Your analogy fails me. Botany is a sub-field of science. Reading tea leaves has nothing to do with it. However the nature of the universe is not an internal term or subject of science. People have been and continue to speculate about the universe before modern science arrived on the scene. Therefore they have a lot to say about the nature of the universe. And what they say is offered in terms of an explanation. For instance, the bible says, I believe, a few words about how the world came about.
Note that I did not offer the contrast between astronomy and astrology, and I assume that the original poster meant to contrast them (when using the phrase "nature of the universe") in the context of where they do intersect.
Wikipedia provides this description of 'astrology', which I think is appropriate for our discussion:
> Astrology is a group of systems, traditions, and beliefs in which
> knowledge of the relative positions of celestial bodies and related
> information is held to be useful in understanding, interpreting, and
> organizing knowledge about personality, human affairs, and other
> terrestrial events.
Astrology attempts to use the position of celestial bodies to understand and predict future events. That is what it has to do with explaining something.
Now you may believe that it does a poor job of doing that, but I am afraid that would be an entirely different point or question.
--ravi
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