Is it to do with the atomic structure or something similar, or am I completely along the wrong lines?
In: 4
ELI5? : Inertia is a fundamental property of any mass. It has nothing to do with atomic structure. We observe all masses to have a property to resist any change in its state of motion.
It can be argued that inertia is an outcome from the observation that laws of physics are independent of location and movement across space and time (same laws everywhere in the universe, at all points of time). But honestly, that’s less of a causal “reason” for inertia. Instead I would frame it as another observation which fits.
Beyond the ELI5: according to general relativity, inertia, like gravity, has something to do with the curvature of space. But unlike gravity, the explanations are not very intuitive (in my opinion), and still subject to debate (in the opinion of more educated physicists).
Would love to stand corrected, in case some physicist can actually ELI5 this.
You can see a discussion on it here:
https://physics.stackexchange.com/questions/69479/why-does-inertia-happen
And another slightly deeper article which I can’t say I fully understand, talking about the issues in explaining inertia: https://www.americanscientist.org/article/the-forgotten-mystery-of-inertia
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