Depending on what it is..but most likely yes.

Galactic Wonders are an 'one per galaxy' thing. Super Projects are an 'one per race' thing. You can have many Super Projects in your empire, but that is only if another race built the 2nd one 9or 3rd..etc) and you stole the planet.

You can build them just by researching the required tech. Note that some wonders require techs not in your tech tree so don't worry about those.

The wonder I almost always want above all others is Eye of the Universe. Sensors IV is the tech for this and it is imo the single greatest available wonder period. ALL ships and ALL SB's have instant (meaning you don't need to take up space with them) INCREDIBLE sensors on them. You can see for great distances wherever a ship is, and this counts freighters in trade routes too! You may not see how helpful this is until you build it for the first time.

There are wonders affecting Hit points, diplomacy, morale, soldier strengths, etc. Many types, use the galactopedia for an easy-to-use reference.

Also note the following distinctions between Galactic Wonder, Civ wonder, Trade Goods. Galactic wonders can only be built by one civ one time. Civ wonders can be built once per civ, and Trade Goods can be built once only for the whole galaxy. Trade goods can then be traded to other civs for money, tech, whatever. But, the return for trading the bonuses associated with the Trade Goods is not worth the money or techs you get, so keep them to yourself and use the edge acquired.

Hope this helps. Galactopedia link Twilight Compatible WWW Link

You're thinking of the Galactic Guide Book. The module is free, but it still takes up space.

Eyes of the Universe gives all ships either 15 sensor range or +10 to existing sensor range (effectively the same thing, as sensor range caps at 15). No module needs to be on the ship, and it is instantly effective on all existing ships. More importantly, you can also see ALL ships on the minimap. Even ships still in the shroud, even in places where you haven't cleared the shroud at all, it's all visible. You may not be able to tell WHAT is there, but knowing something is there (or not there, as the case may be) is a huge benefit. Luckily, the AI does not prioritize this at all.

Note that when you first build EotU, you'll have to click on existing ships to force the game to update their boosted sensor range. For planets, you need to either land or launch a ship to gain the sensor boost.