ESA Integral manoeuvres to improve future observations

Credit: ESA

ESA’s Integral observatory is able to detect gamma-ray bursts, the most energetic phenomena in the Universe.

Since 2002, ESA’s Integral spacecraft has been observing some of the most violent events in the Universe, including gamma-ray bursts and black holes.

While it still has years of life ahead, its fuel will certainly run out one day.

Integral, one of ESA’s longest-serving and most successful space observatories, has begun a series of four thruster burns carefully designed to balance its scientific life with a safe reentry in 2029.

That seems far off, but detailed planning and teamwork now will ensure that the satellite’s eventual entry into the atmosphere will meet the Agency’s guidelines for minimising space debris.

Making these disposal manoeuvres so early will also minimises fuel usage, allowing ESA to exploit the valuable satellite’s lifetime to the fullest.

This is the first time that a spacecraft’s orbit is being adjusted, after 12 years in space, to achieve a safe reentry 15 years in the future, while maximising valuable science return for the subsequent seven to eight years.

“Our four burns will use about half of the estimated 96 kg of fuel available,” says Richard Southworth, spacecraft operations manager at ESA’s Space Operations Centre, ESOC, in Darmstadt, Germany.

“This will influence how Integral’s orbit evolves, so that even after we run out of propellant we will still have a safe reentry in February 2029 as a result of natural orbit decay.

“No further manoeuvres are required between now and then and Integral can continue to operate.”

Debris Mitigation
The latest ESA debris guidelines require that a satellite must be disposed of in such a way that it poses no risk to other satellites in protected orbital regions for more than 25 years.

Although Integral’s early launch date, in 2002, means it is not required to stick to the guidelines, they were followed for planning the disposal.

“We have done a great deal of modelling for Integral’s reentry in 2029,” says Klaus Merz of ESA’s Space Debris Office.

“We’re confident that this month’s manoeuvres will put it on track for a future safe reentry at latitudes in the far south, reducing risk far below guideline levels.”

Without these firings, the fuel supply would run out in perhaps 12–16 more years, after other essentials such as power end Integral's working life, but the satellite would not reenter for up to 200 years, which would present a hazard to other missions.

Hubble observations cast more doubt on Globular clusters formation

This NASA/ESA Hubble Space Telescope image shows four globular clusters in the dwarf galaxy Fornax. 

Credit: NASA, ESA, S. Larsen - Radboud University, the Netherlands

Thanks to the NASA/ESA Hubble Space Telescope, some of the most mysterious cosmic residents have just become even more puzzling.

New observations of globular clusters in a small galaxy show they are very similar to those found in the Milky Way, and so must have formed in a similar way.

One of the leading theories on how these clusters form predicts that globular clusters should only be found nestled in among large quantities of old stars, but these old stars, though rife in the Milky Way, are not present in this small galaxy, and so, the mystery deepens.

Globular clusters, large balls of stars that orbit the centres of galaxies, but can lie very far from the, remain one of the biggest cosmic mysteries. They were once thought to consist of a single population of stars that all formed together.

However, research has since shown that many of the Milky Way's globular clusters had far more complex formation histories and are made up of at least two distinct populations of stars.

Of these populations, around half the stars are a single generation of normal stars that were thought to form first, and the other half form a second generation of stars, which are polluted with different chemical elements.

In particular, the polluted stars contain up to 50-100 times more nitrogen than the first generation of stars.

The proportion of polluted stars found in the Milky Way's globular clusters is much higher than astronomers expected, suggesting that a large chunk of the first generation star population is missing.

A leading explanation for this is that the clusters once contained many more stars but a large fraction of the first generation stars were ejected from the cluster at some time in its past.

This explanation makes sense for globular clusters in the Milky Way, where the ejected stars could easily hide among the many similar, old stars in the vast halo, but the new observations, which look at this type of cluster in a much smaller galaxy, call this theory into question.

Astronomers used Hubble's Wide Field Camera 3 (WFC3) to observe four globular clusters in a small nearby galaxy known as the Fornax Dwarf Spheroidal galaxy.

"We knew that the Milky Way's clusters were more complex than was originally thought, and there are theories to explain why, but to really test our theories about how these clusters form we needed to know what happened in other environments," says Søren Larsen of Radboud University in Nijmegen, the Netherlands, lead author of the new paper.

"Before now we didn't know whether globular clusters in smaller galaxies had multiple generations or not, but our observations show clearly that they do!"

"If these kicked-out stars were there, we would see them but we don't!" explains Frank Grundahl of Aarhus University in Denmark, co-author on the paper.

"Our leading formation theory just can't be right. There's nowhere that Fornax could have hidden these ejected stars, so it appears that the clusters couldn't have been so much larger in the past."

