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How the Sun and Moon Are Helping Sandy’s Waters Rise

As Hurricane Sandy makes landfall on the Northeast coast of the U.S. over the next couple days, we are already seeing reports of higher-than normal tidal surges for a storm this size. Hurricanes always bring high seas along with them thanks to their intense low pressure, but the fact that Hurricane Sandy happened during a full moon (Monday night) is putting that rising water on steroids.

In a full moon (or new moon), the Earth, Sun and Moon are aligned in a way that not only allows the usual lunar pull on the tides, but also a solar pull! It’s stretching the Earth’s oceans like taffy, creating more extreme high tides that will make Sandy’s surge much worse. The Moon has a much greater pull on tides because of its distance to Earth, but the Sun’s mass gives it a serious influence in situations like this.

The top image shows how this phenomenon works, with the radius of the Earth and Moon to scale. The thing that amazes me is how far apart, in size and in distance, these three bodies really are! The bottom image shows the correct size scale for the Sun, Moon and Earth, but only the Earth/Moon distance is to scale. The Sun would be so far away that I’d have to walk into the next office to finish the graphic!

Check out more about full moon tides and hurricanes at Bad Astronomy.