Which event marks the beginning of a supernova?
A) the expansion of a low-mass star into a red giant
B) the beginning of neon burning in an extremely massive star
C) the onset of helium burning after a helium flash in a star with mass comparable to that of the Sun
D) the sudden collapse of an iron core into a compact ball of neutrons
E) the sudden outpouring of X-rays from a newly formed accretion disk
Question 2
As an interstellar cloud of hydrogen gas shrinks in size, its temperature increases
A) because thermal energy is converted to radiative energy.
B) because kinetic energy is converted to radiative energy.
C) because gravitational potential energy is converted to thermal energy.
Three Tasmanian devils feeding. Eating is a social event for the Tasmanian devil, and groups of 2 to
False-color imagery of the Sun, a G-type main-sequence star, the closest to Earth.
Land mass looks like a synapse
Dimmer Distant Supernova
The first commercially successful typewriter, manufactured in quantity beginning in 1874, surely fue
Calculation of body mass index. To determine your BMI, find the value for your height on the left ...