Of course, there is no definitive proof for any other prevailing evolutionary theory dealing with the start of life. Your title just reads a bit misleading to me "it-s-looking-like-we-really-did-come-from-space" Its not looking like that at all to me :)
But its going to take a lot to fully convince me in any direction. Skepticism is a strong component in science.
Respect for your scepticism, and I fully agree. I treated the 'Evolution From Space' book in much the same way. Over the last couple of months I've also read CW's 'Where Did We Come From?' as I needed more convincing of his credentials. I read neo-darwinist Richard Dawkins latest 'The Ancestor's Tale' specifically to see if I could find anything to contradict, or contradicted by 'Evolution From Space'. I couldn't. I did my own research, (carefully) on the net, hence this article. I drew the line at reading the Genesis to get the creationist viewpoint, but then I will admit to having a little bias!
Once again, I'll recommend you have a look at CW latest, 'Search For Our Cosmic Ancestry'. I'd be interested whether your scepticism takes you down the same path mine took me... ;-)
And yes, the title is a bit provocative... But then this is Steem, not a thesis, and I want people to read it :-)