I've been rediscovering the work of Immanuel Velikovsky, who wrote Worlds In Collision in 1950. The crux of his theory was that the planet Venus swung by the earth and caused massive disruptions due to the effects of gravity. He attempted to link this hypothetical event with ancient stories of global floods, polar shifts, a reversal of the earth's spin, and total eclipses that lasted for days. Astronomers strongly deny Velikovsky's claim that Venus has interacted with the earth. However, there are many other large bodies beyond Pluto in our solar system that could have swung by earth on long elliptical orbits and caused the effects described by Velikovsky. We are still discovering dwarf planets in the Kuiper Belt region of the solar system (see Sedna below).
If such an event did happen, it would have been documented by ancient astonomers and astrologers, who were obsessed with the heavens. Velikovsky used historical analysis to assert that a severe planet-wide event did occur about 3500 years ago. This was recorded by witnesses all over the earth in ancient manuscripts and oral legends - the Vedas, the Bible, Eskimo mythology, Mayan calendars, Egyptian hieroglyphics, etc.
These stories contradict each other on many details, as would be expected from eyewitnesses from different cultures. But, it is unlikely that hundreds of very serious people, who did not know each other, would create such dramatic and unbelievable stories, without some element of truth in them. The exact event will probably never be known, but it is a very interesting subject.
Solar System, logarithmic scale:
Velikovsky is best remembered for his compilation of ancient mythology than for his interpretation of them. Velikovsky was severely criticized and ignored by mainstream scientists for the rest of his life, and his ideas have only recently has been getting some attention. It is one of those subjects that professional astronomers do not want to investigate for fear of losing their credibility, which is regrettable.
With the 2012 scare currently being marketed by the entertainment industry, it is quite sobering to read Velikovsky's research into ancient documentation of similar events.
Sidenote: NASA has predicted that we are in for a period of severe solar flares in the next few years, which could cause widespread electrical outages. (Be sure to put a hard drive in a lead-lined box somewhere). It's not the end of the world, we have solar flares every few decades, but it is the first time we have had a major solar flare in the Information Age.