Nasa using asteroid’s close flyby to test warning network 

Observatories worldwide — part of the International Asteroid Warning Network — have been zooming in on the asteroid called 2012 TC4 for weeks to test communication and coordination. Kelley

said it's gone well. Until now, researchers relied on "tabletop" tests, simulations with no actual asteroids involved. The exercise will continue for another week, as

observatories keep tracking the asteroid as it departs Earth's neighborhood. First spotted in 2012 and then disappearing from view until this past July, the asteroid is estimated to

measure 45 feet to 100 feet. Kelley said astronomers should have a better handle on the shape and size of the rock — which they believe is oblong, like a potato — in coming days and weeks,

as more observations pour in. That uncertainty is what provided the challenge for observers, all volunteers in this project. They are using major telescopes in Hawaii and Arizona, among

other places. Puerto Rico's Arecibo Observatory got knocked out by last month's Hurricane Maria and could not take part.