Planetary Grand Alignment
Like clockwork so-called planetary grand alignments have taken place in 1962, 1982, and 2000. This does not mean that the planets line up like pearls on a string. But they sort of gang up on one side of the sun within an angle of roughly 10 to 30 degrees - so the definition is a but mushy.
The uneventful year 1128 A.D. saw one of the tightest planetary alignments.
The doomsday best seller The Jupiter Effect in 1982 spelled out an improbable chain of events that would be triggered by the planets' tug-of-war with the sun: tides raised on the sun's surface would increase sunspot activity, build up the solar wind, that would effect Earth's weather, and subsequently, Earth's spin rate, which would then trigger earthquakes.
No geological disasters happened in 1982 short of a 6.0 magnitude earthquake that killed 1,500 people in Dhamar, northern Yemen. In fact the celestial alignment allowed for NASA to pull off the Voyager 2 "grand tour" of the four outer gas giant planets from 1979 to 1989.
Jupiter contains more mass than all the other planets combined, and yet it is still less than 1 percent of the sun's mass. Therefore Jupiter's influence on the sun is inconsequential.
Alien astronomers could measure Jupiter's gravitational tug as an insignificant 270 mile-per-hour cyclic change in the sun's radial velocity over the planet's 12-year orbital period. Only if Jupiter was moved so close to the sun that its orbital period was measured in days, would some serious tidal effects be seen. This is observed with so-called "hot Jupiters," the exoplanet WASP-18 being the most extreme case.
Running an ephemeris forward in time, with the ease of throttling H.G. Wells' time machine, the next closest thing to a grand alignment comes in 2163 (shown above). Unless we have bombed ourselves back to pre-Columbian society by then, people in 2163 will be too science savvy to give this any thought. They will be bemused by historical accounts of the feared Jupiter Effect by their science-illiterate ancestors.
What's ironic is that any casual surfing of the Internet shows that a lot of people are preoccupied with doom and gloom based on mythology, psychics, and patently flaky ideas. The real Earth-threats, such as global warming, seem to be too easily shrugged off as lacking solid scientific evidence. Go figure.
Image credit: Russell Schweickart / B612 Foundation