... December 11, 1998 . High Redshift Quasars . Credit: Sloan Digital Sky Survey . ... Astronomers use a number known as "Z" to quantify this cosmological redshift and the quasar at the left, with a Z of 5, was just proclaimed the new quasar redshift champion (from left to right the measured Zs are 5.00, 4.90, 4.75). What's the actual distance to quasars with Zs of 5 or so? ... about 15 billion light-years, give or take a few billion light-years depending on your favorite cosmology ! ...

Astronomy Picture of the Day . Edmund Halley's Greatest Discoveries . ... 6.07.1996 . ... Born in 1656, he computed in 1705 that a bright comet was periodic and would make another appearance in 1758. The comet appeared as predicted and is now known as Comet Halley . ... Perhaps Halley's greatest discovery, however, was that his contemporary Isaac Newton had discovered a powerful mathematical formulation of gravity. ... July 1996 . ... NASA Web Site Statements, Warnings, and Disclaimers . ...

... December 30, 1998 . Supernova 1994D and the Unexpected Universe . Credit: High-Z Supernova Search Team , HST , NASA . Explanation: Far away, long ago, a star exploded. ... Supernova 1994D was not of interest for how different it was, but rather for how similar it was to other supernovae . ... The large number and great distances to supernovae measured in 1998 have been interpreted as indicating that we live in a previously unexpected universe . ... About APOD > . ... NASA Technical Rep.: ...

A team of U.S. and German astrophysicists have made the first ever detection of X-rays coming from a comet. ... Following the initial detection, the team reported repeated X-ray emissions from the comet over the next 24 hours. ... One preliminary theory is that X-ray emission from the Sun was absorbed by a cloud of gaseous water molecules surrounding the nucleus of the comet, and then were re-emitted by the molecules in a process physicists call "fluorescence." ... Comets . ...

Astronotes Armagh Planetarium's Stellar Blog! ... Planets . ... Our Galaxy . ... Weird and Fun . ... It came from another galaxy: This artistтАЩs impression shows HIP 13044 b, an exoplanet orbiting a star that entered our galaxy from beyond. ... HIP 13044 is one of tens of millions of stars in the тАЬHelmi streamтАЭ, stars that belonged to a dwarf galaxy consumed by our own Milky Way galaxy, some six to nine billion years ago. ... Tweets that mention ESO finds weird doomed planet from another galaxy | ...

Image credit: Michael Nolan, Arecibo Observatory. These radar images of near-Earth asteroid 2001 SN263 were obtained on 2008 Feb 12 and 13. ... Image from Feb 12 . ... First near-Earth triple asteroid discovered by Arecibo Observatory . ... was discovered this week by astronomers at the sensitive radar telescope at Cornell University?s Arecibo Observatory in Puerto Rico. ... For example, Arecibo has discovered more than half of the near-Earth binary asteroid systems discovered since 1999. ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Co