***What is it?
Patrick Wiggins, NASA solar system ambassador to Utah, recently photographed the close approach of a newly-discovered object in space. The object, designated “2010 AL30,” probably is an asteroid but could be a piece of a rocket that flew to Venus years ago.
It’s strange because its orbit is one year, just like Earth’s. Its peculiar path through the solar system led to the speculation that it might be a rocket stage.
Nobody is sure what it is, though NASA leans toward the asteroid theory.
Space.com quoted NASA researchers as saying the object is about 36 feet long and that it passed 80,000 miles from the Earth at its closest approach on Jan. 13. That’s merely a third of the distance to the moon.
Wiggins took 75 photographs of it through his telescope, each 1 second long, and compiled them into a short movie. Temporarily, the movie is posted HERE.
A mystery about the strange moon Enceladus may be solved.
Enceladus, one of Saturn’s flock of 60-plus moons, stunned scientists in November 2005 when the Cassini probe photographed it and discovered vast geysers of ice particles spewing out of the satellite. A backlit view shows sprays forming a monster jet almost as wide as the moon and reaching more than the moon’s diameter into space. The material erupts from “tiger stripe” markings on the icy surface of Enceladus (pronounced en-SELL-a-dus) and a great ring of this material, which may include dust, extends along its orbit.
[Ice particles blast into space from Enceladus, in this view by Cassini. Photo credit: NASA/JPL/Space Science Institute]
During an earlier pass by Enceladus, Cassini took temperature readings showing that parts of the moon’s “tiger stripes” were remarkably warmer than the rest of the moon. The “tiger stripes” are where material is erupting.
Why was this happening? How long could it continue? If the small moon, only 153 miles across, kept this up for a few hundred million years, would it become depleted?
Another mystery is that the south pole region, where the geysers are at work, has a much younger surface than the rest of Enceladus. It’s less than 100 million years while the surface at the northern sector is believed to be 4.2 billion years old.
By July 2009, NASA had concluded that liquid water “could exist in a deep layer as an ocean or sea and also near the surface.” Beneath the sea was rock; ice formed above the water.
The latest findings, made after Cassini had visited Enceladus repeatedly, were released on Jan. 11. A NASA press release says blobs of warm ice periodically float through the colder ice, rising to the surface to “churn the icy crust” of the moon.
Warmer ice blobs, just above freezing, rise like gigantic “bubbles” of magma beneath an Earthly volcano. When they reach the surface they erupt.
The space agency quotes Francis Nimmo, a planetary scientist at the University of California, Santa Cruz, “Cassini appears to have caught Enceladus in the middle of a burp.
“These tumultuous periods are rare and Cassini happens to have been watching the moon during one of these special epochs.”
So this is not a continuous phenomenon that will empty Enceladus someday.
“The model fits the activity on Enceladus when the churning and resurfacing periods are assumed to last about 10 million years, and the quiet periods, when the surface ice is undisturbed, last about 100 million to two billion years. Their model suggests the active periods have occurred only 1 to 10 percent of the time that Enceladus has existed and have recycled 10 to 40 percent of the surface,” says the release, written by Jia-Rui C. Cook of the Jet Propulsion Laboratory, Pasadena.
NASA says the latest study does prove the churning and the resultant resurfacing to the fissures and jets are linked. But it does show why the south polar region of Enceladus seems so young.
What heats the moon’s interior? NASA isn’t saying for now. But it notes that Cassini found the south polar region to be “swiftly expelling argon, which comes from rocks decaying radioactively …”
Radioactive decay is believed to keep Earth’s interior molten, and another NASA release points out that a bacterial ecosystem found in a mine deep under south Africa is powered by energy released through the radioactive decay of rock.