Key Facts


C/1899 E1 (Swift) is a large comet with a trajectory through the solar system likely originating from the Oort Cloud. NASA JPL has not classified Swift as potentially hazardous because its orbit does not bring it close to Earth.

Swift orbits the sun every 0 days (0.00 years), coming as close as 0.29 AU and reaching as far as -1965.49 AU from the sun. Its orbit is highly elliptical. Based on its brightness and the way it reflects light, Swift is probably between 2658.000 to 5943.469 kilometers in diameter, making it the largest asteroid/dwarf planet, very roughly comparable in size to the U.S. state of Alaska.

No Close Approaches

Swift's orbit is 0.51 AU from Earth's orbit at its closest point. This means that there is an very wide berth between this asteroid and Earth at all times.

Orbital simulations conducted by NASA JPL's CNEOS do not show any close approaches to Earth.

Images and Observations

Swift's orbit is determined by observations dating back to March 7, 1899. It was last officially observed on July 10, 1899. The IAU Minor Planet Center records 92 observations used to determine its orbit.

Accessibility and Exploration

This comet is not considered a viable target for human exploration by the NHATS study.



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Orbital Elements

  • Epoch: 2414779.5 JD
  • Semi-major axis: -982.6 AU
  • Eccentricity: 1.0003
  • Inclination: 146.27°
  • Longitude of Ascending Node: 26.41°
  • Argument of Periapsis: 8.71°
  • Mean Anomaly: 0.0°

Physical Characteristics

  • Diameter: ~3431.463 km

Derived Characteristics

  • Aphelion Distance: -1965.49 AU
  • Perihelion Distance: 0.29 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of C/1899 E1 (Swift) is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.