For timeline, hm... *goes to check first page to see what of the timeline point was asked*
So from when do we start and when do we end...

1) after the earth destruction a few good centuries, so colonies and such are established.
then we get a conflict, maybe a war which roots lie in history and till then everything was status quo. And end some years later either with peace or disposing the thread pullers for the war. -insert some organisation-

2) Or maybe a golden age. we start with the efects of discovering magic by science and the first wizards. Exploitation of the magic. The first organisation/school. First colonies. And end it with earth being in shambles/ruined and colonies being the only place for surviving.

both ideas are if we gonna destroy earth XP

3) A far further, Earth is basically the holy lands. No one lives there anymore, as it heavily protected by -insert organisation of order-. Why would they protect it? We can use that idea for powering magitech. It has to be from earth(farming plants XP? for low tech, and water for mid and maybe ores/dirt for high tech?). So there is a monopoly.  Have space pirates who steal and plunder the transport ships, have rebels. Maybe add that dilemma if we should use magic, or return to live on earth. All conflicts happen and we end it with the resolution of all those conflicts?

4) The dark lord raises again to finish what he/she started. //shot for Harry Poter and star wars references all in one XD Well maybe the first time around earth survived but the second time it got destroyed?