| A | B |
|---|
| arbitrary | determined by chance, whim or impusle |
| coalescing | coming together so as to form a whole |
| accretion | growth or increase in size by gradual addition |
| perturbation | a great disturbance |
| hailed | greeted |
| eccentric | departing from a conventional pattern; deviating from a circular path |
| criterion | a standard or test on which to base a judgement |
| dwarf | tiny; small |
| orbit | the path that a planet follows around the sun; to go around in a path |
| dark matter | invisible substance whose gravity holds galaxies together |
