̽��ֱ�� of Cambridge - satellite

Zero gravity graphene promises success in space

Anonymous — Wed, 31 Jan 2018 07:00:00 +0000

Working as part of a collaboration between the Graphene Flagship and the European Space Agency, researchers from the Cambridge Graphene Centre tested graphene in microgravity conditions for the first time while aboard a parabolic flight – often referred to as the ‘vomit comet’. ̽��ֱ��experiments they conducted were designed to test graphene’s potential in cooling systems for satellites.

“One of graphene’s potential uses, recognised early on, is space applications, and this is the first time that graphene has been tested in space-like applications,” said Professor Andrea Ferrari, who is Director of the Cambridge Graphene Centre, as well as Science and Technology Officer and Chair of the Management Panel for the Graphene Flagship.

Graphene – a form of carbon just a single atom thick – has a unique combination of properties that make it useful for applications from flexible electronics and fast data communication, to enhanced structural materials and water treatments. It is highly electrically and thermally conductive, as well as strong and flexible.

In this experiment, the researchers aimed to improve the performance of cooling systems in use in satellites, making use of graphene’s excellent thermal properties. “We are using graphene in what are called loop-heat pipes. These are pumps that move fluid without the need for any mechanical parts, so there is no wear and tear, which is very important for space applications,” said Ferrari.

“We are aiming at an increased lifetime and an improved autonomy of the satellites and space probes,” said Dr Marco Molina, Chief Technical Officer of the Space line of business at industry partner Leonardo. “By adding graphene, we will have a more reliable loop heat pipe that can operate autonomously in space.”

In a loop-heat pipe, evaporation and condensation of a fluid are used to transport heat from hot electronic systems out into space. ̽��ֱ��pressure of the evaporation-condensation cycle forces fluid through the closed systems, providing continuous cooling.

̽��ֱ��main element of the loop-heat pipe is the metallic wick, where the fluid is evaporated into gas. In these experiments, the metallic wick was coated in graphene, improving the efficiency of the heat pipe in two ways. Firstly, graphene’s excellent thermal properties improve the heat transfer from the hot systems into the wick. Secondly, the porous structure of the graphene coating increases the interaction of the wick with the fluid, and improves the capillary pressure, meaning the liquid can flow through the wick faster.

After promising results in laboratory tests, the graphene-coated wicks were tested in space-like conditions onboard a Zero-G parabolic flight. To create weightlessness, the plane undergoes a series of parabolic manoeuvres, creating up to 23 seconds of weightlessness in each manoeuvre.

“It was truly a wonderful experience to feel weightlessness, but also the hyper-gravity moments in the plane. I was very excited but at the same time a bit nervous. I couldn’t sleep the night before,” said Dr Yarjan Samad, a Research Associate at the Cambridge Graphene Centre.

During the flight, the graphene-coated wicks again demonstrated excellent performance, with more efficient heat and fluid transfer compared to the untreated wicks. Based on these results, the researchers are continuing to develop and optimise the coatings for applications in real space conditions. “ ̽��ֱ��next step will be to start working on a prototype that could go either on a satellite or on the space station,” said Ferrari.

̽��ֱ��research was supported by the Graphene Flagship and the European Space Agency, as a collaboration between researchers from Université libre de Bruxelles, Belgium; the ̽��ֱ�� of Cambridge, UK; the National Research Council of Italy (CNR), Italy; and industry partner Leonardo Spa, Italy.

Inset image: Professor Andrea Ferrari onboard the parabolic flight.

In a series of experiments conducted last month, Cambridge researchers experienced weightlessness testing graphene’s application in space.

This is the first time that graphene has been tested in space-like applications.

Andrea Ferrari

Zero Gravity Graphene – Satellite Loop Heat Pipes - the Flight

Graphene Flagship

Zero gravity graphene

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Gaia results revealed – first data release from the most detailed map ever made of the sky

sc604 — Wed, 14 Sep 2016 11:51:09 +0000

Detailed information about more than a billion stars in the Milky Way has been published in the first data release from the Gaia satellite, which is conducting the first-ever ‘galactic census.’ ̽��ֱ��release marks the first chance astronomers and the public have had to get their hands on the most detailed map ever made of the sky.

Gaia, which orbits the sun at a distance of 1.5 million kilometres from the earth, was launched by the European Space Agency in December 2013 with the aim of observing a billion stars and revolutionising our understanding of the Milky Way. During its expected five-year lifespan, Gaia will observe each of a billion stars about 70 times.

̽��ֱ��unique mission is reliant on the work of Cambridge researchers who collect the vast quantities of data transmitted by Gaia to a data processing centre at the ̽��ֱ��, overseen by a team at the Institute of Astronomy.