The new work is detailed in a paper published today, 20 November 2014, in The Astrophysical Journal. "Nitrogen abundances and multiple stellar populations in the globular clusters of the Fornax dSph" arxiv.org/abs/1409.0541

The latest observations of interstellar particles

Credit: NASA /Goddard /Adler /U. Chicago /Wesleyan

With all the news about Voyager 1 leaving the heliosphere and entering interstellar space you might think that the probe is the first spacecraft to detect interstellar particles.

That isn't entirely true, and the latest observations of interstellar particles has found some very interesting results.

The heliosphere is generated by the Sun's solar wind, a stream of charged (ionized) particles that flows outward from the Sun.

The solar wind interacts with the magnetic field of the sun, and together they create a kind of diffuse bubble of charged particles around the sun known as the heliosphere.

While this heliosphere prevents any interstellar charged particles from reaching us, it is less effective at preventing uncharged interstellar particles from reaching us.

Most of the interstellar wind is ionized like the solar wind, but there are some neutral particles (mostly hydrogen) that moves with the interstellar wind.

Since neutral particles don't interact strongly with the Sun's magnetic field, some of them can slip into the heliosphere, where we can detect them.

This neutral hydrogen comes from the local cloud, seen below, a very tenuous cloud of hydrogen that surrounds our stellar region.

The motion of this hydrogen relative to the Sun depends on the Sun's motion through the cloud and the motion of the cloud itself.

The Sun's motion through the galaxy is quite steady, and it was thought that the cloud's motion was also steady, but long term observations of the hydrogen flow through our solar system has found this is not the case.

In a recent paper in Science researchers compared hydrogen flow measurements from the IBEX satellite (taken during 2009-2010) with observations from Ulysses (1992-2002) and other observations (1972-1978).

What they found was that over the course of 30 years the direction has changed by about 6 degrees.

This may seem like a slow and gradual change, but on a cosmic scale it is huge. The local cloud is about 30 light years across, and the Sun moves through it at a speed of (only) about 50,000 mph (22 km/sec).

While variations in the hydrogen flow are expected as it interacts with variations in the solar wind, those variations average out.

Observing such a rapid change in flow (on a cosmic scale) means either there is turbulent flow within the cloud itself, or the interstellar wind is more dynamic than originally thought.

We've long known that the solar wind is quite dynamic due to the Sun's activity. Now we're finding the interstellar wind may be active as

More information: "Decades-long changes of the interstellar wind through our solar system." Frisch PC, et al. Science. 2013 Sep 6;341(6150):1080-2. DOI: 10.1126/science.1239925

Cosmic Web Imager: Observes 'dim matter'

This is a comparison of the Lyman alpha blob observed with the Cosmic Web Imager and a simulation of the cosmic web based on theoretical predictions. 

Credit: Christopher Martin, Robert Hurt

Caltech astronomers have taken unprecedented images of the intergalactic medium (IGM), the diffuse gas that connects galaxies throughout the universe, with the Cosmic Web Imager, an instrument designed and built at Caltech.

Until now, the structure of the IGM has mostly been a matter for theoretical speculation.

However, with observations from the Cosmic Web Imager, deployed on the Hale 200-inch telescope at Palomar Observatory, astronomers are obtaining our first three-dimensional pictures of the IGM.

The Cosmic Web Imager will make possible a new understanding of galactic and intergalactic dynamics, and it has already detected one possible spiral-galaxy-in-the-making that is three times the size of our Milky Way.

Chris Martin

The Cosmic Web Imager was conceived and developed by Caltech professor of physics Christopher Martin.

"I've been thinking about the intergalactic medium since I was a graduate student," says Martin. "Not only does it comprise most of the normal matter in the universe, it is also the medium in which galaxies form and grow."

Since the late 1980s and early 1990s, theoreticians have predicted that primordial gas from the Big Bang is not spread uniformly throughout space, but is instead distributed in channels that span galaxies and flow between them.

This "cosmic web"(IGM) is a network of smaller and larger filaments crisscrossing one another across the vastness of space and back through time to an era when galaxies were first forming and stars were being produced at a rapid rate.

Martin describes the diffuse gas of the IGM as "dim matter," to distinguish it from the bright matter of stars and galaxies, and the dark matter and energy that compose most of the universe.

Though you might not think so on a bright sunny day or even a starlit night, fully 96 percent of the mass and energy in the universe is dark energy and dark matter (first inferred by Caltech's Fritz Zwicky in the 1930s), whose existence we know of only due to its effects on the remaining 4 percent that we can see: normal matter.

