the.com/comets
frozen leftovers from the solar system's birth, putting on a show four billion years late
means Comets are icy bodies that orbit the sun and grow a glowing head and streaming tail when they draw near enough for the sun's heat to vaporize their frozen material.
from From Greek 'kometes,' meaning 'long-haired,' itself from 'kome,' 'hair of the head' — the ancients saw those luminous tails as flowing locks streaming across the sky. The word traveled through Latin 'cometa' and Old French before settling into English, so every comet still wears, in name, a head of cosmic hair.
- composition
- dirty snowballs of ice, dust, and rock
- two tails
- one of gas, one of dust, both fleeing the sun
- halley returns
- visible roughly every 76 years
- oort cloud
- home base sits nearly a light-year out
- tail direction
- always points away from the sun, never trailing
halley's comet — returns every 75-76 years, last seen 1986, next 2061
comet hale-bopp — brightest comet of the 20th century, visible 1997, won't return for 2,533 years
comet neowise — visible to naked eye in july 2020, closest approach in 6,800 years
comet shoemaker-levy 9 — collided with jupiter in 1994, first observed collision between two solar system bodies