Solar storms trigger Jupiter's intense 'Northern Lights' by generating a new X-ray aurora that is eight times brighter than normal and hundreds of times more energetic than Earth's aurora borealis, finds new UCL-led research using NASA's Chandra X-Ray Observatory.
Artistic rendering of Jupiter's magnetosphere [Credit: JAXA]
It is the first time that Jupiter's X-ray aurora has been studied when a giant storm from the Sun has arrived at the planet. The dramatic findings complement NASA's Juno mission this summer which aims to understand the relationship between the two biggest structures in the solar system—the region of space controlled by Jupiter's magnetic field (i.e. its magnetosphere) and that controlled by the solar wind.
"There's a constant power struggle between the solar wind and Jupiter's magnetosphere. We want to understand this interaction and what effect it has on the planet. By studying how the aurora changes, we can discover more about the region of space controlled by Jupiter's magnetic field, and if or how this is influenced by the Sun. Understanding this relationship is important for the countless magnetic objects across the galaxy, including exoplanets, brown dwarfs and neutron stars," explained lead author and PhD student at UCL Mullard Space Science Laboratory, William Dunn.
The Sun constantly ejects streams of particles into space in the solar wind. When giant storms erupt, the winds become much stronger and compress Jupiter's magnetosphere, shifting its boundary with the solar wind two million kilometres through space. The study found that this interaction at the boundary triggers the high energy X-rays in Jupiter's Northern Lights, which cover an area bigger than the surface of the Earth.
Published today in the Journal of Geophysical Research - Space Physics a publication of the American Geophysical Union, the discovery comes as NASA's Juno spacecraft nears Jupiter for the start of its mission this summer. Launched in 2011, Juno aims to unlock the secrets of Jupiter's origin, helping us to understand how the solar system, including Earth, formed.
Jupiter’s X-ray emission (in magenta and white, for the brightest spot, overlaid on a Hubble Space Telescope optical image) captured by Chandra as a coronal mass ejection reaches the planet on 2 October 2011, and then after the solar wind subsides on 4 October 2011 [Credit: Joseph DePasquale, Smithsonian Astrophysical Observatory Chandra X-ray Center)]
As part of the mission, Juno will investigate Jupiter's relationship with the Sun and the solar wind by studying its magnetic field, magnetosphere and aurora. The UCL team hope to find out how the X-rays form by collecting complementary data using the European Space Agency's X-ray space observatory, XMM-Newton, and NASA's Chandra X-ray observatory.
"Comparing new findings from Jupiter with what is already known for Earth will help explain how space weather is driven by the solar wind interacting with Earth's magnetosphere. New insights into how Jupiter's atmosphere is influenced by the Sun will help us characterise the atmospheres of exoplanets, giving us clues about whether a planet is likely to support life as we know it," said study supervisor, Professor Graziella Branduardi-Raymont, UCL Mullard Space Science Laboratory.
The impact of solar storms on Jupiter's aurora was tracked by monitoring the X-rays emitted during two 11 hour observations in October 2011 when an interplanetary coronal mass ejection was predicted to reach the planet from the Sun. The scientists used the data collected to build a spherical image to pinpoint the source of the X-ray activity and identify areas to investigate further at different time points.
William Dunn added, "In 2000, one of the most surprising findings was a bright 'hot spot' of X-rays in the aurora which rotated with the planet. It pulsed with bursts of X-rays every 45 minutes, like a planetary lighthouse. When the solar storm arrived in 2011, we saw that the hot spot pulsed more rapidly, brightening every 26 minutes. We're not sure what causes this increase in speed but, because it quickens during the storm, we think the pulsations are also connected to the solar wind, as well as the bright new aurora."
Another study out today, led by Tomoki Kimura from the Japan Aerospace Exploration Agency (JAXA) and co-authored by the UCL researchers, reports that the X-ray aurora responds to quieter 'gusts' of solar wind, deepening this connection between Jupiter and the solar wind.
Source: University College London [March 22, 2016]
The surface of Mars – including the location of Beagle-2 – has been shown in unprecedented detail by UCL scientists using a revolutionary image stacking and matching technique.
Original HiRISE image at 25-centimetre resolution and super-resolution restoration (SRR) from six HiRISE images at 6.25-centimetre resolution of the Shaler formation and the John Klein drill-spot on the MSL Curiosity traverse. Note the fine-scale detail shown in the SRR. Map co-ordinates in global system from co-registration with ESA HRSC and NASA MOLA [Credit: UCL/Ade Ashford]
Exciting pictures of the Beagle-2 lander, the ancient lakebeds discovered by NASA's Curiosity rover, NASA's MER-A rover tracks and Home Plate's rocks have been released by the UCL researchers who stacked and matched images taken from orbit, to reveal objects at a resolution up to five times greater than previously achieved.
A paper describing the technique, called Super-Resolution Restoration (SRR), was published in Planetary and Space Science in February but has only recently been used to focus on specific objects on Mars. The technique could be used to search for other artefacts from past failed landings as well as identify safe landing locations for future rover missions. It will also allow scientists to explore vastly more terrain than is possible with a single rover.
Co-author Professor Jan-Peter Muller from the UCL Mullard Space Science Laboratory, said: "We now have the equivalent of drone-eye vision anywhere on the surface of Mars where there are enough clear repeat pictures. It allows us to see objects in much sharper focus from orbit than ever before and the picture quality is comparable to that obtained from landers.
"As more pictures are collected, we will see increasing evidence of the kind we have only seen from the three successful rover missions to date. This will be a game-changer and the start of a new era in planetary exploration."
