountains – immense magnetic structures that thread through the solar atmosphere.

Today at the Royal Astronomical Society National Astronomy Meeting in Belfast (NAM 2008), team leader Dr. Michelle Murray from the Mullard Space Science Laboratory (MSSL, University College London) presented the latest results from Hinode spacecraft combined with computer emulated solar conditions. Since its launch in October 2006, scientists have been using Hinode to examine the solar atmosphere in extraordinary detail. One of it’s premier instruments is the Extreme Ultraviolet Imaging Spectrometer. The EIS generates images of the Sun and gives information on the speed of the moving gases.

At the core of the solar magnetic field, immense jets of hot gas are forced to the surface through increases in pressure. Just like an earthly geyser, when the pressure releases the gases fall back towards the Sun’s surface. But what causes the pressure? Unlike the volcanic activity that drives the terrestrial phenomena, solar fountains are caused by rearrangements of the Sun’s magnetic field, a continual process that results in looping cycles of increasing and decreasing pressure.

“EIS has observed the Sun’s fountains in unprecedented detail and it has enabled us to narrow down the fountains’ origins for the first time”, comments team member and MSSL postgraduate student Deb Baker. “We have also been able to find what drives the fountains by using computer experiments to replicate solar conditions.”

The sun-observing Hinode satellite is now in a sun-synchronous orbit, which allows it to observe the sun for uninterrupted periods lasting months at a time. Using a combination of optical, EUV and X-ray instrumentation Hinode will study the interaction between the Sun’s magnetic field and its corona to increase our understanding of the causes of solar variability.

“The computer experiments demonstrate that when a new section of magnetic field pushes through the solar surface it generates a continual cycle of fountains”, explains Dr. Murray, “but new magnetic fields are constantly emerging across the whole of the solar surface and so our results can explain a whole multitude of fountains that have been observed with Hinode.”