Krypton was not discovered on some far away planet that exploded long ago. It was discovered right here on Earth by the scientists Ramsay and Travers in 1898. They were able to isolate the gas even though it is only one part per million in our atmosphere.
When cooled and solidified, krypton is white while the gas form has green and orange traits. Since krypton is in the far right row of the periodic table, its outermost shell is full with eight electrons.
Where else can you find krypton?
Flash Photography
When you have a really high temperature explosion used in flash photography, you want to make sure everything doesn't burn up. Then it's time to use an inert gas like krypton to surround your very active and hot flash filament.
Fluorescent Lights
Non-reactive gases like argon and krypton are great when it comes to getting them to glow. Over time, krypton has been used in the fluorescent lights. They are probably buzzing over your head right now.
Measurements
Krypton was once used to determine the length of a meter. Scientists stated that the length of a meter was based on the orange-red spectral line of the krypton isotope 86Kr. Over time, the length of a meter changed to be a specific distance that light travels in a vacuum.
Lasers
Because krypton is one of those non-reactive gases, you might find it used in lasers. It's more for laboratory use that something you will see in a store.