CaptainWacky
I want to smell dark matter
You should get a robot tomato feeder and become one.
Hail forms in the clouds under sub-zero conditions, from 0 to -40 degrees Celsius. A tiny seed of ice begins to collect droplets that almost instantly freeze on contact. The more time hailstones spend in the clouds, the more likely they are to collect more droplets and grow. Supercells are special because they exhibit stronger updrafts than normal storms, keeping hail in the air longer and allowing stones to grow bulkier before they fall out of the air.
You’ll notice some of the ice in the hailstones pictured above look clear, while others have a very thick, opaque white color. Ziegler explains that hailstones can form in two different phases that sometimes go back and forth—a dry phase and a wet phase.
The dry phase happens at colder temperatures: When droplets freeze faster on the surface of a stone, they also freeze more compactly, resulting in denser, more opaque ice. As temperatures increase, however, hailstones release heat that’s pushed to the surface, meaning droplets don’t freeze as fast. Air can get captured in between the stone’s surface and the droplet, creating ice that’s more transparent and less dense.
But what’s with the weird shapes of some of these falling balls of ice? Some stones form are shaped like lumps of dirt clumped together, others have icy tentacles stretching out, and others resemble jellyfish heads sent down from the sky like some biblical tale of punishment.
The European Space Agency (Esa) says its comet lander, Philae, has woken up and contacted Earth.
Philae, the first spacecraft to land on a comet, was dropped on to the surface of Comet 67P by its mothership, Rosetta, last November.
It worked for 60 hours before its solar-powered battery ran flat.
The comet has since moved nearer to the sun and Philae has enough power to work again, says the BBC's science correspondent Jonathan Amos.
An account linked to the probe tweeted the message, "Hello Earth! Can you hear me?"
On its blog, Esa said Philae had contacted Earth, via Rosetta, for 85 seconds in the first contact since going into hibernation in November.
"Philae is doing very well. It has an operating temperature of -35C and has 24 watts available," said Philae project manager Stephan Ulamec.
Scientists say they now waiting for the next contact.
The Perseid meteor shower is the most widely observed and dependable annual meteor display of the year, and its peak this week has all the earmarks of being an excellent example of celestial fireworks, weather permitting.
This year, the Perseids will peak in the overnight hours of Wednesday and Thursday (Aug. 12 and 13) just one day before the new moon. Unlike last year, when a brilliant and nearly full moon washed out all but the brightest meteors, 2015 should be a very opportune year for observing "shooting stars" with your own eyes or cameras. Today, NASA released a video on how to see the 2015 Perseid meteor shower.
Another reason that the Perseids could put on a better-than-average show this year is an assist from the planet Jupiter.