Praise then darkness, and creation unfinished

Putting this here partly so I can find them again:

Cricket frogs crossing water: The motion has previously been called "skittering" along the water surface. Video shows that it's similar to what porpoises do. The frogs repeatedly leap out of the water and submerging again, moving forward with each leap (via conuly)


Dragonfly acrobatics: some dragonflies dunk themselves in the water to cool off. They submerge briefly, then fly vertically upwards, and do rapid loop-the-loops to dry off (via andrewducker; paywalled)

Over on File 770, Ingvar has been posting the serial adventures of Trigger Snowflake, a sort of parody of old sf pulp magazines and the Sad Puppies. In the latest episode, a court forbids someone to express gratitude "except within Venostationary orbit."

In the comments, Ingvar noted that they're not sure how crazily big Venostationary orbit is. So, I googled, and found that someone had posted the answer a few years back: about a million and a half kilometers. The search results also led me to something I found more interesting, Emily Lakdawalla’s discussion of keeping a comsat in stationary orbit over Mars, which she was looking at in terms of communications with Mars landers.

The calculations, and the task, are tricky because planets aren’t actually uniform spheres, producing gravitational irregularities that cause a “geosynchronous” satellite to drift over time. So, the satellites need fuel, mostly to keep them over the equator, but also to keep them from shifting longitude. Mars's gravitational field is more irregular than Earth (in part because of those huge shield volcanoes), making it much harder/more expensive to keep a geo”stationary” satellite in position.