Astronomy Picture Of the Day (APOD)M55: Globular Star Cluster
The fifty-fifth entry in Charles Messier's catalog, M55 is a large and lovely globular cluster of around 100,000 stars. Only 20,000 light-years away in the constellation Sagittarius, M55 appears to earth-bound observers to be nearly 2/3 the size of the full moon.
XZ Tauri System Ejects Gas Bubble
Why is the binary star system XZ Tauri emitting a hot bubble of expanding gas? Although astronomers can only presently speculate, the Hubble Space Telescope clearly documents this unusual behavior in three dramatic photographs over the past five years.
Gangly Spiral Galaxy NGC 3184
NGC 3184 is a large spiral galaxy with a small nucleus and long sprawling spiral arms. Although NGC 3184 contains hundreds of billions of stars, the blue color of its spiral arms comes mostly from relatively few bright young blue stars.
M17: Omega Nebula Star Factory
In the depths of the dark clouds of dust and molecular gas known as M17, stars continue to form. Visible in the above recently released representative-color photograph of M17 by the New Technology Telescope are clouds so dark that they appear almost empty of near infrared light.
Approaching the International Space Station
Last Monday the crew of Space Shuttle Atlantis took in this view as they approached the developing International Space Station (ISS). From top to bottom, the astronauts saw a station currently consisting of the Progress supply module, the Zvezda service module, the Zarya cargo module, and the Unity connecting module.
Girdling the second largest planet in the Solar System, Saturn's Rings are one of the most spectacular sights for earthbound telescopes. This image from the orbiting Hubble Space Telescope's STIS instrument, offers a striking view of another kind of ring around Saturn - pole encircling rings of ultraviolet aurora.
Above is a picture of the Earth in x-rays, taken in March of 1996 from the orbiting Polar satellite. Most of the planet is dark with superposed continent and coordinate grids, while the bright x-ray emission near the north pole is shown in red. Why does the Earth have an x-ray glow?
Aurora In West Texas Skies
The aurora borealis, or northern lights, are not a common sight in the southwestern United States. But a strong solar coronal mass ejection in early August triggered geomagnetic storms and aurora which were widely reported, even under west Texas skies.
M82 s Middle Mass Black Hole
Black holes are probably the most bizarre creatures in the modern astronomical zoo. And after years of pondering black holes as either stellar mass objects seen in binary star systems or enormous supermassive black holes at the centers of galaxies, astronomers now have strong evidence
Comet LINEAR: Fade To Black
Only last month the stage was set for Comet LINEAR (C/1999S4 LINEAR) to become the first "naked-eye" comet of Y2K. It didn't fill that role, of course, but it did turn in a very dramatic performance.