Salmoneus wrote: ↑17 Sep 2018 22:59
A bug riding a turtle would seem like a human "riding" a glacier...
Just for fun, I worked this out. Let's take an ant, approximately 1mg. Then let's assume you meant 'tortoise' (because turtles live underwater and wouldn't be convenient to ride). Let's take the common or greek tortoise and say an average weight of 5kg. That's 5 million times heavier than an ant.
For comparison, an average human is 70kg, so an ant is to a tortoise as a human is to something that weighs around 350 million kg. The average iceberg weighs around 100 million kg. This is actually similar to the weight of the largest aircraft carriers - but of course, carriers are made of super-dense material compared to humans, whereas turtles and ants are made of similar stuff. So let's bring it back to something more familiar: elephants. An Indian Elephant is around 5.5 thousand kg.
So, an ant riding a (small) tortoise is the equivalent of one person "riding" a herd of 60,000 elephants yoked together, or one mega-elephant the size of 60,000 elephants put together.
Assuming elephant density remains constant, mass scales with the cube of the linear dimensions. Cube root of 60k is 40, more or less. So we'd be talking about a human riding on an elephant as tall as 40 earth elephants.
Now, an Indian elephant is about 2.5m tall. So 40 elephants comes to about 100m tall. By comparison, Big Ben in London is 96m.
So an ant riding a tortoise would be like a human riding an elephant as tall as big ben.
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Similarly, to give a sense of scale, your tree that's lived since the Carboniferous: something like 1/2 to 2/3rds of the depth of the Grand Canyon has been deposited since then. I can only assume your tree is at the bottom of a very, VERY big hole in the ground...