Thousands of asteroids are near Earth, and Microsoft's director asks threat

                      
Former head of Microsoft's technology holds a meteorite in Bellevue, Washington

More than 14,000 known asteroids buzz in the neighborhood of the Earth. They will miss the planet in the coming decades.

However, hundreds of thousands were more not yet discovered and no one knows if any of them are on a collision course with Earth. So, find and keep track of all the asteroids that can cross the paths of our planet would allow authorities to issue alerts and potentially allow time to divert dangerous.

The community of scientists that includes these apocalyptic possibilities is small and generally friendly - at least it was until Nathan P. Myhrvold intrude. Before Microsoft's chief technology officer, Myhrvold embarked on projects as a compendium of 2,438 pages in six volumes on the culinary know that was celebrated by the chefs. A continuation over cooked, is being prepared.

He also became the scourge of statistical scientists. His latest target is NASA, the US space agency in a fight by the Infrared Data Search Explorer probe Field Vasto (better known by the acronym Wise, in English).

Launched in 2009, Wise photographed 750 million stars, galaxies and other celestial objects, including asteroids heat emissions. The Neowise, an offshoot of the project, used the heat data to calculate the size and reflectivity of 158,000 asteroids.

Myhrvold says that the analysis of Neowise is full of errors. "The bad thing is that nearly everything is wrong. Unfortunately, most of the analysis will never be as accurate as they expected," says he.

He sent his own analysis of Neowise results to the journal "Icarus".
Myhrvold is not claiming that NASA ignored dangers of known asteroids, but scientists know as much as think they know.

He also focused on the proposal for a space telescope with higher price to US $ 500 million - Object Camera Near Earth (Neocam) project led by some of the same scientists whose work he is questioning.

great uncertainty

Most of the millions of asteroids are found between the orbits of Mars and Jupiter, but some dive near the sun. There is no doubt that one of them one day reach Earth.

The larger the asteroid, the greater the potential cataclysm. The reflectivity of the surface - what astronomers call albedo - informs the ease with which it can be detected.

"From the practical perspective of finding asteroids, it is very important to know the distribution of diameters and distribution of albedo," says Myhrvold.
According to NASA scientists, the estimates of the asteroid diameters made by Neowise usually be within 10% of actual size, but Myhrvold says that the uncertainties are much larger, up to 100% in many cases.

Directors of the American space agency disagree. "He's a very intelligent man. But that does not make him an expert in everything," says Lindley Johnson, NASA's efforts supervisor to protect the planet from space rocks.

Other scientists estimate that the critical Myhrvold have merit.

"I think he performed a very useful service when you make an error analysis more careful and alert people that you should not take the data from the Wise table and assume that they are the absolute truth," said Alan W. Harris, researcher at the Space Science Institute.

Even if Myhrvold is correct, Harris believes the data Neowise "has enough validity to be useful for most purposes."

It is not even an astronomer

Myhrvold is not an astronomer. He never did research on asteroids.
Often maligned as a "monster patents" because Intellectual Ventures, a company he founded after leaving Microsoft in 1999, purchased patents and collecting license fees from other firms.

During their ventures paleontology - another hobby - he questioned the research of a professor at Florida State University, Gregory M. Erickson, on the growth rate of dinosaurs. In 2013 document, Myhrvold described alleged statistical errors and stopped short of accusing Erickson to manipulate the data.

Corrections were attached to Erickson several studies, including two in "Nature". Erickson and colleagues maintain that the errors do not alter their findings. The Florida State University considered Erickson innocent of wrongdoing.

"Having someone like Nathan, with different perspective and history, examining with a renewed vision, I do not think there's anything wrong with that. That makes us think", says Kristina Curry Rogers, paleontologist vertebrate the College Macalester in Minnesota, one of the Erickson study's authors in "Nature".

Myhrvold was drawn to research on asteroids when the B612 Foundation, non-profit organization dedicated to the global defense initiatives, asked him a donation of money to the Sentinel, a probe tracking asteroids, valued at $ 450 million, financed by private entities .

"What they did not know is that I was interested in asteroids killers long," Myhrvold says. After all, it is believed that the impact of an asteroid on Earth caused the end of the era of the dinosaurs 66 million years ago.

