Haha..that could be scary xd. Imagine Shiki makes the asteroid lighter and then throws the asteroid at his opponent like throwing a small stone. As the asteroid is no longer under the influence of Shiki's light weight power it will back to its normal weight. The result sure very devastating. But if we follow the law of physic right, Shiki needs to throw the asteroid downward, he cant throws it horizontally. Mean he needs to levitate and then throws the asteroid down towards his opponent. Why he couldn't throws the asteroid horizontally?
It because he needs to have a throwing power of normal weight asteroid. Here he's manipulating the weight of the asteroid, of course he can throw the asteroid very far horizontally when the stone still light but the stone travelled on much lighter weight and not on it's normal weight. So while its traveling the asteroid will abruptly gained its normal weight, that asteroid is surely will lost its traveling momentum it has earlier. It will drop to the ground like a bird that injured its wing while flying. That's why I suggested that Shiki should or need to throw the asteroid downward.
I actually assumed the Space-time flux/disruption is triggered by "mother", not Shiki xd
Or if Shiki, Happy and Rebecca doesn't experiencing any space-time manipulation I suspected something has happened to the Nouma. So Doctor Weisz Steiner got some story behind him
Possible, will wait and see
Shiki having S/T manipulation is an interesting idea
If the atmosphere of Nouma planet has other hidden secret that we not know yet, so it not just only about Ether Crystal formation but the atmosphere bring with it a time rift =D
Mother is an immortal being.