“Gaia’s first major data release is both a wonderful achievement in its own right, and a taster of the truly dramatic advances to come in future years,” said Professor Gerry Gilmore from the Institute of Astronomy, who is also the UK Principal Investigator for Gaia. “Several UK teams have leading roles in Gaia’s Data Processing and Analysis efforts, which convert the huge raw data streams from the satellite into the beautiful science-ready information now made available for the global scientific and public communities. UK industry made critical contributions to the Gaia spacecraft. ̽��ֱ��UK public, including school students, as well as scientists, are sharing the excitement of this first ever galactic census.”

In addition to the work taking place at Cambridge, teams from Edinburgh, the Mullard Space Science Laboratory (MSSL) at UCL London, Leicester, Bristol and the Science and Technology Facilities Council’s Rutherford Appleton Lab are all contributing to the processing of the vast amounts of data from Gaia, in collaboration with industrial and academic partners from across Europe.

̽��ֱ��team in Cambridge, led by Dr Floor van Leeuwen, Dr Dafydd Wyn Evans and Dr Francesca De Angeli, processed the flux information – the amount of energy that crosses a unit area per unit time – providing the calibrated magnitudes of around 1.6 billion stars, 1.1 billion of which are now published as part of the first data release.

̽��ֱ��Cambridge team also check the daily photometric data for unexpected large outliers, which led to the regular publication of photometric science alerts that were ready for immediate follow-up observations from the ground.

“ ̽��ֱ��sheer volume of data processed for this first release is beyond imagination: around 120 billion images were analysed, and most of these more than once, as all the processing is iterative,” said van Leeuwen, who is Gaia photometric data processing lead. “Many problems had to be overcome, and a few small ones still remain. Calibrations have not yet reached their full potential. Nevertheless, we are already reaching accuracies that are significantly better than expected before the mission, and which can challenge most ground-based photometric data in accuracy.”

“This first Gaia data release has been an important exercise for the Gaia data reduction teams, getting them to focus on deliverable products and their description,” said Evans. “But it is only the first small step towards much more substantial results.”

While today marks the first major data release from Gaia, in the two years since its launch, the satellite has been producing scientific results in the form of Gaia Alerts.

Dr Simon Hodgkin, lead of the Cambridge Alerts team said, “ ̽��ֱ��Gaia Alerts project takes advantage of the fact that the Gaia satellite scans each part of the sky repeatedly throughout the mission. By comparing successive observations of the same patch of sky, scientists can search for transients – astronomical objects which brighten, fade, change or move. These transients are then announced to the world each day as Gaia Alerts for both professional and amateur astronomers to observe with telescopes from the ground.”

̽��ֱ��range of Gaia’s discoveries from Science Alerts is large – supernovae of various types, cataclysmic variable stars, novae, flaring stars, gravitational microlensing events, active galactic nuclei and quasars, and many sources whose nature remains a mystery.

Gaia has discovered many supernovae, the brilliant explosions of stars at the end of their lives. Many of these have been ‘Type Ia’ supernovae, which can be used to measure the accelerating expansion of the Universe. But among these apparently typical supernovae there have been some rarer events. Gaia16ada was spotted by Gaia in the nearby galaxy NGC4559, and appears to be an eruption of a very massive, unstable star. ̽��ֱ��Hubble Space Telescope observed this galaxy some years ago, allowing astronomers to pinpoint the precise star which erupted.

Another lucky catch for Gaia was the discovery of Gaia16apd – a supernova which is nearly a hundred times brighter than normal. Astronomers still don't know what the missing ingredient in these ultra-bright supernovae is, and candidates include exotic rapidly spinning neutron stars, or jets from a black hole. Cambridge astronomer Dr Morgan Fraser is trying to understand these events, saying, “We have only found a handful of these exceptionally bright supernovae, compared to thousands of normal supernovae. For Gaia to spot one so nearby is a fantastic result.”

Many of the Gaia Alerts found so far are bright enough to be observable with a small telescope. Amateur astronomers have taken images of supernovae found by Gaia, while schoolchildren have used robotic telescopes including the Faulkes Telescopes in Australia and Hawaii to do real science with transients.

Dr Hodgkin said: “Since the announcement of the first transients discovered with Gaia in September 2014, over one thousand alerts have been released. With Gaia continually relaying new observations to ground, and our team working on finding transients continually improving their software, the discoveries look set to continue well into the future!”

