Sep 8, 2023 - Science

Newly discovered comet set to pass near Earth on its 400-year orbit

Comet Nishimura viewed from L'Aquila, Italy, on Sept. 8.

Comet Nishimura viewed from L'Aquila, Italy, on Sept. 8. Photo: Lorenzo Di Cola/NurPhoto via Getty Images

A newly discovered comet could be visible to the naked eye in coming days as it makes its closet approach to the planet in its orbit around the sun.

Why it matters: Comet Nishimura, which was found by astronomer Hideo Nishimura just last month, has an estimated orbit of over 400 years, meaning it likely last passed near Earth in the 17th century.

How to see Comet Nishimura

Weather permitting, Nishimura will be visible with a telescope or binoculars in the eastern sky before dawn, according to the Planetary Society.

  • It will rise near the horizon between the constellations Cancer and Leo, and will make its closest approach to Earth (77.9 million miles) on Sept. 12. It may become visible with the naked eye, as it should grow brighter as it nears the sun.
  • It will likely pass out of view for people in the Northern Hemisphere on Sept. 13, afterwards becoming visible to those in the Southern Hemisphere.
  • It will reach its closest point to the sun on Sept. 18.

Of note: In addition to Nishimura, five large but harmless asteroids are set to soon pass nearby the planet, according to NASA.

  • Three are about as large a bus and two are similar in size to a plane. The closest asteroid, 2023 RG, will be around 1 million miles away from the planet.

Be smart: Comets and asteroids, while both remnants from the formation of the solar system, fundamentally differ in composition.

  • An asteroid is made of rock, metals and other elements, and most are located in the asteroid belt between Mars and Jupiter.
  • A comet is made up of massive collections of frozen gases, rock and dust, some of which begins to vaporize as the object's orbit brings it close to the hot sun, creating the trademark comet tails.
  • Comets also typically have green heads possibly caused by highly reactive dicarbon molecules getting blown apart by sunlight, though the color never extends to the tails.

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