What made supernova 1987a so useful to study?
A) We saw direct evidence of nickel to iron decay in its light curve.
B) Its progenitor had been observed previously.
C) In the Large Magellanic Cloud, we already knew its distance.
D) It occurred after new telescopes, such as Hubble, could observe it very closely.
E) All of the above are correct.
E
You might also like to view...
In a thick bed of sedimentary rocks we find an igneous dike. The order of formation is
A) together. B) igneous before sedimentary. C) sedimentary before igneous. D) unknown.
A generator produces 60 A of current at 120 V. The voltage is usually stepped up to 4500 V by an ideal transformer and transmitted through a power line of total resistance 1.0 ?
Find the number of turns in the secondary if the primary has 200 turns. A) 4500 B) 7500 C) 200 D) 5
Half-way to the center of a planet of uniform density, your weight compared to that at the surface would be
A) one-quarter. B) one-half. C) three-quarters. D) the same as at the surface. E) zero.
One characteristic of the terrestrial planets is their extensive moon systems
Indicate whether the statement is true or false