Planetary securitySmaller asteroids could cause bigger problems
On 15 February an asteroid burst over the Russian city of Chelyabinsk. Scientists estimate that the Chelyabinsk event was equivalent to an explosion of about 500 kilotons of TNT. At its peak, the airburst appeared to be thirty times brighter than the sun. The asteroid fireball that injured about 1,500 people and damaged more than 7,000 buildings, collapsing roofs, and breaking thousands of windows. Scientists say that because the frequency of a strike of an asteroid of this size has exceeded expectations, with three such strikes in just over a century – Chelyabinsk in 2013, Tunguska in 2008, and a large airburst in the South Atlantic in 1963 — the number of similar-sized asteroids capable of causing damage may be greater than suspected.
Smaller asteroids cause more damage on impact // Source: commons.wikimedia.org
Once in a lifetime, a physicist may get a chance to test his theories and simulations in a real-life event that changes the course of his scientific life. But rarely does that opportunity literally fall from the sky.
This is the impact of the 15 February asteroid that burst over the Russian city of Chelyabinsk on Sandia physicist Mark Boslough, subject of a TV documentary that aired the other night and co-author of a recent cover story in Nature about the asteroid fireball that injured about 1,500 people and damaged more than 7,000 buildings, collapsing roofs, and breaking thousands of windows.
A Sandia Lab release reports that Boslough’s journey to Russia shortly after the impact is chronicled in the NOVA episode “Asteroid; Doomsday or Payday,” which began airing on Public Broadcasting Service stations Wednesday (20 November).
The show focuses on the destructive potential of asteroids, chronicling how Boslough and his colleagues learn that small asteroids can do far more damage than previously thought. The Nature paper also suggests that there may be more small asteroids than formerly thought.
The day the asteroid hit, Boslough learned of the event via Facebook from posts of Russian news stories and YouTube videos showing an object that exploded in the Russian sky.
“I saw it on Facebook long before the sound wave had even arrived in this part of the world,” Boslough said, estimating the transglobal sound wave took more than seven hours to reach New Mexico. “I really didn’t expect to experience this in my lifetime.”
As one of the first scientists to visit Chelyabinsk after the asteroid struck, Boslough set out to discover where the object came from. Because it came down near a populated area, he and his colleagues were able to collect videos from people who caught the asteroid on film and video, especially the ubiquitous Russian dashboard cameras, a staple in establishing blame in traffic mishaps.
“This event was certainly one of the best-documented asteroid events ever,” said Boslough.
Boslough’s goal was to perform stellar calculations of the asteroid’s trajectory by visiting — at night when the stars shone — the exact spots where the footage was recorded.