Of this 4 percent that is normal matter, only one-quarter is made up of stars and galaxies, the bright objects that light our night sky. The remainder, which amounts to only about 3 percent of everything in the universe, is the IGM.

As Martin's name for the IGM suggests, "dim matter" is hard to see. Prior to the development of the Cosmic Web Imager, the IGM was observed primarily via foreground absorption of light—indicating the presence of matter—occurring between Earth and a distant object such as a quasar (the nucleus of a young galaxy).

"When you look at the gas between us and a quasar, you have only one line of sight," explains Martin. "You know that there's some gas farther away, there's some gas closer in, and there's some gas in the middle, but there's no information about how that gas is distributed across three dimensions."

Observation of quasar (QSO 1549+19) taken with Caltech's Cosmic Web Imager. Blue shows hydrogen gas surrounding and inflowing to quasar. 

Credit: Christopher Martin, Robert Hurt

The integral field unit of the Cosmic Web Imager. 

Credit: Matt Matuszewski

More information: Paper 1. resolver.caltech.edu/CaltechAUTHORS:20140303-152428640 Paper 2. resolver.caltech.edu/CaltechAUTHORS:20140303-145821259

NASA Van Allen Probes observations helping to improve space weather models

NASA's Van Allen Probes orbit through two giant radiation belts that surround Earth. 

Their observations help improve computer simulations of events in the belts that can affect technology in space. 

Credit: John Hopkins University Applied Physics Laboratory /NASA

Using data from NASA's Van Allen Probes, researchers have tested and improved a model to help forecast what's happening in the radiation environment of near-Earth space, a place seething with fast-moving particles and a space weather system that varies in response to incoming energy and particles from the sun.

When events in the two giant doughnuts of radiation around Earth, called the Van Allen radiation belts, cause the belts to swell and electrons to accelerate to 99 percent the speed of light, nearby satellites can feel the effects.

Scientists ultimately want to be able to predict these changes, which requires understanding of what causes them.

Now, two sets of related research published in the Geophysical Research Letters improve on these goals.

By combining new data from the Van Allen Probes with a high-powered computer model, the new research provides a robust way to simulate events in the Van Allen radiation belts.

Geoff Reeves

"The Van Allen Probes are gathering great measurements, but they can't tell you what is happening everywhere at the same time," said Geoff Reeves, a space scientist at Los Alamos National Laboratory (LANL), in Los Alamos, N.M., a co-author on both of the recent papers.

"We need models to provide a context, to describe the whole system, based on the Van Allen Probe observations."

Prior to the launch of the Van Allen Probes in August 2012, there were no operating spacecraft designed to collect real-time information in the radiation belts.

Understanding of what might be happening in any locale was forced to rely mainly on interpreting historical data, particularly those from the early 1990s gathered by the Combined Release and Radiation Effects Satellite (CRRES).

Imagine if meteorologists wanted to predict the temperature on March 5, 2014, in Washington, D.C. but the only information available was from a handful of measurements made in March over the last seven years up and down the East Coast.

That's not exactly enough information to decide whether or not you need to wear your hat and gloves on any given day in the nation's capital.

Artist's rendition of the Van Allen Probes in orbit. Credit: NASA

Thankfully, we have much more historical information, models that help us predict the weather and, of course, innumerable thermometers in any given city to measure temperature in real time.

The Van Allen Probes are one step toward gathering more information about space weather in the radiation belts, but they do not have the ability to observe events everywhere at once.

So scientists use the data they now have available to build computer simulations that fill in the gaps.

The recent work centers around using Van Allen Probes data to improve a three-dimensional model created by scientists at LANL.

The project was called DREAM3D, the Dynamic Radiation Environment Assimilation Model in 3 Dimensions. Until now the model relied heavily on the averaged data from the CRRES mission.

The Dynamic Radiation Environment Assimilation Model (DREAM) was developed at LANL to understand and to predict hazards from the natural space environment and artificial radiation belts produced by high altitude nuclear explosions.

DREAM was initially developed as a basic research activity to understand and predict the dynamics of the Earth's radiation belts. 

It uses Kalman filter mathematical techniques to assimilate data from space environment instruments with a physics-based model of the radiation belts.

DREAM can assimilate data from a variety of types of instruments and data with various levels of resolution and fidelity by assigning appropriate uncertainties to the observations.

Data from any spacecraft orbit can be assimilated but DREAM was originally designed to work with input from the LANL space environment instruments on geosynchronous and GPS platforms.

With those inputs, DREAM can be used to specify the energetic electron environment at any satellite in the outer electron belt whether space environment data are available in those orbits or not.

