is oil and coal now useless? and what does gravitanium look like and where would you find it?
Coal can still be used in power plants and factories. Coal is still used in some processes, like making coal coke.
Oil is still used in some ships, such as barges and boats, though they're the "poor-man's" boat. Cars in Erinaum are all Gravitanium craft that fly amongst buildings. Roads are few, but are open for mainly walking. Schools can literally take a field trip to the Moon, or if you live on the Moon, a field trip to Earth. It really depends where you live.
Gravitanium is a luminescent opaque pale-cyan semi-liquid gel (with physical properties close to corn starch and water mixed, and jello) found in places with weak or absent magnetospheres, and places closer to stars. Mercury has a ton of Gravitanium, but since the Sun is hot and radioactive as forget, its a bad idea to go there to get it. Earth has some, but not very much Gravitanium is also found in regions around black holes and wormholes in unbelievable quantities. Erinaum has been getting most of its Gravitanium from the Moon, Mars and Asteroids. With the destruction of Ceres, Gravitanium prices is about to drop dramatically.
Are you implying that you have the same discoveries as Erinaum from Hera?
I am implying that I'm approaching that point in advancement. Erinaum from Hera went into production of portals way faster than it should have. If I went at the same rate that the Heran Erinaum went, I'd be far beyond that.