Science
Related: About this forumAncient tree tells chaotic tale of Earth's magnetic field reversal
By Rich Haridy
February 22, 2021
A perfectly preserved ancient tree fossil has offered scientists a unique peek into a moment 42,000 years ago when the Earths magnetic field went haywire. The impressive study paints a picture of temporary environmental chaos, potentially influencing everything from an increase in cave paintings to the extinction of the Neanderthals.
Without the Earths magnetic field wed have a pretty hard time living on the planet. Beyond helping us simply navigate around the world with a compass, the Earths magnetic field is fundamental to the existence of life. It helps deflect harmful solar winds and keeps our protective atmosphere in place.
But our planets magnetic field is far from static. In fact, it is profoundly dynamic, consistently shifting and fluctuating over time. Every few hundred thousand years it completely flips, with magnetic north switching places with magnetic south.
The last major geomagnetic reversal occurred 780,000 years ago, and plenty of scientists suggest we are well overdue for a similar event. In between these full geomagnetic reversals, which can last up to 10,000 years, we find shorter disruptions to the Earths magnetic field. These events are known as geomagnetic excursions.
More:
https://newatlas.com/environment/ancient-tree-geomagnetic-field-shift-environment-chaos/
Baitball Blogger
(46,684 posts)"If a similar event happened today, the consequences would be huge for modern society. Incoming cosmic radiation would destroy our electric power grids and satellite networks."
Chainfire
(17,474 posts)I can't worry about those kinds of things, there are too many more pressing issues to occupy my fret box.
Baitball Blogger
(46,684 posts)niyad
(113,084 posts)Martin Eden
(12,847 posts)The theory that large chunks of our planet's surface are constantly moving wasn't widely accepted by geologists until technology was developed to map the ocean floor including the magnetization of new rock as it upwelled from below the crust. This provided stunning visual evidence of the mid-Atlantic widening that ocean like a conveyor spreading out from that ridge, with stripe after stripe of magnetic flips.
As early as the 1920's it was postulated that the Americas were once joined with Europe and Africa. Not only did the shapes fit together, but the geologic and fossil records along the coastlines were a near perfect match across the ocean where they were once joined. However, "continental drift" was widely rejected until the late 1960's when the ocean floor with its magnetic flips was mapped.