For the UK teams the future means providing improvements in the pre-processing of the data and extending the processing to cover the photometric Blue and Red prism data. Also data from the Radial Velocity Spectrometer, with major involvement from MSSL, will be included in future releases. ̽��ֱ��photometric science alerts will continue to operate throughout the mission, and summaries of the results will be included in future releases. “Despite the considerable amount of data, the first Gaia data release provides just a taste of the accuracy and completeness of the final catalogue,” said De Angeli.

̽��ֱ��Cambridge Gaia team has also released a dedicated smartphone app, which will allow anyone worldwide to follow the Gaia Alerts discoveries as they happen. Real spacecraft data will be available to the world as soon as it is processed, with users able to follow the discoveries and see what they are. Information to access the app is available at https://gaia.ac.uk.

̽��ֱ��Gaia data processing teams in the UK have been and are being supported by the UK Space Agency and the STFC. STFC helped the set-up of the data applications centre and STFC’s current support involves the UK exploitation of the scientific data to be yielded from the mission. Industrial partners include Airbus, MSSL and e2v Technologies.

̽��ֱ��first results from the Gaia satellite, which is completing an unprecedented census of more than one billion stars in the Milky Way, are being released today to astronomers and the public.

Gaia’s first major data release is both a wonderful achievement in its own right, and a taster of the truly dramatic advances to come in future years.

Gerry Gilmore

ESA/Gaia/DPAC

Gaia’s first sky map

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Dead satellite finds a calm centre at the heart of brightest galaxy cluster in the sky

sc604 — Wed, 06 Jul 2016 17:30:00 +0000

̽��ֱ��result, published in the journal Nature, allows the mass of the Perseus Cluster – a swarm of thousands of galaxies that spans two million light years across and is one of the most massive known objects in the universe – to be calculated more accurately than before. Once this technique can be extended to other clusters, it will allow cosmologists to use them as better probes of our models of the Universe’s evolution from the Big Bang to the present time.

Hitomi (originally known as ASTRO-H) is the sixth in a series of Japanese x-ray observatories. Led by the Japan Aerospace Exploration Agency (JAXA), it is a collaboration of over 60 institutes and 200 scientists and engineers from Japan, the US, Canada, and Europe, including from the ̽��ֱ�� of Cambridge. ̽��ֱ��spacecraft was launched on 17 February 2016 from the Tanegashima Space Center, Japan. However, JAXA announced in April that it was no longer possible to communicate with the satellite.

“Hitomi targeted the Perseus cluster just a week after it arrived in space,” said Matteo Guainazzi, the European Space Agency’s (ESA) Hitomi Resident Astronomer at the Institute of Space and Astronautical Science, Japan. “Perseus is the brightest x-ray galaxy cluster in the sky. It was therefore the best choice to fully demonstrate the power of the Soft X-ray Spectrometer (SXS), an x-ray micro-calorimeter that promised to deliver an unprecedented accuracy in the reconstruction of the energy of the incoming x-ray photons.” Waiting astronomers were not disappointed.

̽��ֱ��Hitomi collaboration found that SXS could measure the turbulence in the cluster to a precision of 10 kilometres/second. But it was the absolute velocity of the gas that took them by surprise. It was just 164 ± 10 kilometres/second. ̽��ֱ��previous best measurement for Perseus was taken with ESA’s XMM-Newton x-ray observatory. Using a different type of spectrometer, it could only constrain the speed to be lower than 500 kilometres/second.

Hitomi’s measurement is therefore much more precise than any similar measurements performed in x-rays so far. “This is due to the outstanding performance and stability of the SXS in space. This demonstrates that the technology of x-ray micro-calorimeters can yield truly transformational results,” said Guainazzi.

̽��ֱ��result indicates that the cluster gas has very little turbulent motions within. Turbulent motions in a fluid are part of our everyday life, as airplane passengers, swimmers, or parents filling a bathtub all experience. ̽��ֱ��study of such chaotic behaviour is also a powerful tool for astronomers to understand the behaviour of celestial objects.

Turbulent energy in Perseus is just four percent of the energy stored in the gas as heat. This is extraordinary considering that the active galaxy NGC 1275 sits at the heart of the cluster. It is pumping jetted energy into its surroundings, creating bubbles of extremely hot gas. It was thought that these bubbles induce turbulence, which keeps the central gas hot.

Hitomi shows that turbulent motion is almost absent from the cluster, and this gives rise to a mystery: what is keeping the cluster’s widespread gas hot?

“This result from Hitomi is telling us that in terms of how cluster cores work, we have to think very carefully about what is going on,” said the paper’s senior author Professor Andy Fabian of Cambridge’s Institute of Astronomy, and part of the Hitomi collaboration.

