Thursday, 14 December 2017

Mars upside down

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Which way is up in space? Planets are usually shown with the north pole at the top and the south pole at the bottom. In this remarkable image taken by ESA’s Mars Express, the Red Planet is seen with north at the bottom, and the equator at the top.


via ESA Space Science
http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Mars_upside_down

Breaking data records bit by bit

Magnetic tapes, retrieved by robotic arms, are used for long-term storage (Image: Julian Ordan/CERN)

This year CERN’s data centre broke its own record, when it collected more data than ever before.

During October 2017, the data centre stored the colossal amount of 12.3 petabytes of data. To put this in context, one petabyte is equivalent to the storage capacity of around 15,000 64GB smartphones. Most of this data come from the Large Hadron Collider’s experiments, so this record is a direct result of the outstanding LHC performance, the rest is made up of data from other experiments and backups.

“For the last ten years, the data volume stored on tape at CERN has been growing at an almost exponential rate. By the end of June we had already passed a data storage milestone, with a total of 200 petabytes of data permanently archived on tape,” explains German Cancio, who leads the tape, archive & backups storage section in CERN’s IT department.

The CERN data centre is at the heart of the Organization’s infrastructure. Here data from every experiment at CERN is collected, the first stage in reconstructing that data is performed, and copies of all the experiments’ data are archived to long-term tape storage.

Most of the data collected at CERN will be stored forever, the physics data is so valuable that it will never be deleted and needs to be preserved for future generations of physicists.

“An important characteristic of the CERN data archive is its longevity,” Cancio adds. “Even after an experiment ends all recorded data has to remain available for at least 20 years, but usually longer. Some of the archive files produced by previous CERN experiments have been migrated across different hardware, software and media generations for over 30 years. For archives like CERN’s, that do not only preserve existing data but also continue to grow, our data preservation is particularly challenging.”

While tapes may sound like an outdated mode of storage, they are actually the most reliable and cost-effective technology for large-scale archiving of data, and have always been used in this field. One copy of data on a tape is considered much more reliable than the same copy on a disk.

CERN currently manages the largest scientific data archive in the High Energy Physics (HEP) domain and keeps innovating in data storage,” concludes Cancio.


via CERN: Updates for the general public
https://home.cern/about/updates/2017/12/breaking-data-records-bit-bit

Spanning disciplines in the search for life beyond Earth

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Following a gold rush of exoplanet discovery, the next step in the search for life is determining which of the known exoplanets are proper candidates for life -- and for this, a cross-disciplinary approach is essential.
via Science Daily
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Giant storms cause palpitations in Saturn's atmospheric heartbeat

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Immense northern storms on Saturn can disturb atmospheric patterns at the planet's equator, finds the international Cassini mission.
via Science Daily
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Wednesday, 13 December 2017

Trilobites: The Great Red Spot Descends Deep Into Jupiter

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The iconic storm plunges 200 miles beneath the clouds of the solar system’s largest planet, and possibly much deeper, according to data from NASA’s Juno spacecraft.
via New York Times

Mars mission sheds light on habitability of distant planets

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Insights from NASA's Mars Atmosphere and Volatile Evolution, or MAVEN, mission about the loss of the Red Planet's atmosphere can help scientists understand the habitability of rocky planets orbiting other stars.
via Science Daily
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Stellar nursery blooms into view

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The OmegaCAM camera on ESO's VLT Survey Telescope has captured this glittering view of the stellar nursery called Sharpless 29. Many astronomical phenomena can be seen in this giant image, including cosmic dust and gas clouds that reflect, absorb, and re-emit the light of hot young stars within the nebula.
via Science Daily
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Graphene for quantum computing

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Quantum computing is a new paradigm in computing that utilizes the benefits of quantum mechanics to enhance the computing experience. Quantum computers will no longer rely on binary digits (0 and 1 states), that computers have relied on since the early beginnings, but will instead use quantum bits, which can be in a superposition of states. Quantum bits, or qubits, have the advantage of being in many states at once, offering parallel computing advantages. For example, they have long been regarded as far superior to classical computers for applications in data encryption.

Although the concept of quantum computers has been known for several decades, practical realizations are still lacking. The main limiting factor has been the critical influence of the environment on a qubit. Most physical systems need to be in perfectly controlled conditions in order to remain in the superposition state, whereas any interaction (mechanical, thermal, or other) with the environment perturbs this state and ruins the qubit. Such perturbation is termed “decoherence” that has plagued many potential qubit systems.

Graphene, having spurred research into numerous novel directions, is naturally also considered as a candidate material host for qubits. For example, back in 2013, a team of researchers from MIT found that graphene can be made into a topological insulator – meaning that electrons with one spin direction move around the graphene edges clockwise, whereas those that have the opposite spin move counterclockwise. They made this happen by applying two magnetic fields: one perpendicular to the graphene sheet, to make the electrons flow at sheet edges only, and another parallel to the sheet, that separates the two spin contributions. Electron spin has long been considered a candidate qubit, because it is inherently a quantum system that is in a superposition of states. In graphene, the spins move along the sheet edges robustly, without much decoherence. Furthermore, the same research showed switching the spin selection on and off, an important feature of q-bit transistors. Nevertheless, extreme conditions such as strong magnetic fields and temperatures near absolute zero are required for this effect in graphene, raising questions about real-world applicability.

Image: Graphene spin qubit, MIT.

This year, the same group discovered a new kind of quantum state that appears when graphene is sandwiched between two superconductors. In this situation the electrons in graphene, formerly behaving as individual, scattering particles, instead pair up in “Andreev states” — a fundamental electronic configuration that allows a conventional, non-superconducting material to carry a “super-current,” an electric current that flows without dissipating energy. Andreev states, like the spin qubits, have very little decoherence, due to their paired configuration. These states are predicted to give rise to Majorana fermions, exotic particles that can be used for quantum computing. Although this experiment is also performed at low temperatures, it is an important proof-of-concept that should in the future open doors towards practical realizations of quantum computing.

Most recently, a group from EPFL in Switzerland devised a new way to use graphene in quantum electronics. In a layered capacitor structure, where graphene forms the capacitor parallel plates and boron nitride makes the insulating layer, quantum capacitance gives rise to novel nonlinear electronic phenomena. In this system small changes in, for example, the intensity of an incident laser beam, give rise to large changes in the measured capacitance of the device. The researchers calculate that one single incident photon could be enough to change qubit states, which is an ideal case of a qubit. Again, low temperatures are required for operation, however a significant advantage of this design is that there is no need for external magnetic fields, rendering this solution a step closer to practical applications.

To summarize, there are several different proposals to use graphene in quantum computers. From spin qubits, to Majorana fermions, to nonlinear capacitors, each has their own advantage. One common theme is that all these solutions are highly novel and innovative, and that the marriage of 2D materials and quantum computing is inevitable in the long run.


via Graphenea

Two tales of one galaxy

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Explore the stars in our galactic neighbour, the Large Magellanic Cloud, as viewed by ESA’s Gaia satellite
via ESA Space Science
http://sci.esa.int/gaia/59855

Explore CERN in the world of Minecraft