00:05In high-latitude permafrost environments and high-altitude mountains, there are a large
00:12number of mysterious regular surface patterning, also known as patterning, such as the Qinghai
00:19Tibet Plateau and other freezing regions in China.
00:23The Svalbard Islands in Norway in the Arctic and the Alpine regions in Ethiopia.
00:31The patterned ground is made up of different kinds of stones and soils, some arranged in
00:37polygonal net, stone circles, and others in strapped spatial patterns.
00:44The origin of these regular patterns has long been puzzling scientists.
00:48But recently, this enigma is starting to be solved.
00:56Scientists now attribute the spontaneous regular patterns to a process called spatial self-organization.
01:04In the periglacial environment, when scouring together with soil freezing thorn cycles are
01:11speculated to drive the aggregation and separation movements of granular particles in the soil,
01:19which eventually result in assorted spatial patterns of stones on the land surfaces.
01:31This idea has been sparked by theoretical and empirical studies in physics, chemistry, biology, and ecology.
01:40However, it is notoriously difficult to test this idea in the field.
01:45The geomorphological systems in cold regions often evolve at extremely slow rates, largely forbidden
01:54human observers to record the processes.
01:58Many existing numerical models have suggested that differential frost heave and radial expansion
02:05of the fine-grained soils can lead to the movement of surface particles to the margins of the plugs
02:12and the formation of the self-organized patterns.
02:15This mechanism can reproduce a variety of large-scale sorted patterns, such as polygons and sorted circles.
02:24But direct experimental evidence for this model is still lacking.
02:29Scientists have long speculated that needle eyes formed in the permafrost layer could play
02:35a role.
02:36A new research led by an international team from China, Japan, the US, and the Netherlands
02:43revisited this old idea with brand new evidence and theory.
02:48The researchers designed an elegant experiment system that allows for the formation of needle
02:54eyes in well-controlled lab conditions.
02:58This system can mimic a time machine with which the observers can push the fast-forward button
03:04to speed up the process of land surface evolution within a microcosm.
03:09Within a couple of weeks, the researchers can now observe the years or even decades-long process
03:16happening in nature.
03:18They use video camera and computer program to automatically track the movement trajectory of
03:25every single stone and reproduce such observed processes in computers with mathematical models.
03:31The researchers found that, driven by the freezing thong cycles in soils, the surface granular particles
03:37migrated towards the stone-rich areas from stone-poor areas.
03:42This is exactly the process where a variety of order spatial patterns of stones arises from.
03:49This group of scientists have replicated the experiment numerous times with all kinds of settings
03:56of needle-eyes properties and stone-field concentration.
04:00They put together these nonlinear relationships between different needle-eyes height and stone-field concentration
04:06to demonstrate that the geomorphological pattern formation process has the same physical principle,
04:12as that underpins the water-oil separation process.
04:26Known as phase-separation mechanism, the phase-separation theory perfectly reproduced the different
04:33types of sorted patterns and found that the activity of needle-eyes plays a dominant role in
04:38shaping this pattern ground.
04:42What makes the scientists more exciting is that their phase-separation model can also perfectly
04:47reproduce the similar sorted patterns found in the Martian boulders by curiosity.
04:53Can this be seen as another evidence, reinforcing the existence of soil-water on Mars?
04:59Just this mean freezing thong cycles also drive the evolution of Martian landscapes.
05:05It's still too early to answer this question, but this study does open many opportunities to
05:12look into geological and geomorphic evolution of Earth-like planets.
05:17Let's see.
05:18Let's see.
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