Source: NASA's Astronomy Picture of the Day.

Explanation: Are asteroids dangerous? Some are, but the likelihood of a dangerous asteroid striking the Earth during any given year is low. Because some past mass extinction events have been linked to asteroid impacts, however, humanity has made it a priority to find and catalog those asteroids that may one day affect life on Earth. Pictured here are the orbits of the over 1,000 known Potentially Hazardous Asteroids (PHAs). These documented tumbling boulders of rock and ice are over 140 meters across and will pass within 7.5 million kilometers of Earth -- about 20 times the distance to the Moon. Although none of them will strike the Earth in the next 100 years -- not all PHAs have been discovered, and past 100 years, many orbits become hard to predict. Were an asteroid of this size to impact the Earth, it could raise dangerous tsunamis, for example. To investigate Earth-saving strategies, NASA successfully tested the Double Asteroid Redirection Test (DART) mission last year. Of course, rocks and ice bits of much smaller size strike the Earth every day, usually pose no danger, and sometimes create memorable fireball and meteor displays.

Good explanation of the difference between work efficiency and step efficiency when talking about parallel algorithms.

cross-posted from: https://beehaw.org/post/677606. Why I'm cross-posting this here as it's mostly a criticism of capitalism.

I got curious about human instincts and ran into this (delightfully retro even though it's from after 2010) page while googling the subject. Haven't read it fully yet but I've found it interesting and figured I'd share.

Abstract. Like all animals, humans have instincts, genetically hard-wired behaviors that enhance our ability to cope with vital environmental contingencies. Our innate fear of snakes is an example. Other instincts, including denial, revenge, tribal loyalty, greed and our urge to procreate, now threaten our very existence. Any attempt to control human behavior is bound to meet with resistance and disapproval. Unless we can change our behavior, humans are facing the end of civilization. Our problem has several elements. (1) We have invented economic and social systems that encourage greedy behavior, and we have actually institutionalized runaway greed. (2) We are in a state of complete denial about the growth of human populations. (3) Earth's finite resources simply cannot support 7.6 billion of us in the style to which we’d like to live. (4) We must make a choice between quantity and quality of human life. (5) To head off the inevitable collapse, we can no longer wait and merely react but we must become proactive. We must find ways to control dangerous human instincts, especially denial, revenge, tribal loyalty, greed and our urge to procreate.

I got curious about human instincts and ran into this (delightfully retro even though it's from after 2010) page while googling the subject. Haven't read it fully yet but I've found it interesting and figured I'd share.

Abstract. Like all animals, humans have instincts, genetically hard-wired behaviors that enhance our ability to cope with vital environmental contingencies. Our innate fear of snakes is an example. Other instincts, including denial, revenge, tribal loyalty, greed and our urge to procreate, now threaten our very existence. Any attempt to control human behavior is bound to meet with resistance and disapproval. Unless we can change our behavior, humans are facing the end of civilization. Our problem has several elements. (1) We have invented economic and social systems that encourage greedy behavior, and we have actually institutionalized runaway greed. (2) We are in a state of complete denial about the growth of human populations. (3) Earth's finite resources simply cannot support 7.6 billion of us in the style to which we’d like to live. (4) We must make a choice between quantity and quality of human life. (5) To head off the inevitable collapse, we can no longer wait and merely react but we must become proactive. We must find ways to control dangerous human instincts, especially denial, revenge, tribal loyalty, greed and our urge to procreate.

Hey does anybody know if there's a description of ActivityPub available that isn't just the spec? I realized I don't actually know how the protocol works, and I'd be interested in learning more. May have to just bite the bullet and dive into the spec – it doesn't actually look too bad based on a quick glance – but a summary would be cool

Original here