Antarctica is sitting on top of Earth's weakest gravitational pull, and it may explain how the ice sheet formed 34 million years ago.
There's a "gravity hole" over the Ross Sea, a region where Earth's gravitational pull is measurably weaker than anywhere else on the planet. It's been there for at least 70 million years.
Scientists just essentially CT-scanned the entire planet using earthquake waves and ran Earth's internal dynamics backwards through 70 million years of history to figure out why.
What they found: ancient tectonic plates that dove beneath Antarctica hundreds of millions of years ago are still sinking through the deep mantle. But about 35 million years ago, a massive upwelling of hot material from near Earth's core began rising beneath the Ross Sea, amplifying the gravity anomaly by 30%.
The gravity shift was so significant it caused Earth's rotation axis to physically wobble, a sharp change in the planet's spin confirmed independently by paleomagnetic records.
And here's the wildest part: the timing of this gravity transition lines up almost perfectly with when Antarctica froze over 34 million years ago. The researchers hypothesize that gravity-driven sea level changes may have helped create the conditions for Earth's largest ice sheet to form.
We're still discovering fundamental things about how our planet works. The Earth is wild.
There's a "gravity hole" over the Ross Sea, a region where Earth's gravitational pull is measurably weaker than anywhere else on the planet. It's been there for at least 70 million years.
Scientists just essentially CT-scanned the entire planet using earthquake waves and ran Earth's internal dynamics backwards through 70 million years of history to figure out why.
What they found: ancient tectonic plates that dove beneath Antarctica hundreds of millions of years ago are still sinking through the deep mantle. But about 35 million years ago, a massive upwelling of hot material from near Earth's core began rising beneath the Ross Sea, amplifying the gravity anomaly by 30%.
The gravity shift was so significant it caused Earth's rotation axis to physically wobble, a sharp change in the planet's spin confirmed independently by paleomagnetic records.
And here's the wildest part: the timing of this gravity transition lines up almost perfectly with when Antarctica froze over 34 million years ago. The researchers hypothesize that gravity-driven sea level changes may have helped create the conditions for Earth's largest ice sheet to form.
We're still discovering fundamental things about how our planet works. The Earth is wild.
2
