On June 16, 1995 NASA and Michigan Technological University (MTU) launched a new website called The Astronomy Picture of the Day (APOD). APOD was presented at a meeting of the American Astronomical Society in 1996. It received a Scientific American Sci/Tech Web Award in 2001.
Whimsical Vermeer composite that ran on APOD's fifth anniversary now digitally re-pixelated using many of the over 5,000 APOD images that have appeared over APOD's tenure
As during each of the 15 years of selecting images, writing text, and editing the APOD web pages, the occasionally industrious Robert Nemiroff (left) and frequently persistent Jerry Bonnell (right) are pictured above plotting to highlight yet another unsuspecting image of our cosmos. Although the above image may appear similar to the whimsical Vermeer composite that ran on APOD’s fifth anniversary, a perceptive eye might catch that this year it has been digitally re-pixelated using many of the over 5,000 APOD images that have appeared over APOD’s tenure.
The brilliant fireball meteor captured in this snapshot was a startling visitor to Tuesday (October 13, 2009) evening's twilight skies over the city of Groningen - Credit: Robert Mikaelyan
Here’s a photo of waxing crescent Moon taken tonight at 19:00 GMT from Amsterdam. Only 2 days and 17 hours old, not many features are visible on the surface. The two prominent craters visible at the bottom just at the terminator are Langrenus (right) and Petavius (left).
Photo of waxing crescent Moon taken tonight through a refractor ATC Monar (D=70mm f/4.6) with Canon 450D, exp. 1/50s
Gamma-ray Bursts (GRBs) are the most powerful explosions in the universe. In a few seconds they release a tremendous amount of energy outshining billions of stars. They were first discovered (accidentally) in 1967 by satellites designed to detect tests of nuclear weapons. Although we detect new GRBs on daily basis, no one knows the exactly the process behind their origin.
The most-widely accepted model proposes that GRBs are created in a gravitational collapse of extremely massive stars into black holes when matter in the accretion disk is heated by neutrinos and driven into narrowly focused jets along the rotational axis.
As the core of a massive star in a distant galaxy collapses, deep inside, twin beams of matter and energy begin to blast their way outward. Within seconds, the beams have eaten their way out of the star, and observers at Earth see it as a gamma-ray burst, GRB 060729A - Credit for caption: Phil Plait SSU NASA E/PO; Images: Aurore Simonnet SSU NASA E/PO
Nevertheless, this model makes it difficult to explain long GRBs with the duration of more than 100 seconds and cannot account for afterglows lasting up to 10,000 observed by the Swift spacecraft.
Professor Komissarov and his colleagues at the University of Leeds accredit the creation of the matter jets to a magnetic mechanism and examine the close binary scenario involving a merger or a WR star (evolved, massive star of over 20 solar masses) with a neutron star or a black hole, in their article Close Binary Progenitors of Long Gamma Ray Bursts.
“The neutrino model cannot explain very long gamma ray bursts and the Swift observations, as the rate at which the black hole swallows the star becomes rather low quite quickly, rendering the neutrino mechanism inefficient, but the magnetic mechanism can.”
You may have seen the Hubble Ultra Deep Field (HUDF) photo before – it is a photo of a clear patch of sky that shows over 10,000 galaxies. It is often called the most important image ever taken because it allowed scientists to estimate that there are over a 100 billion to 1 trillion galaxies in the universe.
This view of nearly 10,000 galaxies is the deepest visible-light image of the cosmos. Called the Hubble Ultra Deep Field, this galaxy-studded view represents a "deep" core sample of the universe, cutting across billions of light-years - Photo Credit: NASA, ESA, S. Beckwith (STScI) and the HUDF Team
Earlier this month a 3D animation rendered using the measured redshift of all 10,000 galaxies in the Hubble Ultra Deep Field image hit YouTube:
Quite an impressive view, isn’t it? Well … here is another one (a tiny part of the huge image below). It is a rarely seen before image that is perhaps a hundred times larger (here’s a link to the BitTorrent of the image [180 MB]) than the HUDF and thus not widely circulated.
In a way, this view is more special because rather than a static photo, it actually is an interactive composite made using the OpenZoom technology, similar to Google Maps. You can pan the “map” using the arrows on your keyboard (or by dragging its parts with your mouse). +/- (or the wheel button) can be used to zoom in and out. Also, you can press ‘F’ to enter the full-screen mode and ‘H’ to return to the original view.
The author of this composite also made available a similar view of the Orion Nebula.
