Two years ago, a paper was published in Nature describing the function of the oldest known scientific computer, a device built in Greece around 100 BCE. ... Read more »
Of all the things you can do with a Science degree, being paid money to stargaze from the top of a volcano in Hawaiʻi has to be one of the more interesting. Tom Kerr is one such lucky astronomer who has been managing operations at UKIRT (UK infrared telescope) – currently the world’s largest telescope dedicated [...]... Read more »
Back in July I wrote about my involvement in a new Zooniverse citizen science project, the then unnamed Project IX. In the last few months, Project IX became the Milky Way Project, and today yesterday it went live! A massive congratulations to Rob and the team who did a fabulous job in getting this all [...]
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In my last post on gamma-ray binaries, I mentioned that only a few of these exotic X-ray binaries (XRB) have been observed, and that they appear to fall into two distinct categories: microquasars, where the gamma-ray emission is caused by leptonic or hadroni particle interactions in the relativistic jet (Inverse Compton Scattering and Neutral Pion Decay respectively) and pulsar wind binaries. where the gamma-rays are [...]... Read more »
H.E.S.S. Collaboration,, Acero, F., Aharonian, F., Akhperjanian, A., Anton, G., Barres de Almeida, U., Bazer-Bachi, A., Becherini, Y., Behera, B., Bernlöhr, K.... (2010) Discovery and follow-up studies of the extended, off-plane, VHE gamma-ray source HESS J1507-622. Astronomy and Astrophysics. DOI: 10.1051/0004-6361/201015187
From far away Saturn’s rings look pretty solid – I’m sure I’m not the only person who, as a child, imagined it’d be possible to skate around the planet on them. In reality, though, they’re made up of millions and … Continue reading →... Read more »
Joseph N. Spitale, & Carolyn C. Porco. (2010) Free Unstable Modes and Massive Bodies in Saturn's Outer B Ring. Astron.J.140:1747-1757,2010. arXiv: 0912.3489v2
Secrets and lies define the government and military, that and being led by bumbling fools. There is no doubt that some military information should be kept secret like technological advances, battle locations and strategies and George W. Bush's IQ. For secrets to be kept away from Wikileaks, cryptography is essential. The new type of cryptography that is being tested by the US military research division, DARPA, is quantum cryptography. Because if codes like DaVinci's Last Supper weren't complicated enough, might as well throw in the most complicated scientific issue in the world today - quantum theory.
Quantum cryptography is based on using electromagnetic waves like light to carry information. Photons carry information as qubits (not Q-bert...unfortunately) and light can be polarized by only allowing a particular magnitude and phase of light through a specialized filter. This polarization gives light a specific binary (0 or 1) property depending on how it is polarized. You can polarize light at different angles and wavelengths thus the photons carry information. If two parties that send and receive the polarized light have detectors to receive and interpret the phase of photons, then a code is born.
The major advantage of using quantum bits for encryption is the Heisenberg Uncertainty Principle which says that if you try to intercept a quantum-coded message, the act of trying to measure one property of a quantum state will disturb another. In other words, if you touch this message (01001100) it will self-destruct in T-minus 1 second.
To add to the complexity, encryption can come in the form of quantum entanglement. Entanglement is the phenomenom that says that two or more separate but similar objects can be linked and respond to changes in eachother, even over a distance. So if a photon is split into two lesser energy photons (like UV into infrared) then those two photons are linked over a theoretically infinite distance. If point A (commonly called Alice) and point B (Bob) are separated but carry entangled photons then they can communicate by changing the properties of one photon and expecting its twin to respond similarly.
Most of this encryption isn't sending long-winded messages about military targets or whether or not Bill inhaled, instead the information sent and received is usually the key to decode encrypted messages sent over regular communication channels. So far, scientists have been able to send 1Mbit/s of information along an optical fiber 20kms in length. The hope is that transmission distances can be extended to even communicate through space to the International Space Station.
The newest rage in quantum encryption is using photons to encode more than just 0's and 1's. Now, in a recent paper published in Science, researchers have been able to measure more than just the phase of the photon but also the angle, which means that the possibilities are infinite for encryption. All of a sudden, entangled photons can communicate both the 0's and 1's and also an entire alphabet of angular information.