However Myhrvold learned about several other initiatives, including Neocam NASA, it would cost almost US $ 500 million (not to mention the rocket to launch it), and the Great Telescope Synoptic Research Centre under construction in Chile.

Each group offered computer simulations of how many asteroids unseen would be found, offering different hypotheses.

In a study published in March in "The Publications of the Astronomical Society of the Pacific," Myhrvold used a simpler approach to make a valid comparison. He examined the volume of space that each telescope could observe, then calculated that invisible asteroid fraction go through that space.

"I thought it seemed reasonable. Nathan certainly offers a fresh look," says Steven R. Chesley, Propulsion Laboratory researcher at NASA's Jet in Pasadena, California.

Myhrvold concluded that the telescope in Chile, a collaboration of US $ 665 million Department of Energy of the United States, the National Science Foundation and other organizations could find 90 percent of asteroids near Earth if more time was spent looking for a position low in the sky near the horizon of the planet.

Zeljko Ivezic telescope project scientist, said that in return would be delayed for two years the end of the research the rest of the cosmos, as well as an additional cost of US $ 100 million; the board of the telescope asked if NASA could help pay this amount.

Finally, Myhrvold, who got rich thanks to his days at Microsoft, decided not to give money to the B612.

He also did not give money to the Great Research Telescope Synoptic who received donations of Bill Gates, his former boss at Microsoft.
When writing the study published in March, Myhrvold talked to people who work on several projects, including Amy Mainzer, principal investigator of Neocam and Neowise.

Myhrvold According to Amy, a ground telescope could not detect asteroids in Earth orbit because it would be too close to the horizon.

That sounded strange to Myhrvold because even amateurs can easily detect distant celestial objects within the Earth's orbit, such as Venus, 42 million kilometers closer to the sun than our planet.

According to Myhrvold, Amy replied that large telescopes were not designed to be singled out as close to the ground, but Chile is, he noted.

Chesley of NASA, is coordinating a more detailed analysis of the telescope asteroid discovery capacity; Preliminary data should be released soon.

In recent presentations, NASA representatives portrayed Neocam more as a complement rather than a competitor. "It's a sports team. There is no system that will only provide us with all the data we need," says Johnson.

NASA did not let Amy grant interview. By answering questions in writing, she wrote that the team keeps Neowise the findings and the results were validated by independent observations and by other researchers.

The principle of hibachi grill

Myhrvold was surprised by the fact that the calculation of the albedo Team Neocam violated one of the basic principles of physics, known as Kirchhoff's law of thermal radiation according to which the brightest objects radiate less heat.

According to Myhrvold, a simple demonstration of this is the bright chrome cooking surface of a hibachi grill in a restaurant. A dark surface grid uncomfortable bathe customers with hot flashes. The models Neocam did not take into account the effects of reflected sunlight, he maintains.

So Myhrvold Neowise examined more closely. One aspect that was considered curious that in a hundred times, the team reported Neowise asteroid diameters that beat exactly with those who had been previously determined by other methods such as the use of radar and overflights spacecraft. "I think is strong evidence that something is wrong."

In turn, Amy explains that the asteroids that beat measurements accurately were used for calibration and that the values ​​defined for them were previously observed.

The asteroid community, though small, includes two scientists with the same name, Alan William Harris, who are not related. Harris of the Space Science Institute, who is 71, is known as "Al the Elder," while "Al, the Young", 64, is a scientist at the German Aerospace Center that created the computer model used by scientists Neowise.

The younger Harris agrees that Myhrvold mentioned a good point about the law of Kirchhoff and that a closer examination of Neowise analysis would be fruitful. previous satellites examined longer wavelengths where the reflected sunlight was not a big problem.

However, he disagrees with Myhrvold of reproachfully. "It demonstrates a very professorial attitude in this respect," he says.

Myhrvold insists not want to take revenge on the scientists Neowise, however, said not considered "unduly bad of me to want to point out that your data is irreproducible."

The law Kirchhoff again be used with Neocam that would make observations of infrared wavelengths relatively short. The Neocam is one of five low-cost missions into account, and NASA must approve one or two of them in September, anticipating its launch in the next decade.

Amy agreed to answer some further questions, noting that these questions would be better answered by the officials who are reviewing the study Myhrvold. "At this point, we believe it is better to allow the peer review process - the basis of the scientific process. - To move forward"