Water Is One Of Those Strange Materials That Expands When It Freezes, Which Raises An Interesting Question:

Water is one of those strange materials that expands when it freezes, which raises an interesting question: what happens to a water drop that freezes from the inside out? A freezing water droplet quickly forms an ice shell (top image) that expands inward, squeezing the water inside. As the pressure rises, the droplet develops a spicule – a lance-like projection that helps relieve some of the pressure.

Eventually the spicule stops growing and pressure rises inside the freezing drop. Cracks split the shell, and, as they pull open, the cracks cause a sudden drop in pressure for the water inside (middle image). If the droplet is large enough, the pressure drop is enough for cavitation bubbles to form. You can see them in the middle image just as the cracks appear.

After an extended cycle of cracking and healing, the elastic energy released from a crack can finally overcome surface energy’s ability to hold the drop together and it will explode spectacularly (bottom image). This only happens for drops larger than a millimeter, though. Smaller drops – like those found in clouds – won’t explode thanks to the added effects of surface tension. (Image credit: S. Wildeman et al., source)

2017 May 6

Galaxy Cluster Abell 370 and Beyond Image Credit: NASA, ESA, Jennifer Lotz and the HFF Team (STScI)

Explanation: Some 4 billion light-years away, massive galaxy cluster Abell 370 only appears to be dominated by two giant elliptical galaxies and infested with faint arcs in this sharp Hubble Space Telescope snapshot. The fainter, scattered bluish arcs along with the dramatic dragon arc below and left of center are images of galaxies that lie far beyond Abell 370. About twice as distant, their otherwise undetected light is magnified and distorted by the cluster’s enormous gravitational mass, dominated by unseen dark matter. Providing a tantalizing glimpse of galaxies in the early universe, the effect is known as gravitational lensing. A consequence of warped spacetime it was first predicted by Einstein a century ago. Far beyond the spiky foreground Milky Way star at lower right, Abell 370 is seen toward the constellation Cetus, the Sea Monster. It is the last of six galaxy clusters imaged in the recently concluded Frontier Fields project.

∞ Source: apod.nasa.gov/apod/ap170506.html

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hannahhaifisch

7 years ago

Physicists Confirm Quantum Theory Proposed in 1930s

http://www.sci-news.com/physics/quantum-tunneling-water-05422.html

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hannahhaifisch

8 years ago

0063

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hannahhaifisch

8 years ago

“XYZ I” by ale_beber_origami http://flic.kr/p/TiaETp

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hannahhaifisch

8 years ago

June 8th Is World Oceans Day - A Day To Celebrate The Oceans That Connect And Sustain All Of Us. Our

June 8th is World Oceans Day - a day to celebrate the oceans that connect and sustain all of us. Our colleagues at the Biodiversity Heritage Library have been leading up to today with a series of blog posts exploring historic publications that mark important milestones in the progress of marine bioscience research and ocean exploration.

Top image: Whale shark from Illustrations of the zoology of South Africa… v.4 (1845) Middle top : radiolarians and jellyfish from Ernst Haeckle’s Kunstformen der Natur (1904) Middle bottom: giant squid from Cassell’s Natural History v.5-6 and cuttlefish from Voyage de la corvette l'Astrolabe Mollusques and Zoophytes Atlas (1833) Bottom: deep sea fish from Valdivia Expedition…1898-1899. Bd. 15, T. 1

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