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posted by Fnord666 on Monday June 25 2018, @03:11AM   Printer-friendly
from the I-disagree dept.

Nathan Myhrvold: 'Nasa doesn't want to admit it's wrong about asteroids'

Nathan Myhrvold is the former chief technology officer of Microsoft, founder of the controversial patent asset company Intellectual Ventures and the main author of the six-volume, 2,300-page Modernist Cuisine cookbook, which explores the science of cooking. Currently, he is taking on Nasa over its measurement of asteroid sizes.

For the past couple of years, you've been fighting with Nasa about its analysis of near-Earth asteroid size. You've just published a 33-page scientific paper [open, DOI: 10.1016/j.icarus.2018.05.004] [DX] criticising the methods used by its Neowise project team to estimate the size and other properties of approximately 164,000 asteroids. You have also published a long blog post explaining the problem. Where did Nasa go wrong and is it over or underestimating size?

Nasa's Wise space telescope [Wide-field Infrared Survey Explorer] measured the asteroids in four different wavelengths in the infrared. My main beef is with how they analysed that data. What I think happened is they made some poor choices of statistical methods. Then, to cover that up, they didn't publish a lot of the information that would help someone else replicate it. I'm afraid they have both over- and underestimated. The effect changes depending on the size of the asteroid and what it's made of. The studies were advertised as being accurate to plus or minus 10%. In fact, it is more like 30-35%. That's if you look overall. If you look at specific subsets some of them are off by more than 100%. It's kind of a mess.

[...] Nasa's reported response has been to stand by the data and the analysis performed by the Neowise team. Can we trust Nasa after this?

They need to have an independent investigation of these results. When my preprint paper came out in 2016, they said: "You shouldn't believe it because it's not peer-reviewed." Well, now it has been peer reviewed. How Nasa handles it at this stage will be very telling. People have suggested to me the reason Nasa doesn't want to admit that anything is wrong with the data is that they're afraid it would hurt the chances of Neocam, an approximately $500m (£380m) telescope to find asteroids that might hit Earth proposed by the same group who did the Neowise analysis.

Previously: Former Microsoft Chief Technologist Criticizes NASA


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  • (Score: 0) by Anonymous Coward on Monday June 25 2018, @05:03AM (1 child)

    by Anonymous Coward on Monday June 25 2018, @05:03AM (#697967)

    "Who gives a flying f about the absolute size of the asteroids? "
    People smarter than you.

    "All I care about is if NASA (or whoever) got the orbits right -- and if any are headed our way in the near future."
    Small asteroids will burn in the Earth's atmosphere so it does not matter if they is headed our way. So the size is important, not just for the smart people doing the "scientific stuff".

  • (Score: 0) by Anonymous Coward on Monday June 25 2018, @10:57AM

    by Anonymous Coward on Monday June 25 2018, @10:57AM (#698069)

    OK, I'll refine my rant -- based on this page (which also seems a little confused),
        https://www.jpl.nasa.gov/asteroidwatch/fastfacts.php [nasa.gov]

    ...
    Space rocks smaller than about 25 meters (about 82 feet) will most likely burn up as they enter the Earth's atmosphere and cause little or no damage.

    If a rocky meteoroid larger than 25 meters but smaller than one kilometer ( a little more than 1/2 mile) were to hit Earth, it would likely cause local damage to the impact area.

    We believe anything larger than one to two kilometers (one kilometer is a little more than one-half mile) could have worldwide effects. At 5.4 kilometers in diameter, the largest known potentially hazardous asteroid is Toutatis.
    ...

    If size estimates can be off by a factor of 2(?) then I'd like to know the orbits of anything that looks like ~12 meters or larger--those warrant further study.