https://www.yahoo.com/news/articles/harvard-physicist-says-massive-interstellar-194908857.html

Avi Loeb does it again. He claims the latest interstellar visitor can’t be a comet because its tail precedes it, not follows, along behind it.

Any amateur astronomer (or even sub-teen space groupie) can tell you a comet tail is NOT streaming along behind it, it points AWAY from the sun. Volatiles in the comet are pushed AWAY from it by the light pressure and solar wind from the sun. It doesn’t matter which way the comet is moving, the tail always points away from the sun. Think of a flag on a ship sailing a windy sea. It doesn’t matter what the ship’s course is, just which way the wind is blowing.

When a comet passes perihelion. that is, is traveling away from the sun, its tail may exhibit a curve as the position of the sun relative to the comet rapidly changes. But as it heads away from the source of solar wind, its tail precedes it.

AAAAARRRGGGHHH!