A movie of Triton made from Voyager 2’s fly-by 25 years ago
Using restored images taken by Voyager 2 when it flew past Neptune’s moon Triton 25 years ago, scientists have produced a new map and movie of the moon.
Tag: science
GAO report: Bergdahl hostage swap broke law
The law is such an inconvenient thing: A new GAO report concludes that the Obama administration broke the law when it exchanged five Taliban leaders for Bowe Bergdahl.
The weight of Comet 67P/C-G
Scientists, using radio and orbital data from Rosetta, have made their first estimate of the mass of Comet 67P/C-G.
For the Rosetta mission, this task comes under the umbrella of the Radio Science Investigation (RSI). Using 80 hours worth of tracking data between 6 August, since arriving at the comet, and up to 9 August, the RSI team made a first estimate of the comet’s mass as approximately 1×10^13 kg +/-10%, or about 10 trillion kilograms.
This is very much a preliminary number which will be refined significantly as the spacecraft continues its travels with the comet.
More here. This mass, when considered in conjunction with the nucleus’s size, suggests a very low density. If you could find an ocean large enough it would float.
Sea plankton on the outside of ISS
Russian scientists have found traces of sea plankton on the outside surface of the International Space Station.
The article is sadly lacking in many details, other than noting that the evidence suggests the organisms could live a long time in this harsh environment.
Posted en route to Spokane, Washington.
Curiosity retreats from Hidden Valley
Finding its sandy floor slipperier than expected, engineers have backed Curiosity out of Hidden Valley to drill some holes while they reassess the rover’s route.
The rover’s wheels slipped more in Hidden Valley’s sand than the team had expected based on experience with one of the mission’s test rovers driven on sand dunes in California. The valley is about the length of a football field and does not offer any navigable exits other than at the northeastern and southwestern ends. “We need to gain a better understanding of the interaction between the wheels and Martian sand ripples, and Hidden Valley is not a good location for experimenting,” said Curiosity Project Manager Jim Erickson of JPL. …
Curiosity reversed course and drove out of Hidden Valley northeastward. On the way toward gaining a good viewpoint to assess a possible alternative route north of the valley, it passed over the pale paving stones on the ramp again. Where a rover wheel cracked one of the rocks, it exposed bright interior material, possibly from mineral veins.
More and more, the journey to Mount Sharp appears to be increasingly adventurous for the rover.
Rosetta spirals in
The Rosetta science team has released a video and press release describing the upcoming maneuvers as it spirals into a close orbit of Comet 67P/C-G.
I’ve posted the video below the fold. If all goes well Rosetta will be circling the comet at a distance of about six miles come October 10.
» Read more
A brief history of USB
Link here.
The life story of a meteorite
A close analysis of a meteorite that landed on the roof of a California home have allowed scientists to traces its history from inception to Earth impact.
Did Stardust capture stardust?
Scientists now believe that the spacecraft Stardust captured seven particles from interstellar space during its seven year journey.
Inside the canister, a tennis racket-like sample collector tray captured the particles in silica aerogel as the spacecraft flew within 149 miles (about 240 kilometers) of a comet in January 2004. An opposite side of the tray holds interstellar dust particles captured by the spacecraft during its seven-year, three-billion-mile journey.
Scientists caution that additional tests must be done before they can say definitively that these are pieces of debris from interstellar space. But if they are, the particles could help explain the origin and evolution of interstellar dust. The particles are much more diverse in terms of chemical composition and structure than scientists expected. The smaller particles differ greatly from the larger ones and appear to have varying histories. Many of the larger particles have been described as having a fluffy structure, similar to a snowflake. [emphasis mine]
It appears that for these seven particles, the scientists conclude they are likely interstellar particles because of the speed in which they were traveling when captured as well as their make-up. Both suggest an origin outside the solar system.
However, we should be cautious about this. The data still remains tenuous and preliminary. More work obviously needs to be done to pin this down definitively. More information here.
Michael Mann’s court suit under attack
Good news: Groups from across the political spectrum are expressing their opposition to Michael Mann’s court suit against his critics.
On Monday, The Reporters Committee for the Freedom of the Press — along with 26 other groups including The Washington Post, Bloomberg and Fox News — filed an “amici curiae,” or “friend of the court,” brief with the D.C. Court of Appeals. An amici curiae is a brief submitted to a court to raise additional points of view to sway a court’s decision.
“While Mann essentially claims that he can silence critics because he is ‘right,’ the judicial system should not be the arbiter of either scientific truth or correct public policy,” the brief states, adding that “a participant in the ‘rough-and-tumble’ of public debate should not be able to use a lawsuit like this to silence his critics, regardless of whether one agrees with Mann or defendants.”
Just as Mark Steyn and Rand Simberg said it, I will say it also: Michael Mann is a fraud. He has no idea what it means to be a scientist, and should have been fired by his university after his climategate emails were uncovered. Instead, his university’s investigation was a whitewash and as much a fraud as Mann is.
67P/C-G in 3D
The Rosetta team, by taking two images seventeen minutes apart, have created a 3D image of Comet 67P/C-G.
You will need the red/blue filter glasses, but if you have them, take a look, it is quite cool.
It ain’t gravity holding this asteroid together
Astronomers have discovered that near Earth asteroid 1950DA is spinning so fast that gravity can’t hold it together. Instead, it is kept whole by cohesive forces called van der Waals forces, predicted but never detected before on an asteroid.
This is the coolest factoid from the article, however:
“We found that 1950 DA is rotating faster than the breakup limit for its density,” said Rozitis. “So if just gravity were holding this rubble pile together, as is generally assumed, it would fly apart. Therefore, interparticle cohesive forces must be holding it together.”
In fact, the rotation is so fast that at its equator, 1950 DA effectively experiences negative gravity. If an astronaut were to attempt to stand on this surface, he or she would fly off into space unless he or she were somehow anchored.
The important take away from this discovery is that it will be very easy to break this kind of asteroid up, turning a large and big threat into a collection of small but harmless rocks.