Thousands of asteroids are passing through Earth’s neighborhood all the time. Although the odds of a direct hit on the planet any time soon are slim, even a small asteroid the size of a house could explode with as much energy as an atomic bomb.

So scientists at NASA are charged with scanning the skies for such dangerous space rocks. If one were on a collision course with our planet, information about how big it is and what it’s made of would be essential for deflecting it, or calculating the destruction if it hits.

For the last couple of years, Nathan P. Myhrvold, a former chief technologist at Microsoft with a physics doctorate from Princeton, has roiled the small, congenial community of asteroid scientists by saying they know less than they think about these near-Earth objects. He argues that a trove of data from NASA they rely on is flawed and unreliable.

Since 2011, a NASA project known as Neowise has cataloged the sizes and reflectivity of 158,000 asteroids, and it claimed that its diameter estimates were often within 10 percent of the actual size. Dr. Myhrvold said the uncertainties were much greater, largely because NASA researchers were using data from a satellite designed for observing distant objects, not nearby asteroids. “The science is terrible,” he said.