Observationally, how can we tell the difference between a white-dwarf supernova and a massive-star supernova?
A) A massive-star supernova is brighter than a white-dwarf supernova.
B) A massive-star supernova happens only once, while a white-dwarf supernova can repeat periodically.
C) The light of a white-dwarf supernova fades steadily, while the light of a massive-star supernova continues to brighten for many weeks.
D) The spectrum of a massive-star supernova shows prominent hydrogen lines, while the spectrum of a white-dwarf supernova does not.
E) We cannot yet tell the difference between a massive-star supernova and a white-dwarf supernova.
Question 2
What are the two geological features that appear to set Earth apart from all the other terrestrial worlds?
A) a dense core and plate tectonics B) mantle convection and a thick atmosphere
C) significant volcanism and tectonics D) plate tectonics and widespread erosion
White-footed mouse
Emperor penguins with their black and white plumage stand out against the snow and colonies
Adolescent white lion in Kruger National Park, South Africa.
A typical open-end wrench. Note the size difference on each end and that the head is angled 15 ...
White Blood Cells