A Rutgers University researcher has confirmed a phenomenon that has been happening every 400,000 years or so for the last 200 million years, and it involves our planet and a couple of other planets in our Milky Way neighborhood.
You ever have those people in your life that, whenever you’re around them, can just kind of knock you out of your orbit?
Well, the Earth does, too! Except those people are planets and they go by the name of “Jupiter” and “Venus.”
Scientists are finally confirming what they’ve suspected for many years, that every 405,000 years the gravitational pull of Jupiter and Venus warp the Earth’s orbit from a circular orbit around the Sun to one that’s 5% elliptical. When the gravitational pull is gone, the Earth resumes its circular orbit and the whole cycle starts all over again.
This phenomenon is known as the Milankovitch cycle and is named after the Serbian astronomer and geophysicist Milutin Milankovic.
In the 1920s, he hypothesized that variations in eccentricity, axial tilt, and precession of the Earth’s orbit resulted in cyclical variation in the solar radiation reaching the Earth, and that this orbital forcing strongly influenced climatic patterns on Earth.
Similar astronomical hypotheses had been advanced in the 19th century by Joseph Adhemar, James Croll and others, but verification was difficult because there was no reliably dated evidence, and because it was unclear which periods were important.
Now, however, thanks to the work Rutgers University geomagnetics researcher Dennis V. Kent who’s studied ancient rock samples from deep under Arizona’s petrified forrest, scientists are getting a clearer picture of how this process works.
In 2013, Kent and his team began drilling rock cores in excess of 1,500 feet long (457 metres) from a butte in the park, analysing them for radioisotopes that indicated their age and evidence of reversals in the polarity of the Earth’s magnetic field.
“It’s an astonishing result because this long cycle, which had been predicted from planetary motions through about 50 million years ago, has been confirmed through at least 215 million years ago,” says geomagnetics researcher Dennis V. Kent from Rutgers University.
“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.”
They went on to say that is is “the most regular astronomical pattern linked to the Earth’s annual turn around the Sun.”
“The beauty of this one is that it stands alone. It doesn’t change. All the other ones move over it.”
While CO2 in the atmosphere is still the biggest variable affecting our climate today, scientists are beginning to understand how Earth has undergone more subtle prolonged heating and cooling periods as a planet.