From The New York Times, Olympics 2014: The Science of Snowmaking:
Machines make snow the same way nature does, by freezing water droplets. But they do it a few feet above the ground, rather than in the much colder conditions high in the atmosphere. Snowmaking machines employ a few thermodynamic tricks to help, but at times there is a limit to what physics can do…
…a droplet may not freeze entirely during the few seconds it takes to fall to the ground — what snowmakers call hang time.
“We’re basically making eggs,” Mr. Moulton said — icy shells around still-liquid centers.
Related snow videos: when nature handles it, How Is Snow Made?
How can we know the size, composition, and atmospheric makeup of distant exoplanets? NASA explains the details in this Alien Atmospheres video.
By observing periodic variations in the parent star’s brightness and color, astronomers can indirectly determine an exoplanet’s distance from its star, its size, and its mass. But to truly understand an exoplanet astronomers must study its atmosphere, and they do so by splitting apart the parent star’s light during a planetary transit.
Watch more astronomy videos, including Measuring the Universe and The Hubble Ultra Deep Field.
via Boing Boing.
With its exceptional hearing, the red fox can detect when a small animal is scurrying around up to 3 feet under the snow, and their high jump to surprise and catch that animal — called “mousing” — is pretty spectacular. But even more spectacular is what we can’t see: the possible influence of magnetic alignment.
Jaroslav Červený and a large research team observed almost 600 mousing jumps by 84 foxes, and based on the data, they proposed that “…mousing red foxes may use the magnetic field as a ‘range finder’ or targeting system to measure distance to its prey…” From Ed Yong in 2011:
If they pounced to the north-east, they killed on 73% of their attacks; if they jumped in the opposite direction, they success rate stayed at 60%. In all other directions, only 18% of their pounces were successful…
Many animals have magnetoreception capabilities including birds, bats, mice, mole rats, fruit flies, honeybees, turtles, lobsters, sharks and stingrays.
If Červený is correct, then the red fox is unique in many ways. It would be the first animal known to use a magnetic sense to hunt, and the first to use magnetic fields to estimate distance rather than direction or position.
File under: magnetic field. Related jumping: pronking springboks.