I'm not sure where I read this but someone posted about a race which I can't choose when I started the game. How can I get them? Also, I got a Sphere of the New Era Artifact through a daily reward. If I use it, can I get to choose those other races?

You can unlock several races by doing their respective mission chains.

So, I need to complete the missions to get them?

yes. check out the Wiki for a list of of the races you can unlock.

Yep. You have unlocked the Zolazin chain, which starts with "The Glaviz Vendetta".
I would not use this race though, I would do the Kronyn chain, which starts with "Anomalous Appearance". I know that you will need a lot of Flux Probes to do that mission, so you need to find yourself a good legion, or find some good friends.
Here, this might help you. It's a link to the Galaxy Legion wiki. Galaxy Legion races page

visit the Galaxy Legion wiki for the answer to your Q:

http://galaxylegion.com/wiki/index.php/Races

edit: beaten to the punch

as for Joseph's comment, i am going zolazin saboteur myself this weekend ... kronyn has some okay stuff, but it is a long chain and i have most of the research that i need for my current playstyle. the rest i can pick up as i go, so i will be aiming for taltherian when it comes available to me at r230.

Zolazin Saboteur is helpful to legionmates, but not so much to you, so I would have to say Kronyn (unless you have all the research you need).

well, i was trying to get the dominion auto-blasters by r200, and the saboteur medal is one of the few left to me that does not require me to rank up. i need 110 more medal points ... i will get 25 tomorrow when i collect as an inergon, raids and hacks will get me 70, the sab will get me 10 (and the incubus design) by the end of january ... and that still leaves me 5 short. i was thinking about hunting down a lazuli and a drannik, but the dranniks are in very short supply in my rank range

the other possibility is the 25M research medal, but that would mean switching back to vygoid after january, so that i can get there in 10 weeks (mid-April).

of course, if i scan a rift-worthy planet, that would also do the trick

Correction: The Zolazin chain starts the the mission entitled "The Glaviz Incident".

Whoops, sorry....
Thanks for catching that Dexter!

Thanks for all the replies!

what does the governor proffession do?

p.s sry if it not the right place to ask

Governor increases the chance of random planet events by 3x.