What will this mean to Bond, Langdon and Gagdet? Faster and more secure encryption for the military which means more secrets. It isn't clear if these secrets will include the "Don't Ask. Don't Tell" policy.
Leach J, Jack B, Romero J, Jha AK, Yao AM, Franke-Arnold S, Ireland DG, Boyd RW, Barnett SM, & Padgett MJ (2010). Quantum correlations in optical angle-orbital angular momentum variables. Science (New York, N.Y.), 329 (5992), 662-5 PMID: 20689014
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Leach J, Jack B, Romero J, Jha AK, Yao AM, Franke-Arnold S, Ireland DG, Boyd RW, Barnett SM, & Padgett MJ. (2010) Quantum correlations in optical angle-orbital angular momentum variables. Science (New York, N.Y.), 329(5992), 662-5. PMID: 20689014
When you’re reading sci-fi stories in which some of the characters find themselves in need to cover hundreds or thousands of light years very quickly without a warp drive, they manage to make it through time and space via a convenient wormhole. It’s not the worst way to go since wormholes are supposed to exist, [...]... Read more »
A recent study presents some promising data regarding the abundance of rocky planets around other stars. Continue reading →... Read more »
Howard, A., Marcy, G., Johnson, J., Fischer, D., Wright, J., Isaacson, H., Valenti, J., Anderson, J., Lin, D., & Ida, S. (2010) The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters. Science, 330(6004), 653-655. DOI: 10.1126/science.1194854
In part I of this blog post I told you how supernovae type Ia have proven to be so important in defining today’s standard model of Cosmology. I did, however, leave out some important details so let’s get stuck right in.... Read more »
J. Nordin, L. Ostman, A. Goobar, R. Amanullah, R. C. Nichol, M. Smith, J. Sollerman, B. A. Bassett, J. Frieman, P. M. Garnavich.... (2010) Spectral properties of Type Ia supernovae up to z~0.3. Astronomy and Astrophysics. arXiv: 1011.6227v1
Google any of the myriad artists impressions of blazars and relativistic jets available online and they all share one common feature: the jet streams out helically from the central accretion disc/black hole region in a long thin straight line that would make any Roman road builder green with envy. For example (image: University of Michigan): Artists Impression of a [...]... Read more »
Raiteri, C., Villata, M., Bruschini, L., Capetti, A., Kurtanidze, O., Larionov, V., Romano, P., Vercellone, S., Agudo, I., Aller, H.... (2010) Another look at the BL Lacertae flux and spectral variability. Astronomy and Astrophysics. DOI: 10.1051/0004-6361/201015191
The most distant object in the known universe is a highly luminous , a single explosion discovered near maximum light, at a of 8.2, a time when the universe was only 630 million years old, less than 5 percent of its current age. The most distant known galaxy lies at a redshift of 6.96, the light we see now left the galaxy just 750 million years after the . However, both these records have now been broken by a galaxy discovered by the Hubble Space Telescope which has a redshift of 8.56 and an estimated distance of 87 , making it the most distant object currently known.First seen in the Hubble , the deepest single image ever taken in near-infrared light, the galaxy (known as UDFy-38135539) was initially classified as a candidate high redshift object based on its colours. Now, a team led by Matthew Lehnert at the in France, has used spectroscopic observations to confirm that the object is the most distant galaxy so far detected.Since the universe is expanding, the further away an object is, the faster it appears to be moving away from us. This results in a shift in wavelength of the light emitted from an object (known as ) with the size of the shift relating to the distance between us and the object. (This is similar to the shift in pitch you hear when a police car travels past at high speed.) This effect allows distances to be calculated by measuring the shift in spectral lines from known chemicals. Lehnert's team used a sensitive spectrograph on the located in Chile to observe the spectrum of this galaxy and found an emission line which is likely to be caused by hydrogen shifted to redder wavelengths by the relative motion between the galaxy and us.This is an exciting discovery because it is the first galaxy discovered in the so-called , the period in the history of the universe where the between the newly formed galaxies was being - the light from young, hot stars stripped electrons from hydrogen atoms. The authors used the measured light from the galaxy to calculate the size of the region of surrounding gas which the galaxy should have been able to ionise on its own and found that, in order to explain the size of the which is consistent with the observations, there must be other sources of radiation. One suggestion is that dwarf galaxies clustering around larger, more easily observed galaxies, may be responsible for this additional radiation, but there are other explanations.While observations such as these are difficult with current ground-based telescopes due to the faint nature of these distant sources, the planned next generation of larger and more sensitive ground- and space-based instruments should make observations of such sources much easier.This blog post is a news story from the , aired in the edition.... Read more »
