Author Archives: Robert Zimmerman

New results from the Sloan Digital Sky Survey

From the second press conference at the AAS meeting today, results from the Sloan Digital Sky Survey, which has been surveying the sky in incredible detail over the past eleven years:

  • The largest digital color image of the heavens, covering one third of the sky, imaging a half a billion stars and galaxies. Despite looking the sky in wide-field view, the data also has incredible close-up detail. This has and will continue to provide astronomers a precise baseline reference for future research.
  • A 3D reconstruction of the local galactic neighborhood, showing the three dimensional position of the visible galaxies within a billion light years. They plan to use the new Sloan color image above to further extend this 3D reconstruction out to seven billion light years.
  • The largest map of the Milky Way’s outer regions, showing the streams of stars captured from other galaxies, absorbed in the past galactic mergers that formed the Milky Way.

All this data will be available for anyone to dig around in.


New discoveries by Planck

From the first press conference at the AAS meeting today, focused on recent discoveries from the European space telescope Planck:

  • has identified 10,000 cold spots in Milky Way, all believed to be places where stars will soon begin to form. They range widely in size, and are from 30 to 10,000 light years from us.
  • Planck’s all sky survey has found 189 giant galaxy clusters, 20 of which are newly discovered. “The largest gravitationally bound objects in the universe.” Very hot, filled with hot gas.

Fermi detects beams of antimatter produced above thunderstorms on Earth

More from the AAS meeting: The Fermi Gamma-Ray Space Telescope has detected beams of antimatter produced above Earth’s thunderstorms. Key quote:

Scientists think the antimatter particles were formed in a terrestrial gamma-ray flash, a brief burst produced inside thunderstorms and shown to be associated with lightning. It is estimated that about 500 such flashes occur daily worldwide, but most go undetected. . . . The spacecraft was located immediately above a thunderstorm for most of the observed terrestrial gamma-ray flashes. But, in four cases, storms were far from Fermi. In addition, lightning-generated radio signals detected by a global monitoring network indicated the only lightning at the time was hundreds or more miles away. During one flash, which occurred on Dec. 14, 2009, Fermi was located over Egypt. But the active storm was in Zambia, some 4,500 kilometers (2,800 miles) to the south.


Preliminary findings suggest that the Arkansas birds died from impact trauma

Preliminary findings from the USGS National Wildlife Health Center suggest that the mass bird die-off that occurred in Arkansas was from impact trauma. Key quote:

The State concluded that such trauma was probably a result of the birds being startled by loud noises on the night of Dec. 31, arousing them and causing them to fly into objects such as houses or trees. Scientists at the USGS NWHC performed necropsies—the animal version of an autopsy—on the birds and found internal hemorrhaging, while the pesticide tests they conducted were negative. Results from further laboratory tests are expected to be completed in 2-3 weeks.


Hanny’s Voorwerp: evidence of a quasar that has turned off

Hanny’s Voorwerp: a strange object near a galaxy that has baffled astronomers is now seen as a light echo from when the galaxy’s central quasar was still active. More importantly, this is evidence that the quasar went quiescent sometime in the last 70,000 to 200,000 years. For a quasar to turn off so quickly is a surprise for astronomers.


Kepler’s most recent discovery: A rocky Earthlike planet!

Bumped. Scroll down for updates!

From the abstract of Geoffrey Marcy’s talk today at 6:30 pm (Eastern) at this week’s meeting in Seattle of the American Astronomical Society:

The NASA Kepler Mission has discovered over 700 candidate planets, with most having diameters less than 5 times that of Earth and some as small as that of Earth. One planet has a radius, mass, and density in a new domain having no counterpart in our Solar System, opening a new chapter in planetary science. [emphasis mine]

A press conference is scheduled for 11 am (Eastern). Stay tuned!

Update I. A NASA press release just made public says that Kepler has discovered a rocky planet only 1.4 times the size of the Earth.

Kepler 10b [is] a rocky planet with a mass 4.6 times that of Earth and with an average density of 8.8 grams per cubic centimeter — similar to that of an iron dumbbell.

The press conference is ongoing, but the Kepler results are still to come.

Update II. The star the planet orbits, Kepler 10, is similar to our Sun in mass and size, but older, about 8 billion years old, and is 560 light years away. Kepler 10 is also a relatively bright star in the Kepler field of view, about 11 magnitude.

The planet’s orbit itself is only 8.4 days long. Its density, 8.8 grams per cubic centimeter, is 8.8 times greater than Earth’s. This data, based on all planet models, also suggests that the planet should be a rocky planet like the Earth, though heavier and larger with a surface gravity twice that of Earth.

Since the planet orbits so close to its sun, it is a scorched world, very hot. The scientists expect that it has no atmosphere. It is also probably tidally locked, with one side always facing its Sun.

Update III: Geoffrey Marcy, one of the world’s premier exoplanet scientists, is now commenting on these Kepler results, saying he considers this discovery “among the most profound discoveries in human history.”

Update IV: In answer to a press question, the scientists speculated that the planet might have formed as a gas giant farther from the star, then migrated inward and had its gas atmosphere stripped away. No one knows yet if this is true however.

Studies of further transits might learn more about the planet, such as the temperatures between its two hemispheres. As the planet orbits the star and its illuminated side comes into view, they can see the change in temperature and thus track it. Right now they think the sunlight side could be as hot as 2500 degrees Fahrenheit.

If you want to watch the press conference for yourself, they will be posting the video here.

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