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  • In Depth | 1P Halley – NASA Solar System Exploration
    The History of Halley's Comet Until the time of English astronomer Edmond Halley (1656-1742), comets were believed to make only one pass through the solar system But in 1705, Halley used Isaac Newton's theories of gravitation and planetary motions to compute the orbits of several comets
  • Asteroids, Comets Meteors - NASA Solar System Exploration
    Asteroids and comets – and the meteors that sometimes come from them – are leftovers from the formation of our solar system 4 6 billion years ago
  • In Depth | Kuiper Belt – NASA Solar System Exploration
    Objects that remain there occasionally collide, producing smaller objects fragmented by the collision, sometimes comets and also dust that's blown out of the solar system by the solar wind Structure and Characteristics The Kuiper Belt represents an enormous, donut-shaped volume of space in the outer solar system
  • In Depth | 19P Borrelly – NASA Solar System Exploration
    How Comet 19P Borrelly Got Its Name Comets are usually named for their discoverer (s) or for the name of the observatory or telescope used in the discovery Since Alphonse Borrelly discovered this comet, it is named after him The letter "P" indicates that 19P Borrelly is a "periodic" comet, meaning it has an orbital period of less than 200 years
  • In Depth | Our Solar System – NASA Solar System Exploration
    The planetary system we call home is located in an outer spiral arm of the Milky Way galaxy Our solar system consists of our star, the Sun, and everything bound to it by gravity – the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; dwarf planets such as Pluto; dozens of moons; and millions of asteroids, comets, and meteoroids Beyond our own solar system, there
  • Directory - NASA Solar System Exploration
    NASA’s real-time science encyclopedia of deep space exploration Our scientists and far-ranging robots explore the wild frontiers of our solar system
  • In Progress - NASA Solar System Exploration
    NASA’s real-time science encyclopedia of deep space exploration Our scientists and far-ranging robots explore the wild frontiers of our solar system
  • Thanks - NASA Solar System Exploration
    NASA’s real-time science encyclopedia of deep space exploration Our scientists and far-ranging robots explore the wild frontiers of our solar system


















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