Saturday, July 9, 2011

NASA Envisions Alien Worlds

NASA/JPL-Caltech/R. Hurt (SSC-Caltech)

Out of the Dust, a Planet is Born
In this artist's conception, a possible newfound planet spins through a clearing, detected around the star CoKu Tau 4 by the Spitzer Space Telescope, in a nearby star's dusty, planet-forming disc. The possible planet is theorized to be at least as massive as Jupiter, and may have a similar appearance to what the giant planets in our own solar system looked like billions of years ago.


NASA/JPL-Caltech
NASA/JPL-Caltech
This Planet Smells Funny
Giant planet GJ 436b in the constellation Leo is missing something--and that something is swamp gas. To the surprise of astronomers who have been studying the Neptune-sized planet using NASA's Spitzer Space Telescope, GJ 436b has very little methane--an ingredient common to many planets in our own solar system. This artist's concept shows the unusual, methane-free world partially eclipsed by its star.Models of planetary atmospheres indicate that any world with the common mix of hydrogen, carbon and oxygen, and a temperature up to 1,000 Kelvin (1,340 degrees Fahrenheit) should have a large amount of methane and a small amount of carbon monoxide. But at about 800 Kelvin (or 980 degrees Fahrenheit), GJ 436b it does not. The finding demonstrates the diversity of exoplanets and the need for further study.

ESA/C.Carreau
ESA/C.Carreau
Steaming Hot Planet
This artist's impression shows a gas-giant exoplanet transiting across the face of its star. Infrared analysis by NASA's Spitzer Space Telescope of this type of system provided the breakthrough.The planet, HD 189733b, lies 63 light-years away in the constellation Vulpecula. It was discovered in 2005 as it transited its parent star, dimming the star's light by some three percent.
 
NASA/JPL-Caltech/Harvard-Smithsonian CfA
NASA/JPL-Caltech/Harvard-Smithsonian CfA
Fantastic Four Galaxies with Planet
This artist's concept shows what the night sky might look like from a hypothetical planet around a star tossed out of an ongoing four-way collision between big galaxies (yellow blobs). NASA's Spitzer Space Telescope spotted this "quadruple merger" of galaxies within a larger cluster of galaxies located nearly 5 billion light-years away.Though the galaxies appear intact, gravitational disturbances have caused them to stretch and twist, flinging billions of stars into space, nearly three times as many stars as are in our Milky Way galaxy. The tossed stars are visible in the large plume emanating from the central, largest galaxy. If any of these stars have planets, their night skies would be filled with the monstrous merger, along with other galaxies in the cluster (smaller, bluish blobs).This cosmic smash-up is the largest known merger between galaxies of a similar size. While three of the galaxies are about the size of our Milky Way galaxy, the fourth (center of image) is three times as big. All four of the galaxies, as well as most other galaxies in the huge cluster, are blob-shaped ellipticals instead of spirals like the Milky Way.Ultimately, in about one hundred million years or so, the four galaxies will unite into one. About half of the stars kicked out during the merger will fall back and join the new galaxy, making it one of the biggest galaxies in the universe.
 
NASA/ESA/G. Bacon(STScI)
NASA/ESA/G.Bacon(STScI)
Exoplanet HR 8799b
This is an artistic illustration of the giant planet HR 8799b.The planet was first discovered in 2007 at the Gemini North observatory. It was identified in the NICMOS archival data in a follow-up search of NICMOS archival data to see if Hubble had also serendipitously imaged it.The planet is young and hot, at a temperature of 1500 degrees Fahrenheit. It is slightly larger than Jupiter and may be at least seven times more massive. Analysis of the NICMOS data suggests the planet has water vapor in its atmosphere and is only partially cloud covered. It is not known if the planet has rings or moons, but circumplanetary debris is common among the outer planets of our solar system.
 
NASA/JPL
NASA/JPL
Chemical Soups Around Cool Stars
This artist's conception shows a young, hypothetical planet around a cool star. A soupy mix of potentially life-forming chemicals can be seen pooling around the base of the jagged rocks. Observations from NASA's Spitzer Space Telescope hint that planets around cool stars - the so-called M-dwarfs and brown dwarfs that are widespread throughout our galaxy - might possess a different mix of life-forming, or prebiotic, chemicals than our young Earth.

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