Sand and water make a remarkable team when it comes to building. But the substrate – the surface you build on – makes a big difference as well. Take a syringe of wet sand and drip it onto a waterproof surface (bottom right), and you’ll get a wet heap that flows like a viscous liquid. Drop the same wet sand onto a surface covered in dry sand (bottom left), and the drops pile up into a tower. Watch the sand drop tower closely, and you’ll see how new drops first glisten with moisture and then lose their shine. The excess water in each drop is being drawn downward and into the surrounding sand through capillary action. This lets the sand grains settle against one another instead of sliding past, giving the sand pile the strength to hold its weight upright. (Video and image credit: amàco et al.)
A new study publishing this week in the Astrophysical Journal by Gary Prézeau of NASA’s Jet Propulsion Laboratory, Pasadena, California, proposes the existence of long filaments of dark matter, or “hairs.” http://ift.tt/1NdQIKk
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“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!
“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!
ESIST.Tech/tv/ recommends | Physics | CERN: The Big Bang Machine | https://esist.tech/tv/
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For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.
Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are connected to one another via hydrogen atoms, an interaction known as hydrogen bonding. These interactions play an important role in nature, because they are responsible for specific properties of proteins or nucleic acids and, for example, also ensure that water has a high boiling temperature.
To date, it has not been possible to conduct a spectroscopic or electron microscopic analysis of hydrogen and the hydrogen bonds in single molecules, and investigations using atomic force microscopy have also not yielded any clear results.
Dr. Shigeki Kawai, from Professor Ernst Meyer’s team at the Swiss Nanoscience Institute and the Department of Physics at the University of Basel, has now succeeded in using a high-resolution atomic force microscope to study hydrogen atoms in individual cyclic hydrocarbon compounds.
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