Before (25 centimetre) and after (5 centimetre) super-resolution restoration (SRR) images showing the MER-A Spirit Home Plate region. Note the movement of the rover in the lower right-hand corner. In the full-size images, the rover’s tracks can be clearly seen. Map co-ordinates in global system from co-registration with ESA HRSC and NASA MOLA [Credit: UCL/Ade Ashford]
Even with the largest telescopes that can be launched into orbit, the level of detail that can be seen on the surface of planets is limited. This is due to constraints on mass, mainly telescope optics, the communication bandwidth needed to deliver higher resolution images to Earth and the interference from planetary atmospheres. For cameras orbiting Earth and Mars, the resolution limit today is around 25cm (or about 10 inches).
By stacking and matching pictures of the same area taken from different angles, Super-Resolution Restoration (SRR) allows objects as small as 5cm (about 2 inches) to be seen from the same 25cm telescope. For Mars, where the surface usually takes decades to millions of years to change, these images can be captured over a period of ten years and still achieve a high resolution. For Earth, the atmosphere is much more turbulent so images for each stack have to be obtained in a matter of seconds.
The UCL team applied SRR to stacks of between four and eight 25cm images of the Martian surface taken using the NASA HiRISE camera to achieve the 5cm target resolution. These included some of the latest HiRISE images of the Beagle-2 landing area that were kindly provided by Professor John Bridges from the University of Leicester.
"Using novel machine vision methods, information from lower resolution images can be extracted to estimate the best possible true scene. This technique has huge potential to improve our knowledge of a planet's surface from multiple remotely sensed images. In the future, we will be able to recreate rover-scale images anywhere on the surface of Mars and other planets from repeat image stacks" said Mr Yu Tao, Research Associate at UCL and lead author of the paper.
The team's 'super-resolution' zoomed-in image of the Beagle-2 location proposed by Professor Mark Sims and colleagues at the University of Leicester provides strong supporting evidence that this is the site of the lander. The scientists plan on exploring other areas of Mars using the technique to see what else they find.
View the image gallery on Flickr.
Source: University College London [April 26, 2016]
A team of Caltech researchers that has spent years searching for the earliest objects in the universe now reports the detection of what may be the most distant galaxy ever found. In an article published August 28, 2015 in Astrophysical Journal Letters, Adi Zitrin, a NASA Hubble Postdoctoral Scholar in Astronomy, and Richard Ellis -- who recently retired after 15 years on the Caltech faculty and is now a professor of astrophysics at University College, London -- describe evidence for a galaxy called EGS8p7 that is more than 13.2 billion years old. The universe itself is about 13.8 billion years old.
Galaxy EGS8p7, as seen from the Hubble Space Telescope (wide and top right) and Spitzer Space Telescope (inset, bottom right), taken in infrared [Credit: I. Labbe (Leiden University), NASA/ESA/JPL-Caltech]
Earlier this year, EGS8p7 had been identified as a candidate for further investigation based on data gathered by NASA's Hubble Space Telescope and the Spitzer Space Telescope. Using the multi-object spectrometer for infrared exploration (MOSFIRE) at the W.M. Keck Observatory in Hawaii, the researchers performed a spectrographic analysis of the galaxy to determine its redshift. Redshift results from the Doppler effect, the same phenomenon that causes the siren on a fire truck to drop in pitch as the truck passes. With celestial objects, however, it is light that is being "stretched" rather than sound; instead of an audible drop in tone, there is a shift from the actual color to redder wavelengths.
Redshift is traditionally used to measure distance to galaxies, but is difficult to determine when looking at the universe's most distant -- and thus earliest -- objects. Immediately after the Big Bang, the universe was a soup of charged particles -- electrons and protons -- and light (photons). Because these photons were scattered by free electrons, the early universe could not transmit light. By 380,000 years after the Big Bang, the universe had cooled enough for free electrons and protons to combine into neutral hydrogen atoms that filled the universe, allowing light to travel through the cosmos. Then, when the universe was just a half-billion to a billion years old, the first galaxies turned on and reionized the neutral gas. The universe remains ionized today.
Prior to reionization, however, clouds of neutral hydrogen atoms would have absorbed certain radiation emitted by young, newly forming galaxies -- including the so-called Lyman-alpha line, the spectral signature of hot hydrogen gas that has been heated by ultraviolet emission from new stars, and a commonly used indicator of star formation.
A graphic representation of the extreme distance of galaxy EGS8p7. To the far right is the W. M. Keck telescope used for the observation, to the far left is the Big Bang, and at the center is the galaxy. The scale above indicates the progression of ever more distant discoveries and the corresponding year, and at the bottom is a time scale equivalent to distance. Finally, the inset to top left charts the observations made across two nights with the MOSFIRE spectrometer that resulted in the detect [Credit: Adi Zitrin/Caltech]
Because of this absorption, it should not, in theory, have been possible to observe a Lyman-alpha line from EGS8p7.
"If you look at the galaxies in the early universe, there is a lot of neutral hydrogen that is not transparent to this emission," says Zitrin. "We expect that most of the radiation from this galaxy would be absorbed by the hydrogen in the intervening space. Yet still we see Lyman-alpha from this galaxy."
They detected it using the MOSFIRE spectrometer, which captures the chemical signatures of everything from stars to the distant galaxies at near-infrared wavelengths (0.97-2.45 microns, or millionths of a meter).
"The surprising aspect about the present discovery is that we have detected this Lyman-alpha line in an apparently faint galaxy at a redshift of 8.68, corresponding to a time when the universe should be full of absorbing hydrogen clouds," Ellis says. Prior to their discovery, the farthest detected galaxy had a redshift of 7.73.
