500 years? That seems longer/farther away than most eras to predict.
America wouldn't be in it's big, overpowered position where it can invade dirt poor countries with tanks. (I'm American, and I'm not bashing other Americans, just questioning our military past.) China would have been the most powerful country on Earth, but wouldn't be in 2509. Look at America, it only became a world power in WWI. It's not even a century later, and our economy is going down.
There would have likely been a WoMD attack so big that a large chunk of the world's landmass would be reduced to Fallout 3 type enviroments. Racism would still be around, but it would be very different. In such a time of primitive survival, people would either stick to their own race and help eachother survive, or form new catagories based on hair style, eye color, or anything we can think of. Once conditions got better, society would start becoming civilized again.
Other than that, I can't really think of anything else, due to all the levels of wealth throughout the world. I couldn't say it would return to a level of modern day America with slight downgrades because that's not the current situation around the world. All of this is just speculation, and loose opinions gathered based on current treands. (On a side note, I'm not being racist when I say "people would stick to their own race". I'm saying that it is likely that all races would separate and new racism would begin.)