Why Nature Loves Fractals

Trees, blood vessels, and rivers all follow branching patterns that make their pieces look very similar to their whole. We call this repeating, self-similar shape a fractal, and this Be Smart video explores why these branching patterns are so common, both in living and non-living systems. For trees, packing a large, leafy surface area onto the smallest amount of wood makes sense; the tree needs plenty of solar energy (and water and carbon dioxide) to photosynthesize, and it has to be efficient about how much it grows to get that energy. Similarly, our lungs and blood vessels need to pack a lot of surface area into a small space to support the diffusion that lets us move oxygen and waste through our bodies. Non-living systems, like the branches of viscous fingers or river deltas or the branching of cracks and lightning, rely on different physics but wind up with the same patterns because they, too, have to balance forces that scale with surface area and ones that scale with volume. (Video and image credit: Be Smart)

#biology #branchingFlow #diffusion #fluidDynamics #fractals #mathematics #physics #riverDeltas #science #trees #viscousFingering

Growing Downstream

This astronaut photo shows Madagascar’s largest estuary, as of 2024. On the right side, the Betsiboka River flows northwest (right to left, in the image). Less than 100 years ago, most of the estuary was navigable by ships, but now more than half of it is taken up by the river delta. Upstream on the river, extensive logging and expansions to farmland have caused severe soil erosion; the river carries that sediment downstream, dyeing the waters reddish-orange. As the river branches and the flow slows, that sediment falls out of suspension, building up islands and seeding new sand bars further downstream.

In the image above, you can compare the 2024 delta to the way it looked in 1984. Letters A, B, C, and D mark the downstream-most islands from 1984. Today newer islands and sand bars sit even further downstream. (Image credit: NASA; via NASA Earth Observatory)

#astronaut #erosion #flowVisualization #fluidDynamics #physics #riverDeltas #rivers #science #sedimentTransport #sedimentation

Streams of blue and yellow braid across Iceland’s volcanic landscape in this award-winning photo from Miki Spitzer. Glacial water shows an icy blue and sediments glisten in gold. Together, their interplay creates an arresting delta viewed from above. (Image credit: M. Spitzer; via WNPA)

https://fyfluiddynamics.com/2024/06/earths-treasure/

#fluidDynamics #fluidsAsArt #glacier #physics #riverDeltas #rivers #science #sedimentTransport

#ClimateChange makes underlying problems worse, and there are plenty of those in #RiverDeltas

"Our analysis shows that certain risks are more critical to some deltas than others. These risks include land subsidence, increasing population density, intensive agriculture, ineffective governance and a lack of capacity to adapt."

#ClimateChangeIsTheLastStraw
https://theconversation.com/river-deltas-are-threatened-by-more-than-climate-change-leaving-hundreds-of-millions-of-people-at-risk-218304

Referenced link: https://phys.org/news/2023-03-river-deltas-valuable-threat.html
Discuss on https://discu.eu/q/https://phys.org/news/2023-03-river-deltas-valuable-threat.html

Originally posted by Phys.org / @physorg_com: http://nitter.platypush.tech/physorg_com/status/1636744202032672768#m

#Riverdeltas: Valuable and under threat @OneEarth_CP https://phys.org/news/2023-03-river-deltas-valuable-threat.html

Gràcies a tots els que heu participat avui al webinar sobre #RiverDeltas al @europarl_cat.

L’#EbreDelta necessita mesures urgents i de llarg termini per revertir la regressió de la línia de costa. Cal voluntat d’entesa per part del govern espanyol i la CHE.

#DeltasClimateChange
https://nitter.cattube.org/toni_comin/status/1334202503433482241#m

2020-12-02 18:27:19