Fabian is working on the possibility of sound waves as the means of spreading the energy evenly throughout the gas. This is because in a sound wave, energy can be moved while the medium itself remains more or less stationary.

There are wider implications for this work too. Clusters of galaxies are the largest bound structures in the Universe. At the same time, they are also the smallest self-contained ‘boxes’. This means that matter is not flowing in or out of a cluster of galaxies. Instead, they each represent an island in which cosmic evolution has played out and been recorded.

Computer models of the expanding Universe use the distribution of cluster masses as an observational test of whether they are correct. Calculating the mass of a cluster depends upon the ratio of turbulent to quiescent gas. Any way of more accurately measuring turbulence allows better masses to be calculated, and therefore better computer models of the whole Universe to be developed.

Unfortunately, just a few weeks after the Perseus observation, a malfunction in the attitude control system put Hitomi into an uncontrollable spin that resulted in the break up and loss of the satellite.

“It is really disappointing that we have lost Hitomi and can’t go on with the programme that we had to look at many more clusters,” says Fabian.

̽��ֱ��next mission that will be capable of fully following up the Hitomi programme is ESA’s Athena, an X-ray observatory scheduled for launch in the 2020s.

“Scientifically and technically, the Hitomi results are an exciting foretaste of Athena,” said David Lumb, ESA's Athena Study Scientist. “ ̽��ֱ��demonstration of a radically new imaging spectrometer instrument concept gives huge confidence for future developments for Athena.”

Athena will have 100 times more collecting area and 100 times more pixels than Hitomi. Among the key scientific objectives of Athena are to investigate the evolution of clusters of galaxies including their interplay with energy injection from supermassive black holes.

“ ̽��ֱ��Hitomi data show the potential that will be unleashed with Athena vastly increased imaging capability and sensitivity,” said Lumb.

Reference:
Hitomi Collaboration. ‘ ̽��ֱ��quiet intracluster medium in the core of the Perseus cluster.’ Nature (2016). doi:10.1038/nature18627.

Adapted from an ESA press release.

With its very first – and last – observation, the Hitomi x-ray observatory has discovered that the gas in the Perseus cluster of galaxies is much less turbulent than expected, despite being home to NGC 1275, a highly energetic active galaxy.

This result is telling us that in terms of how cluster cores work, we have to think very carefully about what is going on.

Andy Fabian

Background: NASA/CXO; Spectrum: Hitomi Collaboration/JAXA, NASA, ESA, SRON, CSA

X-ray view of the Perseus cluster

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Your chance to ‘scream in space’ using smartphone technology

fpjl2 — Thu, 25 Oct 2012 13:04:33 +0000

It was Ridley Scott’s film Alien that gave us the now legendary tagline: In space no one can hear you scream. Now, a Cambridge student society will use the technology in your pocket to find out if this is really the case.

Cambridge ̽��ֱ�� Spaceflight (CUSF) will be uploading videos of people screaming into a specially developed smartphone app, housed on a Google Android phone that will be shot into space as part of a satellite payload in early December. Once in orbit, the phone will play the screams at full volume, while at the same time recording audio.

̽��ֱ��phone will then relay back to Earth pictures of each ‘scream’ video playing against the spectacular view from the phone's inbuilt camera, along with a sound file that may or may not contain the scream captured in the vacuum of space, although the members of CUSF are not holding their collective breath.

“Obviously, we’re not expecting to get much back, there may be some buzzing, but this is more about getting young people interested in satellites and acoustics, perhaps encouraging them to consider future study in science or engineering” said Edward Cunningham, a physics undergraduate at Churchill College and one of the members of CUSF.

With this in mind, the team are asking members of the public to submit their own screams for galactic transmission - by uploading a short ‘scream’ video to YouTube, and submitting their entry.

Each video must be at most ten seconds long, and there will be ten winning screams which can be voted for by the public on the project’s website. Screams must be entered before midnight on Sunday 4th November, after which the winning videos will be announced and loaded onto the phone in readiness for a launch before the end of this year.

̽��ֱ��‘scream in space’ app is one of four phone apps that will be on board STRaND-1 - a smartphone nanosatellite - built by a team from Surrey Satellite Technology Ltd and the ̽��ֱ�� of Surrey’s Space Centre. During the summer of 2011, the STRaND (Surrey Training Research and Nanosatellite Demonstration) team ran a Facebook competition to find apps to go into orbit - and CUSF’s screaming app was one of the winners.

“We came across the competition and wanted to enter, which got us thinking about what smartphones have that a standard satellite doesn’t,” said Cunningham. “Smartphones have got a speaker and a microphone, so we wanted to do something engaging with these functions.”

