Orbits of Jupiter, Venus affect Earth

Who knew? The orbits of planets hundreds of millions of miles away can change weather patterns on Earth.

Every 405,000 years, gravitational tugs from the planets Jupiter and Venus gradually affect Earth’s climate, according to a study published Monday.

In fact, this pattern has been going on for at least 215 million years and allows scientists to more precisely date geological events like the spread of dinosaurs.

“Scientists can now link changes in the climate, environment, dinosaurs, mammals and fossils around the world to this 405,000-year cycle in a very precise way,” said the study’s lead author, Dennis Kent, an expert in paleomagnetism at Columbia University’s Lamont-Doherty Earth Observatory and Rutgers University.

“The climate cycles are directly related to how the Earth orbits the sun, and slight variations in sunlight reaching Earth lead to climate and ecological changes,” Kent said.

Jupiter and Venus are such strong influences because of their size and proximity. Venus is the nearest planet – at its farthest, only about 162 million miles – and roughly similar in mass to Earth. Jupiter is much farther away but is the solar system’s largest planet.

The study says that every 405,000 years, due to wobbles in our orbit caused by the gravitational pulls of the two planets, seasonal differences on Earth become more intense. Summers are hotter and winters colder; dry times drier, wet times wetter.

At the height of the cycle, more rain falls in the tropics, allowing lakes there to fill up. This compares to the other end of the cycle, when seasonal rains in the tropics “are less and lakes have much less of a tendency to become as full,” Kent said.

The results showed that the 405,000-year cycle is the most regular astronomical pattern linked to the Earth’s annual turn around the sun, he said.