Slashdot Mirror
India and NASA to Explore Moon Together
hotsauce writes "NASA administrator Griffin on a visit to Indian space facilities in Bangalore has signed an agreement to explore the moon with the Indian Space Research Organization (ISRO). This agreement will see NASA instruments on a 2008 Indian moon mission, and further cooperation is being explored. An Indian paper has a different take on the visit. Interesting answer by Griffin on NASA outsourcing to ISRO."
Griffin said NASA was not looking to outsource some of its work to ISRO. NASA was looking to combine the resources both agencies to undertake ventures of mutual interest.
(Yeah, yeah, I know I'm enabling bad behavior, but slashdot needs all the help it can get.)
"I will take the Ring," he said, "though I do not know the way."
The summary author would have been more correct in linking to the following story rather than attempting to make commentary by selecting the link they did: http://sify.com/news/fullstory.php?id=14200860
It's not "another take" they link to, but rather "another story". Related, yes, but lets try a little harder (yes, it's slashdot, etc, etc but it doesn't hurt to try)
FYI: Roche limit does not apply for three reasons first the fragment is probably held together by chemical bonds not gravity and second on a near miss there is little time for such effects to take place. (Yes over time a glass of water will evaporate in a low humidity room but it take more than a few min for that to be significant.) And finally even where the fragment to break apart each fragment would continue more or less on the same path which would cause it to miss the earth.
.0098km/s/s = 0.00445km/s/s and that's tangential to it's path but it's passing the earth at that point so it makes little difference. Steeping back to 30,000 KM the object is accelerating at .00111km/s but most of that vector is not pulling the asteroid into a collision course. You can think of it as a large vector along it's path and a much smaller vector pulling it into a collision course. The further out you go the smaller the net force and the smaller the fraction that's pulling the object into a collision course.
As to why you ignore the earth's gravity in all but the closest near miss: With a V relative of 15km(km/s) and a distance of 15,360 KM the object is being accelerated by a force of (12,756.3/(12,756.3+15,360)) *
Earth's gravity is important when you want to know how the object is being deflected but it does little to alter the probability of impact for objects with a high relative velocity.
PS: Feel free to calculate the two vectors at 30,000KM and 60,000KM on a near miss.
(Now with line breaks...)