One possible reason the object may be visible despite the hydrogen-absorbing clouds, the researchers say, is that hydrogen reionization did not occur in a uniform manner. "Evidence from several observations indicate that the reionization process probably is patchy," Zitrin says. "Some objects are so bright that they form a bubble of ionized hydrogen. But the process is not coherent in all directions."
"The galaxy we have observed, EGS8p7, which is unusually luminous, may be powered by a population of unusually hot stars, and it may have special properties that enabled it to create a large bubble of ionized hydrogen much earlier than is possible for more typical galaxies at these times," says Sirio Belli, a Caltech graduate student who worked on the project.
"We are currently calculating more thoroughly the exact chances of finding this galaxy and seeing this emission from it, and to understand whether we need to revise the timeline of the reionization, which is one of the major key questions to answer in our understanding of the evolution of the universe," Zitrin says.
Author: Rod Pyle | Source: California Institute of Technology [September 04, 2015]
Archaeologists have begun detailed exploration work on the Curtain Theatre, one of William Shakespeare’s least well-known playhouses, in east London.
Culture Minister Ed Vaizey (left) officially marked the beginning of the dig at the site in Shoreditch, East London, where archaeologists from the MOLA excavated 10ft down [Credit: PA]
The playhouse, which saw the first performance of Henry V, is now at the centre of a new residential development, The Stage, offering experts from the Museum of London a rare chance to excavate a key cultural location.
The dig was officially launched by Ed Vaizey MP, Minister for Culture and the Digital Economy just days after the nation marked the 400th anniversary of the playwright’s death.
Trial explorations began in 2012 which offered promising indications that the site, two to three metres below modern ground level, has been well preserved.
Museum of London Archeology (Mola) is hoping to uncover more clues about the physical structure and use of the theatre and shed new light on the cultural makeup of the area and performances in the 16th and 17th centuries.
Archaeologists have started digging through the 18th century remains that encase the Curtain Theatre and now they have reached key layers from the 16th and 17th centuries.
Senior Mola archaeologist Heather Knight said: “We hope to find out more about the structure of the theatre – where Henry V was first performed – which will give us a clearer indication of how Elizabethan playhouses were used and the evolution of theatre.
“There is also the possibility of finding fragments of props, costumes or items used by the audience, including food remains or drinking vessels, which could tell us more about theatre productions and culture at the time. We look forward to sharing our findings in due course.”
Once the detailed dig is complete, the remains of the Curtain will be preserved in-situ, and artefacts discovered and records taken during the excavation will be studied in detail.
A display of the finds will sit alongside the theatre remains as part of a cultural and visitor centre at The Stage , a new £750million mixed-use scheme including 33,000 sq ft of retail, over 200,000 sq ft of office space, and more than 400 homes.
Mr Vaizey said: “Shoreditch is one of London’s most vibrant locations, and its prominence as a theatrical hotspot during Shakespeare’s time highlights this area’s enduring cultural appeal.”
Author: Giles Broadbent | Source: The Wharf [April 27, 2016]
Some of the final results sent back by ESA's Venus Express before it plummeted down through the planet's atmosphere have revealed it to be rippling with atmospheric waves – and, at an average temperature of -157°C, colder than anywhere on Earth.
Visualisation of Venus Express during the aerobraking manoeuvre, during which the spacecraft orbited Venus at an altitude of around 130 km from 18 June to 11 July 2014. In the month before, the altitude was gradually reduced from around 200 km to 130 km [Credit: ESA - C. Carreau]
As well as telling us much about Venus' previously-unexplored polar regions and improving our knowledge of our planetary neighbour, the experiment holds great promise for ESA's ExoMars mission, which is currently winging its way to the Red Planet. The findings were published in the journal Nature Physics.
ESA's Venus Express arrived at Venus in 2006. It spent eight years exploring the planet from orbit, vastly outliving the mission's planned duration of 500 days, before running out of fuel. The probe then began its descent, dipping further and further into Venus' atmosphere, before the mission lost contact with Earth (November 2014) and officially ended (December 2014).
However, Venus Express was industrious to the end; low altitude orbits were carried out during the final months of the mission, taking the spacecraft deep enough to experience measurable drag from the atmosphere. Using its onboard accelerometers, the spacecraft measured the deceleration it experienced as it pushed through the planet's upper atmosphere – something known as aerobraking.
"Aerobraking uses atmospheric drag to slow down a spacecraft, so we were able to use the accelerometer measurements to explore the density of Venus' atmosphere," said Ingo Müller-Wodarg of Imperial College London, UK, lead author of the study. "None of Venus Express' instruments were actually designed to make such in-situ atmosphere observations. We only realised in 2006 – after launch! – that we could use the Venus Express spacecraft as a whole to do more science."
When Müller-Wodarg and colleagues gathered their observations Venus Express was orbiting at an altitude of between 130 and 140 kilometres near Venus' polar regions, in a portion of Venus' atmosphere that had never before been studied in situ.
Venus Express aerobraking [Credit: ESA - C. Carreau]
Previously, our understanding of Venus' polar atmosphere was based on observations gathered by NASA's Pioneer Venus probe in the late 1970s. These were of other parts of Venus' atmosphere, near the equator, but extrapolated to the poles to form a complete atmospheric reference model.
These new measurements, taken as part of the Venus Express Atmospheric Drag Experiment (VExADE) from 24 June to 11 July 2014, have now directly tested this model – and reveal several surprises.
For one, the polar atmosphere is up to 70 degrees colder than expected, with an average temperature of -157°C (114 K). Recent temperature measurements by Venus Express' SPICAV instrument (SPectroscopy for the Investigation of the Characteristics of the Atmosphere of Venus) are in agreement with this finding.
