Scientists Drastically Underestimate Size Of Near-Earth Comet

When scientists announce that a near-Earth object will make an uncomfortably close flyby of our planet, we rest easy knowing that their calculations will be accurate. But while a trajectory is predictable, sometimes calculations of the size of these objects can be dramatically wrong.

In January, the PanSTARRS telescope at the University of Hawaii first identified P/2016 BA14, a near-Earth comet that sailed past Earth on March 22. The third closest comet flyby ever recorded, the object flew within 2.2 million miles of our planet.

This series of images of Comet 67P/Churyumov–Gerasimenko was captured by Rosetta’s OSIRIS narrow-angle camera on July 26, 2015 from a distance of about 170 km.

As it approached, scientists estimated that BA14 was no more than 410 feet wide.

But after observing the comet for three nights with NASA’s Goldstone Solar System Radar in California, scientists discovered it was much larger, roughly 3,000 ft. in diameter.

“The radar images show that the comet has an irregular shape: looks like a brick on one side and a pear on the other,” said Shantanu Naidu of NASA’s Jet Propulsion Laboratory, who led the study. (PNA/Sputnik) JBP/SSC