"Something wicked this way comes." Shakespeare's Macbeth, Act IV, Scene 1.
Photographer: Patrick Wiggins, Wiggins Observatory, Tooele, Utah

Most North Americans slept through the morning of January 13, 2010 as near-earth-object (NEO) 2010 AL30 silently moved across the night-sky at about a one-third of the distance to the Moon - 122,000 kilometers. 2010 AL30 is an asteriod about 10 to 15 meters across. An amateur astronomer in Utah followed its passage using a 35cm telescope and CCD camera. 2010 AL30 is estimated to be part of a NEO population of several thousand similar objects. On average, one 10-15 meter asteriod passes within one lunar distance of the Earth about once a week. If 2010 AL30 had entered the Earth's atmosphere, it would have created an air burst equivalent to between 50kT and 100kT (kilotonnes of TNT). The Hiroshima "Fat Man" atom bomb had a yield between 13-18kT.

On January 22, 2010, the National Research Council of the National Academy of the Sciences released its final report, requested by the United States Congress, that recommended an optimal approach to complete the census of NEOs larger than 140 meters in size and an optimal approach for deflecting a NEO that threatens impact with the Earth. The Report recommended that the census of NEOs be expanded to include NEOs between 30 and 50 meters in diameter. NASA's NEO program estimates that "with an average interval of about 100 years, rocky or iron asteroids larger than about 50 meters would be expected to reach the Earth's surface and cause local disasters or produce the tidal waves that can inundate low lying coastal areas." A 50 meter diameter NEO can create a blast equivalent to 1MT (megatonnes of TNT).

There have been no significant asteriod caused deaths in historical times due to the infrequency of the major events and that when such events do occur, they are more likely to happen over unpopulated regions such as oceans. Noting that without better surveys, accurate estimates of the risk of NEO impacts cannot be made, the Report made best-current estimates for the global risk of death-by-shark at 3-7 persons per year, death-by-asteriod at 91 persons-per-year and death-by-automobile at 1,200,000 persons per year. The Report opined that when smaller impact events do occur, they will have severe local effects and cause societal disruption.

Related links

National Research Council, National Academy of Sciences. Jan. 23, 2010. Press Release on Issuing of Final Report titled "Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies"  (includes link to download report).

Near Earth Object Program, NASA. Jan. 12, 2010. Small Asteroid 2010 AL30 Will Fly Past The Earth. Press Release.

Near Earth Object Program, NASA. 2010. Orbit Diagram for 2010 AL30. Web applet.

Near Earth Object Program, NASA. 2010. "Sentry Risk" Table  (dynamic table of NEOs being monitored for potential impact risk, including known less than 50 meter diameter objects).

Near Earth Object Program, NASA. 2010. "Target Earth", Chapter in "NEO Basics" web document (100 year average impact frequency for less than 50 meter diameter objects).

Near Earth Object Program, NASA. 2010. NEO Program Homepage.

Catalina Sky Survey. 2010. Catalina Sky Survey Homepage  (Current NEO survey with 21,000 NEO discoveries).

Lincoln Laboratory, MIT, USAF and NASA. 2010. Lincoln Near Earth Asteroid Research (LINEAR) Homepage (Current NEO survey with 2,100 NEO discoveries).

Univ. of Arizona. 2010. Univ. of Arizona Spacewatch Program Homepage.

Jet Propulsion Laboratory. 2010. JPL's WISE Satellite Near Earth Object (NEOWISE) homepage (Program to detect NEOs using the WISE infra-red observatory satellite).

Jet Propulsion Laboratory and NASA. Jan. 10, 2010. WISE JPL-Berkeley FAQ Requesting NEO confimation. Web document.

IAU Minor Planet Center, Harvard Univ. 2010. IAU Minor Planet Center NEO Confirmation Request List. Table. (current ephemerides for NEOs needing observation).

Spaceguard Foundation. 2010. Priority List for NEO Observations. Table. 

NEODyS, Univ. of Pisa. 2010. Near Earth Objects Dynamic Site (NEODyS) Object Information Server. (current orbital elements for NEOs).

Arecibo Observatory, National Astronomy and Ionosphere Center. 2010. Arecibo Radar Observatory Homepage  (radar imaging of asteriods).

Minor Planet Section, Association of Lunar and Planetary Observers. 2010. Minor Planet Bulletin (a quarterly amateur publication focusing on photographing light-curves of asteriods and listing which minor and major asteriods are currently visible).