earendel.net successfully implements both mastodon api/w3c standard activitypub but is 28 billion lightyears away. Although they are able to communicate through a series of relays through to the interplanetary internet relays to mastodon/pleroma/misskey servers, responses are....very slow. So slow, that chances are pretty good none of the servers which are responding to their federation attempts will exist by the time the next set of responses comes from them. Their users want to learn about earth and try to respond but by the time their responses get here the earth will be a dust, part of a long since dead sun.

Is earendel.net part of the fediverse?