Circling a Black Hole at its Photon Sphere . ... One particularly interesting place near a black hole is its photon sphere, where photons can orbit in circles, a sphere 50 percent further out than the event horizon. Were you to look out from the photon sphere of a black hole , half of the sky would appear completely black, half of the sky would appear unusually bright, and the back of your head would appear across the middle. ... Disclosure: Video creator Robert Nemiroff is an editor for APOD.) ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... 2013 July 2 . Circling a Black Hole at its Photon Sphere . ... One particularly interesting place near a black hole is its photon sphere , where photons can orbit in circles, a sphere 50 percent further out than the event horizon . Were you to look out from the photon sphere of a black hole , half of the sky would appear completely black, half of the sky would appear unusually bright, and the back of your head would appear across the middle. ... About APOD | ...

... The TRACE images may be used without restrictions in publications of any kind. ... These two images, taken on 18 November 2000 at 15:54UT and 16:11UT, respectively, show such an event: the red circle in the image to the left shows a region where many loops are cooling, with bright loop tops (the intensity scales with the square root of the image to reduce the dynamic range). ... See also a collection of images related to the Sun, other cool stars, and solar-terrestrial effects . ... Images | ...

... SEARCH ASP SITE: Match ALL words Match ANY word . ... ASP Conference Series . ... Accidental Astrophysics: The Devil's In the Magnitudes, Part II . ... The star second to the Sun in brilliance is Sirius. ... Recall the magnitude system, passed down to us through a hundred generations of sky watchers, as a means of quantifying stellar brightness ("Accidental Astrophysics," May/June, p. 9). ... Yes, it is a magnitude difference, but that difference is due to the distance between us and the star. ...

... Circumstellar disc of beta Pictoris: constraints on grain properties from polarization. To appear in the Astronomy & Astrophysics . abs , src , ps ] . ... Dust influx to Titan from Hyperion . ... abs ] . ... Characteristics of bulges and disks in interacting galaxies . ... Dust grains around Herbig Ae/Be stars: porous, cometary-like grains? ... To appear in the Astronomy & Astrophysics Supplement . ... Finally, Links may lead you to more options (e.g. via the LANL preprint system). ...

... The blue bubble is a planetary nebula known as Abell 33. Planetary nebulae are created when an aging star blows away its outer layers of gas in a gigantic cosmic bubble. ... Creating the illusion of the cosmic diamond is a bright star along the rim of the nebula. ... The star is about 700 light years away, that is halfway between Earth and the nebula. ... At the centre of the ring, you can see the remains of the star that created this planetary nebula, now a white dwarf . ...

This month's Geminid meteor shower is expected to peak around the late evening of Tuesday 13th/early hours of Wednesday 14th. The shower is usually one of the best of the annual meteor showers, with many relatively bright, slow- to medium-speed fireballs. ... These meteors are believed to originate from the near-Earth asteroid, Phaethon, discovered by a NASA satellite in 1983. ... FOR FURTHER INFORMATION CONTACT: John McFarland at the Armagh Observatory, College Hill, Armagh, BT61 9DG. ...

Astronomy Discussion Forums . ... Atm ћ Astrophotography ћ Blackholes ћ Blackholes2 ћ CCD ћ Celestron ћ Domes ћ Education . ... New Model: How Do The Sun And Moon Appear To Move Across The Sky . ... Post Message | ... focused on the Sun and the Moon as they appear from the given location of the Earth surface: . ... www.astronomy.net . About Astronomy Net | ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

... 2004: . ... An increase in star brightness is followed by a decrease in asphericity and wind velocity to the point where stationary and even accreting fraction of the wind appears in extremely bright objects together with a flowing out fraction. ... Based on an analysis of observations obtained with BTA and on the published data it was found that degree of abnormality of energy distribution in continuum of magnetic chemically peculiar stars increases with an increase of their rotation period. ...

The red colors in this image show the galaxy M66 as it appears at the submillimeter wavelength of 850 microns, while the white background shows the galaxy as it appears in visible light. Regions of cold dust that appear as dark streaks in the white image glow brightly in the red image. ...

