Combustion, which refers to a phenomenon that occurs when planets are considered too close to the Sun, is a topic that seems to be interpreted differently by many astrologers I’ve learned from and respect. Some say they’ve either never found it to be the case in their practical experience or, at least, that it’s not the case with Mercury (the most common planet to be located so close to the Sun) and/or has mixed results. Some astrologers also feel the Moon cannot become combust, while others list it along with the other planets. I’ve also heard more than one astrologer suggest combustion is very real but that the required orbs are just much tighter than indicated in classical texts.
Those texts state specific orbs of combustion for different planets – (although the orbs vary a bit depending on which text is referenced) – and generally take a very negative view of combust planets. James Braha mentioned in an ACVA (American College of Vedic Astrology) lecture that he feels combust planets have a multi-layered effect that both brightens and agitates, giving the example of models with a combust Venus, who, despite their beauty, often have difficult love lives. The late Narendra Desai mentioned in another ACVA lecture that he felt Mercury, being so used to closeness with the Sun, doesn’t actually become combust. Chakrapani Ullal’s ACVA lecture on the topic is informative but also interestingly ambivalent; he suggests his own observations regarding combustion have been mixed.
It’s been my own observation that an unusual percentage of highly intelligent people have a very combust Mercury… and also that an unusual percentage of these people are anxious and neurotic. Possible anxiety and neurosis aside, it would be difficult for anybody to convince me that a combust Mercury makes one more likely to be intellectually slow or have trouble communicating, which I’ve heard from other astrologers whom I respect (but disagree with on this account). Even in regard to anxiety and neurosis, correlation doesn’t necessarily mean much; highly intelligent people may just be more likely to be anxious or neurotic. Similarly, without considering astrological factors, there’s plenty about modeling that seems as if it could make one’s love life more difficult. The number of variables involved in life is enough to make pinning down the facts about certain topics problematic at times… and that applies to most fields, not just astrology.