̽��ֱ��STRaND-1 project will be testing the capabilities of a smartphone to control a satellite in space. ̽��ֱ��phone will run on Android's open-source operating system. A computer, built at the Surrey Space Centre, will test the vital statistics of the phone once in space. When all the tests are complete, the plan is to switch off the micro-computer and the smartphone will be used to operate parts of the satellite. At its lowest, the phone will orbit 400km above the Earth, roughly the same as the International Space Station.

"Modern smartphones are pretty amazing," said Shaun Kenyon, the project manager at Surrey Satellite Technology. “We want to see if the phone works up there, and if it does, we want to see if the phone can control a satellite."

Using smartphone technology to control space hardware is something that CUSF themselves continue to explore. ̽��ֱ��student society has already sent several Android smartphones into the stratosphere as flight computers for high altitude balloon launches, building custom apps to navigate.

“This project reflects the gradual shift of the space sector out of the exclusive domain of governments with multi-billion budgets, and into the hands of smaller ventures,” said Cunningham. “With the Android phone, you benefit from the extensive development carried out in the consumer context, and for almost no money at all. It's no coincidence that NASA has a PhoneSat project of their own.”

CUSF have previously shown that an Android phone works successfully as a standalone flight computer at a similar altitude to the one Felix Baumgartner recently performed his skydive from, but the opportunity to produce an app to run on the first smartphone in orbit is one CUSF members are thrilled about:

“ ̽��ֱ��principle of using a low-cost consumer device to do something high tech and new on a shoestring budget is something we really endorse. We often use readily available materials in our own projects,” said Cunningham.

“STRaND-1 is doing something that has never been done before and something you definitely can’t do every day. We see the project as a great opportunity to promote interest in space and also have some fun!”

For more information, contact Fred Lewsey (fred.lewsey@admin.cam.ac.uk) at the ̽��ֱ�� of Cambridge Office of External Affairs and Communications.

Cambridge students will be loading human screams onto a smartphone that will be blasted into outer space later this year. ̽��ֱ��public are invited to submit their screams, which will be emitted while in orbit at the same time as the phone records - to test if it’s possible to capture the sound of screaming in space.

It's no coincidence that NASA has a PhoneSat project of their own.

Edward Cunningham

CUSF

Image taken in stratosphere using Android phone, from previous CUSF project ‘Squirrel 3’ which used smartphone to pilot high-altitude balloon

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Yes

New light shed on explosive solar activity

lw355 — Mon, 02 Jul 2012 10:00:34 +0000

̽��ֱ��study published today by ̽��ֱ�� of Cambridge scientists working with colleagues in India and the USA is the first to visualise the movement of gases at one million degrees in coronal loops – solar structures that are rooted at both ends and extend out from active regions of the Sun. Active regions are the ‘cradle’ for explosive energy releases such as solar flares and coronal mass ejections (CMEs).

̽��ֱ��observation will help scientists understand what is considered to be one of the most challenging issues in astrophysics – how solar structures are heated and maintained in the upper solar atmosphere. Extreme solar activity can lead to severe space storms that interfere with satellite communications and damage electric power transmission grids on Earth. Solar activity is cyclical, with the next maximum forecast to occur around May 2013, and severe space weather is now listed very high on the UK’s 2012 National Risk Register of Civil Emergencies.

Based on observations from the Hinode satellite (a joint Japanese, NASA, European Space Agency and UK project), the new findings provide the first evidence of plasma upflows travelling at around 20 km per second in the one million degree active region loops. ̽��ֱ��scientists suggest that the upflow of gases is probably the result of “impulsive heating” close to the footpoint regions of the loops.

“Active regions are now occurring frequently across the Sun. We have a really great opportunity to study them with solar spacecraft, such as Hinode and the Solar Dynamics Observatory (SDO),” said co-author Dr Helen Mason from the ̽��ֱ�� of Cambridge’s Department of Applied Mathematics and Theoretical Physics. “Probing the heating of the Sun's active region loops can help us to better understand the physical mechanisms for more energetic events which can impinge on the Earth’s environment.”

Previous ultraviolet images of the Sun taken by NASA’s SDO have shown large loops of hot gas guided by the Sun’s magnetic field and rooted near sunspots. Despite such remarkable developments in the observations and theory of active regions over the past few decades, the question remained as to how solar plasma is heated and rises up into the loops in the first place.

