Dictionary of Space Concepts

Short Definition:

NEO, or near-Earth object, is a celestial body which is in the size range of meters to tens of kilometres, that orbits the sun and approaches the earth within the distance of 1.3 AU (astronomical units).

Detailed Definition:

Among the 600,000 known asteroids, only 20,000 of them are NEOs. To be classified as such, the object must be natural and cannot be manmade. Some of them could potentially hit the earth and for this reason, some organisation keep track of them everyday. Historically speaking, NEOs have had an impact of the earths geological and biological history. Most of the NEOs are Apollo asteroids (55.4%), meaning that they come from the Apollo asteroid group. The second most common are Amor asteroids (36.4%), and third most common are Aten asteroids (7.7%).

Etymology:

Acronym of "near-Earth object."

Sample Sentence:

An astronomer would for example say during a lecture: “The Amor asteroid, 433 Eros, was the first NEO discovered in 1898, by D. Witt of Berlin, Germany, using a photographic plate to record its position.”

Translations:

• French:
• German:
• Polish: NEO (obiekt bliski Ziemi) 
• Swedish:
  

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