askscience

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Pre-Bronze-Age Earth must have had sufficient easily accessible deposits of copper, tin, iron, gold and other metals in such abundance to equip vast armies. How likely is it that similar metal ore veins can be found in a native state on the surface of Mars?	907
Our galaxy is 100,000 light years across, how do astronomers calculate what it looks like "now" using star positions as they appear now?	11
Is mammal dung special? Are mammals comparatively greater consumers of fruits and vegetables, and so have plants evolved to serve primarily mammals? Why is guano so special?	3
What gives us that feeling whether we "know" something or not? Why is it so hard to get that feeling when studying something hard, yet so easy to get it when told a simple conspiracy theory?	1
If two relativistic observers each see a different longitudinal length scale and clock time how can they agree on each other's speed?	1
My weather app says there's a 50% chance of rain for the day, but the hourly forecast says 0% every hour. How does the sum of zero probability add up to 50%?	1
Most of us have a instant repulsion to insects touching us, yet it's adorable to have ones like ladybugs, butterflies, fireflies, etc. land on us. Humans have an 'uncanny valley,' is there something similar for insects?	1
The so-called "forever chemicals" - PFAS - are chemically inert, how do they cause cancer? Is it a purely physical interaction?	1
Orb weaver spiders create these giant webs with numerous connections reaching at least 15 feet, but the web is almost perfectly planar. How can a spider know where the attachment points need to be to all be in the same plane?	1
If the speed of light is a property of space itself why do the vacuum electric permittivity and permeability happen to have the right values to match c? If c is the "speed of causality" what do μ and ε have to do with causality?	1

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