Astronomy
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Scientists Now Know: We're Not From Here! Summary & comments by Dan Eden for Viewzone "This first full-sky map of Sagittarius shows its extensive interaction with the Milky Way," Majewski said. "Both stars and star clusters now in the outer parts of the Milky Way have been 'stolen' from Sagittarius as the gravitational forces of the Milky Way nibbled away at its dwarf companion. This one vivid example shows that the Milky Way grows by eating its smaller neighbors." The study's map of M giants depicts 2 billion years of Sagittarius stripping by the Milky Way, and suggests that Sagittarius has reached a critical phase in what had been a slow dance of death.
Scientists Now Know: We're From Sagittarius Dwarf Galaxy!
Asteroids, Meteors & Comets
"Cassini is indebted to Voyager for its many fascinating discoveries and for pavingthe way for Cassini," says Linda Spilker, Cassini project scientist at JPL, who started her career working on Voyager from 1977 to 1989. "On Cassini, we still compare our data to Voyager's and proudly build on Voyager's heritage." But the Voyager Mission left a few mysteries that Cassini has not yet solved. One of the most perplexing mysteries is Saturn's hexagpn. NASA scientists first spotted a hexagonal weather pattern when they stitched together Voyager images of Saturn's north pole. Cassini has obtained higher-resolution pictures of the hexagon – which tells scientists it's a remarkably stable wave in one of the jet streams that remains 30 years later – but scientists are still not sure what forces maintain the object.
The Unsolved Mystery of Saturn's Hexagon -4 Times the Size of Earth
Strongest evidence yet indicates Enceladus hiding saltwater ocean
This image shows icy spray spewing from Saturn's moon, Enceladus. Credit: NASA/JPL/Space Science Institute The new discovery was made during the Cassini-Huygens mission to Saturn , a collaboration of NASA, the European Space Agency and the Italian Space Agency. Launched in 1997, the mission spacecraft arrived at the Saturn system in 2004 and has been touring the giant ringed planet and its vast moon system ever since. The plumes shooting water vapor and tiny grains of ice into space were originally discovered emanating from Enceladus -- one of 19 known moons of Saturn -- by the Cassini spacecraft in 2005. The plumes were originating from the so-called "tiger stripe" surface fractures at the moon's south pole and apparently have created the material for the faint E Ring that traces the orbit of Enceladus around Saturn.
An oxygen atmosphere has been found on Saturn 's second largest moon , Rhea, astronomers announced Thursday—but don't hold your breath for colonization opportunities. For one thing, the 932-mile-wide (1,500-kilometer-wide), ice-covered moon is more than 932 million miles (1.5 billion kilometers) from Earth. For another, the average surface temperature is -292 degrees Fahrenheit (-180 degrees Celsius). And at less than 62 miles (100 kilometers) thick, the newfound oxygen layer is so thin that, at Earthlike temperatures and pressure, Rhea's entire atmosphere would fit in a single midsize building. Still, the discovery implies that worlds with oxygen-filled air may not be so unusual in the cosmos. (Related: "Potentially Habitable Planets Are Common, Study Says." )
Saturn Moon Has Oxygen Atmosphere
Artist concept of Cassini spacecraft. Image credit: NASA/JPL (PhysOrg.com) -- Scientists analyzing data from NASA's Cassini spacecraft now have the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth.
Tempest-from-hell seen on Saturn
The Sounds of Pulsars
A pulsar is a highly magnetised neutron star, with a radius of 10-15 km, having somewhat greater mass than the Sun which has a radius of approximately 1 million km. Radiation is beamed out along the magnetic poles and pulses of radiation are received as the beam crosses the Earth, in the same manner as the beam from a lighthouse causes flashes. Being enormous cosmic flywheels with a tick attached, they make some of the best clocks known to mankind. These sounds directly correspond to the radio-waves emitted by the brightest pulsars in the sky as received by some of the largest radio telescopes in the world.
Quark Star (update)
Some of the strange stuff that is coming out about quark stars: 1) that quark stars may be connected to dark matter (or even dark energy?) Some dark matter might just be “strangelets” roaming the cosmos, blasted free from quark stars: http://usat.ly/7q6vov or http://www.usatoday.com/tech/science/space/2009-12-07-quarkstar07_ST_N.htm
12 August 2011 Last updated at 10:09 GMT By Jason Palmer Science and technology reporter, BBC News TrES-2b is literally darker, on average, than coal A dark alien world, blacker than coal, has been spotted by astronomers. The Jupiter-sized planet is orbiting its star at a distance of just five million km, and is likely to be at a temperature of some 1200C. The planet may be too hot to support reflective clouds like those we see in our own Solar System, but even that would not explain why it is so dark. The research will be published in the journal Monthly Notices of the Royal Astronomical Society.
