Today I Learned: Volume 4


til geology space sauna weather biology cosmology space paradox

Hey hi! This is yet another TIL thing. Check it out for rolling stones, unfortunate deaths, more gas giants and other stuff.


There is a geological phenomenon called the sailing stones where stones move through landscape and leave long trails in their wake. All without human or animal intervention.

There are many theories on how this is happening. Most researchers would claim that this happens with the power of wind alone, but this timelapse video suggests that the more likely cause is the Ice Shove.

But what really got my attention is that it also happens on other planets. Mars, for instance. This one is actually caused by the winds, though.

Update: here’s a more recent research


World Sauna Championship is a real thing.

Well, it was a real thing. It would be held annually in Finland from 1999 to 2010. Then one of the competitors died and another was very seriously injured during the contest. There were no more contests after that.

On a brighter note, here’s a list of unusual deaths on Wikipedia.


Gas Giants have extreme weather conditions, with the winds reaching up to 1,800 km/h. Also, Saturn has a weird hexagon thing on its pole:

Photo from Wikipedia

Thanks to the lack of land that usually slows the storms here on Earth, the ones on Gas Giants are that much more persistent. Say, The Great Red Spot on Jupiter has been around at least for 300 years, and likely longer than that.

As for the hexagon, the researchers suggest that it is a naturally occuring phenonemon, and even managed to reproduce it in a lab. But we all know that it is actually a derelict alien artifact, right?


A relatively huge, µm-scale virus has been found in a 30,000-year-old ice core sample. It is the largest virus known to science, and is vastly different from other viruses out there.

There are several things about the Pithovirus that are unusual, aside from its size. For starters, their genome is about the same size or even larger than that of many bacteria. Another one is that the Pithovirus does most of its reproduction right in the cytoplasm, and not in the nucleus like many others.

This finding is important in that it demonstrates that viruses can indeed survive in permafrost.


Olbers’ paradox is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe.

Surprisingly, this confusion is not quite trivial to dissolve. The argument goes thus:

  • Divide the universe into a series of concentric shells, each 1 light year thick
  • Suppose there are N stars between layers 1,000,000,000 and 1,000,000,001
  • There should be 4 × N stars in another shell between 2,000,000,000 to 2,000,000,001 light years away.
  • Each star in the second shell would appear four times dimmer than in the first shell
  • Thus the total light received from the shells is equal

Actually, I think I will not include an explanation here. Can you come up with one in comments on your own?

P.S. See also: xkcd

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