The massive explosion at the end of a star's life is called a supernova, a cataclysmic event where a star briefly outshines its entire galaxy, releasing immense energy and scattering heavy elements into space, leaving behind either a neutron star or a black hole. 

A wallaby is a small to medium-sized marsupial from Australia and New Guinea, closely related to kangaroos but generally smaller, known for its powerful hind legs for hopping, a balancing tail, and a pouch (marsupium) for carrying young. They're herbivorous, come in various types like brush, rock, and hare wallabies, and are classified by their habitat, thriving in forests, scrublands, and rocky terrains. 

The common term for a neck injury caused by a sudden, forceful jerk of the head (forward and backward) is whiplash, which involves stretching or tearing of neck muscles and ligaments, often from car accidents or falls.

London, England, boasts the world's first subway line, known as the London Underground or "the Tube" (or "underground railway"), which opened on January 10, 1863, running steam locomotives between Paddington and Farringdon Street. This revolutionary system, initially using steam-powered trains in cut-and-cover tunnels, paved the way for modern urban underground transport. 

The most populous bird in the world is the Domestic Chicken (Gallus gallus domesticus), with populations numbering in the tens of billions (around 22-26 billion), far exceeding any wild bird.