We present a time-lapse sequence of 20 near-infrared ( J and K band) snapshots of the central 20 20 of the Crab pulsar wind nebula, taken at subarcsecond resolution with the Hokupa`a/QUIRC adaptive optics camera on the Gemini North Telescope and sampled at intervals of 10 minutes and 24 hr. It is observed that the equatorial wisps and polar knots in the termination shock of the pulsar wind appear to fluctuate in brightness on kilosecond timescales. ...

... Night Sky Questions . Q. I saw a bright light streak across the sky last night. ... A. Meteors are the bright trails left by fragments of natural space debris called meteoroids (usually chunks of rock or metal) falling through the EarthтАЩs atmosphere. ... As the Earth moves around the Sun over a year, planets will move in and out of view, so the sky changes.To confirm if it was one of the planets, go to www.heavens-above.com . ... Q. I saw a bright light moving steadily across the sky last night. ...

... BLUE STRAGGLER STARS are unusually hot and bright stars found in the cores of ancient star clusters known as globulars. ... BACKGROUND (from wikipedia): Blue straggler stars are stars in open or globular clusters that are hotter and bluer than other cluster stars having the same luminosity. ... There is evidence in favor of this view, notably that blue straggler stars appear to be much more common in dense regions of clusters, especially in the cores of globular clusters. ...

... Comet Animation . ... Comet structures are diverse and very dynamic, but they all develop a surrounding cloud of diffuse material, called a coma, that usually grows in size and brightness as the comet approaches the Sun. ... As comets approach the Sun they develop enormous tails of luminous material that extend for millions of kilometers from the head, away from the Sun. ... The evaporated molecules boil off and carry small solid particles with them, forming the comet's coma of gas and dust. ...

... This program was created for correlating chosen regions in the series of fts images. ... Chosen regions' . ... In this section the program counts the integral for each region of the grid for each image. ... As a matter of fact, the integral is total brightness of the region and it is counted by 'int_tabulated' IDL function. ... In addition, the program will show the count of the regions which correlate with the corresponding region (the brighter region means the bigger count) and its contour. ...

... Laboratory for Spectroscopy of Molecular Structures . ... News . ... A new article entitled Description of optical properties of cholesteric photonic liquid crystals based on Maxwell equations and Kramers-Kronig relations has appeared in Physical Review E. Congratulations to Grigoriy Ksyonz on his first publication! . 25 th February 2013 . ... 22 nd November 2012 . ... 22 nd February 2012 . 4 th Workshop on Liquid Crystals for Photonics 2012 will take place in Hong Kong December 9-11, 2012. ...

True Color Image Gallery: Galactic SNR | Magellanic Cloud SNR . ... Chandra Proposer's Guide pile up section ] During frame readout, the ACIS CCDs take 40 microsec to (parallel) transfer the charge by one pixel. As a result of this, each frame readout, each pixel is exposed for 40 microsec to a source (plus cosmic X-ray background) at each location along its column. ... Note also that the image does not just trail, it extends along the whole column. ... Chandra Supernova Remnant Catalog . ...

... Usually, H I is seen as bright emission against a darker background, but under the right viewing conditions, it can also be seen as dark absorption against a brighter background. In the case where the background is itself H I emission, the hydrogen is said to be self-absorbed, and the radiative transfer process is termed H I self-absorption (HISA). ... Shown below is a single CGPS H I 21cm spectral line channel at a radial velocity of -41 km/s in the Local Standard of Rest, at l =140њ, b =+1њ. ...

... Most Important Journals . Less Popular Astronomical Journals . Physics . Space, Selectial mechanics, .. Russian Journals . ... Astrophysics & Astronomy . ... Astronomical Journal . ... New Astronomy . ... Publications of the Astronomical Society of the Pacific . ... STScI News . Space Telescope Insitute Newsletter . ... Journal of Astronomical Data . ... Journal of High-Energy Physics (mirror in CERN ) [astro, grav, hi-energy .. ... Journal of Experimental and Theoretical Physics . ...