Even with very limited data input and relatively simple physics models, DREAM specifies the space environment in the radiation belts to a high level of accuracy.

DREAM is currently being tested and evaluated as we transition from research to operations.

NASA Odyssey: Longest-serving Mars spacecraft relocated to aid new observations

No NASA Mars orbiter has been in a position to observe morning daylight on Mars since the twin Viking orbiters of the 1970s. 

Credit: NASA/JPL

NASA's Mars Odyssey spacecraft has tweaked its orbit to help scientists make the first systematic observations of how morning fogs, clouds and surface frost develop in different seasons on the Red Planet.

The maneuver took place Tuesday, Feb. 11. Odyssey team engineers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Lockheed Martin Space Systems of Denver, designed the gentle move to accelerate Odyssey's drift toward a morning-daylight orbit.

The desired change will occur gradually until the intended orbit geometry is reached in November 2015 and another maneuver halts the drift.

The change will enable observation of changing ground temperatures after sunrise and after sunset in thousands of places on Mars.

Those observations could yield insight about the composition of the ground and about temperature-driven processes, such as warm-season flows observed on some slopes, and geysers fed by spring thawing of carbon-dioxide ice near Mars' poles.

Jeffrey Plaut

"We're teaching an old spacecraft new tricks," said Odyssey Project Scientist Jeffrey Plaut of JPL.

"Odyssey will be in position to see Mars in a more different light from ever before."

Neither Odyssey, nor any other NASA Mars orbiter since the 1970s, has flown an orbital pattern with a view of the ground in morning daylight.

Earlier NASA orbiters and the European Space Agency's (ESA) Mars Express orbiter have provided some tantalizing views of morning mists on Mars, but have concentrated on afternoon observation times when views of the surface are less hazy.

Odyssey was launched in 2001 and began its science mission 12 years ago this month. It is the longest-working spacecraft ever sent to Mars.

NASA's Mars Odyssey spacecraft passes above Mars' south pole in this artist's concept. The spacecraft has been orbiting Mars since October 24, 2001. Credit: NASA/JPL

Odyssey completed Tuesday's maneuver at 12:03 p.m. PST (3:03 p.m. EST).

It used four thrusters, each providing about 5 pounds (22 newtons) of force for a 29-second burn.

David Lehman

"This veteran spacecraft performed exactly as planned," said Odyssey Project Manager David Lehman of JPL.

Odyssey flies in an orbit nearly over the poles and synchronized with the sun.

The south-to-north leg of the orbit provided an advantage for the orbiter's Gamma Ray Spectrometer (GRS) to have its cooling equipment pointed away from the sun.

The spectrometer checked for evidence of water near the Martian surface.

It has made important discoveries of how widely water ice—detected as hydrogen— and other elements are distributed on Mars.

Massive neutrinos solve a cosmological conundrum

UK Scientists have solved a major problem with the current standard model of cosmology identified by combining results from the Planck spacecraft and measurements of gravitational lensing in order to deduce the mass of ghostly sub-atomic particles called neutrinos.

The UK team, from the universities of Manchester and Nottingham, used observations of the Big Bang and the curvature of space-time to accurately measure the mass of these elementary particles for the first time.

Planck spacecraft

The recent Planck spacecraft observations of the Cosmic Microwave Background (CMB) - the fading glow of the Big Bang - highlighted a discrepancy between these cosmological results and the predictions from other types of observations.

The CMB is the oldest light in the Universe, and its study has allowed scientists to accurately measure cosmological parameters, such as the amount of matter in the Universe and its age.

But an inconsistency arises when large-scale structures of the Universe, such as the distribution of galaxies, are observed.

Professor Richard Battye, from the University of Manchester's School of Physics and Astronomy, said: "We observe fewer galaxy clusters than we would expect from the Planck results and there is a weaker signal from gravitational lensing of galaxies than the CMB would suggest.

"A possible way of resolving this discrepancy is for neutrinos to have mass. The effect of these massive neutrinos would be to suppress the growth of dense structures that lead to the formation of clusters of galaxies."

Cosmic Microwave Background (CMB)

Neutrinos interact very weakly with matter and so are extremely hard to study.

They were originally thought to be massless but particle physics experiments have shown that neutrinos do indeed have mass and that there are several types, known as flavours by particle physicists.

The sum of the masses of these different types has previously been suggested to lie above 0.06 eV (much less than a billionth of the mass of a proton).

Adam Moss

In this paper, Professor Battye and co-author Dr Adam Moss, from the University of Nottingham, have combined the data from Planck with gravitational lensing observations in which images of galaxies are warped by the curvature of space-time.

They conclude that the current discrepancies can be resolved if massive neutrinos are included in the standard cosmological model.

