with all the racial mixing going on, how will people look like in the next century? mixing of the races.

It would be nice to think there is enough racial mixing
for us to envision a "post-race" world in another century, but I very much doubt that is
the case, and even if that were to occur, geographical evolution would eventually sort
us out in some way that would make people different
again.

From a genetic perspective, how racially mixed
people will look is rather difficult to predict.  Think about the people you know who
have parents from different races.  The physical characteristics are likely to be quite
different in each, and each is a unique blend of the genes of the parents.  My own
children, who are biracial, are a good example.  People can tell they are brothers, but
they have very different appearances.

And even if we all
become completely mixed, with no discernible racial characteristics at all, we must all
eventually adapt in some way to the environment in which we live.  If we live far from
the equator, our skins must get lighter, so that we can absorb more vitamin D when we do
get some sun, for example. In spite of the fact that we speak about a global village, in
order to have civilization, most people need to be geographically "fixed," which means
adaptation to one's surroundings, with those best adapted surviving to hand down their
genes.

On another note, racial differentiantion is largely
a social construct, not a biological "fact."  The DNA of an African-American person can
have more in common with the white person across the street than with another
African-American person.  Perhaps we can all live in a post-racial world if we come to
understand this.  I have included a link to an article on this
topic.