Jeff Raglin

Comment Threads

• DavidTC commented on On the Great Filter, existential threats, and griefers
  I've always thought people were overlooking the obvious reason for the Fermi paradox: Interstellar space travel might be impossible. People seem to be assuming interstellar space travel is only difficult because of the distance, and the distance can be ignored by robots plus time. But what if it's not? What if there's a problem besides the distance? I'm not sure why it would be so hard. Perhaps there is some sort of radiation out there between stars that destroys electronics, or damages most metals. Perhaps there are some sort of 'currents' that cause space ships to constantly drift in random...
• Alan Bostick commented on On the Great Filter, existential threats, and griefers
  "What's the theoretical range on those things, anyway?" Assume a Dyson swarm with a radius of 10 AU, and that the superlaser component on each little orbiting bit is coherent with all of its neighbors, so that in effect the Dyson swarm is a single coherent radiator, emitting a more-or-less Guassian beam in the direction of its target with an aperture radius of 10 AU. Use a visible laser, like an argon-ion laser, wavelength 514 nm. The effective collimated range of the beam is going to be pi * R^2 / lambda, and feeding these numbers in, we get a...
• Jay commented on On the Great Filter, existential threats, and griefers
  Perhaps there is some sort of radiation out there between stars that destroys electronics, or damages most metals... The radiation is bad enough, but I suspect the larger problem is more prosaic. Micrometeorites aren't terribly uncommon, and hitting even a pebble at relativistic velocities (millions to hundreds of millions of meters per second) is probably not survivable. We're talking about impact speeds that make bullets look like glaciers....
• DavidTC commented on On the Great Filter, existential threats, and griefers
  Micrometeorites aren't terribly uncommon, and hitting even a pebble at relativistic velocities (millions to hundreds of millions of meters per second) is probably not survivable. Now that is a damn good point. And it's worth noticing that we only know how common micrometeorites are within the solar system...for all we know, they could 100 times worse outside, without the sun and planets to catch them. Moving at nearly random velocities, which means that some of them are moving impossibly fast. Assuming there is not any actual way to build a 'deflector shield', interstellar space travel is utterly screwed. So, yeah:...
• SFreader commented on On the Great Filter, existential threats, and griefers
  DNA transposition, and a novel (6th) DNA base that may be a major player in epigenetics could provide more opportunity for guessing what may/may not be technically possible in either scenario (a) aliens visit/alter us/adapt to us, and/or (b) our ability to plan and architect changes to ourselves as we head out to the stars. http://www.sciencedaily.com/releases/2015/05/150511162817.htm Excerpt: "Transposable elements are DNA sequences that are capable of changing their genome position by cut and paste or copy and paste through the enzyme transposase. This ability can be harmful for hosts if transposable elements destroy functioning genes, but it can also bring...