In multiple different movies and fiction, there's the threat of a burning space comet heading for Earth, threatening to kill everyone and destroy the planet.
One example is the animated Comet in Moominland (1992).
When they look at it in a telescope, and later it's seen on the sky, it's depicted as a burning ball with a trail, seemingly going sideways, to the right, past Earth. If it were heading toward Earth, wouldn't it have no visible "tail", but simply be a big round burning ball which gets increasingly bigger?
Am I fundamentally missing something here? Why do they so often depict it appearing "sideways" rather than "frontways"? Would a comet heading straight to Earth ever appear to be going past Earth, or for some reason have a trail/tail to the left of the big burning sphere, even though it's coming for us?