Astronomy Picture Of the Day (APOD)Global Warming Predictions
How much will the Earth's surface warm up over the lives of our children? No one is sure. Compared to the past 100 million years, the Earth is currently enduring a relative cold spell, possibly about four degrees Celsius below average.
Flowing Barchan Sand Dunes on Mars
When does Mars act like a liquid? Although liquids freeze and evaporate quickly into the thin atmosphere of Mars, persistent winds may make large sand dunes appear to flow and even drip like a liquid.
The View Near a Black Hole
In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes.
NGC 1333 Stardust
NGC 1333 is seen in visible light as a reflection nebula, dominated by bluish hues characteristic of starlight reflected by dust. A mere 1,000 light-years distant toward the heroic constellation Perseus, it lies at the edge of a large, star-forming molecular cloud.
Medieval Astronomy from Melk Abbey
Discovered by accident, this manuscript page provides graphical insight to astronomy in medieval times, before the Renaissance and the influence of Nicolaus Copernicus, Tycho de Brahe, Johannes Kepler, and Galileo. The intriguing page...
Castle and Full Moon
Clouds couldn't hide this bright Full Moon as it rose last week over the medieval castle of Tourrette-Levens near Nice, France. Exactly full on April 9 at 1456 UT, it followed the March equinox, making it the first Full Moon of spring in the north and autumn in the southern hemisphere.
Jagged Shadows May Indicate Saturn Ring Particles
What's causing unusual jagged shadows on Saturn's rings? No one is yet sure. As Saturn nears equinox, its rings increasingly show only their thin edge to the Earth and Sun. As a result, Saturn's moons now commonly cast long shadows onto the rings.
M101: The Pinwheel Galaxy
Why do many galaxies appear as spirals? A striking example is M101, shown above, whose relatively close distance of about 27 million light years allow it to be studied in some detail. Recent evidence...
M39: Open Cluster in Cygnus
Lying just at the limit of human perception is a picturesque starfield containing one of the larger open clusters on the northern sky. Spanning an angle larger than the Moon, M39's relatively few stars lie only about 800 light years distant toward the constellation of Cygnus.
The Big Picture
Intricate, glowing nebulae that shine in planet Earth's night sky are beautiful to look at in deep images made with telescopes and sensitive cameras. But they are faint and otherwise invisible to the naked-eye. That makes their relative location and extent on the sky difficult to appreciate.