Lehnert, M., Nesvadba, N., Cuby, J., Swinbank, A., Morris, S., Clément, B., Evans, C., Bremer, M., & Basa, S. (2010) Spectroscopic confirmation of a galaxy at redshift z . Nature, 467(7318), 940-942. DOI: 10.1038/nature09462
Small lumps of rock hit the Moon quite regularly, but in 2009 two artificial projectiles impacted on the lunar surface in an experiment designed to search for water in the permanent shadows of a crater near the lunar south pole. Hints of subsurface water on the Moon had already been found in 1999 when NASA's spacecraft detected signatures of concentrated hydrogen, the "H" in "H2O", near the lunar poles. The Lunar CRater Observation and Sensing Satellite, or , was a low-cost mission launched together with the in June 2009. The mission consisted of the Centaur upper stage of the Atlas-V launch vehicle, and a shepherding spacecraft equipped with various cameras and sensors. Moving at a speed of 1.5 miles per second, the Centaur stage impacted the lunar surface on October 9th 2009, sending up a plume of material from the permanently shadowed floor of the crater Cabeus. The LCROSS spacecraft observed the impact before flying through the plume to impact the surface some four minutes later. In the October 22nd issue of magazine, several teams working on data from the impact publish their findings.Cabeus crater was chosen for the experiment as it contains an area which is permanently in shadow, due to its location close to the lunar south pole. The low temperatures, combined with the movement of soil () by micrometeorite impacts (known as "") which buries accumulated material, makes such craters ideal places to search for - chemicals which are solid only at very low temperatures. from a neutron spectrometer aboard the Lunar Prospector spacecraft suggested that ice could make up between half and one percent of the soil near the lunar poles, and from a neutron detector on the Lunar Reconnaissance Orbiter showed a strong hydrogen signal, originally thought to be from water ice. But observations of the LCROSS plume, made with another instrument (, an ultraviolet spectrograph) on-board LRO, showed that as much of the hydrogen signal comes from as it does from water. Water is thought to have accumulated from cometary impacts, distributing water across the lunar surface in the ejecta, but it is far from certain where the molecular hydrogen originated.The results from the nine instruments on-board the LCROSS shepherding spacecraft, on October 22nd, show signatures of numerous different chemicals, including water vapour, water ice and , a common result of the breaking up of water molecules. Using the spectra obtained, the LCROSS team calculated that the maximum amount of water vapour and ice visible in the field of view of the instruments was 155 kilograms. By estimating the amount of material that was excavated by the Centaur impact and became observable by reaching sunlight, they calculated that the concentration of water in the lunar regolith at the impact site was 5.6 percent. They also found that the observed abundances of other volatile compounds, such as ammonia, sulphur dioxide and carbon monoxide, were far higher than the abundances found in comets, suggesting that molecule formation may be going on in these shadowed regions on the surfaces of cold dust grains.This blog post is a news story from the , aired in the edition.... Read more »
Colaprete, A., Schultz, P., Heldmann, J., Wooden, D., Shirley, M., Ennico, K., Hermalyn, B., Marshall, W., Ricco, A., Elphic, R.... (2010) Detection of Water in the LCROSS Ejecta Plume. Science, 330(6003), 463-468. DOI: 10.1126/science.1186986
Gladstone, G., Hurley, D., Retherford, K., Feldman, P., Pryor, W., Chaufray, J., Versteeg, M., Greathouse, T., Steffl, A., Throop, H.... (2010) LRO-LAMP Observations of the LCROSS Impact Plume. Science, 330(6003), 472-476. DOI: 10.1126/science.1186474
Hayne, P., Greenhagen, B., Foote, M., Siegler, M., Vasavada, A., & Paige, D. (2010) Diviner Lunar Radiometer Observations of the LCROSS Impact. Science, 330(6003), 477-479. DOI: 10.1126/science.1197135
