Hacker News Reader

Comment by nnx | Hacker News Reader

This is so intriguing indeed.

Maybe most creatures on such planets would evolve towards unihemispheric sleep, as some Earth species did (eg. dolphins).

Unihemispheric slow-wave sleep (USWS) is sleep with one half of the brain while the other half remains alert.

https://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep

View on HN

I was wondering if such creatures would sleep at all with 24 hour daylight. They might evolve other mechanisms to get the same benefits.

Lions sleep 22 hours/day, even though it is light during many of those hours.

Light/dark is only one factor in sleep, there are others.

Evolution on earth is heavily influenced on dark/light cycles through its entire history. No evolutionary path that has received this influence can tell us anything about what would happen, on things that are highly correlated to it, for one that has never received this influence.

of course, but the reasons lions sleep far more than the day/night cycle requires are a factor that applies elsewhere, and thus might result in something similar.

It's tough to say, there is more than one purpose for sleep, and it may have served other purposes in the evolutionary history that no longer benefit all organisms. For example, humans no longer need to be safely holed up while predators roam the Savannah at night.

It's also hard to know of the infinitely many evolutionary twists and turns lifeforms in the Universe may take, how many of those pathways involve something like sleep - especially on planets without a diurnal cycle.

Anything and everything is a wild guess based on a sample of one where extraterrestrial life is concerned.

Why would you assume there'd be animals at all?

Reply on news.ycombinator.com