Geometric Animations / 170402

Hold a buoyant sphere like a ping pong ball underwater and let it go, and you’ll find that the ball pops up out of the water. Intuitively, you would think that letting the ball go from a lower depth would make it pop up higher – after all, it has a greater distance to accelerate over, right? But it turns out that the highest jumps comes from balls that rise the shortest distance. When released at greater depths, the buoyant sphere follows a path that swerves from side to side. This oscillating path is the result of vortices being shed off the ball, first on one side and then the other. (Image and research credit: T. Truscott et al.)

ESIST.Tech/tv/ recommends | Physics | CERN: The Big Bang Machine | https://esist.tech/tv/

Tetrahedrite with Siderite

Locality:  Saint-Pierre-de-Mesage, Vizille, Rhone-Alpes, France

0029

https://player.vimeo.com/video/58293122?title=0&byline=0&portrait=0

Hannah Reber, “Untitled (spin the bottle)”, 2013, installation version #3

Hubble Views The Final Frontier For Dark Matter

“This phenomenon of gravitational lensing stretches galaxies into streaks and arcs, magnifying them, and creating multiple images. It also enables us to reconstruct the mass distribution of the cluster, revealing that it’s mostly due to dark matter.”

When you look out at the distant Universe, you can see all sorts of things: stars, galaxies, clusters of galaxies, going as far back into the distant past as our telescopes can image. But where you have the greatest concentrations of mass, an extreme phenomenon emerges: that of gravitational lensing. Any foreground objects lying behind that mass will have their light stretched, magnified and distorted by the intervening matter. Recently, as part of the Hubble Frontier Fields program, the telescope followed-up on galaxy cluster Abell 370, and revealed the most spectacular gravitational lensing signal ever seen in a galaxy cluster. Most importantly, it provides some very strong evidence not only for dark matter’s existence, but for its presence distinct from any galaxies at all.

Come get the full story in images, videos, and no more than 200 words on this edition of Mostly Mute Monday!