This is not an atmospheric phenomenon. It is a solar system body situated 135 to 150 million kms from the Earth this week and receding. The moon is 300,000kms away for comparison.
The head is about 10-20 kms across (bigger than Mt Everest)
The inner coma surrounding the head is over 4 times larger than Earth with the full coma size likely to be half as large as the Sun.
The tail stretches 0.2 AU, or 30 million kms from the head out to space (assuming 15 degrees).
Enormous tons of water vapour and dust are being emitted from the comet every second. The exact figure is not known.
Comets developed in the outer solar system, are therefore icy, gassy, dusty objects.
The comet will not collide with Earth. It was closest to Earth on Jan 15 at 122 million kms distant.
