Yes.
Australia is moving northwards about 7cm every year.
1 year old enough when they stop with their parents
A 17 year old girl does not have any rights when moving away from home in Australia as the legal age to move out is 18.
No, Australia is not moving to Antarctica. While Australia does have research stations and territorial claims in Antarctica, geographically Australia remains a separate continent located in the Southern Hemisphere.
she sent them to Australia in Harry Potter and the deathly hallows.
sad
No.
New Zealanders have been moving to Australia at a rapid pace which is growing each year. The biggest effects involve currency and commerce because there is less money coming into the government each year.
If said sixteen-year-old also lives in Australia, it is both possible and legal.Said sixteen-year-old girl's parents may or may not agree that this is possible.
Contact the school and/or the parents of the child. Inform them (calmly) that their daughter is making your son (and you) uncomfortable with her behaviour, and that you would like it to stop immediately.
In most cases, a parent cannot legally stop a 17-year-old from moving out if they are considered a legal adult in their jurisdiction. However, parents may still have legal obligations or responsibilities towards their child until they reach the age of majority. It is advisable for the parent and child to seek guidance from a legal professional to understand their rights and responsibilities in this situation.