Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbit intersects Earth's orbit and which may therefore pose a collision danger.
Due to their size and proximity, NEOs are also more easily accessible for spacecraft from Earth and are important for future scientific investigation and commercial development.
In fact, some near-Earth asteroids can be reached with a much smaller change in velocity than the Moon.
In the United States, NASA has a congressional mandate to catalogue all NEOs that are at least 1 kilometer (0.6 miles) wide.
At this size and larger, an impacting NEO would cause catastrophic local damage and significant to severe global consequences.
Approximately 800 of these NEOs have been detected.
According to the most widely accepted estimates, there are still 200 more that have not been found yet.
The United States, European Union and other nations are currently scanning for NEOs in an effort called Spaceguard.
Currently efforts are under way to use an existing telescope in Australia to cover the approximately 30 percent of the sky that is not currently surveyed.
Torino Scale The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and ... >
read more
Near-Earth asteroid Near-Earth asteroids (NEAs) are asteroids whose orbits are close to Earth's orbit. Some NEAs' orbits intersect Earth's so they pose a collision ... >
read more
Asteroid belt The asteroid belt is a region of the solar system falling roughly between the planets Mars and Jupiter where the greatest concentration of asteroid ... >
read more
Asteroid Asteroids, also called minor planets or planetoids, are a class of astronomical object. The term asteroid is generally used to indicate a diverse ... >
read more
Dysnomia (moon of Eris) Dysnomia, is a moon of the dwarf planet Eris. The satellite is about 60 times fainter than Eris, and its diameter is estimated to be approximately ... >
read more
Neptune's natural satellites Neptune has 13 known moons. The largest by far is Triton, discovered by William Lassell just 17 days after the discovery of Neptune itself. It took a ... >
read more
Deimos (moon) Deimos is probably an asteroid that was perturbed by Jupiter into an orbit that allowed it to be captured by Mars, though this hypothesis is still in ... >
read more
Meteorite A meteorite is a small extraterrestrial body that impacts the Earth's surface. While in space they are called meteoroids, and while falling through ... >
read more
Lunar space elevator A lunar space elevator (also called a moonstalk) is a proposed cable running from the surface of the Moon into space. It is similar in concept to the ... >
read more
Transit of Venus A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against (and hence ... >
read more