When is the next alignment of the planets?
Since the planets all orbit in different planes, they can never align precisely in a straight line, or even come close. Even if they could, there would be no effect on Earth other than a pretty light show. The combined gravitational effect of all of the planets on Earth is much less than the *change* in the gravitational effect of the Moon as it makes its elliptical orbit around Earth and its distance varies by up to 40,000 miles.
