ESA Pharao space clock delivered to ISS - Video

ESA has welcomed the arrival of Pharao, an important part of ESA's atomic clock experiment that will be attached to the International Space Station in 2016.

Delivered by France's CNES space agency, Pharao is accurate to a second in 300 million years, which will allow scientists to test fundamental theories proposed by Albert Einstein with a precision that is impossible in laboratories on Earth.

Time is linked to gravity and, for example, passes faster at the top of Mount Everest than at sea level.

These effects have been proved in experiments on Earth but the Atomic Clock Ensemble in Space, ACES, will make more precise measurements as it flies 400 km high on humanity's weightless laboratory.

Comparing clocks under different gravity levels allows researchers to test Einstein's theories on space-time and other theories in fundamental physics.

To achieve its accurate timekeeping, the Pharao space clock uses lasers to cool caesium atoms down to -273 C, close to absolute zero.

Internet of clocks
Accurate timekeeping is vital for pinpointing our location, secure banking and fundamental science, but it is not easy to compare data from the many atomic clocks on Earth.

ACES is more than just one clock in space. Pharao will be accompanied by the Space Hydrogen Maser, which uses a different technique to keep track of time.

This clock uses hydrogen atoms as a frequency reference and offers better stability but for a shorter time.

By coupling the two clocks, ACES will provide the scientists with a unique, highly stable time reference in space.

The project will link together atomic clocks in Europe, USA, Japan and Australia with their space counterparts via microwave and optical links to create an 'internet of clocks' and to deliver precise timekeeping.

Connecting all these clocks is a significant part of ACES, with France's Cadmos User Support and Operations Centre taking responsibility for operating the instruments on the Station.

ESA astronaut Thomas Pesquet will be on the orbital outpost when ACES arrives in 2016. Using the Station's robotic arm, the 375 kg payload will be installed on a platform outside Europe's Columbus space laboratory.

ESO ALMA upgrade to supercharge Event Horizon Telescope

ALMA's new hydrogen maser atomic clock arrives and is ready for installation at the ALMA high site. Supplemental oxygen is used due to the thin air at that altitude (5,000 meters, 16,500 feet).

The team includes Jay Blanchard, Univ. Concepcion (left); Christophe Jacques, NRAO (front); Jack Meadows, NRAO (back); and Enrique Garcia, ALMA Correlator Group (right, partly obscured). Credit: Carlos Padilla (NRAO/AUI/NSF)


Scientists recently upgraded the Atacama Large Millimeter/submillimeter Array (ALMA) by installing an ultraprecise atomic clock at ALMA's Array Operations Site, home to the observatory's supercomputing correlator.

This upgrade will eventually allow ALMA to synchronize with a worldwide network of radio astronomy facilities collectively known as the Event Horizon Telescope (EHT).

Once assembled, the EHT, with ALMA as the largest and most sensitive site, will form an Earth-sized telescope with the magnifying power required to see details at the edge of the supermassive black hole at the center of the Milky Way.

Before ALMA can lend its unmatched capabilities to this and similar scientific observations, however, it must first transform into a different kind of instrument known as a phased array.

This new version of ALMA will allow its 66 antennas to function as a single radio dish 85 meters in diameter. It's this unified power coupled with ultraprecise timekeeping that will allow ALMA to link with other observatories.

A major milestone along this path was achieved recently when the science team performed what could be considered a "heart transplant" on the telescope by installing a custom-built atomic clock powered by a hydrogen maser.

This new timepiece uses a process similar to a laser to amplify a single pure tone, cycles of which are counted to produce a highly accurate 'tick'.

ALMA's original time reference, a clock based on rubidium gas, will be retired and used as a spare after the maser is completely integrated with ALMA's electronics.

Shep Doeleman, the principal investigator of the ALMA Phasing Project and assistant director of the Massachusetts Institute of Technology's Haystack Observatory, participated during the maser installation via remote video link.

"Once the phasing is complete, ALMA will use the ultraprecise ticking of this new atomic clock to join the aptly named Event Horizon Telescope as the most sensitive participating site, increasing sensitivity by a factor of 10," he said.


