5 ms·

So is rest of the earth; Youtube channel Vsauce covered this in one their videos https://youtu.be/mxhxL1LzKww?t=721 https://youtu.be/mxhxL1LzKww?t=721

peteretep 5y ago
"So is rest of the earth" ... when taken as a whole, though. Switzerland is not flat as a pancake, for example.
- HJain13 5y ago
  From what I understood from the video, the surface irregularities a general pancake can have when stretched to dimensions of the earth would lead to 10km high feature; Given even Mt. Everest is <9km, I am not sure why Switzerland wouldn't fit the definition edit: Typo
  - pintxo 5y ago
    If you stretch the pancake only to the dimensions of Switzerland, the vertical features would be a lot less high. And Switzerland has quite some height differences within a small area.
    - cjwilliams 5y ago
      Or a more extreme example: If you stretched the pancake to just the width of Everest clearly Everest would be less flat.
  - brudgers 5y ago
    The peaks measure ~9km above sea level. The deepest portions of the ocean add another 3-4km.
    - tnli 5y ago
      Not sure how to read this, but have you heard of the Mariana Trench?
tejohnso 5y ago
I recall Neil deGrasse Tyson mentioning that the whole earth would be smoother than the smoothest billiards ball if scaled down. I found that surprising.
- gregoriol 5y ago
  Wow, that scale! Thanks for posting that! If my calculations are right, Earth's diameter is about 12000km and its highest/lowest places are about 10km, so about 0.001 If a billiard ball is about 10cm, it's highest/lowest places equivalent to earth would be 0.1mm. Not sure what are the standards for billiard smoothness, but that seems very smooth to me.
  - zokier 5y ago
    0.1mm is not very smooth. According to wikipedia, 150 grit sandpaper has average particle size of 90-100µm edit: of course there is vigorous internet commentary about billiard ball smoothness compared to earth: https://possiblywrong.wordpress.com/2011/01/03/is-the-earth-like-a-billiard-ball-or-not/ https://possiblywrong.wordpress.com/2011/01/03/is-the-earth-... https://skeptics.stackexchange.com/questions/10763/is-earth-as-smooth-as-a-billiard-ball https://skeptics.stackexchange.com/questions/10763/is-earth-... https://billiards.colostate.edu/faq/ball/smooth/ https://billiards.colostate.edu/faq/ball/smooth/ Which mostly seem to agree that earth definitely is not as smooth as a (new) billiards ball, but there is lots of debate about the details.
  - aardvark179 5y ago
    A billiard ball is about 50mm in diameter. I guess the question is to what tolerance they are made. I wouldn’t expect a small feature to stick up (you’d be able to feel or see those fairly easily) but the overall deviation from a perfect sphere could easily be that large.
- B1FF_PSUVM 5y ago
  Me too, I was going with "smoother than an orange", the billiard or bowling ball seem excessive - https://what-if.xkcd.com/46/ https://what-if.xkcd.com/46/ posted here

peteretep 5y ago

"So is rest of the earth" ... when taken as a whole, though. Switzerland is not flat as a pancake, for example.

HJain13 5y ago
From what I understood from the video, the surface irregularities a general pancake can have when stretched to dimensions of the earth would lead to 10km high feature; Given even Mt. Everest is <9km, I am not sure why Switzerland wouldn't fit the definition edit: Typo
- pintxo 5y ago
  If you stretch the pancake only to the dimensions of Switzerland, the vertical features would be a lot less high. And Switzerland has quite some height differences within a small area.
  - cjwilliams 5y ago
    Or a more extreme example: If you stretched the pancake to just the width of Everest clearly Everest would be less flat.
- brudgers 5y ago
  The peaks measure ~9km above sea level. The deepest portions of the ocean add another 3-4km.
  - tnli 5y ago
    Not sure how to read this, but have you heard of the Mariana Trench?

tejohnso 5y ago

I recall Neil deGrasse Tyson mentioning that the whole earth would be smoother than the smoothest billiards ball if scaled down. I found that surprising.

gregoriol 5y ago
Wow, that scale! Thanks for posting that! If my calculations are right, Earth's diameter is about 12000km and its highest/lowest places are about 10km, so about 0.001 If a billiard ball is about 10cm, it's highest/lowest places equivalent to earth would be 0.1mm. Not sure what are the standards for billiard smoothness, but that seems very smooth to me.
- zokier 5y ago
  0.1mm is not very smooth. According to wikipedia, 150 grit sandpaper has average particle size of 90-100µm edit: of course there is vigorous internet commentary about billiard ball smoothness compared to earth: https://possiblywrong.wordpress.com/2011/01/03/is-the-earth-like-a-billiard-ball-or-not/ https://possiblywrong.wordpress.com/2011/01/03/is-the-earth-... https://skeptics.stackexchange.com/questions/10763/is-earth-as-smooth-as-a-billiard-ball https://skeptics.stackexchange.com/questions/10763/is-earth-... https://billiards.colostate.edu/faq/ball/smooth/ https://billiards.colostate.edu/faq/ball/smooth/ Which mostly seem to agree that earth definitely is not as smooth as a (new) billiards ball, but there is lots of debate about the details.
- aardvark179 5y ago
  A billiard ball is about 50mm in diameter. I guess the question is to what tolerance they are made. I wouldn’t expect a small feature to stick up (you’d be able to feel or see those fairly easily) but the overall deviation from a perfect sphere could easily be that large.
B1FF_PSUVM 5y ago
Me too, I was going with "smoother than an orange", the billiard or bowling ball seem excessive - https://what-if.xkcd.com/46/ https://what-if.xkcd.com/46/ posted here