Can Necrons delete Terra?

Can Necrons just delete Terra.

Not "would" they, but "can" they?

Side note: if the tyranids pose too great a threat to the galaxy could the royal court of thanatos just delete the systems the Swarm Lord controls?

Can Necrons just delete Terra.

Not "would" they, but "can" they?

Side note: if the tyranids pose too great a threat to the galaxy could the royal court of thanatos just delete the systems the Swarm Lord controls?