Asteroid Neo
NEO is the abbreviated name for Near-Earth Objects. These objects include comets and asteroids, which are pushed by the gravity of nearby planets into orbits that allow them to enter the vicinity of Earth. Comets that form are mostly made of ice and dust in the cold outer planetary system, while most rocky asteroids formed in the warmer inner solar system between the orbits of Mars and Jupiter.
Scientific interest in comets and asteroids is primarily because they are relatively unchanged remains from the formation of the solar system about 4.6 billion years ago. The four giant outer planets were formed as a result of the clumping of billions of comets. The leftover remains of that formation process became the comets we see today. Also, today's asteroids are the leftover remains of the initial agglomeration of the four inner planets.
The Earth is always vulnerable to collisions by comets and asteroids, but large impacts are very rare. The last major impact was about 65 million years ago, which likely led to the extinction of the dinosaurs.
Today, NASA periodically explores, traces and characterizes asteroids and comets passing relatively close to Earth, using both ground-based and space-based telescopes.
The near-Earth object monitoring program, known as Spaceguard, detects these objects, characterizes them, and predicts their paths; To determine their potential to pose a risk to our planet. Research has announced that there is currently no threat from any asteroids the size of the one that allegedly wiped out the dinosaurs.
“The risk of Earth being hit by a large asteroid without being detected and warned has decreased dramatically,” says Tim Spahr, director of the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. But the situation is different with medium-sized asteroids, which can destroy a large urban area if they hit Earth in the wrong place.
However, recent observations from NASA's Wide-field Infrared Survey Explorer, or WIDE, indicate that the number of medium-sized near-Earth asteroids is much lower than previously thought. The results of the programme's survey project, known as NEOWISE, found a larger decline in the estimated populations of medium-sized asteroids than the observed populations of large asteroids. Astronomers now estimate that there are 19,500 rather than 35,000 medium-sized asteroids near Earth; Scientists find that this improved understanding of these populations may be an indication that the danger to Earth may be less than previously estimated.
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