(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 be fair, the origin of our planetâs water is an intricate story stretching back some 13.8 billion years to the Big Bang. And a key part of the story, centering on two particular solar system denizens, has been hotly debated for decades.