The polar atmosphere is also not as dense as expected; at 130 and 140 km in altitude, it is 22% and 40% less dense than predicted, respectively. When extrapolated upward in the atmosphere, these differences are consistent with those measured previously by VExADE at 180 km, where densities were found to be lower by almost a factor of two.
"This is in-line with our temperature findings, and shows that the existing model paints an overly simplistic picture of Venus' upper atmosphere," added Müller-Wodarg. "These lower densities could be at least partly due to Venus' polar vortices, which are strong wind systems sitting near the planet's poles. Atmospheric winds may be making the density structure both more complicated and more interesting!"
This figure shows the density of Venus' atmosphere in the northern polar regions at altitudes of 130 to 190 km. All data points were gathered during different phases of the Venus Express Atmospheric Drag Experiment (VExADE), performed between 2008-2013 (values above 165 km) and from 24 June to 11 July 2014 (values below 140 km); the black dots to the lower right were from the aerobraking phase (AER), the black dots to the upper left from the Precise Orbit Determination phase (POD), and the grey dots from torque measurements (TRQ). Each coloured line represents a different scientific model of Venus' atmosphere. The dark blue line shows a model based on data from NASA's Pioneer Venus spacecraft, dubbed VTS3 (Hedin et al., 1983), which uses observations of Venus' equatorial latitudes gathered from 1978-1980 (extrapolated to the poles). The cyan line corresponds to another reference model of Venus' neutral upper atmosphere based on Pioneer Venus, named Venus International Reference Atmosphere (VIRA, Keating et al.,1985). The red line corresponds to a model (Venus Polar Atmosphere Model) currently being developed by Ingo Müller-Wodarg. This model seeks to bridge the data gap shown in the figure from 140-165 km and present a unified vertical density profile for Venus' upper polar atmosphere [Credit: I. Müller-Wodarg (Imperial College London, UK)]
Additionally, the polar region was found to be dominated by strong atmospheric waves, a phenomenon thought to be key in shaping planetary atmospheres – including our own.
"By studying how the atmospheric densities changed and were perturbed over time, we found two different types of wave: Atmospheric gravity waves and planetary waves," explained co-author Sean Bruinsma of the Centre National D'Etudes Spatiales (CNES), France. "These waves are tricky to study, as you need to be within the atmosphere of the planet itself to measure them properly. Observations from afar can only tell us so much."
Atmospheric gravity waves are similar to waves we see in the ocean, or when throwing stones in a pond, only they travel vertically rather than horizontally. They are essentially a ripple in the density of a planetary atmosphere – they travel from lower to higher altitudes and, as density decreases with altitude, become stronger as they rise. The second type, planetary waves, are associated with a planet's spin as it turns on its axis; these are larger-scale waves with periods of several days.
We experience both types on Earth. Atmospheric gravity waves interfere with weather and cause turbulence, while planetary waves can affect entire weather and pressure systems. Both are known to transfer energy and momentum from one region to another, and so are likely to be hugely influential in shaping the characteristics of a planetary atmosphere.
"We found atmospheric gravity waves to be dominant in Venus' polar atmosphere," added Bruinsma. "Venus Express experienced them as a kind of turbulence, a bit like the vibrations you feel when an aeroplane flies through a rough patch. If we flew through Venus' atmosphere at those heights we wouldn't feel them because the atmosphere just isn't dense enough, but Venus Express' instruments were sensitive enough to detect them."
This frame shows a visualization of raw data from the Venus Express Atmospheric Drag Experiment (VExADE), performed from 24 June to 11 July 2014, at altitudes of 130-140 km in the atmosphere of Venus. The black lines show 16 of the spacecraft's 18 orbital trajectories from that period. The grey background is a normalised map of the atmospheric gravity waves that were detected. The non-uniformity represents density perturbations in Venus' polar atmosphere; darker patches are less dense, and lighter patches more dense, than their surroundings. The average density perturbation amplitude is around 10% of the mean background density. The results of the VExADE experiment, reported in Nature Physics (Müller-Wodarg et al., 2016), showed that strong atmospheric gravity waves dominate the polar regions of Venus' atmosphere [Credit: ESA/Venus Express/VExADE/Müller-Wodarg et al., 2016]
Venus Express found atmospheric waves at an altitude of 130-140 km that the team think originated from the upper cloud layer in Venus' atmosphere, which sits at and below altitudes of approximately 90 km, and a planetary wave that oscillated with a period of five days. "We checked carefully to ensure that the waves weren't an artefact of our processing," said co-author Jean-Charles Marty, also of CNES.
This is not just a first for Venus Express; while the aerobraking technique has been used for Earth satellites, and was previously used on NASA-led missions to Mars and Venus, it had never before been used on any ESA planetary mission.
However, ESA's ExoMars Trace Gas Orbiter, which launched earlier this year, will use a similar technique. "During this activity we will extract similar data about Mars' atmosphere as we did at Venus," added Håkan Svedhem, project scientist for ESA's ExoMars 2016 and Venus Express missions.
"For Mars, the aerobraking phase would last longer than on Venus, for about a year, so we'd get a full dataset of Mars' atmospheric densities and how they vary with season and distance from the Sun," added Svedhem. "This information isn't just relevant to scientists; it's crucial for engineering purposes as well. The Venus study was a highly successful test of a technique that could now be applied to Mars on a larger scale – and to future missions after that."
Scientists have discovered that the mineral jarosite breaks down organic compounds when it is flash-heated, with implications for Mars research.
Curiosity self-portrait during drilling aim [Credit: NASA/JPL-Caltech/MSSS]
Jarosite is an iron sulphate and it is one of several minerals that NASA’s Curiosity Mission is searching for, as its presence could indicate ancient habitable environments, which may have once hosted life on the red planet.
