NASA Accused Of Flawed Asteroid Mission By Former Microsoft Executive
NASA has reportedly been accused of underestimating the size of asteroids, indicating there are dangers of large asteroids striking the planet. The accusations were made by Dr Nathan Myhrvold, a former Microsoft executive who is also a billionaire techie and amateur asteroid hunter among other things. Myhrvold used NASA's own data to conclude that the space agency's Wide-field Infrared Survey Explorer (WISE) space telescope had underestimated the sizes of over 157,000 asteroids by as much as 100 percent.
Launched in December 2009 by NASA, WISE is an infrared wavelength astronomical space telescope that was later put on a sabbatical in February 2011. The telescope was reactivated to carry out a four month mission termed NEOWISE to search for asteroids, comets and other such Near Earth Objects (NEO). The mission took the help of heat data to measure the size and reflectivity of 157,000 asteroids. Incidentally, reflectivity of an asteroid denotes how easily it can be spotted.
Myhrvold, interestingly, is not debating whether NASA has overlooked threats from the known asteroids; rather he has argued whether the teams of researchers know as much as they think they do. Myhrvold criticized the WISE and NEOWISE teams on their wrong calculations of asteroid sizes in a paper that he wrote. The techie accused the NEOWISE results of being full of bad statistics and analysis. "The bad news is it's all basically wrong," Nathan Myhrvold said. "Unfortunately for a lot of it, it's never going to be as accurate as they had hoped. None of their results can be replicated. I found one irregularity after another". Furthermore, NEOWISE's data was said to be "very funky, ad hoc, invalid set of statistical analyses", implying a flawed mission.
Earlier, in 2011, the WISE and NEOWISE teams had maintained that calculations of an asteroid's diameter are often within 10 percent of the actual size. However, Myhrvold puts in the argument that the accuracy for calculating asteroid diameters should be 30 percent and not merely 10. He further suggested that some of the errors in size estimation could be as much as 100 percent. In addition, according to a report, the former Microsoft exec felt that NASA ignored the margin of error that is a result of extrapolating a small sample size, as well as neglected to pay attention to Kirchhoff's law of thermal radiation in their asteroid thermal models.
At the moment, representatives from NASA have maintained that the issues being taken up by Myhrvold will be best addressed by experts who are peer reviewing his paper. Moreover, the contents of Myhrvold's paper were deemed as "overly simplistic" with assumptions that were not valid.