Antarctic Ozone Hole Widens
It's back, and it's bigger than ever. The ozone hole that has been a cause of concern in recent years has again reformed over Earth's South Pole. The seasonal recurrence of the ozone hole was expected, although the size of the hole has never ...
White Dwarf Stars Cool
Diminutive by stellar standards, white dwarf stars are also intensely hot ... but they are cooling. No longer do their interior nuclear fires burn, so they will continue to cool until they fade away. This Hubble Space Telescope image covers a ...
X-Ray Moon and X-Ray Star
An x-ray star winks out behind the Moon in these before (left) and after views of a lunar occultation of the galactic x-ray source designated GX5-1. The false color images were made using data from the ROSAT (ROentgen SATellite), orbiting ...
Andromeda Island Universe
How far can you see? The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy some two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous ...
IC 418: The Spirograph Nebula
What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing tool, planetary nebula IC 418 shows patterns that are not well understood. Perhaps they are related to chaotic ...
CFHT Star Trails
High atop a dormant volcano in Hawaii, an eye 3.6-meters wide stares at a faint light on the night sky. Unlike a human eye, which collects light for only a fraction of a second at a time, a telescope such as the Canada-France-Hawaii Telescope ...
Aurora Persei
Last month, skywatchers were treated to an unexpected coincidence: bright aurorae occurred during the Perseid Meteor Shower. The above picture was taken August 12 and captures eerie looking aurorae and a faint Perseid meteor above Cross Lake in ...
Henrietta Leavitt Calibrates the Stars
Humanity's understanding of the relative brightness and variability of stars was revolutionized by the work of Henrietta Swan Leavitt (1868-1921). Working at Harvard College Observatory, Leavitt precisely calibrated the photographic magnitudes ...
X-Ray Moon
This x-ray image of the Moon was made by the orbiting ROSAT (Röntgensatellit) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray ...
SOHO Sungrazer
SOHO, the space-based SOlar and Heliospheric Observatory, has become by far the reigning champion facility for discovering comets, its total having recently reached 200. As might be expected of a solar observatory, most of the SOHO discovered ...