In a new study published today in the journal Astrobiology, researchers from Imperial College London and the Natural History Museum replicated a technique that one of the Curiosity Rover’s on-board instruments is using to analyse soil samples, in its quest to find organic compounds. They tested a combination of jarosite and organic compounds. They discovered that the instrument’s technique -which uses intense bursts of heat called flash-heating – broke down jarosite into sulphur dioxide and oxygen, with the oxygen then destroying the organic compounds, leaving no trace of it behind.
The concern is that if jarosite is present in soil samples that Curiosity analyses, researchers may not be able to detect it because both the jarosite and any organic compounds could be destroyed by the flash-heating process.
In 2014, Professor Mark Sephton, co-author of today’s study, investigated the mineral perchlorate. This mineral also causes problems for flash-heating experiments as it breaks down to give off oxygen and chlorine gas, which in turn react with any organic compounds, breaking them down into carbon dioxide and water. Professor Sephton showed that though perchlorate was problematic, scientists could potentially use the carbon dioxide resulting from the experiment to detect the presence of organic compounds in the sample being analysed.
Professor Sephton, from the Department of Earth Science and Engineering at Imperial College London, said: “The destructive properties of some iron sulphates and perchlorate to organic matter may explain why current and previous missions have so far offered no conclusive evidence of organic matter preserved on Mars’ surface. This is despite the fact that scientists have known from previous studies that organic compounds have been delivered to Mars via comets, meteorites and interplanetary dust throughout its history.”
Jarosite on quartz [Credit: Dave Dyet http://www.dyet.com]
To make Curiosity’s search for signs of life more effective, the team are now exploring how Curiosity might be able to compensate for the impact of these minerals on the search for organic compounds. Their work could have important implications for both the Curiosity mission and also the upcoming European-led ExoMars 2018 Rover mission, which will be drilling for subsurface samples of the red planet and using the same flash-heating method to look for evidence of past or present alien life.
James Lewis, co-author of the study from the Department of Earth Science and Engineering at Imperial College London, added: “Our study is helping us to see that if jarosite is detected then it is clear that flash-heating experiments looking for organic compounds may not be completely successful. However, the problem is that jarosite is evidence of systems that might have supported life, so it is not a mineral that scientists can completely avoid in their analysis of soils on Mars. We hope our study will help scientists with interpreting Mars data and assist them to sift through the huge amount of excellent data that Curiosity is currently generating to find signs that Mars was once able to sustain life.”
On Earth, iron sulphate minerals like jarosite form in the harsh acidic waters flowing out of sulphur rich rocks. Despite the adverse conditions, these waters are a habitat for bacteria that use these dissolved sulphate ions. This makes these minerals of great interest to scientists studying Mars, as their presence on the red planet provide evidence that acidic liquid water was present at the same time the minerals formed, which could have provided an environment favourable for harbouring ancient microbial Martian life.
On board Curiosity, the Sample Analysis at Mars (SAM) instrument analyses soil samples for evidence of organic compounds by progressively heating samples up to around 1000 C, which releases gases. These gases can then be analysed by techniques called gas chromatography and mass spectrometry, which can identify molecules in the gas and see if any organic compounds are present. It is these SAM instrument experiments that the researchers behind today’s study replicated with jarosite and organic compounds.
The researchers stress that not all sulphates break down to react with organic compounds. For example, those containing calcium and magnesium would not break down until extremely high temperatures were reached during the analysis, and therefore would not affect any organic compounds present.
The team suggest that if jarosite is found in samples on Mars, then it may be possible for Curiosity’s SAM instrument to distinguish a spike in carbon dioxide level, which, as Professor Sephton has shown previously with perchlorate, would act as an indicator that organic material is present and being broken down by the heating process.
The next step will see the researchers using synthetic jarosite in their experiments, which will enable a cleaner decomposition process to occur when the mineral is flash-heated. This will allow for more precise quantitative measurements to be taken when the oxygen is being released. Ultimately, they hope this will enable more precise calculations to be carried out on Mars mineral samples to find ways in which Curiosity can identify the presence of these mineral to mitigate their impact on organic matter.
The jarosite samples used in the experiments in the study were collected from Brownsea Island in Dorset, with the permission and assistance from the National Trust.
Source: Imperial College London [February 19, 2015]
The British Museum is to stage a major exhibition on two lost Egyptian cities and their recent rediscovery by archaeologists beneath the Mediterranean seabed. Opening in May 2016 for an extended run of six months, The BP exhibition Sunken cities: Egypt’s lost worlds will be the Museum’s first large-scale exhibition of underwater discoveries. It will show how the exploration of Thonis-Heracleion and Canopus – submerged at the mouth of the River Nile for over a thousand years – is transforming our understanding of the relationship between ancient Egypt and the Greek world and the great importance of these ancient cities.
300 outstanding objects will be brought together for the exhibition including more than 200 spectacular finds excavated off the coast of Egypt near Alexandria between 1996 and 2012. Important loans from Egyptian museums rarely seen before outside Egypt (and the first such loans since the Egyptian revolution) will be supplemented with objects from various sites across the Delta drawn from the British Museum’s collection; most notably from Naukratis – a sister harbour town to Thonis-Heracleion and the first Greek settlement in Egypt.
Likely founded during the 7th century BC, Thonis-Heracleion and Canopus were busy, cosmopolitan cities that once sat on adjacent islands at the edge of the fertile lands of the Egyptian Delta, intersected by canals. After Alexander the Great’s conquest of Egypt in 332BC, centuries of Greek (Ptolemaic) rule followed. The exhibition will reveal how cross-cultural exchange and religion flourished, particularly the worship of the Egyptian god of the afterlife, Osiris.
