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morganism comments on The map of the risks of aliens - Less Wrong

7 Post author: turchin 22 August 2016 07:05PM

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Comment author: morganism 23 August 2016 12:31:27AM 3 points [-]

There is also the factor that what we know about stellar evolution is way off.

Is possible that larger stars flare more often than we think.

Is also possible that all the theories of disc accretion are totally wrong. One of the first discovered discs has already dissipated. There are lots of problems with all the planetesimals formation theories. Micron,centimeter, meter and kilometer models all show disruption in even slow collisions. Meteorites all show major fractionation, and re-cementing with mud. Combinations of glass crystals, amorphourous glasses, and crystalline minerals, with greater than 2 orders of magnitude in the formation temps. Major planets gaining and loosing angular momentum and changing places in the solar system. If DA is wrong, it would appear that the only reason we have lasted this long, is that we are 4 deg off the plane of the solar system. It seems to me that entire planetary cores must be tossed out of the star, and wander thru the system disrupting rotations and orbits. The cores of the ice giants, are reputed to be near the size of the Jovian moons, Mars and Earths moon also. Just saying...

Comment author: turchin 23 August 2016 02:22:29AM *  1 point [-]

It all supports Rare Earth idea. But it has two type of factors: which had ended, and which are still here, like absence of nearby gamma ray burst. The second type is real danger, as some of them may be long overdue.

The best situation would be that rare earth theory is true, but all dangers are in the past. But it also means that the future of the whole Universe is in the hands of humankind.