Join our SkyWatch hosts for a weekly conversation that highlights news from the world of astronomy. Listen in via your computer or MP3 player as they bring the latest discoveries down to Earth. SkyWatch also includes HubbleWatch, a monthly round-up of news from NASA's Hubble Space Telescope.

Show 224: Asteroid Bombardment

June 18, 2009

An asteroid strikes Earth in this artist’s depiction. Credit: Don Davis/NASA
An asteroid strikes Earth in this artist’s depiction. Credit: Don Davis/NASA

Asteroids – were they a boon or bane when they struck Earth billions of years ago? One would think the period of bombardment was not a good thing for a planet! But a new study shows that the bombardment may actually have created environments where microbial organisms could have survived if they were already there. The study also suggests that such environments may have existed on other planets, such as Mars.

Show 223: Extreme Life

June 11, 2009

Astronaut Scott Parazynski on Mount Everest.
Astronaut Scott Parazynski on Mount Everest.

A former NASA astronaut is searching for signs of hardy life on Mount Everest, which could provide a window into extreme environments that organisms might inhabit on hostile-appearing planets elsewhere in universe. Scott Parazynski’s mission makes him the first astronaut to scale Mount Everests.

Show 222: HubbleWatch for May 2009

May 31, 2009

Astronomers capture an image of a star eight years before its explosive death, casting light on the development of supernovae. A jet of radiation and plasma caused by a black hole is starting to flicker. And recently developed techniques are being used on the Hubble archive to glean new information from old images.

Show 221: Mission to Hubble

June 4, 2009

Hubble after being released by the shuttle's robotic arm.
Hubble after being released by the shuttle's robotic arm.

The Hubble Space Telescope has been restored after the hugely successful servicing mission by the Space Shuttle Atlantis astronauts and the hundreds of personnel who work on Hubble at NASA and elsewhere. Two new instruments are onboard, two instruments were repaired, and the telescope received new batteries, gyroscopes, and a computer for handling the science data.

Show 220: Black Holes or Galaxies?

May 28, 2009

A graph shows the mass of galaxies versus the mass of their central black holes.
A graph shows the mass of galaxies versus the mass of their central black holes.

Astronomers may have solved the cosmic chicken-and-egg problem of which formed first in the early universe — galaxies or the supermassive black holes seen at their cores. Astronomers believe almost all galaxies have massive black holes at their centers, as well as smaller black holes sprinkled throughout. Evidence is piling up that black holes came first.

Show 219: The Search for Theia

May 21, 2009

An artist's depiction of one of the STEREO probes.
An artist's depiction of one of the STEREO probes.

The solar system might once have had another planet named Theia. Some researchers believe it existed 4.5 billion years ago and possibly collided with Earth to form our Moon. NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft are on their way to look for the debris that would be left over after such a collision.

Show 218: New Planet Sparks Curiosity

May 14, 2009

Artist's depiction of the Gliese 581 planetary system
Artist's depiction of the Gliese 581 planetary system

Astronomers have searched diligently for a planet of the size of Earth. Researchers would love to find such a planet in the zone appropriate for liquid water – what they call “the habitable zone.” New observations from the European Southern Observatory indicate that the star Gliese 581 has a fourth planet in addition to the known 3. The other planets are large “super earths” and one Neptune-sized planet. But the new planet is about twice the mass of Earth, and could be close to the habitable zone as well.

Show 217: Hubble's 19th Birthday

May 7, 2009

Hubble anniversary image of galaxy clusters 1E 0657-556.
Hubble anniversary image of galaxy clusters 1E 0657-556.

Hubble is celebrating its 19th anniversary by releasing new, beautiful images. One image shows a complex interaction of four galaxies in a group called Arp 194. This group’s numerous star clusters formed recently as a result of the galaxies’ gravitational interaction. A second image of two clusters of colliding galaxies, called 1E 0657-556, was also released for the birthday. The galaxies passed through one another, leaving large amounts of gas behind, in the center of the collision.

PODCASTING is a way of making audio broadcasts of all kinds available on the Internet. Listeners can either hear the show via the Web site or subscribe to the podcast to download it to a portable MP3 player. Our SkyWatch podcasts are free.

Carol Christian
& Jim O'Leary