NASA Finds Fewer Near-Earth Asteroids Than Previously Thought
The Wide-field Infrared Survey Explorer (WISE) telescope created by NASA has shown that the number of medium-sized asteroids near earth is much lower than previously anticipated. The telescope has also managed to find over 90% of the largest, most important asteroids near the planet. NASA agreed to meet this goal in 1998. New information shows that there are just under 20,000 asteroids near Earth, where the previous figure was 35,000 or higher. This shows a slightly lower risk to Earth from space debris large enough to damage the planet. However, the research only shows that the number of mid-sized asteroids was smaller. The hazards from large asteroids or those that are the closest may be higher.
The telescope measured the number of asteroids that are orbiting within 120 million miles of the sun. This puts them in the area of Earth’s orbit. The results of the NEOWISE hunting mission was published in Astrophysical Journal. While the telescope didn’t manually record every object, taking a census of a small section allowed for a fairly accurate estimate to be formed of the entire population. Infrared light scanning was used in early 2010 and 2011 to take thousands of high-quality photographs of the sky. The data also gave clearer estimates of the asteroids in the belt between Jupiter and Mars.
The new infrared method used by WISE captured more information than every before because dark objects and asteroids were also measured. Non-reflective objects are harder to see with visible-light methods. In total, 93% of the asteroids that are at least as a big as a small mountain have been found. These are the asteroids that would have global consequences if they crashed into Earth. NASA also believes that it has now found all of the asteroids near Earth that are as big as the asteroid that wiped out the dinosaurs.