This one's a little interesting. Not the same bonus found in past Civs, but the +% to research can easily be done in XML and is already done by existing buildings in the game.
Those that have played
Thomas' War may have noticed a little message on the top of the screen every 10 turns or so:
This was adapted from the star system found in Gods of Old. This modcomp basically does two things. First, the game now announces a new astrological sign being in the ascendant every 10 turns. (Basically the game uses a random number generator to choose a number from 0-11 and displays TXT attached to it). This on its own is purely aesthetic. I've set it to random for balance reasons but you can change the frequency and order in the python (I've labeled where I do both).
This is also 'separate' from the wonder itself. Everyone sees it all game. It's just a small message, in truth you probably won't even notice it if you aren't paying attention so it's not distracting yet at the same time adds flavor.
Now, Gods of Old used this system attached to Religion to give specific bonus. Theoretically you can attach it to anything such as civilizations or events. I created a wonder then, that will give a new bonus every time the 'stars' change.
Aries: Free Great General Counter Experience (doubled if Imp)
Taurus: Free Production Bonus in all Cities
Gemini: Free Culture Bonus in all Cities
Cancer: No Bonus
Leo: Increases Your Total Gold Reserves
Virgo: Free Missionary of Your State Religion (no bonus if no state religion)
Libra: Espionage Bonus
Scorpio: Negative Bonus in all Cities
Sagittarius: Free Defensive Unit (based on your tech level, if applicable civs will get their UU)
Capricorn: Free Food Bonus in all Cities
Aquarius: Free Great People Points in Owner City (these are pure points so they don't dilute your Great People ratio, also doubled with Phi, national epic, etc.)
Pisces: +1 Population in Owner City
Some of these bonuses are strong, some are weak, some don't do anything, and one is actually negative. It's all part of the fun of the wonder.
(Basically bare bones the python-wonder will give a random bonus every ten turns. This is just placed in the context of a theme which adds some flavor the the game. The star system can be attached to other things if you know how to handle the python).
All the python is labeled, searching for 'Copernicus' should find the changes. I recommend downloading and using Winmerge to combine files.