Now, the new research provides the first visualisation of plasma flow by showing the movement of gases within the loop as ‘blueshifts’ in diagnostic images using the extreme ultraviolet imaging spectrometer (EIS) on the Hinode satellite. Spectral lines produced by the spectrometer act like ‘fingerprints’ or the ‘bar code’ in a supermarket – the lines identify the multitude of elements and ions within the loop and shifts in the position of the lines provide information on the motion of the plasma. Although the Sun is composed mainly of hydrogen and helium, there are also other trace elements, such as oxygen and iron, in the hot ionised gas within the loops.

̽��ֱ��scientists suggest that the gas movement is caused by a process of “chromospheric evaporation” in which “impulsive heating” on a small scale can result in the heating of the solar active regions but on a larger scale can lead to huge explosions, such as solar flares or coronal mass ejections.

“It is believed that magnetic energy builds up in an active region as the magnetic field becomes distorted, for example by motions below the surface of the Sun dragging the magnetic fields around,” explained Mason, whose research is partially funded by the UK’s Science and Technology Facilities Council (STFC). “Sometimes magnetic flux can emerge or submerge and affect the overlying magnetic field. We believe that solar plasma surges upwards when impulsive heating results from magnetic reconnection which occurs either in the loops or close to the Sun’s surface. These disruptions are sometimes relatively gentle but can also be catastrophic.”

Commenting on the newly published study, Professor Richard Harrison MBE, Head of Space Physics and Chief Scientist at the STFC Rutherford Appleton Laboratory, said: “ ̽��ֱ��Sun governs the environment in which we live and it is the so-called solar active regions that drive extreme conditions leading to the explosive flares and the huge eruptions; understanding these active regions is absolutely critical for the study of what we now call space weather. ̽��ֱ��work published by in this paper is a key element of that work, applying innovative analyses to the observations from the UK-led Hinode/EIS instrument.”

̽��ֱ��researchers hope that a better understanding of active regions might one day help scientists to identify the magnetic field structures that lead to explosive solar energy releases and use this as a means for predicting when such events will occur.

̽��ֱ��study is published today in Astrophysical Journal Letters.

̽��ֱ��first images of an upward surge of the Sun’s gases into quiescent coronal loops have been identified by an international team of scientists. ̽��ֱ��discovery is one more step towards understanding the origins of extreme space storms, which can destroy satellite communications and damage power grids on Earth.

Probing the heating of the Sun's active region loops can help us to better understand the physical mechanisms for more energetic events which can impinge on the Earth’s environment.

Dr Helen Mason

SDO/AIA (NASA)

Sun's active region loops

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Yes

Twinkle, twinkle, little star: I’m going to know what you are

ns480 — Thu, 26 Apr 2012 08:30:37 +0000

A powerful data centre being turned on today at the Institute for Astronomy (IoA) will process the vast amount of imaging data sent back to Earth by a satellite which is due to be launched into space in August 2013. ̽��ֱ��Gaia satellite, whose heart is the largest digital camera ever built, will orbit the Sun at a distance of 1.5 million km from Earth and will feed the data centre with a billion-pixel video of a billion stars, galaxies, quasars and solar system asteroids for five years after launch.

̽��ֱ��installation of the data centre, funded by the UK Space Agency, coincides with the 50th Anniversary of the launch of the British satellite research programme, Ariel-1, which was devoted to studying the ionosphere - a part of the upper atmosphere.

̽��ֱ��Gaia satellite, which has been hailed as the premier European astrophysics space mission of the decade, will deliver an extraordinarily precise census of the Milky Way in three dimensions.

“As Gaia slowly spins, it will create a billion-pixel video of the Milky Way, watching everything move, and deducing what is there, and where it is,” explained Professor Gerry Gilmore, from the IoA and the UK Principal Investigator for UK involvement in the mission. “On its five-year mission, Gaia will produce a vast amount of information - almost inconceivable in its scope.”

In 1989, the European Space Agency (ESA) launched Hipparcos, the first –and so far the only - satellite to chart the positions of stars, which produced a primary catalogue of about 118,000 stars, followed by a secondary catalogue, called Tycho, of over 2 million stars.

Technology has improved to such an extent since Hipparcos was launched that Gaia will be able to measure a star’s position and motion 200 times more accurately, and will measure one billion stars.

In order to process Gaia's photometric data, the team has worked for several years to develop a system that can calibrate the 'raw' transmitted photometric data. Even highly compressed, the data transmitted by the satellite over the five-year mission would fill over 30,000 CDROMs (1300 DVDs). Many times that amount will be produced during the processing of the data as intermediate results of computations.

