Lensing caused by various analytic spacetimes. For all panels, we use Figure 3 as a background, oriented such that the camera is pointed at the white reference dot. The camera has a 60 degree feld of view and is at a distance of 15 Schwarzschild radii from the origin measured using Kerr- Schild coordinates. The top row shows Minkowski and Schwarzschild spacetimes. The bottom row shows two views of the Kerr spacetime, with dimensionless spin x = 0.95, viewed with the camera pointing parallel to the spin axis of the black hole (bottom left) and perpendicular to the spin axis (bottom right). (Credit: A. Bohn, F. Hebert, W. Throwe, D. Bunadar, K. Henriksson, M. Scheel, N. Taylor)
The difficult part of this work is calculating the trajectory of the photons using the physics of general relativity. These equations are notoriously non-linear, so physicist sometimes simplify them by assuming that a system remains constant in the time it takes for light to pass by. The difficulty with black hole binaries is that this assumption does not hold— these objects orbit so rapidly as they approach each other that space-time warps, even during the time it takes for light to pass by.
A BBH system of equal-mass black holes with no spin, viewed near merger with the orbital angular momentum out of the page. (Credit: A. Bohn, F. Hebert, W. Throwe, D. Bunadar, K. Henriksson, M. Scheel, N. Taylor)
Andy Bohn(et al.) at Cornell University in Ithaca, New York, reveals how in-spiraling black hole pairs should distort the light field around them. The team has concluded that from large distances, binaries are more or less indistinguishable from single black holes. Only a relatively close observer would be able to see the fascinating detail that they have simulating or one with very high resolving power.
The first observation of much bigger deflections, such as those produced by black holes or black hole pairs, will be something of a triumph for whoever spots them first.
via physics arxiv
Friday, September 19, 2014
When space probes, such as Rosetta and Cassini, fly over certain planets and moons, in order to gain momentum and travel long distances, their speed changes slightly for an unknown reason. A researcher has now analyzed whether or not a hypothetical gravitomagnetic field could have an influence. However, other factors such as solar radiation, tides, or even relativistic effects or dark matter could be behind this mystery. An artist’s rendition of Rosetta probe during a flyby. (Credit: ESA/C.Carreau) via
The starboard truss of the International Space Station while Space Shuttle Endeavour docked with the station. The newly installed Alpha Magnetic Spectrometer (AMS) is visible at center left. (Credit: NASA) via
The dome of the Blanco Telescope, which houses DECam, the 570-megapixel CCD camera used for the Dark Energy Survey, at the Cerro Tololo Inter-American Observatory in Chile. (Credit: Reidar Hahn) via
The lonely landscape of Rosetta’s comet – Comet 67P/Churyumov-Gerasimenko from a distance of just 29 kilometers (Credit: ESA) via
Mosaic of southern hemisphere of Miranda, the innermost regular satellite of Uranus, with radius of 236 km. Projection is orthographic, centered on the south pole. Visible from left to right are Elsinore, Inverness, and Arden coronae. (Credit: NASA/Jet Propulsion Laboratory/Ted Stryk) via
An international team of physicists has shown that the mass ratio between protons and electrons is the same in weak and in very strong gravitational fields. Pictured above is the laser system with which the hydrogen molecules were investigated on earth. (Credit: LaserLaB VU University Amsterdam/Wim Ubachs) via
The MIT BioSuit, a skintight spacesuit that offers improved mobility and reduced mass compared to modern gas-pressurized spacesuits. (Credit: Jose-Luis Olivares/MIT) via
Friday, September 5, 2014
Artist impression of the Square Kilometer Array. If all goes according to plan in the next decade, we could see these small perturbations on the moon—and begin to solve some of the mysteries of space. (Credit: SKA) via
Space travelers from around the world are headed to China this month for an international Planetary Congress, which will explore the possibilities for expanding human spaceflight cooperation among different countries. Pictured above is China’s first astronaut, Yang Liwei, is now vice director of the China Manned Space Engineering Office. (Credit: CMS) via
An animation of the quicksort algorithm sorting an array of randomized values. The red bars mark the pivot element; at the start of the animation, the element farthest to the right hand side is chosen as the pivot. (Credit: RonaldH) via
Rather than keeping all its eggs in D-Wave’s basket, Google’s “Quantum A.I. Lab” announced that it is starting a collaboration with an academic quantum computing researcher, John Martinis of the University of California-Santa Barbara. (Credit: Wiki, Timmer) via
In the grasp of the Japanese robotic arm, NanoRack’s CubeSat deployer releases a pair of miniature satellites last month. (Credit: NASA) via