Source: USA Today
Who knew? The orbits of planets hundreds of millions of miles away can change weather patterns here on Earth.
Every 405,000 years, gravitational tugs from the planets Jupiter and Venus gradually affect Earth's climate and life forms, according to a new 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 study lead author Dennis Kent, an expert in paleomagnetism at Columbia University's Lamont-Doherty Earth Observatory and Rutgers University.
The cycle has been happening for hundreds of millions of years, from before the rise of dinosaurs, and is still active today, scientists say.
“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,” said Kent, who studies Earth’s magnetic field.
Jupiter and Venus are such strong influences because of their size and proximity. Venus is the nearest planet to us — at its farthest, only about 162 million miles — and roughly similar in mass. 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 here 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.
Right now, we are in the middle of the cycle, as the most recent peak was around 200,000 years ago.
The climate impact from the planets pales when compared to how humans are affecting the planet from burning fossil fuels, for example. "It's pretty far down on the list of so many other things that can affect climate on times scales that matter to us," Kent said.
"All the carbon dioxide we're pouring into the air right now is the obvious big enchilada. That's having an effect we can measure right now. The planetary cycle is a little more subtle."
The study appeared in the Proceedings of the National Academy of Sciences, a peer-reviewed scientific journal.
Source: USA Today
Note: I personally do not agree with the author of the above article that "All the carbon dioxide we're pouring into the air right now is the obvious big enchilada." Earth has gone through very radical changes in its global climate several times across its entire history, and I doubt that carbon dioxide emissions would have had anything to do with that.
Medieval maps have been found upon which the natural outline of Antarctica was entirely visible as it exists under the ice, suggesting that there may have been no ice on Antarctica at all in those days. But blaming climate change on carbon dioxide emissions is of course a political goldmine, because it...
- allows for carbon capping, carbon taxing and carbon trading; and it
- makes the concept of (the already proposed) population reduction politically debatable, and by consequence, socially acceptable.
In addition to that, solar activity and solar flares in particular have also already been shown to gravely affect the climate at the site of impact. But solar activity cannot be taxed or traded, of course.