They estimate that the sum of masses of neutrinos is 0.320 +/- 0.081 eV (assuming active neutrinos with three flavours).

Dr Moss said: "If this result is borne out by further analysis, it not only adds significantly to our understanding of the sub-atomic world studied by particle physicists, but it would also be an important extension to the standard model of cosmology which has been developed over the last decade."

More Information: 'Evidence for Massive Neutrinos from Cosmic Microwave Background and Lensing Observations' DOI:10.1103/PhysRevLett.112.051303

ESA Herschel Video: 37 thousand science observations

This animation shows the timeline of over 37 000 scientific observations made by ESA's Herschel space observatory throughout its entire mission, condensed into less than a minute.

The animation was prepared by Pedro Gómez-Alvarez in the Herschel Science Centre Community Support Group and presented by Herschel's Project Scientist Göran Pilbratt during the opening session of The Universe Explored by Herschel symposium held at ESA's ESTEC facility, in Noordwijk, the Netherlands, last month.

The animation runs from launch, on 14 May 2009, until the infrared observatory made its last observation on 29 April 2013.

Running through the centre of the graphic is the 'ecliptic plane' tracing the paths of the planets with respect to Herschel's viewpoint from its orbit around L2, which is located 1.5 million kilometres behind the Earth as viewed from the Sun.

A horseshoe shape marks the Galactic Plane, the direction in which much of the Milky Way's mass lies, and where many of Herschel's observations were focused.

In total, Herschel observed almost a tenth of the entire sky for over 23 500 hours, providing new views into the previously hidden Universe, pointing to unseen star birth and galaxy formation, and tracing water through the Universe from molecular clouds to newborn stars and to their planet-forming discs and belts of comets.

Its two camera/imaging spectrometers, PACS (Photoconductor Array Camera and Spectrometer) and SPIRE (Spectral and Photometric Imaging Receiver), which together covered wavelengths of 55–670 microns, provided about two thirds of Herschel's sky coverage in parallel imaging mode.

These data points are shown in yellow. PACS and SPIRE photometry observations are indicated in blue and green, which together with spectroscopy performed with PACS, SPIRE and the third science instrument, HIFI (Heterodyne Instrument for the Far Infrared, covering wavelength bands of 157–212 microns and 240–625 microns) make up the remainder.

ESO ALMA Observations of the Herbig-Haro 46/47 Molecular Outflow

This unprecedented image of Herbig-Haro object HH 46/47 combines radio observations acquired with the Atacama Large Millimeter/submillimeter Array (ALMA) with much shorter wavelength visible light observations from ESO's New Technology Telescope.

The ALMA observations (orange and green, lower right) of the newborn star reveal a large energetic jet moving away from us, which in the visible is hidden by dust and gas.

To the left (in pink and purple) the visible part of the jet is seen, streaming partly towards us. 

Credit: ALMA (ESO/NAOJ/NRAO)/ESO/H. Arce. Acknowledgements: Bo Reipurth

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have obtained a vivid close-up view of material streaming away from a newborn star.

By looking at the glow coming from carbon monoxide molecules in an object called Herbig-Haro 46/47 they have discovered that its jets are even more energetic than previously thought.

The very detailed new images have also revealed a previously unknown jet pointing in a totally different direction.

Young stars are violent objects that eject material at speeds as high as one million kilometres per hour. When this material crashes into the surrounding gas it glows, creating a Herbig-Haro object.

A spectacular example is named Herbig-Haro 46/47 and is situated about 1400 light-years from Earth in the southern constellation of Vela (The Sails).

This object was the target of a study using ALMA during the Early Science phase, whilst the telescope was still under construction and well before the array was completed.

The new images reveal fine detail in two jets, one coming towards Earth and one moving away.

The receding jet was almost invisible in earlier pictures made in visible light, due to obscuration by the dust clouds surrounding the new-born star.

ALMA has not only provided much sharper images than earlier facilities but also allowed astronomers to measure how fast the glowing material is moving through space.

These new observations of Herbig-Haro 46/47 revealed that some of the ejected material had velocities much higher than had been measured before.

This means the outflowing gas carries much more energy and momentum than previously thought.

Héctor Arce

The team leader and first author of the new study, Héctor Arce, Yale University explains that "ALMA's exquisite sensitivity allows the detection of previously unseen features in this source, like this very fast outflow.

It also seems to be a textbook example of a simple model where the molecular outflow is generated by a wide-angle wind from the young star."

The observations were obtained in just five hours of ALMA observation time – even though ALMA was still under construction at the time – similar quality observations with other telescopes would have taken ten times longer.

