Explanation why it looks green:
When the UV light from our sun hits the di-atomic carbon contained in its core, it causes this molecule to split up & releasing energy in the form of electromagnetic radiation at the specific wavelength of 518 nanometers which our eyes interpret as green.
Explanation of its brightness:
It will be brightest in our sky during February 2023 when it will be closest to Earth at a distance of 0.28 AU (42 million km) from us. It will then exhibit its highest apparent magnitude of 6, compared to #NeoWise in July 2020 which had a highest apparent magnitude of 1. Therefore #ZTF will be a 100 times fainter than NeoWise at its closest because this scale is logarithmic.
Explanation of its name:
According to the naming convention of the IAU (International Astronomical Union):
C = unlike Haley's comet which takes 200 years to orbit the sun, this one is a non periodic comet with a long-period instead taking thousands of years to complete its orbit
2022 = the year of its discovery
E = indicates the first half of March during which it was discovered
3 = indicates that it's the third comet discovered in that half month
ZTF = the observatory that made this discovery was "Zwicky Transient Facility".
