asteroid

asteroid — noun

1. a rocky object in space, much smaller than a planet, that travels around the sun

1.名詞B2
釋義

a rocky object in space, much smaller than a planet, that travels around the sun — most are found in a wide belt between Mars and Jupiter.

例句

NASA tracks every large asteroid that passes near Earth.

subject + tracks + asteroid (typical scientific use)

Japan's Hayabusa2 probe reached the asteroid Ryugu in 2018 and brought rock samples back to Earth.

named mission + asteroid + named target (mission collocation)

同義詞
  • minor planet

    the formal scientific term used in astronomy papers

  • planetoid

    older or literary word for the same kind of object

  • space rock

    informal everyday phrase used in news reports

文法句型

asteroid + verb (orbit, hit, strike)

用法筆記

Subject of verbs like 'orbit', 'pass', 'strike', 'hit'. Distinguish from 'comet' (icy, with a glowing tail) and 'meteor' (the streak of light when a small rock burns in the atmosphere).

常見錯誤

❌A bright asteroid streaked across the night sky.
✅A bright meteor streaked across the night sky.
💡once a rock enters Earth's atmosphere and glows, it is a meteor, not an asteroid.
❌The asteroid had a long shining tail behind it.
✅The comet had a long shining tail behind it.
💡tails belong to comets; asteroids are dry rocks.

asteroid — adjective