By the 8th century AD, the sea had reclaimed the cities and they lay hidden several metres beneath the seabed, their location and condition unclear. Although well-known from Egyptian decrees and Greek mythology and historians, past attempts to locate them were either fruitless or very partial. The exhibition will show how a pioneering European team led by Franck Goddio in collaboration with the Egyptian Ministry of Antiquities made use of the most up-to-date technologies to find them.
Thanks to the underwater setting, a vast number of objects of great archaeological significance have been astonishingly well preserved. Pristine monumental statues, fine metalware and gold jewellery will reveal how Greece and Egypt interacted in the late first millennium BC. These artefacts offer a new insight into the quality and unique character of the art of this period and show how the Greek kings and queens who ruled Egypt for 300 years adopted and adapted Egyptian beliefs and rituals to legitimise their reign.
The exhibition will feature a number of extraordinary, monumental sculptures. A 5.4m granite statue of Hapy, a divine personification of the Nile’s flood, will greet visitors as they enter the space. Masterpieces from Egyptian museums such as the Apis bull from the Serapeum in Alexandria will be shown alongside magnificent recent finds from the sea. One such piece is the stunning sculpture from Canopus representing Arsinoe II (the eldest daughter of Ptolemy I, founder of the Ptolemaic dynasty). The Graeco-Macedonian queen became a goddess beloved to both Egyptians and Greeks after her death and is depicted here as the perfect embodiment of Aphrodite, a goddess of beauty ‘who grants fortunate sailing’.
The exhibition will also cover the arrival of Greeks in Egypt, when they were hosts and not rulers; privileged but controlled by the pharaohs. A complete stela from Thonis-Heracleion advertises a 380BC royal decree of the Egyptian pharaoh Nectanebo I. It states that 10% of the taxes collected on all goods imported from the ‘Sea of the Greeks’ into Thonis-Heracleion and on all trade operations at Naukratis were to be donated to an Egyptian temple.
A wide range of objects, from modest to grand and costly, bears witness to the piety of both inhabitants and visitors at these major religious centres. Lead models of barges uncovered in the sacred waterway linking Thonis-Heracleion to Canopus are unique and moving finds. They are associated with the Mysteries of Osiris, the most popular festival celebrated annually across Egypt during the month of Khoiak (mid-October to mid-November). Ranging in size from 6 to 67cm, these reproduce in metal a flotilla of 34 papyrus barges that would have been displayed on a waterway to celebrate the first sacred navigation of the festival. According to religious texts, each barge was to measure 67.5 cm and to bear the figure of an Egyptian god, and would have been illuminated by 365 lamps. The lead barges are lasting testimonies possibly left by people who, long ago, celebrated this festival in the Canopic region.
Only a tiny proportion of these sites have revealed their secrets. The on-going underwater archaeological mission continues to bring to light new masterpieces and further research every year as the most recent finds from 2012 will show.
Sir Richard Lambert, Chairman of the British Museum, said, “It’s hugely exciting to be announcing the British Museum’s first large-scale exhibition of underwater discoveries and to be welcoming these important loans to London. We are grateful to BP for their ongoing support without which ambitious exhibitions such as these would simply not be possible. We’re also delighted to be working with Franck Goddio, his expert team at IEASM, the Hilti Foundation and of course our Egyptian colleagues to bring the extraordinary story of these lost cities to life.”
His Excellency Nasser Kamel, Ambassador of the Arab Republic of Egypt to the United Kingdom, said, "As well as looking for partners to invest in the Egyptian economy, Egypt is always searching for partners to help in exploring its heritage and treasures which are still hidden under its lands, and waters. This exhibition shows that despite what we know of its tremendous history and culture, Egypt still has a lot more to offer to?the world and we thank our partners in the UK, such as BP, for working with us in utilising our resources to develop our economy and through such an exhibition unraveling our history as well. I invite the people of Britain to visit this exhibition to get a glimpse of what Egypt has to offer, and come to Egypt to live that experience."
Bob Dudley, Group Chief Executive, BP, said, “BP is proud to support this fascinating exhibition which showcases the power of science and the pioneering spirit to discover what lies beneath the surface of the Nile Delta. By sharing these underwater treasures the British Museum is opening a whole new frontier for visitors to explore, and we are pleased to be a part of it.”
Franck Goddio, President of Institut Europeen d’Archeologie Sous-Marine (IEASM) and exhibition co-curator said “My team and I, as well as the Hilti Foundation, are delighted that the exhibition with discoveries from our underwater archaeological expeditions off the coast of Egypt will be on display at the British Museum. It enables us to share with the public the results of years of work at the sunken cities and our fascination for ancient worlds and civilisations. Placing our discoveries alongside selected masterpieces from the collections of Egyptian museums, complemented by important objects from the British Museum, the exhibition presents unique insights into a fascinating period in history during which Egyptians and Greeks encountered each other on the shores of the Mediterranean.”
Aurelia Masson-Berghoff, exhibition curator at the British Museum said “People sometimes assume that when two cultures mix, the essence of each is diluted and, as a result, weakened; this exhibition demonstrates the opposite. It is a rare opportunity to reveal the beauty and strength of Late Pharaonic art and culture, alongside the latest research on the momentous intermingling between Egyptian and Greek communities in Egypt at this time. We are illustrating this vibrant cosmopolitan world through Egyptian, Greek and ‘hybrid’ artworks, rarely ever displayed side by side. It shows ancient Egypt not as an isolated civilisation, but as the outward looking, influential and inclusive society that it was.”