More information: This research was presented in a paper entitled "ALMA Observations of the HH 46/47 Molecular Outflow" by Héctor Arce et al, to appear in the Astrophysical Journal. (PDF)

ESA's ESO VLT: Observations Identifies Rare "Green Bean" Galaxy

A new galaxy class has been identified using observations from ESO's Very Large Telescope (VLT), the Gemini South telescope, and the Canada-France-Hawaii Telescope (CFHT).

Nicknamed "green bean galaxies" because of their unusual appearance, these galaxies glow in the intense light emitted from the surroundings of monster black holes and are amongst the rarest objects in the Universe.

Read the full Research Paper Here

Many galaxies have a giant black hole at their centre that causes the gas around it to glow. However, in the case of green bean galaxies, the entire galaxy is glowing, not just the centre.

These new observations reveal the largest and brightest glowing regions ever found, thought to be powered by central black holes that were formerly very active but are now switching off.

Astronomer Mischa Schirmer of the Gemini Observatory had looked at many images of the distant Universe, searching for clusters of galaxies, but when he came across one object in an image from the Canada-France-Hawaii Telescope he was stunned -- it looked like a galaxy, but it was bright green.

It was unlike any galaxy he had ever seen before, something totally unexpected. He quickly applied to use ESO's Very Large Telescope to find out what was creating the unusual green glow.

"ESO granted me special observing time at very short notice and just a few days after I submitted my proposal, this bizarre object was observed using the VLT," says Schirmer.

"Ten minutes after the data were taken in Chile, I had them on my computer in Germany. I soon refocused my research activities entirely as it became apparent that I had come across something really new."

The new object, J2240, lies in the constellation of Aquarius (The Water Bearer) and its light has taken about 3.7 billion years to reach Earth.

After the discovery, Schirmer's team searched through a list of nearly a billion other galaxies and found 16 more with similar properties, which were confirmed by observations made at the Gemini South telescope.

General Background

In many galaxies the material around the supermassive black hole at the centre gives off intense radiation and ionises the surrounding gas so that it glows strongly.

These glowing regions in typical active galaxies are usually small, up to 10% of the diameter of the galaxy. However, the team's observations showed that in the case of J2240, and other green beans spotted since, it is truly huge, spanning the entire object.

J2240 displays one of the biggest and brightest such regions ever found. Ionised oxygen glows bright green, which explains the strange colour that originally caught Schirmer's attention.

"These glowing regions are fantastic probes to try to understand the physics of galaxies -- it's like sticking a medical thermometer into a galaxy far, far away," says Schirmer.

"Usually, these regions are neither very large nor very bright, and can only be seen well in nearby galaxies.

However, in these newly discovered galaxies they are so huge and bright that they can be observed in great detail, despite their large distances."

Uranus: Keck observations brings weather into sharp focus

A paired picture of Uranus, the sharpest, most detailed picture of the distant planet to date, reveals a raft of new details about the planet's enigmatic atmosphere. 

The north pole of Uranus (to the right in the picture) is characterised by a swarm of storm-like convective features, and an unusual scalloped pattern of clouds encircles the planet's equator. 

The infrared image was taken using the Keck II telescope in Hawaii. 

Credit: Lawrence Sromovsky, Pat Fry, Heidi Hammel, Imke de Pater

In 1986, when Voyager swept past Uranus, the probe's portraits of the planet were "notoriously bland," disappointing scientists, yielding few new details of the planet and its atmosphere, and giving it a reputation as the most boring planet of the solar system.

Now, however, thanks to a new technique applied at the Keck Observatory, Uranus is coming into sharp focus through high-resolution infrared images, revealing in incredible detail the bizarre weather of the seventh planet from the sun.

The images were released in Reno, Nev. today (Oct. 17, 2012) at a meeting of the American Astronomical Society's Division of Planetary Sciences and provide the best look to date of Uranus's complex and enigmatic weather.

The planet's deep blue-green atmosphere is thick with hydrogen, helium and methane, Uranus's primary condensable gas.

Larry Sromovsky

Winds blow mainly east to west at speeds up to 560 miles per hour, in spite of the small amounts of energy available to drive them.

Its atmosphere is almost equal to Neptune's as the coldest in our solar system with cloud-top temperatures in the minus 360-degree Fahrenheit range, cold enough to freeze methane.

Large weather systems, which are probably much less violent than the storms we know on Earth, behave in bizarre ways on Uranus, explains Larry Sromovsky, a University of Wisconsin-Madison planetary scientist who led the new study using the Keck II telescope.

"Some of these weather systems," Sromovsky notes, "stay at fixed latitudes and undergo large variations in activity. Others are seen to drift toward the planet's equator while undergoing great changes in size and shape. Better measures of the wind fields that surround these massive weather systems are the key to unraveling their mysteries."