Expanding the Frontiers of Astronomy
Supermassive black holes lurk at the center of all galaxies and contain millions or even billions of times the mass of our Sun. These space-bending behemoths are so massive that nothing, not even light, can escape their gravitational influence.

Understanding how a black hole devours matter, powers jets of particles and energy, and distorts space and time are leading challenges in astronomy and physics.

The black hole at the center of the Milky Way is a 4 million solar mass giant located approximately 26,000 light-years from Earth in the direction of the constellation Sagittarius.

It is shrouded from optical telescopes by dense clouds of dust and gas, which is why observatories like ALMA, which operate at the longer millimeter and submillimeter wavelengths, are essential to study its properties.

Supermassive black holes can be relatively tranquil or they can flare up and drive incredibly powerful jets of subatomic particles deep into intergalactic space; quasars seen in the very early Universe are an extreme example.

The fuel for these jets comes from in-falling material, which becomes superheated as it spirals inward.

Astronomers hope to capture our Galaxy's central black hole in the process of actively feeding to better understand how black holes affect the evolution of our Universe and how they shape the development of stars and galaxies.

ALMA maser installation team in front of a small portion of the ALMA antennas. Left to right: Jay Blanchard, Univ. Concepcion; Jack Meadows, NRAO; Neil Nagar, Univ. Concepcion; and Christophe Jacques, NRAO. Credit: Carlos Padilla (NRAO/AUI/NSF)

A phased ALMA will arrive just in time to observe a highly anticipated cosmic event, the collision of a giant cloud of dust and gas known as G2 with our Galaxy's central supermassive black hole.

It is speculated that this collision may awaken this sleeping giant, generating extreme energy and possibly fueling a jet of subatomic particles, a highly unusual feature in a mature spiral galaxy like the Milky Way. The collision is predicted to begin in 2014 and will likely continue for more than a year.

High resolution imaging of the event horizon also could improve our understanding of how the highly ordered Universe as described by Einstein meshes with the messy and chaotic cosmos of quantum mechanics – two systems for describing the physical world that are woefully incompatible on the smallest of scales.

Other independent research will target molecules in space to determine whether or not the fundamental constants of nature have changed over cosmic time.

Proposed nuclear clock (ACES) may keep time with the Universe

The exquisite accuracy of atomic clocks is widely used in applications ranging from GPS navigation systems and high-bandwidth data transfer to tests of fundamental physics and system synchronisation in particle accelerators.

A proposed new time-keeping system tied to the orbiting of a neutron around an atomic nucleus could have such unprecedented accuracy that it neither gains nor loses 1/20th of a second in 14 billion years - the age of the Universe.

"This is nearly 100 times more accurate than the best atomic clocks we have now," says one of the researchers, Scientia Professor Victor Flambaum, who is Head of Theoretical Physics in the UNSW School of Physics.

"It would allow scientists to test fundamental physical theories at unprecedented levels of precision and provide an unmatched tool for applied physics research."

In a paper to be published in the journal Physical Review Letters - with US researchers at the Georgia Institute of Technology and the University of Nevada - Flambaum and UNSW colleague Dr Vladimir Dzuba report that their proposed single-ion clock would be accurate to 19 decimal places.

The exquisite accuracy of atomic clocks is widely used in applications ranging from GPS navigation systems and high-bandwidth data transfer to tests of fundamental physics and system synchronization in particle accelerators.

"With these clocks currently pushing up against significant accuracy limitations, a next-generation system is desired to explore the realms of extreme measurement precision and further diversified applications unreachable by atomic clocks," says Professor Flambaum.

"Atomic clocks use the orbiting electrons of an atom as the clock pendulum. But we have shown that by using lasers to orient the electrons in a very specific way, one can use the orbiting neutron of an atomic nucleus as the clock pendulum, making a so-called nuclear clock with unparalleled accuracy."

Because the neutron is held so tightly to the nucleus, its oscillation rate is almost completely unaffected by any external perturbations, unlike those of an atomic clock's electrons, which are much more loosely bound.