The Museo Civico Archeologico is hosting Egypt. Millennia of Splendour. Beneath the two towers, the splendour of a civilisation that lasted thousands of years and has always fascinated the entire world, has sprung back to life: the Egypt of the pyramids, pharaohs and multiform gods, but also that of sensational discoveries, captivating archaeology, passionate collecting and rigorous scholarship.
The exhibition ‘Egypt’, which is being held at the Museo Civico Archeologico in Bologna, is not just an exposition of high visual and scientific impact, but also an unprecedented international enterprise: the Egyptian collection of the National Museum of Antiquities in Leiden, Netherlands – among the top ten in the world – and that of the Bologna museum – among the most important in Italy for the quantity, quality and state of conservation of its collections – have been brought together in an exhibition space measuring around 1,700 metres, filled with art and history.
500 finds, dating from the Pre-Dynastic Period to the Roman Period, gave been brought from the Netherlands to the Bologna museum. And, together with the masterpieces from Leiden and Bologna, the exhibition also includes important loans from the Museo Egizio in Turin and the Museo Egizio in Florence, creating a network of the most important Italian museums.
For the first time, the masterpieces of the two collections are being displayed side by side, including the Stele of Aku (Twelfth–Thirteenth Dynasty, 1976–1648 BC), the ‘major domo of the divine offering’, with a prayer describing the otherworldly existence of the deceased in a tripartite world divided into sky, earth and the beyond; gold items attributed to General Djehuty, who led the Egyptian troops to victory in the Near East for the great conqueror Pharaoh Thutmose III (1479–1425 BC); the statues of Maya, superintendent of the royal treasury of Tutankhamen, and Merit, a chantress of the god Amun, (Eighteenth Dynasty, reigns of Tutankhamen and Horemheb, 1333–1292 BC), the most important masterpieces in the National Museum of Antiquities in Leiden have left the Netherlands for the first time for the Bologna exhibition; and, among the numerous objects attesting to the refined lifestyle of the most wealthy Egyptians, a Mirror Handle (1292 BC) in the shape of a young woman holding a small bird in her hand.
Statue of Maya and Merit, XVIII Dynasty, reign of Tutankhamon (1333 – 1323 BC) and Horemheb (1319 – 1292 BC) [Credit: Museo Civico Archeologico, Bologna]
Lastly, for the first time 200 years after the discovery of his tomb in Saqqara, the exhibition offers the unique and once-in-a-lifetime opportunity to see the important Reliefs of Horemheb reunited: Horemheb was the head commander of the Egyptian army during the reign of Tutankhamen, then rising to become the final sovereign of the Eighteenth Dynasty, from 1319 to 1292 BC and the reliefs are divided between the collections in Leiden, Bologna and Florence.
Thousands of years of the history of a unique civilisation revealed in a major exhibition that brings together masterpieces from important world collections and tells of the pyramids and pharaohs, the great captains and priests, the gods and other divinities, and the people that made Egyptian history and that, thanks to discoveries, archaeology and collecting, never stop enchanting, revealing, intriguing, fascinating and charming generation after generation.
The Seven Exhibition Sections
The Pre-Dynastic and Archaic Periods – At the Origins of History: The transition from raw material to form, from the oral tradition to the written one and from prehistory to history was a fundamental moment for Egyptian civilisation. The Leiden collection is rich in materials documenting the central role played by nature during this long cultural and artistic evolution.
Mirror handle, XVIII Dynasty (1539 – 1292 BC) [Credit: Museo Civico Archeologico, Bologna]
The exhibition opens with a selection of these objects, which are strikingly modern in style, including a vase from the Naqada IID Period (named for a site in Upper Egypt and datable between 3375 and 3325 BC) decorated with ostriches, hills and water motifs. The scene depicted on this vase takes us back to an Egypt characterised by a flourishing landscape later changed over time by climatic changes. Ostriches, here painted red, along with elephants, crocodiles, rhinoceros and other wild animals were common in the Nile region at the time.
The Old Kingdom – A Political/Religious Model Destined for Success and its Weaknesses: The historic period of the Old Kingdom (from the Third to the Sixth Dynasty, roughly between 2700 and 2192 BC) is known for the pyramids and for the consolidation of a bureaucracy at the apex of which stood an absolute sovereign, considered a god on earth and lord of all of Egypt.
This definition of State and its worldly and otherworldly rules, which were highly elitist, are well documented by funerary objects, of which the Leiden museum has a particularly rich collection, including a calcite (alabaster) table for offerings.
Offerings to the deceased were a fundamental part of the funerary ritual, ensuring life after death. The uniqueness of this table, which belonged to a high state official named Defdj, lies in its circular shape, which was unusual, as well as the repetition of the concept of the offering as indicated by the inscription, the sculpted receptacles and, most importantly, the central depiction corresponding to the hieroglyph hotep (offering), or a table upon which one places a loaf of bread.
Pectoral element, blue lotus, XVIII Dynasty, reign of Thutmosis III (1479 – 1425 BC) [Credit: Museo Civico Archeologico, Bologna]
The Middle Kingdom – The God Osiris and a New Perspective on Life in the Afterworld: The end of the Old Kingdom and the period of political breakdown that followed it led to major changes in Egyptian society, within which the individual had greater responsibility for his own destiny, including in the afterworld. Any Egyptian with the means to build a tomb complete with a sufficient funerary assemblage could now aspire to eternal life. The god Osiris, lord of the afterworld, became Egypt’s most popular divinity.
Many steles now in Leiden and Bologna came from his temple in Abydos, one of Egypt’s most important cult centres. Among them is that of Aku, major domo of the divine offering, who dedicated the stele to Min-Hor-nekht, the form of the ithyphallic god Min worshipped in the city of Abydos. Aku’s prayer to the god describes an otherworldly existence in a tripartite world: the sky, where the deceased were transfigured into stars, the earth, where the tomb was the fundamental point of passage from life to death, and the beyond, where Osiris granted the deceased eternal life.
