If you made a beach using grains the proportionate size of the stars in the Milky Way, what would that beach look like?

Jeff Wartes

Sand is interesting.^{[Citation needed]}

"Are there more grains of sand than stars in the sky?" is a popular question which has been tackled by many people. The upshot is that there are probably more stars in the visible universe than grains of sand on all of Earth's beaches.

When people do those calculations, they often dig up some good data on the number of stars, then do some hand-waving about sand grain size to come up with a number for the sand grains on Earth.[1]From a practical point of view, geology and soil science are more complicated than astrophysics. We're not going to tackle that issue today, but to answer Jeff's question, we do need to figure out what the deal with sand is.[2]"i like sand because i don't really know what it is and there's so many of it"

—@darth__mouth Specifically, we need to have some idea of what grain sizes correspond to clay, silt, fine sand, coarse sand, and gravel, so we can understand how our galaxy would look and feel if it were a beach.[3]Instead of just containing a bunch of them.

Fortunately, there's a wonderful chart by the US Geologic Survey that answers all these questions and more. For some reason, I find this chart very satisfying—it's like the erosion geology edition of the electromagnetic spectrum chart.

According to surveys of sand,[4]There are apparently lots of them. the grains found on beaches tend to run from 0.2mm to 0.5mm (with the finest layers on top). This corresponds to medium-to-coarse sand in the chart. The individual grains are about this big:

If we assume the Sun corresponds to a typical sand grain, then multiply by the number of stars in the galaxy, we come up with a large sandbox worth of sand.[5]I mean, you come up with a bunch of numbers, but imagination turns them into a sandbox.

However, this is wrong. The reason: Stars aren't all the same size.

There are a number of widely-circulated YouTube videos comparing star sizes. They do a good job of getting across just how staggeringly large some stars are. Although it's easy to get lost in the videos and lose track of scale, it's clear that some of the grains in our sandbox universe would be more like boulders.

Here's how the main-sequence[6]The stars in the main part of their fuel-burning lifecycle. star-sand grains look:

They mostly fall into the "sand" category, though the larger Daft Punk stars cross the line into "granules" or "small pebbles".

However, that's just the main sequence stars. Dying stars get much, much bigger.

When a star runs out of fuel, it expands into a red giant. Even ordinary stars can produce huge red giants, but when a star that's already massive enters this phase, it can become a true monster. These red supergiants are the largest stars in the universe.

These beachball-sized sand stars would be rare, but the grape-sized and baseball-sized red giants are relatively common. While they're not nearly as abundant as Sun-like stars or red dwarfs, their huge volume means that they'd constitute the bulk of our sand. We would have a large sandbox worth of grains ... along with a field of gravel that went on for miles.

The little sand patch would contain 99% of the pile's individual grains, but less than 1% of its total volume. Our Sun isn't a grain of sand on a soft galactic beach; instead, the Milky Way is a field of boulders with some sand in between.

But, as with the real Earth seashore, it's the rare little stretches of sand between the rocks where all the fun seems to happen.

Comic URL: http://www.lefthandedtoons.com/1598/

Michael Fennel es un pintor un tanto particular: durante los últimos 16 años ha estado investigando una técnica de pintura basada en la disposición de humo sobre lienzo. El resultado, como podéis comprobar, es brillante (vale, no es la palabra más adecuada para hablar de algo básicamente negro, pero creo que me entendéis).

Aunque la técnica de Fennel permanece en secreto, está claro que no lo hace a base de fumar frente al lienzo. Posiblemente lo coloque en horizontal sobre velas (o algún motor) de forma que pueda crear el dibujo desde el reverso y sea la proximidad a la llama la que defina los contornos y la intensidad. O a lo mejor la pintura al humo es algo completamente distinto; no se sabe con exactitud y quizás allí radique parte de su encanto.

Visto en Gizmodo

Comic URL: http://www.lefthandedtoons.com/1596/

We just received a wonderful update from Alice Pasquini sharing her recent works in Madrid. Big or small, we love how she continues to leave her mark all around the world.

Comic URL: http://www.lefthandedtoons.com/1595/

Comic URL: http://www.lefthandedtoons.com/1594/

This is part of a series of portraits of my friend @franceszonita . I used blue black fountain pen ink + soft pastels on a rough watercolor paper. #portrait #ink #robertalejandro

Comic URL: http://www.lefthandedtoons.com/1592/

Comic URL: http://www.lefthandedtoons.com/1590/

An awesome compilation of “text book art” from the Internet! Enjoy!

[Via TechEblog | @___ayatakaoisii]

Económico, práctico y, sobre todo, muy original.
Ideal para abuelitos innovadores y creadores de tendencias en el mundo de la moda.

Visto en imgur

Hemos visto con anterioridad multitud de complementos para que el gato pueda vivir sus propias aventuras en casa sin destruir nuestro mobiliario. Lo que propone Goldtatze es más de lo mismo pero llevado al extremo.

Con todas estas plataformas, puentes, nidos y obstáculos los gatos no pueden menos que ser felices y olvidar de una vez por todas esa manía suya de ser unas criaturas diabólicas que cambian de personalidad cuando hay una cámara de fotos cerca.

Sí es cierto que esto también añade otro peligro, ya que el ataque puede provenir de cualquier lugar de la casa, pero yo creo que estarán lo suficientemente entretenidos como para no seguir sus instintos. Si no es así, bueno, un gato aéreo es decididamente un enemigo a tener en cuenta.

Visto en Web Urbanist

Aunque a primera vista lo primero que parece Onewheel es el último grito para los skaters, en realidad su concepto tiene mucho más que ver con el surf urbano. Sus creadores aseguran que querían saber lo que era surfear la ciudad y, tras cinco años de duro trabajo, han conseguido dar con el prototipo que les permitirá hacerlo.

Onewheel funciona de forma muy sencilla: una vez subido en él y tras haberlo encendido y cargado, Onewheel avanzará hacia el lugar donde sienta más peso corporal. Supongo que con el tiempo aparecerán virtuosos que hagan espectáculos con él, pero la idea es que sea un medio de transporte más o menos tranquilo, para aquellos que piensan que usar un segway te convierte automáticamente en el tipo malo de la película.

Visto en Geeks are Sexy

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