Oct 20, 2021 06:44 PM
Thousands of tiny ‘ice needles’ may explain mysterious stone patterns on Earth … and Mars
https://www.livescience.com/ice-needles-...formations
INTRO: Some of the most breathtaking zen garden patterns on the planet owe their existence to an unlikely artist: thousands of tiny "ice needles." From swirls to circles to orderly rows, each delicate design is created when similarly-sized stones clump together across a landscape.
New research published in the Proceedings of the National Academy of Sciences documents, for the first time, how ice needles create intricate patterns of stone in various landscapes. As ice needles freeze, they nudge small rocks to one side or another. Over time, the rocks become concentrated in one area, forming a design. The work confirms more than a century's worth of scientific speculation about the relationship between ice needles and stone patterns, said study coauthor Bernard Hallet, a geologist at the University of Washington. And it might shed light on the origins of an even more mysterious set of patterns — ones found on Mars... (MORE)
Earth Tipped on Its Side 84 Million Years Ago, New Evidence Suggests
https://www.sciencealert.com/there-s-evi...-years-ago
EXCERPTS: We know that true polar wander (TPW) can occasionally tilt whole planets and moons relative to their axes, but it's not entirely clear just how often this has happened to Earth. Now a new study presents evidence of one such tilting event that occurred around 84 million years ago – when dinosaurs still walked the Earth.
Researchers analyzed limestone samples from Italy, dating back to the Late Cretaceous period (100.5 to 65.5 million years ago), looking for evidence of shifts in the magnetic record that would point towards an occurrence of TPW. Bacteria fossils trapped in the rock, forming chains of the mineral magnetite, offer some of the most convincing evidence yet of true polar wander in the Late Cretaceous – and it may help settle a scientific debate that's been going on for decades.
"This observation represents the most recent large-scale TPW documented and challenges the notion that the spin axis has been largely stable over the past 100 million years," the researchers explain in their paper.
[...] According to the study, there was around a 12 degree tilt on Earth around 84 million years ago, which was corrected relatively quickly – within about 5 million years, the equivalent of a "cosmic yo-yo" in the words of the researchers...(MORE - missing details)
https://www.livescience.com/ice-needles-...formations
INTRO: Some of the most breathtaking zen garden patterns on the planet owe their existence to an unlikely artist: thousands of tiny "ice needles." From swirls to circles to orderly rows, each delicate design is created when similarly-sized stones clump together across a landscape.
New research published in the Proceedings of the National Academy of Sciences documents, for the first time, how ice needles create intricate patterns of stone in various landscapes. As ice needles freeze, they nudge small rocks to one side or another. Over time, the rocks become concentrated in one area, forming a design. The work confirms more than a century's worth of scientific speculation about the relationship between ice needles and stone patterns, said study coauthor Bernard Hallet, a geologist at the University of Washington. And it might shed light on the origins of an even more mysterious set of patterns — ones found on Mars... (MORE)
Earth Tipped on Its Side 84 Million Years Ago, New Evidence Suggests
https://www.sciencealert.com/there-s-evi...-years-ago
EXCERPTS: We know that true polar wander (TPW) can occasionally tilt whole planets and moons relative to their axes, but it's not entirely clear just how often this has happened to Earth. Now a new study presents evidence of one such tilting event that occurred around 84 million years ago – when dinosaurs still walked the Earth.
Researchers analyzed limestone samples from Italy, dating back to the Late Cretaceous period (100.5 to 65.5 million years ago), looking for evidence of shifts in the magnetic record that would point towards an occurrence of TPW. Bacteria fossils trapped in the rock, forming chains of the mineral magnetite, offer some of the most convincing evidence yet of true polar wander in the Late Cretaceous – and it may help settle a scientific debate that's been going on for decades.
"This observation represents the most recent large-scale TPW documented and challenges the notion that the spin axis has been largely stable over the past 100 million years," the researchers explain in their paper.
[...] According to the study, there was around a 12 degree tilt on Earth around 84 million years ago, which was corrected relatively quickly – within about 5 million years, the equivalent of a "cosmic yo-yo" in the words of the researchers...(MORE - missing details)