Story highlights Satellite experts use "groundbreaking" process to track Flight 370's final hours

The Malaysia Airlines Boeing 777's last position was "in the middle of the Indian Ocean, west of Perth"

Satellite official: Hopefully, this will trigger a "mandate that all aircraft should be constantly tracked"

(CNN) Monday's announcement by Malaysia's Prime Minister acknowledging that missing Flight 370 ended in the southern Indian Ocean opens the door to a big question: How did new number crunching confirm the Boeing 777's path?

Now we know for sure "there's no way it went north," said Inmarsat Senior Vice President Chris McLaughlin.

Malaysian Prime Minister Najib Razak said Monday that the plane was last tracked over the middle of the Indian Ocean, west of Perth, Australia. Malaysian Airlines has informed passengers' relatives that "all lives are lost," a relative told CNN.

JUST WATCHED How Inmarsat found MH370's path Replay More Videos ... MUST WATCH How Inmarsat found MH370's path 05:58

Monday's announcement brings new questions about the mystery that has captivated the planet for more than two weeks. It also provoked a call that all airliners be constantly tracked.

The mathematics-based process used by Inmarsat and the UK's Air Accidents Investigation Branch (AAIB) to reveal the definitive path was described by McLaughlin as "groundbreaking."