Imke de Pater

To get a better picture of atmospheric flow on Uranus, Sromovsky and colleagues Pat Fry, also of UW-Madison, Heidi Hammel of the Association of Universities for Research in Astronomy (AURA), and Imke de Pater of the University of California at Berkeley, used new infrared techniques to detect smaller, more widely distributed weather features whose movements can help scientists trace the planet's pattern of blustery winds.

"We're seeing some new things that before were buried in the noise," says Sromovsky, a senior staff scientist at UW-Madison's Space Science and Engineering Center.

Heidi Hammel

"My first reaction to these images was 'wow' and then my second reaction was WOW," says AURA's Heidi Hammel, a co-investigator on the new observations and an expert on the atmospheres of the solar system's outer planets.

"These images reveal an astonishing amount of complexity in Uranus's atmosphere. We knew the planet was active, but until now much of the activity was masked by noise in our data."

The complexity of Uranus's weather is puzzling, Sromovsky explains. The primary driving mechanism must be solar energy because there is no detectable internal energy source.

"But the sun is 900 times weaker there than on Earth because it is 30 times further from the sun, so you don't have the same intensity of solar energy driving the system," explains Sromovsky.

"Thus the atmosphere of Uranus must operate as a very efficient machine with very little dissipation. Yet the weather variations we see seem to defy that requirement."

The new Keck II pictures of the planet, according to Sromovsky, are the "most richly detailed views of Uranus yet obtained by any instrument on any observatory.

No other telescope could come close to producing this result." Sromovsky and his colleagues used Keck II, located on the summit of Hawaii's 14,000-foot extinct volcano Mauna Kea, to capture a series of images that, when combined, help increase the signal to noise ratio and thus tease out weather features that are otherwise obscured.

In two nights of observing under superb conditions, Sromovsky's group was able to obtain exposures of the planet that provide a clear view of the planet's cloudy features, including several new to science.

The group used two different filters in an effort to characterize cloud features at different altitudes. "The main objective was to find a larger number of cloud features by detecting those that were previously too subtle to be seen, so we could better define atmospheric motions," Sromovsky notes.

New features found by the Wisconsin group include a scalloped band of clouds just south of Uranus's equator and a swarm of small convective features in the north polar regions of the planet, features that have never been seen in the southern polar regions.

"This is a very asymmetric situation," says the Wisconsin scientist. "There is certainly something different going on in those two polar regions." One possible explanation, is that methane is pushed north by an atmospheric conveyor belt toward the pole where it wells up to form the convective features observed by Sromovsky's group.

"The 'popcorn' appearance of Uranus's pole reminds me very much of a Cassini image of Saturn," adds de Pater.

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Saturn's Icy Moon, Iapetus struck by 50-Mile Wide Landslides

A giant landslide on Iapetus reaches halfway across a 75-mile (120 kilometer) impact crater.

CREDIT: NASA/JPL/Space Science Institute

Long landslides spotted on Saturn's moon, Iapetus, could help provide clues to similar movements of material on Earth.

Scientists studying the icy satellite have determined that flash heating could cause falling ice to travel 10 to 15 times farther than previously expected on Iapetus.

Extended landslides can be found on Mars and Earth, but are more likely to be composed of rock than ice.

Despite the differences in materials, scientists believe there could be a link between the long-tumbling debris on all three bodies.

"We think there's more likely a common mechanism for all of this, and we want to be able to explain all of the observations," lead scientist Kelsi Singer of Washington University, Dept of Earth and Planetary Sciences, reported.

ESA Mars Express spots Wrinkle Ridges and Grabens in Tempe Terra

Tempe Terra is located at the northeastern edge of the Tharsis volcanic region and forms the transition zone between the southern highlands and the northern lowlands.

This area is characterised by a large variety of tectonic structures and is one of the most geologically diverse on Mars.

These images from the High Resolution Stereo Camera (HRSC), operated by the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) on board ESA's Mars Express spacecraft, which were acquired on 17 July 2011, show a large number of interesting geological phenomena.

The effects of different forces can be seen adjacent to one another. These have led to both extension of the Martian crust and crustal compression, which has created 'wrinkle ridges'.

The most striking result of the crustal extension is a linear graben running across the entire image and only broken by misalignment in a few places.

This graben is up to a kilometre wide and is overlaid by a large impact crater some 12 kilometres across and its ejecta; inside the crater, the graben is covered by younger sediments.

The images show a section of the HRSC image strip located at 42 degrees north and 304 degrees east, obtained during orbit 9622 with a resolution of about 18 metres per pixel.

