Silver Discoverer, Silversea's latest addition to its award-winning expedition fleet, welcomes her first guests today, exactly 20 years to the day since the company launched its first ultra-luxury cruise ship. Setting sail at 4:30 p.m. on her inaugural voyage from the port city of Broome, in northern Western Australia, the 120-guest, all-suite expedition ship will spend 10 days exploring the Kimberley Coast's jaw-dropping landscapes and ancient human history. A vast, rugged region…