̽��ֱ��new installation consists of a cluster of 108 identical servers used for the bulk of the data processing, and 9 additional servers used for monitoring, backup and control. ̽��ֱ��108 processing servers each have 2 6-core CPUs, 48 gigabytes of RAM and 9 terabytes (a terabyte is 1000 gigabytes) of hard-disk storage. Therefore the bulk processing system as a whole has 1296 processing cores, around 5 terabytes of RAM and nearly 1 petabyte (1000 terabytes) of hard-disk storage for use during the active processing. ̽��ֱ��individual servers are connected by a high-speed 40 gigabit Infiniband network to allow rapid communication and transfers of large data volumes.

̽��ֱ��system will process the photometric data from Gaia during the 5-6 years of mission operation, and for two years afterwards, to produce a calibrated set of measurements which can be freely used by the astronomical community.

Dr Floor van Leeuwen, from the IoA, is project manager and coordinator of the consortium that will process the Gaia photometric data, which involves 60 scientists across Europe, of the 400 in total in the Gaia project. “We installed our major computer processing capability, and now are very busy bring together the huge processing effort which will use this impressive hardware system to turn images into science. We need to be ready for Gaia’s launch, just next year After so many years preparation, this is excitingly, but challengingly, soon.” he said.

Gaia is one of the most important current space projects for the UK, which has won approximately €80 million of contracts from ESA to build parts of the spacecraft.

Remarkably, its two optical telescopes are capable of measuring the positions of celestial objects to an accuracy of up to 10 microarcseconds, comparable to the diameter of a human hair at a distance of 1000 km. To determine the properties of stars, Gaia will also split their emitted light into a spectrum before communicating the data back to Earth.

After launch, a 10 m diameter ‘skirt’ will unfold around the satellite to shade the telescopes and generate its own energy from solar panels.

Gaia is expected to discover a multitude of new objects both in our solar system - including brown dwarfs and white dwarfs, supernovae and extra-solar planets - as well probe the distribution of dark matter , map over 500,000 quasars in the Universe, and measure the local structure of space-time.

Added Gilmore: “By creating the first precise 3-D chart of our galaxy, Gaia will help scientists understand the enormous range of complexities related to the origin, structure and evolution of our Milky Way, the past history of the Sun’s location in the Milky Way, and the time and place where the chemical elements of which we are made were created, as well as discover new objects, from potentially killer asteroids to explosions in the distant Universe.”

A team of astronomers at the ̽��ֱ�� of Cambridge is taking the next big step in a European-wide programme which will lead to the creation of the first three-dimensional map of more than a billion stars.

As Gaia slowly spins, it will create a billion-pixel video of the Milky Way, watching everything move, and deducing what is there, and where it is.

Professor Gerry Gilmore

European Space Agency

Gaia Deployable Sunshield Assembly

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Yes

Probing the Universe: Kavli Institute for Cosmology

bjb42 — Sat, 01 May 2010 14:16:42 +0000

It may be one of Cambridge’s newest buildings but its historic roots lie in one of the ̽��ֱ��’s oldest scientific research departments. ̽��ֱ��£4 million Kavli Institute for Cosmology Cambridge (KICC), opened in 2009, is built just yards from the ̽��ֱ�� Observatory, where astronomical research has been carried out since the early 19th century. In the intervening years, Cambridge has developed an international reputation for ground-breaking discoveries about the origin, evolution and structure of the Universe, thanks to research in the Institute of Astronomy, the Department of Physics’ Cavendish Laboratory and the Department of Applied Maths and Theoretical Physics (DAMTP).

̽��ֱ��driving force for the new Institute was to bring together some of the groups from these departments, as Professor George Efstathiou, Director of KICC, explained: ‘ ̽��ֱ��spread of research across departments owes much to the natural divisions that resulted from the diverse ‘tool boxes’ used to study different areas of cosmology, such as the events following the Big Bang, the birth of stars, the structure of the Universe and so on. Today, though, there are increasing overlaps and it makes sense to integrate research programmes where there is common ground.’

KICC is now home to 55 scientists, including many graduate students from each department, and is also recruiting a new generation of research scientists: Drs George Becker, Ian McCarthy and Carrie MacTavish are the first Kavli Institute Fellows to be appointed, funded by an endowment from ̽��ֱ��Kavli Foundation to pursue independent research in Cambridge.

‘Fossil record’ of the early Universe

Where did our Universe come from? What is it made of? How is it evolving? To help answer some of the most fundamental questions about the Universe, researchers at KICC are members of international collaborations that are making use of some the most advanced scientific instruments ever constructed – satellites such as the £1.7 billion Planck and Herschel Observatories launched by the European Space Agency last year. Such instruments will provide insight into events that happened billions of years ago – the Universe’s unique ‘fossil record’ – by analysing the light emitted in the distant past but which is only reaching us now.