Landscape shaped by water as well as tectonic forces
To the north of the graben, in the right third of the image, the terrain falls away to the lowlands by over 1000 metres. The landscape here is marked by several extensive valley systems.

Upslope, a number of smaller, dendritic valleys partially covered by impact craters can be made out. Many younger craters in the region south of the graben that still have well-preserved contours exhibit lobate, concentric structures in their interior that have been caused by a slow moving plastic material.

These features, referred to by geologists as concentric crater fill, can be found in a number of places on Mars - including Phlegra Montes, the subject of last month's images.

Prominent mesas are visible in the upper left section of the image, to the southwest. They reveal the original terrain level of the Martian southern highlands. Also conspicuous are the clearly structured ejecta of several impact craters. These partially cover the older flow and graben systems and therefore occurred later. Older, large impact craters have been almost completely covered with sediment or filled with ejecta.

Tempe Terra was first described by Greek astronomer Eugenios Antoniadis (1870-1944, later known as Eugene Michel Antoniadi through his work in France).

His observations of the Tempe Terra region with a powerful new telescope at the Paris Observatory in Meudon during the opposition of Mars in 1909 - described in detail in 1930 - disproved the theory circulating among astronomers that the 'canali' observed by Giovanni Schiaparelli in 1877 were artificial canals; Schiaparelli himself had serious doubts about this interpretation.

ESA Proba-2 tracks Comet Lovejoy through Sun’s fiery corona

ESA’s Proba-2 micro-satellite joined a flotilla of spacecraft observing deep-frozen Comet Lovejoy’s plunge through the million degree corona enshrouding the Sun, providing a close-up extreme ultraviolet view of the comet passing just 120 000 km from the Sun’s surface – and then, surprisingly, surviving.

Lovejoy had not been predicted to endure its swing by the Sun, but is now headed back out to the colder outer reaches of the Solar System, and should be visible from Earth’s northern hemisphere in mid-January.

Proba-2’s SWAP imager took part in a coordinated effort to track Comet Lovejoy as it came closest to the Sun on 16 December, working along with the ESA/NASA SOHO solar watchdog, Japan’s Hinode mission, NASA’s twin STEREO spacecraft and its Solar Dynamics Observatory.

SWAP showed the comet as a bright streak in the solar corona, with interactions between the comet tail causing brief coronal brightening and wiggles in the comet’s tale.

This was only the second time ever that a comet has been observed through an extreme-ultraviolet (EUV) solar telescope. The instrument’s observations – interrupted briefly as Proba-2 crossed behind Earth – show the comet going behind the Sun and then emerging back into view from the other side.

Comets are drawn to the gravitational pull of the Sun like moths to a flame – SOHO has identified thousands of Sun-grazing comets over the last 16 years. But up until now, what happens when a comet draws closest to the Sun has been a mystery.

Comets in the Sun’s neighbourhood usually seen with ‘coronagraph’ telescopes that block out the bright solar disc to observe the faint solar corona they are tuned for. This makes detailed images of comets nearing the Sun very hard to obtain.

It turns out however that EUV imagers that detect the extreme ultraviolet corona from the solar disk can also show the comet. Since the dust and other material making up a comet’s tail do not radiate at EUV wavelengths, this came as a surprise.

British Astronomical Association - Britain's leading organisation for observational astronomy

British Astronomical Association - Britain's leading organisation for observational astronomy 

Damian Peach - Amateur Astronomer of the year 2011

NASA Earth Observations: Oil Slick in the Gulf of Mexico

Oil Slick in the Gulf of Mexico : Natural Hazards

On May 24, 2010, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite captured this false-color, high-resolution view of the very tip of the Mississippi River Delta.

Ribbons and patches of oil that have leaked from the Deepwater Horizon well offshore are silver against the light blue color of the adjacent water. Vegetation is red.

In the sunglint region of a satellite image—where the mirror-like reflection of the Sun gets blurred into a wide, bright strip—any differences in the texture of the water surface are enhanced.

Oil smoothes the water, making it a better “mirror.” Oil-covered waters are very bright in this image, but, depending on the viewing conditions (time of day, satellite viewing angle, slick location), oil-covered water may look darker rather than brighter.

The relative brightness of the oil from place to place is not necessarily an indication of the amount of oil. Any oil located near the precise spot where the Sun’s reflection would appear if the surface of the Gulf were perfectly smooth and calm is going to look very bright in these images.

The cause of the dark patch of water in the upper left quadrant of the image is unknown. It may indicate the use of chemical dispersants, skimmers, or booms, or it may be the result of natural differences in turbidity, salinity, or organic matter in the coastal waters.