Astronomy Picture Of the Day (APOD)Galileo, Cassini, and the Great Red Spot
Imagine a hurricane that lasted for 300 years! Jupiter's Great Red Spot indeed seems to be a giant hurricane-like storm system rotating with the Jovian clouds. Observed in 1655 by Italian-French astronomer Jean-Dominique Cassini it is seen here over 300 years later - still going strong - in a mosaic of recent Galileo spacecraft images.
The Hydra Cluster of Galaxies
You are flying through space and come to ... the Hydra Cluster of Galaxies. Listed as Abell 1060, the Hydra Cluster contains well over 100 bright galaxies. Clusters of galaxies are the largest gravitationally-bound objects in the universe.
A Violet Moon
Checking out the Galileo spacecraft's cameras during its December 1992 flyby of Earth's Moon, controllers took this dramatically illuminated picture through a violet filter. The view looks down on the Moon...
Tonight: A Blue Moon
How often does a Full Moon occur twice in a single month? Exactly once in a Blue Moon. In fact, the modern usage of the term "Blue Moon" refers to the second Full Moon in a single month. Tonight's Blue Moon (Universal Time) will be the first since September 1993.
A Dust Jet From Hale-Bopp
Approaching the inner Solar System, comet Hale-Bopp's icy nucleus is heated by sunlight, accelerating its production of dust and gas. Shrouded in the resulting cloud, known as the coma, the cometary nucleus remains hidden from direct view.
Huck Finn's New Sky View
Huck Finn's New Sky View Credit : R. Williams, The HDF Team (STScI), NASA
Driving to the Sun
How long would it take to drive to the Sun? Brittany, age 7, and D.J., age 12, ponder this question over dinner one evening. James, also age 7, suggests taking a really fast racing car while Christopher, age 4, eagerly agrees.
The Cygnus Loop
15,000 years ago a star in the constellation of Cygnus exploded -- the shockwave from this supernova explosion is still expanding into interstellar space! The collision of this fast moving wall of gas with...
Hale-Bopp on Schedule
Late March and early April of 1996 marked a banner season for viewing the spectacular naked-eye comet Hyakutake. The spring of 1997 could well offer a similar cometary wonder, Comet Hale-Bopp. Discovered last year while approaching the inner solar sytem Hale-Bopp has been eagerly watched for signs that it will indeed brighten spectacularly.
COMPTEL Explores The Radioactive Sky
Diffuse gas clouds laced with radioactive aluminum atoms (Al26) line the plane of our Milky Way Galaxy! How do we see them? Relying on the Compton Effect, the COMPTEL instrument onboard NASA's immense orbiting Compton Gamma Ray Observatory can "see" the 1.8 million electron Volt gamma rays emitted by the radioactive decay.