‘ ̽��ֱ��furthest back we can currently detect corresponds to light that was emitted 300,000 years after the Big Bang, just under 13.7 billion years ago, when the Universe was as hot as the surface of the Sun,’ explained Professor Anthony Lasenby, Deputy Director of KICC. ‘When it was emitted, it was visible light, but because the Universe has expanded by a factor of over a thousand, it has stretched out and become cosmic microwave background radiation.’ ̽��ֱ��Planck satellite will measure tiny fluctuations in the radiation with the highest accuracy ever achieved.

Working in partnership with over 40 institutes as part of the pan-European Planck collaboration, Cambridge scientists have been part of the satellite’s scientific programme since its inception in 1993, and are now involved in analysing and interpreting the vast amounts of data delivered back to Earth. ̽��ֱ��satellite will complete a full scan of the whole sky every six months until the end of 2011, providing information to test theories of the early Universe and the origin of cosmic structure.

Shifting into the red

After the Big Bang, the first stars are thought to have formed out of a network of matter that grew from the tiny fluctuations seen in the cosmic microwave background. Dr Martin Haehnelt, Dr George Becker and others at KICC are studying the composition of this network, which is known as the intergalactic medium. ‘ ̽��ֱ��energy released from the first stars would have had a dramatic impact on the medium around them, changing the way future stars and galaxies would form,’ Dr Becker explained. ‘We can study the intergalactic medium from when the Universe was about a billion years old through to the present, but we’d like to go even earlier, closer to the Big Bang, because it contains the fingerprint of the initial and changing conditions needed to form what we see today.’

To do this, cosmologists are looking at the high-redshift Universe. As the Universe expands, light produced by distant stars and galaxies is stretched to longer wavelengths, changing the apparent colour of the light: the more distant the object, the redder its light becomes by the time it reaches Earth. As a result, highly redshifted objects trace the earliest phases of the Universe’s evolution. Using the ̽��ֱ��’s Darwin supercomputer, Dr Becker is analysing data showing the thermal and gaseous history of the Universe to understand the ingredients needed for galaxy formation.

Researchers at the Kavli are also studying the high-redshift Universe in order to catch first sight of young galaxies. By searching the sky at unprecedented levels of sensitivity, a team led by Dr Haehnelt has discovered very faint traces of long-searched-for galaxies.

Radio telescopes of the future

Kavli scientist Dr John Richer is the UK Project Scientist for ALMA, the Atacama Large Millimetre Array, a huge radio telescope sited in the Atacama Desert of northern Chile. ALMA is the result of collaboration between 17 countries worldwide. When completed in 2013, it will provide the first detailed images of the gaseous component of high-redshift galaxies; in addition, it will map the structure of the discs of material that surround newly formed stars in which planetary systems are known to form. To do this, ALMA will combine data from 66 radio antennas to construct a telescope with an effective diameter of 10 miles, using the technique of aperture synthesis that won Cambridge astronomers Sir Martin Ryle and Professor Antony Hewish the 1974 Nobel Prize in Physics.

Meanwhile, a Cambridge team led by Dr Paul Alexander is providing crucial input into the science, design and costing of the Square Kilometre Array (SKA) radio telescope; Dr Alexander leads the UK technical work on the SKA design, heading a team split between Cambridge, Manchester and Oxford. Construction of the first phase of the instrument is expected in 2015, with completion in 2020. Dr Alexander explained the importance of this new development: ‘ ̽��ֱ��SKA will be 100 times more sensitive than the radio telescopes of the present generation, and will be able to survey the sky up to one million times faster. This will enable us to probe the so-called ‘dark ages’ of the Universe before thefirst stars shed light, observe the formation of galaxies, test theories of gravity and study the role of cosmic magnetism.’

Writing the history of the Universe

̽��ֱ��scientific goals of KICC are ambitious: ‘ ̽��ֱ��concept of reconstructing, in three dimensions, events that happened over a time span of nearly 14 billion years is no longer just a dream,’ said Professor Efstathiou. ‘Working with the international community, and as part of the wider Kavli family of 15 institutes worldwide, we hope to make dramatic discoveries about the history, fabric and evolution of the Universe as we reach further into the sky.’

For more information about research at the Kavli Institute for Cosmology, please visit www.kicc.cam.ac.uk/

Scientists at Cambridge’s Kavli Institute are studying how the Universe developed after the Big Bang by analysing light emitted up to 13.7 billion years ago.

̽��ֱ��concept of reconstructing, in three dimensions, events that happened over a time span of nearly 14 billion years is no longer just a dream.

Professor George Efstathiou

ESA and the HFI consortium; Axel Mellinger

Region mapped by Planck satellite

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