Xplanet
I always thought that Xplanet is one of those ancient X apps that work despite being totally outdated, with aliased edges and overall painful graphics.
Turns out I was more than half wrong.
It's derived from xearth which has been around since 1993. Xplanet itself seems to have been around since at 1999, saw its latest release in 2016 and is still maintained.
It can be scripted, tweaked & tuned to display stunning hi-res views of the earth (from NASA imagery), with real time cloud cover.
Also our moon and other celestial bodies of our solar system.
I fell into the rabbit hole and wrote some scripts around it: