A minute planet; a body that could or did come together with many others under gravitation to form a planet.
- ‘When the planets formed 4.6 billion years ago, they formed from an agglomeration of many planetesimals, or small solid celestial bodies.’
- ‘Although planets, moons and planetesimals may seem to be very different astronomically, their common origin shows that this is not so.’
- ‘Asteroids are small bodies in space - the numerous leftover planetesimals from which the planets were made nearly 4.6 billion years ago.’
- ‘As planetesimals grow still larger, their gravitational attraction increases, allowing them to become even more effective at accreting nearby planetesimals.’
- ‘Like the hills and valleys on a contour map the gravity wells of suns, planets, moons, and planetesimals showed up.’
attributive Relating to planetesimal bodies.
- ‘His greatest contribution, however, was his planetesimal hypothesis of the origin of the planets.’
- ‘Models of planetesimal disks suggest that low relative velocities between the bodies produce accretion (objects hit and stay together) rather than fragmentation (objects break up and disperse).’
- ‘After all, planetesimal sized portions of the Solar System cannot be considered to be orbiting the Earth, except in the obvious case of the Moon.’
Early 20th century: from planet, on the pattern of infinitesimal.
We take a look at several popular, though confusing, punctuation marks.