No, not a comet ... the planet Mercury. Mercury is a small planet, but one thing we don't need is comets the size of Mercury ... (although this is the year 2020, I'm starting to think anything can happen.
)
The tail is made of Sodium which sputters out of the ground under the relentless blast of a Sun filled sky.
Some decades ago I dropped a small piece of Sodium into an ink well in the physics lab at Dartmouth St, Secondary Modern School as a joke. It did a passable imitation of Mount Vesuvius on heat ... and got me the long walk for the cane and punishment book.
https://spaceweathergallery.com/indi...load_id=169723