I'm confused how you could measure the radius of the traveller when you don't actually know how far away it is from Earth? That's like saying oh cos I can cover a full moon with my thumb at arms length, the moon must be the size of my thumb.. Also, as a Physicist I can clarify that when it says 'Electroweak' it means the unification of both electromagnetism and the weak interaction (the interaction of particles decaying through a mechanism) into a single 'state'. I also know that this unification doesn't exist in our time, but during the time around the Big Bang and has been created in particle colliders at high temperatures/energy. So what it means by electroweak material is anyone's guess.. More than likely Bungie just pulling a complicated word out of their rear ends to make something sound clever..