Giant spiral galaxies such as Andromeda and the Milky Way outshine and outweigh most of their galactic peers. They grew so large both by swallowing lesser galaxies and by grabbing gas from the space around them. New observations of exotic “tadpole” galaxies are shedding light on how the Milky Way assembled its most luminous component: the starry disk that is home to the sun and Earth.

First spotted in the 1990s, tadpole galaxies sport bright heads, which spawn brilliant new stars, and long, faint tails. Most tadpoles are billions of light-years distant, meaning they were more common when the universe was young. From such great distances, though, studying the odd galaxies is difficult.

Thus, Jorge Sánchez Almeida of the Astrophysics Institute of the Canary Islands and his colleagues scrutinized seven rare tadpoles that happen to lie much closer, within 600 million light-years of Earth. Analyzing light from telescopes on the island of La Palma, the astronomers determined the speeds of different parts of each galaxy, demonstrating that most of the tadpoles rotate, just as the disks of spiral galaxies do.

via “Tadpole” Galaxies Offer Snapshots of the Milky Way’s Youth: Scientific American.

NASA’s Curiosity rover reaches out in ‘handshake’ like gesture to welcome the end of solar conjunction and resumption of contact with Earth. This mosaic of images was snapped by Curiosity on Sol 262 (May 2, 2013) and shows her flexing the robotic arm with dramatic scenery of Mount Sharp in the background. Two drill holes are visible on the surface bedrock below the robotic arm’s turret where she discovered a habitable site.
Credit: NASA/JPL-Caltech/Ken Kremer-(kenkremer.com)/Marco Di Lorenzo

NASA’s Curiosity rover has reached out in a Martian ‘handshake’ like gesture welcoming the end of solar conjunction that marks the resumption of contact with her handlers back on Earth – evidenced in a new photo mosaic of images captured as the robot and her human handlers contemplate a short traverse to a 2nd drilling target in the next few days.

“We’ll move a small bit and then drill another hole,” said John Grotzinger to Universe Today. Grotzinger, of the California Institute of Technology in Pasadena, Calif., leads NASA’s Curiosity Mars Science Laboratory mission.

The rover science team and Grotzinger have selected that 2nd drill location and are itching to send the rover on her way to the bumpy spot called “Cumberland.”

via Universe Today — Space and astronomy news.

NASA’s Hubble Space Telescope has found the building blocks for Earth-sized planets in an unlikely place– the atmospheres of a pair of burned-out stars called white dwarfs.

These dead stars are located 150 light-years from Earth in a relatively young star cluster, Hyades, in the constellation Taurus. The star cluster is only 625 million years old. The white dwarfs are being polluted by asteroid-like debris falling onto them. Hubble’s Cosmic Origins Spectrograph observed silicon and only low levels of carbon in the white dwarfs’ atmospheres. Silicon is a major ingredient of the rocky material that constitutes Earth and other solid planets in our solar system. Carbon, which helps determine properties and origin of planetary debris, generally is depleted or absent in rocky, Earth-like material.

“We have identified chemical evidence for the building blocks of rocky planets,” said Jay Farihi of the University of Cambridge in England. He is lead author of a new study appearing in the Monthly Notices of the Royal Astronomical Society. “When these stars were born, they built planets, and there’s a good chance they currently retain some of them. The material we are seeing is evidence of this. The debris is at least as rocky as the most primitive terrestrial bodies in our solar system.”

via NASA – NASA’s Hubble Space Telescope Finds Dead Stars ‘Polluted with Planet Debris.