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Show 332: Asteroid Trailing Earth
May 5, 2011
The solar system contains many small objects in addition to the well-known planets, moons and large asteroids. Some of these objects linger around the planets, and Earth has its own collection. Astronomers recently discovered a new member of this group, an asteroid with an orbit almost identical to Earth’s orbit around the Sun. Due to gravitational perturbations caused by Earth, the asteroid drifts slightly in its orbit, so relative to Earth and the Sun it appears to be in a “horseshoe” shaped orbit. These orbits are very rare, and only a few were previously known.
Show 331: Titan Rain
April 28, 2011
For the first time, scientists have captured signs of rain appearing on Saturn’s giant moon, Titan, at latitudes close to the equator, where conditions have been dry for years. At Titan’s frigid temperatures, the precipitation that descends is not water rain, but methane rain.
Show 330: HubbleWatch for April 2011
April 25, 2011
A strange green blob creeps up on an unsuspecting galaxy. And Hubble monitors a cosmic explosion unlike anything ever seen before.
Show 329: Odd Explosion
April 21, 2011
NASA’s SWIFT satellite is very productive at detecting blasts of gamma ray radiation from stars and black holes. Recently it detected an unusual explosion. The mystery explosion was more energetic and lasted longer than other such blasts. Astronomers used many telescopes, including the CHANDRA X-ray Observatory and the Hubble Space Telescope, to study the object. Is it a star being ripped apart by a supermassive black hole in the center of a galaxy?
Show 328: Messenger Orbits Mercury
April 14, 2011
NASA’s Messenger spacecraft became the first spacecraft to enter orbit around the planet Mercury on March 17, 2011. It could help solve a number of lingering mysteries about this sweltering world close to the Sun.
Show 327: Eclipse Shadows
April 7, 2011
REBROADCAST — Solar eclipses come in several varieties and provide spectacular views for observers on the Earth. As the Moon moves between the Earth and the Sun, the Moon’s shadow is cast into space. Sometimes this shadow intersects the Earth. Eclipses can be total, when the Moon completely obscures the Sun; grazing, when the Moon only covers part of the Sun; and annular, when the Moon and Sun are aligned, but the Moon does not cover the Sun completely. Eclipse shadows are visible to satellites that observe the Earth. In some cases, the images are quite spectacular, and show the path of the eclipse across the planet.
Show 326: Steppenwolf Planet
March 31, 2011
Most of the searches for planets that could support life are focused on looking at stars. For life to form and survive, at least water-based life, the planet needs to be at a particular location in proximity to its star so that the temperature is just right. New computer simulations suggest that life might actually survive on a “rogue planet” that has been ejected from its planetary system through gravitational interaction with other planets. With a blanket of ice and geothermal heating, life on such a wandering planet might exist…. For a while.
Show 325: Explosive Eta Carinae
March 24, 2011
A new image from Chile’s Gemini Observatory shows previously hidden details at the center of the unstable Eta Carinae star system. The high-resolution view begins to reveal the secrets of the star system’s outburst in 1843, when it became the second brightest star in the sky.
