Nav: Home

How landscapes and landforms 'remember' or 'forget' their initial formations

April 26, 2018

Crescent dunes and meandering rivers can "forget" their initial shapes as they are carved and reshaped by wind and water while other landforms keep a memory of their past shape, suggests a new laboratory analysis by a team of mathematicians.

"Asking how these natural sculptures come to be is more than mere curiosity because locked in their shapes are clues to the history of an environment," explains Leif Ristroph, an assistant professor at New York University's Courant Institute and the senior author of the paper, which appears in the journal Physical Review Fluids. "In our lab experiments, we found that some shapes keep a 'memory' of their starting conditions as they develop while others 'forget' the past entirely and take on new forms."

The paper's authors, who also included Megan Davies Wykes, a former postdoctoral researcher at the Courant Institute and currently postdoctoral researcher at the University of Cambridge, Jinzi Huang, a doctoral student of mathematics, and George Hajjar, an NYU undergraduate, note that this understanding is vital in geological dating and in understanding how landscapes form.

Shape "memory" and its "loss"--or the retention of or departure from earlier formations--are key issues in geomorphology, the field of study that tries to explain landforms and the developing face of the Earth and other celestial surfaces. The morphology, or shape of a landscape, is the first and most direct clue into its history and serves as a scientific window for a range of questions--such as inferring flowing water on Mars in the past as well as present-day erosion channels and river islands.

"The answer to the question 'What's in a shape?' hinges on this memory property," explains Ristroph, who directs NYU's Applied Math Lab, where the research was conducted.

To shed light on these phenomena, Ristroph and his colleagues replicated nature's dissolvable minerals--such as limestone--with a ready-made stand-in: pieces of hard candy. Specifically, they sought to understand how the candy dissolved to take different forms when placed in water.

To mimic different environmental conditions, they cast the candy into different initial shapes, which led to different flow conditions as the surface dissolved. Their results showed that when the candy dissolved most strongly from its lower surface, it tended to retain its overall shape--reflecting a near-perfect memory. By contrast, when dissolved from its upper surface, the candy tended to erase or "forget" any given initial shape and form an upward spike structure.

The key difference, the team found, is the type of water flow that "licks" and reshapes the candy. Turbulent flows on the underside tend to dissolve the candy at a uniform rate and thus preserve the shape. The smooth flow on an upper surface, however, carries the dissolved material from one location to the next, which changes the dissolving rate and leads to changes in shape.

"Candy in water may seem like a far cry from geology, but there are in fact whole landscapes carved from minerals dissolving in water, their shapes revealed later when the water table recedes," he adds. "Caves, sinkholes, stone pillars and other types of craggy terrain are born this way."
-end-
The paper may be downloaded here: https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.3.043801

New York University

Related Memory Articles:

Memory of the Venus flytrap
In a study to be published in Nature Plants, a graduate student Mr.
Memory protein
When UC Santa Barbara materials scientist Omar Saleh and graduate student Ian Morgan sought to understand the mechanical behaviors of disordered proteins in the lab, they expected that after being stretched, one particular model protein would snap back instantaneously, like a rubber band.
Previously claimed memory boosting font 'Sans Forgetica' does not actually boost memory
It was previously claimed that the font Sans Forgetica could enhance people's memory for information, however researchers from the University of Warwick and the University of Waikato, New Zealand, have found after carrying out numerous experiments that the font does not enhance memory.
Memory boost with just one look
HRL Laboratories, LLC, researchers have published results showing that targeted transcranial electrical stimulation during slow-wave sleep can improve metamemories of specific episodes by 20% after only one viewing of the episode, compared to controls.
VR is not suited to visual memory?!
Toyohashi university of technology researcher and a research team at Tokyo Denki University have found that virtual reality (VR) may interfere with visual memory.
The genetic signature of memory
Despite their importance in memory, the human cortex and subcortex display a distinct collection of 'gene signatures.' The work recently published in eNeuro increases our understanding of how the brain creates memories and identifies potential genes for further investigation.
How long does memory last? For shape memory alloys, the longer the better
Scientists captured live action details of the phase transitions of shape memory alloys, giving them a better idea how to improve their properties for applications.
A NEAT discovery about memory
UAB researchers say over expression of NEAT1, an noncoding RNA, appears to diminish the ability of older brains to form memories.
Molecular memory can be used to increase the memory capacity of hard disks
Researchers at the University of Jyväskylä have taken part in an international British-Finnish-Chinese collaboration where the first molecule capable of remembering the direction of a magnetic above liquid nitrogen temperatures has been prepared and characterized.
Memory transferred between snails
Memories can be transferred between organisms by extracting ribonucleic acid (RNA) from a trained animal and injecting it into an untrained animal, as demonstrated in a study of sea snails published in eNeuro.
More Memory News and Memory Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Warped Reality
False information on the internet makes it harder and harder to know what's true, and the consequences have been devastating. This hour, TED speakers explore ideas around technology and deception. Guests include law professor Danielle Citron, journalist Andrew Marantz, and computer scientist Joy Buolamwini.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.