SERIOUSLY -- There is a "citizen scientist" web community called Galaxy Zoo where people can categorize images of galaxies regarding shape, etc.
A number of years ago a Dutch woman name Hanni ran across a GREEN galaxy image and she jokingly posted a topic Give PEAS a Chance.
Several other regulars then also noticed green galaxies and posted images of THOSE. When it got to around 8 different galaxies, THE PROFESSIONAL ASTRONOMERS WHO RUN THE SITE searched the database and found around TWO HUNDRED FIFTY such galaxies. NO ONE had ever noticed "green" galaxies before.
They created a new OFFICIAL CLASSIFICATION called "GREEN PEA" GALAXIES.