You can validate the chain of bitcoin headers in less than 3 seconds with about 1.5kB of data on your phone RIGHT NOW through the magic of starks.

zerosync.org/demo/

nostr:npub1sg6plzptd64u62a878hep2kev88swjh3tw00gjsfl8f237lmu63q0uf63m nostr:npub1aeh2zw4elewy5682lxc6xnlqzjnxksq303gwu2npfaxd49vmde6qcq4nwx