... 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. ...

... The Cat's Eye Nebula . ... The USNO Millennium Time Ball . ... Spanning over 25,000 light-years, comparable to the distance from the Sun to the center of our own Milky Way galaxy, a cosmic jet seen in X-rays blasts from the center of Centaurus A. Only 10 million light-years away, Centaurus A is a giant elliptical galaxy - the closest active galaxy to Earth. In the Heart of the Tarantula Nebula . ... Neptune is the eighth most distant planet from the Sun, thirty times the Earth-Sun distance. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. March 25, 1998 . Planetary Nebula NGC 7027 in Infrared . ... NICMOS , HST , NASA . Explanation: NGC 7027 is one of the smallest known planetary nebulae . Even so, NGC 7027 is 14,000 times larger than the Earth-Sun distance . Planetary nebula are so named because the first few discovered appeared similar to planets. ... About APOD > . ...

... July 13, 1999 . The Flame Nebula in Infrared . ... Explanation: What lights up the Flame Nebula? Fifteen hundred light years away towards the constellation of Orion lies a nebula which, from its glow and dark dust lanes, appears like a billowing fire. ... Rather the bright star Alnitak , the easternmost star in the Belt of Orion visible to the nebula's right, shines energetic light into the Flame that knocks electrons away from the great clouds of hydrogen gas that reside there. ...

We present new images of the reflection nebula surrounding the R Coronae Borealis Star, UW Centauri. ... Instead, the morphology of the nebula appears to change as different parts are illuminated by light from the central star that is modulated by shifting thick dust clouds near its surface. ... In this way, the central star acts like a lighthouse shining through holes in the dust clouds and lighting up different portions of the nebula. ... ADS Citation Query . citations = 21 . ...

Photon Scattering: Basic Principle of Photon Scattering . Audio Narration is available . No Scattering: Photon Source and Detector . ... For optical photons, scattering goes as wavelength to the -4 power. In the case of blue photons compared to red photons, this means that blue photons are about 10 times more likely to get scattered than red photons. ... Watch the blue photons scatter away from the detector . ... Interstellar dust make stars appear redder than they really are . ...

... Gift Center . ... Why do aurorae appear strongest within rings centered on Earth's poles instead of filled-in circles? ... RELATED TOPICS: AURORAE . The visible aurorae result from electrons that move along magnetic field lines from space into the upper atmosphere. ... Just make sure you're registered with the website. Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

... The GALFA Continuum Transit Survey group ( GALFACTS ; PI: A. R. Taylor) has conducted several test observations and will begin an all-sky full-Stokes continuum survey later this year with the new P-ALFA spectrometer. ... Sample Perseus images of GALFA H I 21cm-line and full-Stokes continuum emission are shown below along with maps of molecular (CO) gas, thermal dust, and ionized gas optical emission for comparison. ... The GALFA H I emission appears to envelop the molecular cloud gas traced by CO. ...

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. ...

The Experiment: To find the first galaxies . Understand basic properties of star formation/galaxies ? guess how a young galaxy, or protogalaxy would appear . ... New stars very blue: will appear redder at large distances (redshift). Dust protects gas from radiation. Dust is heated and is luminous at infrared wavelengths. ... Gas in close to a group of galaxies (cluster) may become very hot and emit X-rays. Previous slide . Next slide . Back to first slide . ...

... Data Reduction FAQ > The reduced science spectrum displayed in the Reflex window appears good but when I try to plot it, it is quite different. How can I get it? ... Observing with ESO Telescopes . ... ESO-MIDAS . ... Reflex . ... ESO Data . ... ESO HST Image Galleries . ... ESO Data Access Policy . ... ESO Science Newsletter . ... ESO Annual Reports . ... Seminars at ESO Santiago . ... Seminars at ESO Garching . ... ESO Telescope Bibliography . ... Last Update: 01.04.14 ESO . ...