This Study Criticizing Nasa’s “Bad Science” About Asteroids Is Pretty Bad Science
Myhrvold’s paper, which he uploaded, is 110 pages long and has yet to go through the peer review process – where a study is vetted by experts unaffiliated with the research before publication. . He analyzed results from NASA’s Wide-Field Infrared Survey Explorer (WISE) spacecraft, which has been in operation since 2009 and can read the heat signatures of asteroids likely to approach Earth. A mission called NEOWISE translates that thermal data into size estimates using empirical models — mathematical models based on things scientists have observed on individual asteroids.
Myhrvold says his study completely debunks the statistical methods used by NASA scientists to estimate the size of asteroids in the NEOWISE mission. They say he has no idea what he’s talking about. In fact, a Nasa statement claims that Myhrvold made such profound miscalculations that he produced particularly incorrect size estimates for asteroids that have already been verified using other methods.
“For every mistake I found in his paper, if I got a bounty, I’d be rich,” Ned Wright, lead researcher at WISE at the University of California, told Science Magazine.
“If they really digest everything and say it’s not strong, I’m all ears for how I can make it stronger, but I guess that’s just dismissive,” Myhrvold told the Post. Myhrvold views the field of astrophysics as dangerously closed to the outside world. He says some of the “most experienced people working on asteroids” have told him privately that they can’t replicate the results he criticizes, but no one wants to upset the status quo.
“The fact that I’m independent and outside of the establishment makes it easier for me to challenge these things,” he said.
Amy Mainzer, Principal Investigator for NEOWISE, pointed out that many of the measurements from her projects have in fact been replicated and confirmed. Japan recently operated an infrared telescope called Akari, similar to WISE, and it measured many of the same asteroids.
“There’s a really good newspaper out there that does a really good job of comparing these size estimates,” Mainzer told the Post. “Everyone makes their own calculation and the diameters match.”
Not to mention that his work has been peer-reviewed, unlike Myhrvold’s. Experts checked his work for obvious errors, and he cannot say the same.
“Science is a human process, and it is true that human beings review these results, but peer review is a scientist’s best friend,” she said. “It has its bumps and bumps, but the science is interactive and peer review is what makes it strong. It’s the foundation of science.”
Myhrvold submitted his article for review in the journal Icarus, but it has not yet been accepted. He stands by his decision to put it online — and sit down with The New York Times — before getting that stamp of approval from the scientific community.
“Some of the things I’ve heard from third parties are, ‘wow, we’ll see if this goes through peer review’, which makes me think they’re going to ambush it in the review by peers,” Myhrvold said. He added that he had been trying to get WISE scientists to comment on his work for months, but they had refused to respond until he made his work public. Mainzer disputes this, saying she offered corrections to the document that Myhrvold ignored, including a glitch he considers a possible sign of fraud.
“In more than 100 cases, the reported asteroid sizes matched the previous articles exactly, i.e. within the metre. It’s just not possible for this to happen accidentally,” he said. declared.
“The points about peer reviewing my paper are totally valid when what I’m doing suggests something totally new,” he added, “but where I’m pointing out they’ve copied a lot of data from other sources, it’s not about me, it’s about them.”
He said he had no way of knowing if it was a sign of intentional fraud, but he believed it was possible.
“We tried to explain this many times,” Mainzer said. These measurements, she continued, are intentionally taken from other sources — they are used to calibrate measurements made using the spacecraft with previously observed data. This is not an error or fraud, but standard procedure.
It also challenges the underlying thesis of the review, that NEOWISE’s calculations ignore Kirchhoff’s law of thermal radiation. The law says that objects that are brighter emit less infrared radiation, and Myhrvold was shocked to see this ignored in the modeling. From the New York Times:
“A simple demonstration of this, Dr. Myhrvold said, is the shiny chrome cooking surface of a restaurant hibachi grill. A dark grill surface would bathe diners in waves of uncomfortable heat. NEOCAM models do not have taken into account the effects of reflected sunlight, he said.”
“Of course, this model doesn’t conserve energy perfectly, and nobody ever said it was,” Mainzer said. The model, she explains, sweeps away some of the complexities of an asteroid’s heat distribution to compensate for the fact that asteroids have incredibly complex surfaces. Scientists using these models don’t have all the data points they would need to perform a perfect calculation, and that’s the whole point of using the model in the first place.
“The journal is fundamentally useless in the sense that it complains about a model that has always been clear to not satisfy physical laws,” Ned Wright told the Post. “So the question is, does it work, is it a good approximation anyway, and the answer to that seems to be generally yes.”
A model that took into account all of this additional, usually unknown data would produce more accurate measurements, Wright said, but Myhrvold’s paper does not.
“What he did was change one of the ways he doesn’t satisfy physical laws, and I don’t know how much of that is an error in his computer program and how much is a result of the change he’s implementing, but what he finds makes the model worse, so he took a useful approximation and made it worse,” Wright said. He added that variations in reflectivity are probably much less of a problem. than the new document suggests.
“There are no shiny metallic asteroids,” he said. “Everything in the asteroid belt is covered in dirt, that seems to be what happens when you’re in space for a long time.”
Several scholars were quoted in the New York Times article praising Myhrvold for raising questions – an important aspect of the scientific method – but notably, none of them went so far as to agree with his conclusions. A glance at a popular Yahoo group for astronomy researchers shows many a raised eyebrow.
But Myhrvold, who has previously published work refuting the statistical methods of paleontologists, suspects he will soon have potential collaborators coming out of the woodwork no matter what “mud blow” NASA subjects him to.
“The path I have taken is surely not the easiest,” he said.
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