A static variable is a memory resource created at compile-time that exists through a program start to finish. They must have their types explicitly specified.
A static lifetime is a memory resource that lasts indefinitely to the end of a program. Note that by this definition some static lifetime resources can be created at runtime.
Resources with static lifetimes have a special lifetime specifier 'static.
'static resources will never drop.
If static lifetime resources contain references they must all be 'static (anything less would not live long enough).
Memory detail:
unsafe { ... } blocks to perform some operations that the compiler cannot make memory guarantees about. The R̸͉̟͈͔̄͛̾̇͜U̶͓͖͋̅Ṡ̴͉͇̃̉̀T̵̻̻͔̟͉́͆Ơ̷̥̟̳̓͝N̶̨̼̹̲͛Ö̵̝͉̖̏̾̔M̶̡̠̺̠̐͜Î̷̛͓̣̃̐̏C̸̥̤̭̏͛̎͜O̶̧͚͖͔̊͗̇͠N̸͇̰̏̏̽̃ should not be talked about casually.