Paige, D., Siegler, M., Zhang, J., Hayne, P., Foote, E., Bennett, K., Vasavada, A., Greenhagen, B., Schofield, J., McCleese, D.... (2010) Diviner Lunar Radiometer Observations of Cold Traps in the Moon's South Polar Region. Science, 330(6003), 479-482. DOI: 10.1126/science.1187726
Mitrofanov, I., Sanin, A., Boynton, W., Chin, G., Garvin, J., Golovin, D., Evans, L., Harshman, K., Kozyrev, A., Litvak, M.... (2010) Hydrogen Mapping of the Lunar South Pole Using the LRO Neutron Detector Experiment LEND. Science, 330(6003), 483-486. DOI: 10.1126/science.1185696
Looking up at the sky on any clear, dark, night, you can’t help but get a deep and often meaningful impression of the infinite voids of space. But in reality this is merely an illusion, as the universe is actually very, very crowded. I’m not talking about all the man-made space junk that we’ve launched [...]... Read more »
Chen, A., Piano, G., Tavani, M., Trois, A., Dubner, G., Giacani, E., Argan, A., Barbiellini, G., Bulgarelli, A., Caraveo, P.... (2010) Study of the gamma-ray source 1AGL J2022 4032 in the Cygnus region . Astronomy and Astrophysics. DOI: 10.1051/0004-6361/201015279
Not only are GPS devices useful, they’re also an ongoing experiment that keeps confirming special relativity’s spot on descriptions of how time flows for fast-moving objects. Without constant adjustments, GPS would be quickly rendered unusable because accurate timing of the signals being sent between the satellites and the moving object they’re supposed to track is [...]... Read more »
Angelo Tartaglia, Matteo Luca Ruggiero, & Emiliano Capolongo. (2010) A null frame for spacetime positioning by means of pulsating sources. Advances in Space Research. arXiv: 1001.1068v3
Until the last century, astronomy had one very practical purpose, navigation. Ancient mariners used stars such as the North Star and the Southern Cross to work out where in the ocean they were. With the advent of modern methods (the most up to date of which is GPS) navigating by the stars fell by the wayside. Now a new method that combines the ancient idea of stellar aids to navigation with some of the principles of GPS has been suggested to accurately determine the position of spacecraft, and it uses dead stars.... Read more »
Mike Georg Bernhardt, Tobias Prinz, Werner Becker, & Ulrich Walter. (2010) Timing X-ray Pulsars with Application to Spacecraft Navigation. Proceedings of Science. arXiv: 1011.5095v1
Astrophysics and Gravitation:
Fundamental constants: Big G revisited
Davis, R. (2010). Fundamental constants: Big G revisited Nature, 468 (7321), 181-183 DOI: 10.1038/468181b
Credit: Nature. a, A spherical 'source mass' (ms) is brought near a pendulum's spherical bob (the 'test mass', mt) and causes the bob to move a small distance z from its usual resting position (grey). The gravitational force between the two masses (left side of equation), which depends on Newton's constant (G), can be obtained from a measurement of z provided that k is known (see b). b, The value of k is found by measuring the period (P) of the freely swinging pendulum. To compute the value of G, we need measurements of L, z, ms and P (but not mt). Parks and Faller's experiment was based on four cylindrical source masses of 100 kilograms each, two pendulums and many other refinements.
From the abstract:
Measuring Newton’s constant of gravitation is a difficult task, because gravity is the weakest of all the fundamental forces. An experiment involving two simple pendulums provides a seemingly accurate but surprising value.
For more, see Fundamental constants: Big G revisted.
Galaxy Zoo Supernovae
Galaxy Zoo (2010). Galaxy Zoo Supernovae arXiv arXiv: 1011.2199v2
This paper presents the first results from a new citizen science project: Galaxy Zoo Supernovae which, with 2500 volunteers, has categorized almost 14,000 supernovae candidates.
For more, see Galaxy Zoo paper goes supernova.
“Youngest” Nearby Black Hole
Credits: X-ray: NASA/CXC/SAO/D.Patnaude et al, Optical: ESO/VLT, Infrared: NASA/JPL/Caltech
From the Press Release:
This composite image shows a supernova within the galaxy M100 that may contain the youngest known black hole in our cosmic neighborhood. In this image, Chandra’s X-rays are colored gold, while optical data from ESO’s Very Large Telescope are shown in red, green, and blue, and infrared data from Spitzer are red. The location of the supernova, known as SN 1979C, is labeled… This approximately 30-year age, plus its relatively close distance, makes SN 1979C the nearest example where the birth of a black hole has been observed, if the interpretation by the scientists is correct.
