Astronomy questions 4 people interested in answering?

... ok what time really is, the sun location on the orbital axis... 365.242199 days for earth to make a full rotation around the sun... 24 hours in a day, 60 mins in an hours, 60 secs in one min.... thats all time really is ... but when you dont have the sun... then how will you measure time ?? I guess the time stands still, when there is no gravity