The spike "explosion" has the same desing and colors as the portals in the training mode or above the yoru ship in icebox map, so i think the black and white sphere isn't an explosion, it's a portal or a wormhole to take the radianite to the alternal dimension that we saw in Duality short.

I think they want to save our earth from a problem that they had with the radianite. What do you think?