Sure, black holes can have finite age, that seems perfectly reasonable… well no, not really. The “age” of a black hole is an exceptionally complicated, verging on philosophical, matter that I’ll have to write about.
For more, see Black Hole Baby Spotted Being Born, Youngest nearby black hole found, Youngest Nearby Black Hole.
High Energy Physics and Particles:
Andresen, G., & et al. (2010). Trapped antihydrogen Nature DOI: 10.1038/nature09610
From the abstract:
Antihydrogen, the bound state of an antiproton and a positron, has been produced2, 3 at low energies at CERN (the European Organization for Nuclear Research) since 2002. Antihydrogen is of interest for use in a precision test of nature’s fundamental symmetries. … Here we demonstrate trapping of antihydrogen atoms. …This result opens the door to precision measurements on anti-atoms, which can soon be subjected to the same techniques as developed for hydrogen.
For more, see Antiatoms Bottled for First Time, Antimatter atoms held captive by physicists.
General Relativity, Quantum Gravity, et al.:
V. G. Gurzadyan, & R. Penrose (2010). Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity arXiv arXiv: ... Read more »
V. G. Gurzadyan, & R. Penrose. (2010) Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity. arXiv. arXiv: 1011.3706v1
Belgiorno, F., Cacciatori, S., Clerici, M., Gorini, V., Ortenzi, G., Rizzi, L., Rubino, E., Sala, V., & Faccio, D. (2010) Hawking Radiation from Ultrashort Laser Pulse Filaments. Physical Review Letters, 105(20). DOI: 10.1103/PhysRevLett.105.203901
Veronika E. Hubeny. (2010) The Fluid/Gravity Correspondence: a new perspective on the Membrane Paradigm. arXiv. arXiv: 1011.4948v1
Inflationary cosmology, which is the current model of how physics sees space and time, gets pretty tangled in how it describes the Big Bang and its immediate after-effects. All sorts of odd quantum states, asymmetries, and exotic particles had to come into existence after a violent event that carved out an ever-expanding bubble of space, [...]... Read more »
V. G. Gurzadyan, & R. Penrose. (2010) Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity. n/a. arXiv: 1011.3706v1
On Thursday, two giants of astronomy met in the sleepy German city of Bonn to debate one of the basic tenets of our current cosmological vision: the existence of dark matter. In the blue corner was Simon White aka. the Reigning Champion, Director at the Max Planck Insitute for Astrophysics (MPA) in Garching, and figurehead of the concordance cosmology model we all know and live by. In the red corner, Pavel Kroupa aka. the Challenger, Professor at the Argelander Institute in Bonn and well-known expert on stellar populations and dynamics.... Read more »
P. Kroupa, B. Famaey, K. S. de Boer, J. Dabringhausen, M. S. Pawlowski, C. M. Boily, H. Jerjen, D. Forbes, G. Hensler, & M. Metz. (2010) Local-Group tests of dark-matter Concordance Cosmology: Towards a new paradigm for structure formation. Astronomy . arXiv: 1006.1647v3
Forty years ago today the Lunokhod-1 lunar rover landed on the Moon. This Soviet mission was the first remote controlled robot to operate outside Earth and it spent an impressive 11 months pottering around up there exploring the Mare Imbrium, even though, as you can see from the picture at the top of this post, [...]... Read more »
Its been a good week for the Herschel-ATLAS survey that I work on – last Friday we released our first set of data to the public and this Friday we’re publishing some exciting results, led by Mattia Negrello from the Open University, on a new way to find cosmic lenses. Gravitational lensing occurs when light [...]... Read more »
Negrello, M., Hopwood, R., De Zotti, G., Cooray, A., Verma, A., Bock, J., Frayer, D., Gurwell, M., Omont, A., Neri, R.... (2010) The Detection of a Population of Submillimeter-Bright, Strongly Lensed Galaxies. Science, 330(6005), 800-804. DOI: 10.1126/science.1193420
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