(ËvÉr bÉl) adj. 1. of or consisting of words: verbal ability. 2. spoken rather than written; oral: verbal communication. 3. concerned with words only, rather than with the ideas, facts, or realities expressed: a purely verbal distinction. 4. corresponding word for word; verbatim: a verbal translation.
Because their hypothesis requires that Earth arose from water-containing materials already present in the inner solar system, it's called the wet-accretion hypothesis. Most of Earth's water has an indigenous origin, says Drake.
To carry so much water, the impactor that doused Earth must have come from between Mars and Jupiter, Morbidelli says. Computer models that he and his colleagues described in the Oct. 1, 2001 Icarus show how this might have happened.