Google translate returns Es ist party zeit!
Probably this is because you entered two separate words. I tried "Partyzeit" which is the real word, the translator doesn't know it from German to English. Even in times when everyone thinks AI and Smarthomes and other stuff should replace human thinking, it isn't the case - so don't blindly trust automatic translators.
Is it possible then to construct the following single word
It actually is possible to construct such a word. Start it with a capital letter.
Generally composite words are common in german. Some advertising or also verbal speech tries to be more interesting by using unusual composite words. This one indeed is unusual and such words are a little more complex to understand than paraphrasing them but people should know what you mean.
If you should use it or not depends on if you want to attract attention or not. If not I'd try to avoid that and say/write something else.
Or would it have to be two words, as in Es ist gedankenexperiment zeit!
(Think of Capitals too...) No this is unusual.
A little better is to write that as
Gedankenexperiment-Zeit (with a -) but to me (-> personal opinion) this now appears still a little unusual but no longer unusual enough to be really extraordinary.
Perhaps there is a better and different way to to say it?
A more convenient way is to say
Es ist Zeit für Gedankenexperimente