Skip to comments.Distant planetoid Sedna gives up more secrets
Posted on 04/15/2005 11:23:49 PM PDT by LibWhacker
The distant planetoid Sedna appears to be covered in a tar-like sludge that gives it a distinctly red hue, a new study reveals. The findings suggests the dark crust was baked-on by the Sun and has been untouched by other objects for millions of years.
Sedna appears to be nearly the size of Pluto and was discovered in November 2003. It is the most distant object ever seen within the solar system and travels on an elongated path that stretches from 74 to 900 times the distance between the Sun and the Earth.
Astronomers have struggled to explain such an extreme orbit, but many believe a star passing by the Sun about 4 billion years ago yanked the planetoid off its original, circular course.
Now, observations by the same team that discovered Sedna suggest the object has since led an uneventful life. Infrared spectra taken with the Gemini Observatory in Hawaii show the surface of the planetoid contains little methane ice, found in significant amounts on Pluto, and little water ice, seen on Plutos moon, Charon. Hydrocarbon sludge
Chad Trujillo, the team's lead researcher at the Gemini Observatory, says collisions with other objects may have helped expose the icy interiors of Pluto and Charon and believes a lack of collisions might explain Sedna's ice-free surface.
He says Sedna, which is probably made up of an equal mixture of ice and rock, may be covered with a metre or so of hydrocarbon sludge. This sludge is produced when the Sun's ultraviolet radiation and charged particles alter the chemical bonds between atoms in the ice.
"You just get this big tangle of carbon and hydrogen bonds, which turns the surface dark like asphalt or tar," he told New Scientist. A similar "space weathering" process occurs on a 200-kilometre-wide object called Pholus, which lies near Saturn and is also very red. Less crowded environment
Scott Gaudi, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US, says the new work supports previous theories showing Sedna evolved in a more distant, less crowded environment than Pluto and Charons. "Maybe it was lifted to its higher orbit early on and lived out there for a long time," he says.
But Gaudi recently discovered that, in at least one way, Sedna appears more conventional than previously thought. When Sedna was discovered, astronomers used a 1.3-metre telescope to observe the planetoid's period of rotation, concluding it rotated once every 20 days - an abnormally slow rate which they attributed to the gravitational tugs of a moon. But in March 2004, the mystery deepened when the Hubble Space Telescope failed to detect any moon.
Now, Gaudi and colleagues have taken more than 140 images of Sedna with a 6.5-metre telescope and found that actually Sedna rotates once every 10 hours. "Most things in the solar system rotate with periods of 10 hours or less, so this is what youd expect," says Gaudi.
The study by Trujillo and colleagues will be published in an upcoming issue of the Astrophysical Journal.
If Pluto is a planet, denying Sedna its planetary rights is gross injustice
Now, observations by the same team that discovered Sedna suggest the object has since led an uneventful life.
At least Sedna hasn't been yanked around for a while and enjoys an uneventful life now. I felt better about Sedna until I read:
He says Sedna, which is probably made up of an equal mixture of ice and rock, may be covered with a metre or so of hydrocarbon sludge.
I know it's George Bush's fault that Sedna is covered with about 3 ft of sludge, but that's life in this solar system.
With the price of gas being what it is, I'm glad we're discovering more objects in the solar system that are covered with hydrocarbon sludge. Now we just have to give Halliburton the contract to retrieve it.
Drilling? Don't be silly, you skim it off the top. Think of a hydrocarbon 7-ll Slurpy. Of course, the 7-ll would be about 8 billion miles away....:)
In re to Sedna, perhaps it's originally a member of the OX/IX globular clusters that orbit further out, and send killer comets into the inner solar system every 26 million years, as they pass THROUGH each other(on nearly identical orbits). 65 million years ago(dino-whacking asteroid)is 2 1/2 cycles ago. At least Brian Marsden thinks it(OX/IX)is a plausible explanation...
One yard thick, covering a planetoid with a what circumference. How many years worth of oil is that? No environmental concerns, off-planet harvesting, what's not to like?
You got it wrong. No drilling is required.
Think Eastern Kentucky...... think strip mining
The landscape will be destroyed!!!
Of course Pluto's status as a planet is still hotly debated. It could be a while before Sedna is properly renamed after a Roman or Greek diety.
Obscure, but Interesting Bump.
Pluto is called a planet only because of tradition.
Oops! I just now detected the barb. Poor Sedna low self esteem. It will probably become a rogue.
Sounds like some of the stuff on the bottom of my oven.
...followed by a
Note: this topic is from 4/15/2005. Thanks LibWhacker.
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