物理学家说，沙丘之间相互作用，相互“交流”

物理学家说，沙丘之间相互作用，相互“交流”

Whether on land or underwater, sand dunes usually appear in large groups. But even when these natural formations are in close touch with their neighbours, they still need their personal space from time to time.

无论是在陆地上还是在水下，沙丘总是成群出现。但即使这些自然形态与它们的邻居有密切的联系，它们仍然不时地需要自己的私人空间。

When two identical dunes migrate over long distances, physicists have found these structures will unexpectedly change their pace so they end up evenly spread out, prompting speculation about how these mounds of sand can 'communicate'.

当两个相同的沙丘长距离移动时，物理学家发现这些结构会出人意料地改变它们的速度，所以它们最终会均匀地分散开来，这引发了人们对这些沙丘如何“交流”的猜测。

They're definitely communicating, physicist Nathalie Vriend from Cambridge University said in an interview with The Washington Post.

来自剑桥大学的物理学家Nathalie Vriend在接受《华盛顿邮报》的采访时说:“它们确实在交流。”

Obviously, sand dunes can't speak to each other. But the researchers argue that the influence dunes have on the forces moving them - such as wind or water - changes how those forces affect other dunes around them, making these physical structures 'communicate' their position.

很明显，沙丘之间不能相互交流。但研究人员认为，沙丘对风或水等移动它们的力量的影响改变了这些力量对周围其他沙丘的影响，使这些物理结构“传达”了它们的位置。

This is contrary to what many theoretical models have supposed about dune migration, which occurs so slowly and across such great distances that it's extremely difficult to study.

这与许多理论模型对沙丘迁移的假设相反，沙丘迁移发生得如此缓慢，跨越如此遥远的距离，以至于很难进行研究。

Generally, these structures are seen as self-propelling autonomous agents that can sometimes collide and consume each other, but not necessarily collaborate.

一般来说，这些结构被看作是自我推动的自主主体，它们有时会相互碰撞和消耗，但不一定会相互协作。

We've discovered physics that hasn't been part of the model before, says Vriend.

Vriend说:“我们已经发现了以前模型中没有的物理学。”

By creating a rotating water-filled channel, the team was able to keep two identical dunes swirling in circles for hours at a time. Rather than moving at the same initial pace, the dune in front initially sped up.

通过创建一个旋转的充满水的通道，该团队能够让两个相同的沙丘一次旋转几个小时。前面的沙丘一开始并没有以同样的速度移动，而是加速了。

Once it had travelled 180 degrees to reach the opposite side of the circular channel, the leading dune slowed down to the same pace as the other.

当它转了180度到达环形水道的另一边时，领头的沙丘就放慢了速度。

The flow structure behind the front dune is like a wake behind a boat, explains Vriend, "and affects the properties of the next dune."

“前面沙丘后面的流动结构就像船后面的尾流，”Vriend解释说，“并影响下一个沙丘的性质。”

By creating turbulence in the water flow, the first dune pushes the one behind it. In other words, the leading structure is interacting with and repelling its downstream neighbour - 'communicating' through its wake, and giving up very little of its own mass in the process.

通过在水流中制造湍流，第一个沙丘推动后面的沙丘。换句话说，主导的结构与下游的邻居相互作用并相互排斥——通过尾流“交流”，在这个过程中只放弃了很少的一部分。

This repulsion for nearby sand dunes has been observed in satellite images before, but the forces behind it have never been understood.

这种对附近沙丘的排斥在以前的卫星图像中已经被观察到，但其背后的力量却从未被了解。

We conclude therefore that it is plausible that the structure of natural underwater dune fields is controlled and stabilised by the same dune-dune repulsion mechanism observed in this work, the authors write.

作者写道:“因此，我们得出的结论是，自然水下沙丘场的结构似乎是由在这项研究中观察到的相同的沙丘-沙丘推斥机制控制和稳定的。”

If this activity also exists on land, it could be incredibly important for climate change preparation. Over the years, global warming has increased dune movement in certain parts of the world, including in the US, Africa, and Antarctica.

如果这种活动也存在于陆地上，它可能对气候变化的准备工作非常重要。多年来，全球变暖已经增加了世界某些地区的沙丘移动，包括美国、非洲和南极洲。

Figuring out where these massive structures of sand are headed - and how they travel - could allow us to prepare farms, roads, infrastructure and livelihoods for the oncoming collision.

弄清楚这些巨大的沙子结构将走向何方——以及它们如何移动——可以让我们为即将到来的碰撞准备好农场、道路、基础设施和生计。

The study was published in Physical Review Letters.

这项研究发表在《物理评论快报》上。