UK Space Community benefits from £4.75m in Infrastructure Investment

The UK Space Agency will be channeling the new investment into three cutting-edge projects, including £3 million for a computing infrastructure at the International Space Innovation Centre for processing Earth observation data and making it more accessible for the UK space sector.

The three projects will rely on advances in computing, timing and data-handling to provide added benefits for industry and academia.

Centre for Climate Monitoring and Evaluation from Space (CEMS)
The CEMS at the International Space Innovation Centre will provide multi-sensor processing and a whole range of other tools and facilities for access, manipulation, visualisation and exploitation of data at realistic costs for companies (including SMEs).

UK Gaia Mission Data Processing and Analysis Centre (DPAC)
The University of Cambridge is receiving £0.75 million for a high performance computing system for the UK facility that will process the data from Gaia – Europe’s mission to examine the Milky Way in unprecedented 3-D detail.

The new computing system for the DPAC will support the effective use of mission data across the UK and beyond, including high bandwidth links to the data visualisation facilities at ISIC, Harwell.

Acquire and Exploit the Highest Quality Timing Data from Space (ACES)
Subject to approval by ESA and its Member States, £1M will be used to install a space-to-ground link from the planned ACES atomic clock system aboard the International Space Station to the National Physical Laboratory in Teddington, thus allowing an ultra-precision space-based timing signal to be made available to the UK's leading centre of metrology.

The funding will also allow specialised hardware to be provided to distribute the signal to key research and application development users in the UK.

The new funding for these projects is part of the Government’s multi-million pound e-infrastructure investment to provide UK scientists and businesses with access to the most sophisticated technology, keeping them at the cutting-edge of research and development. Minister for Universities and Science David Willetts said:

“We should not think of infrastructure as just roads and railways – it’s also the networks and systems that underpin our world-leading science and research base.

This ambitious and forward-looking programme of investment will be vital for businesses and universities alike. It will improve research and manufacturing processes and reduce the time and money it takes to bring a product to market.

“This will drive growth and innovation across a whole range of sectors and ensure our leading institutions and companies are able to exploit the very latest technology.”

GPS, relativity, and nuclear detection - YouTube

Thanks to GPS, planes, cars and cellphones can quickly be guided to any destination. The system uses a network of satellites, but how do they relay the correct coordinates from space?

In our latest One-Minute Physics episode, animator Henry Reich explains why GPS is just a big clock in space. By communicating with four time-keeping satellites, a GPS device can determine it's exact position - but that's after it corrects for the effects of general relativity.

If you enjoyed this video, check out the rest of our One-Minute Physics series. You can find out how to break the speed of light in your backyard or see how a particle can also be a wave.

CAesium Fountain atomic clock with the world's best long-term accuracy

A caesium fountain clock that keeps the United Kingdom's atomic time is now the most accurate long-term timekeeper in the world. 

This has been ascertained by a new evaluation of the clock that will be published in the October 2011 issue of the international scientific journal Metrologia by a team of physicists at the National Physical Laboratory (NPL) in the United Kingdom and Penn State University in the United States. 

This image shows the clock, NPL-CsF2, which is located at the National Physical Laboratory in Teddington, U.K. The whole device is approximately 8.2 feet (2.5 m) high.

Atoms are tossed up 3.2 feet (1 m), approximately 12 inches (30 cm) above the cavity that is contained inside a vacuum vessel. 

The large external cylinder screens the atoms inside the clock from the relatively large and unstable external magnetic field. Credit: National Physical Laboratory, United Kingdom.

The atomic clock housed in Britain's National Physical Laboratory (NPL) is the world's most accurate, according to new research.

The clock is a caesium fountain clock, meaning that the "tick" is provided by the measurement of the energy required to change the caesium atoms' spin.

Caesium atoms are placed into a cavity, and exposed to electromagnetic radiation of different wavelengths. Once the spin "flips", the waves are at the right frequency to define what a second is.

