Perigean spring tide Perigean spring tide A proxigean spring tide (also known as a perigean spring tide) is a tide that occurs three or four times per year when the Moon's perigee (its closest point to Earth during its 29.5-day elliptical orbit) coincides with a spring tide (when the Earth, Sun and Moon are nearly aligned every two weeks). This tide usually adds only a couple of inches to normal spring tides. The Moon's orbit around Earth is elliptical, which causes the Moon to be closer to Earth and farther away at different times. The Moon and the Sun are aligned every two
From the Earth to the Moon the Moon. It seems appropriate to us to share with you some of the reflections of the crew as the modern-day Columbia completes its rendezvous with the planet Earth and the same Pacific Ocean tomorrow." In "Back to the Future Part III", Clara Clayton in 1885 asks Emmett Brown if he believes mankind will ever "travel to the moon the way we travel across the country on trains." Being from the future Doc already knows that doesn't happen for another 84 years, but he affirms they will while quoting a passage of "From the Earth to the Moon". Clara calls