Interesting Stuff Thread

He [Rick Grosberg] and his colleagues studied two closely related 'cushion stars', Cryptasperina pentagona and C. hystera, living on the Australian coast. They're identical in appearance but live in different regions, with Hystera occuring on a few beaches and islands at the far southern end of the range of pentagona.

And their sex lives are very, very different. Pentagona has male and female individuals that release sperm and eggs into the water where they fertilize, grow into larvae and float around for a few months before settling down and developing into adult sea stars.

Hystera, by contrast, are hermaphrodites that brood their young internally and give birth to miniature sea stars ready to grow to adulthood.

"It's as dramatic a difference in life history as in any group of organisms," says Grosberg.

The Mad Hatter wrote: »

I think it's pretty marvelous. My sister bought one as a birthday present for her (now ex-)boyfriend a few years ago. So what if it has no relevance to anyone other than the gift-giver and receiver? As thoughts go, it's one of the nicest ones out there.

I also believe it's possible to buy lakes in Canada or something like that in the same way.

"It just about ticks every box you have when it comes to looking for life on another world," says Nasa astrobiologist Chris McKay. "It has got liquid water, organic material and a source of heat. It is hard to think of anything more enticing short of receiving a radio signal from aliens on Enceladus telling us to come and get them."

Cassini's observations suggest Enceladus possesses a subterranean ocean that is kept liquid by the moon's internal heat. "We are not sure where that energy is coming from," McKay admits. "The source is producing around 16 gigawatts of power and looks very like the geothermal energy sources we have on Earth – like the deep vents we see in our ocean beds and which bubble up hot gases."

Cassini swept over Enceladus at a height of 173km and showed that it did indeed possess an atmosphere, albeit a thin one consisting of water vapour, carbon dioxide, methane and nitrogen. "It was wonderful," says Dougherty. "I just thought: wow!"