In the case of caesium, that quantity is defined as 9.2GHz (or, to be appropriately exact, 9,192,631,770Hz). When the spin flips, the clock operators can set the frequency at that point, and work backward to determine the exact length of a second.

The international Bureau of Weights and Measures takes readings from a selection of "primary frequency standards", in France, the US, Germany, Japan -- and, the most accurate of them all, in the UK.

A team led by NPL's Krzysztof Szymaniec and colleagues at Pennsylvania State University found that Britain's atomic clock was accurate to one part in 4,300,000,000,000,000, nearly doubling the accuracy found when the clocks were last measured in 2010. That level of precision means that NPL's clock wouldn't stray by more than a second in 138 million years.

While that might seem like overegging the pudding in terms of making sure your alarm clock goes off in time for you to get to work, the definition of most electrical units are based on these measurements, and given the vast amounts of energy and data pouring through the world's computer systems, even a tiny change can have measurable economic impact.

"The frequency we measure is not necessarily the one prescribed by the definition of a second, which requires that all the external fields and 'perturbations' would be removed," Szymaniec stated. "In many cases we can't remove these perturbations; but we can measure them precisely, we can assess them, and introduce corrections for them."

"It's vital for the UK as an economy to maintain a set of standards, a set of procedures, that underpin technical development," he added.

ESA GIOVE-B: Maser Atomic Clock ticking

Three years after ESA’s Galileo prototype GIOVE-B reached orbit, the passive hydrogen maser at its heart is still ticking away as the most precise atomic clock ever flown in space for navigation – that is, until the first Galileo satellites join it later this year.

Launched by Soyuz rocket from Baikonur in Kazakhstan on 27 April 2008, GIOVE-B was ESA’s second Galileo In-Orbit Validation Element satellite to fly. The first, GIOVE-A, made it to orbit on 28 December 2005.

The satellites had the same goals: secure the radio frequencies provisionally allocated to Europe’s Galileo satnav system by the International Telecommunications Union, gather data on the radiation environment of medium Earth orbit, and validate key Galileo payloads in orbit.

	Hydrogen maser clock

“GIOVE-B has now been in orbit for 36 months, nine months more than its nominal lifetime,” said Valter Alpe, overseeing GIOVE operations for ESA.

“Both satellites are still working well. GIOVE-A has reached 64 months in orbit. This longevity is partly due to an unusually mild solar cycle, but also reflects well on the operating margins built into their design.

“Most notably, GIOVE-B’s passive hydrogen maser – Europe’s main technological advance for Galileo – is still operating as precisely as planned.

We haven’t experienced any real surprises. As a result, much the same design is being used for the operational Galileo satellites.”

Read more of this story here at ESA portal

ESA Portal - PHARAO atomic clock agreement signed by ESA and CNES

PHARAO atomic clock agreement signed by ESA and CNES

15 December 2009



ESA Portal - PHARAO atomic clock agreement signed by ESA and CNES

PHARAO atomic clock agreement signed by ESA and CNES

15 December 2009
ESA PR 31-2009 Today at the Paris headquarters of the French space agency (CNES), Simonetta Di Pippo, ESA Director of Human Spaceflight, and Thierry Duquesne, CNES Director for Strategy, Programmes and International Relations, signed an agreement that paves the way for the launch of a high-accuracy atomic clock to be attached to the outside of the European Columbus laboratory onboard the International Space Station (ISS).

The PHARAO (Projet d’Horloge Atomique par Refroidissement d’Atomes en Orbite) atomic clock, which will be combined with another atomic clock, the Space Hydrogen Maser (SHM), to form ESA’s Atomic Clock Ensemble in Space (ACES), will have an accuracy of 1x10^-16, corresponding to a time error of about one second over 300 million years.

This new generation of atomic clocks in space will be instrumental in enabling accurate testing of Einstein’s theory of general relativity. In addition, it will contribute to the accuracy and long-term stability of global timescales, e.g. International Atomic Time (TAI) and Coordinated Universal Time (UTC), and also help in the development of applications in the field of geodesy, and support applications involving remote sensing via the GNSS network.