From the Middle to the New Kingdom – Territorial Control at Home and Abroad: The defeat of the Hyksos, ‘princes from foreign lands’ who invaded and governed northern Egypt for a few generations, marked the beginning of the New Kingdom. An extremely aggressive foreign policy enriched Egypt, and this was one of its periods of greatest splendour. The social class of professional warriors rose to the top of the state hierarchy and spawned a number of ruling dynasties.
Relief with prisoners of war paraded by Egyptian soldiers before Tutankhamun, XVIII Dynasty, reign of Tutankhamun (1333 – 1323 BC) [Credit: Museo Civico Archeologico, Bologna]
The wealth and prestige of these soldiers was also expressed in the production of sophisticated objects, including the gold items attributed to Djehuty, a general under the pharaoh Thutmose III. The Egyptian goldsmith’s art has survived in works of high artistic and economic value, an example being the pectoral element on view in the exhibition.
This piece is a sophisticated exemplar attributed to the tomb of General Djehuty, the man to whom the sovereign Thutmose III entrusted control of his foreign territories. Representing a blue lotus flower, a symbol of rebirth and regeneration, it must have served as the central element of an elaborate pectoral. The scroll engraved on the back suggests that the piece was given personally by Thutmose III.
The Saqqara Necropolis of the New Kingdom: The Leiden and Bologna museums can be considered ‘twins’ in a certain sense, since they house two important groups of antiquities from Saqqara, one of the necropolises of the city of Memphis. During the New Kingdom, this early Egyptian capital returned to its role as a strategic centre for the expansionist policy of the sovereigns of the Eighteenth Dynasty.
This is seen in the funerary monuments of high state officials who held administrative, religious and military roles, including the tombs of the superintendent of Tutankhamen’s royal treasury, Maya, and his wife, Merit, chantress of Amun, and that of Horemheb, head commander of Tutankhamen’s army and the pharaoh’s crown prince.
Stele od Aku, XII-XIII Dynasties (1976 – 1648 BC) [Credit: Museo Civico Archeologico, Bologna]
The statues of Maya and Merit arrived in the Netherlands in 1829 as part of the collection of Giovanni d’Anastasi. More than a century and a half would pass before, in 1986, a British/Dutch archaeological expedition identified the tomb from which they came, southeast of the pyramid of Djoser at Saqqara. These statues, which are the greatest masterpieces in the collection of the National Museum of Antiquities in Leiden, left the Dutch museum for the first time to be displayed in the exhibition.
It should be noted that, when the Egypt Exploration Society of London and the National Museum of Antiquities in Leiden began excavation work southeast of the Djoser pyramid in 1975, the goal was to find the tomb of Maya and Merit. It was therefore a great surprise when they instead discovered the burial of General Horemheb, who had capped off his stunning career by becoming the last sovereign of the Eighteenth Dynasty.
His tomb, which has a temple structure, is characterised by a pylon entrance, three large courts and three cult chapels facing onto the innermost court, which has a peristyle structure. This court is where most of the reliefs preserved in Leiden and Bologna were found, narrating Horemheb’s most important military feats against the populations bordering Egypt: the Asians, Libyans and Nubians.
The New Kingdom – Prosperity after the Conquest: Refined furnishings, musical instruments, table games and jewellery: these are just a few of the luxury goods attesting to the widespread prosperity enjoyed in Egypt as a result of the expansionist policy of the sovereigns of the New Kingdom. Through these sophisticated objects, it is possible to conjure up moments of everyday life, imagining what it was like living inside a royal palace or the residence of a high official. One example in the exhibition is a mirror handle in the graceful, sensual shape of a young women holding a small bird in her hand.
Anthropoid sarcophagus of Peftjauneith, XXVI Dynasty (664 -525 BC) [Credit: Museo Civico Archeologico, Bologna]
Egypt in the First Millennium: In the first millennium BC, Egypt was characterised by the increasingly clear weakness of its central power to the advantage of local governors who gave themselves the role of ruling dynasts. The loss of political and territorial power weakened Egypt’s defence capacity at its borders, opening the way for Nubian, Assyrian and Persian invasions. The temples remained strong centres of power, and managed a sizeable portion of the economy and the transmission of knowledge, taking on the role of a political intermediary between the ruling power and the devout populace.
Many of the masterpieces on view in the exhibition were part of the funerary assemblages of priests and came from important temple areas. Among them is the sarcophagus of Peftjauneith, which represents the likeness of the god Osiris, wrapped in a linen shroud and with a green face evoking the concept of rebirth. The refined decoration of this sarcophagus confirms the high rank of its owner (the superintendent of the possessions of a temple in Lower Egypt) in the temple sphere. Of particular note is the interior scene of the sky goddess Nut swallowing the sun every evening (to the west) to then give birth to it in the morning (to the east).
Alexander the Great’s conquest of Egypt in 332 BC ended the ‘pharaonic’ phase of Egyptian history. The period of Greek domination was begun by his successors, the Ptolemies, the last of whom was the renowned Cleopatra VII.
The golden decline of Egypt would continue for many more centuries, beyond the Roman conquest in 31 BC up to Arab domination in the sixth century AD.
The dialogue between old and new, local and foreign that distinguished the Greco-Roman period brought a return to high artistic achievements, including the celebrated Fayum portraits, exquisite examples of which from the Leiden collection are on view in the exhibition
Source: Museo Civico Archeologico in Bologna [October 19, 2015]