Comments approved out by the Wide Field Infrared Explorer to Survey (Wide-field Infrared Survey Explorer, or WISE, for its acronym), NASA, have yielded the best on record count Today the population of potentially hazardous asteroids in our solar system. Also known as "PHAs" (acronym for Potentially Hazardous English Asteroids), these asteroids have orbits within about eight million kilometers (five million miles) from Earth's orbit and are large enough to survive passing through the Earth's atmosphere and cause damage on a regional,
or even higher. NEOWISE The project, which is part of the WISE mission is dedicated to hunting asteroids, took samples of 107 PHAs with to make predictions about the entire population. The findings indicate that there are about 4,700 PHAs, about 1,500, with diameters exceeding approximately 100 meters (330 feet). So far, it is estimated that found 20 to 30 percent of these objects.
Whereas in previous estimates of the amount predicted PHAs were similar, it was only approximations. NEOWISE has generated a credible estimate of the total quantity of objects and their sizes. As the WISE Space Telescope captured the infrared light, or heat, asteroids, could detect light and dark objects alike, which resulted in a more representative view of the entire population.
"The analysis carried out by the NEOWISE project showed us that we have a good start to find these objects really represent an impact hazard to Earth," said Lindley Johnson, who is an executive Object Observation Program Near Earth (Near-Earth Object Observation Program, in English) in the NASA headquarters. "But there are still many more out there, and they need to perform a joint effort over the next couple of decades to find all that could cause serious injury or could become the target of a mission in the future."
The new analysis suggests that about twice the PHA previously thought to be living in low-inclination orbits, which are more or less aligned with the plane of the orbit of Earth.
"Our team was surprised to find an overabundance of PHAs with low inclination," said Amy Mainzer, who is the principal investigator of NEOWISE at the Jet Propulsion Laboratory (JPL Jet Propulsion Laboratory or, for its acronym in English) NASA. "As these PHAs tend to make close approaches to Earth, these objectives can provide the best opportunity for the new generation of exploration carried out on humans and robots."
The analysis was performed using the NEOWISE project suggests a possible origin for low-inclination PHA: Many of them may have originated from the collision of two asteroids in the main belt, which is located between Mars and Jupiter. A larger body, with a low inclination orbit, may have been fragmented in the main belt, thereby causing some of the pieces reach orbit closest to Earth and eventually to become PHAs.
The low inclination PHA appear to be somewhat brighter and smaller than other near-Earth asteroids. The finding that the PHA tend to be bright says something about its composition is more likely to be composed of rock, like granite or metal. This information is important in assessing the potential danger posed to space rocks on Earth. The composition of the bodies may affect the rate at which they could burn in our atmosphere, if it were to produce a match.