As a 6 solar-mass star leaves the main sequence on its way to becoming a red supergiant, its luminosity
A) remains roughly constant.
B) decreases.
C) first increases, then decreases.
D) increases.
E) first decreases, then increases.
Question 2
Which of the following statements best describes the current state of understanding regarding the apparent acceleration of the expansion of the universe?
A) The cause of the acceleration is well-understood, and attributed to the particles that make up dark energy.
B) The acceleration is very important in the cosmos today, but the evidence indicates that it will eventually slow down, allowing the universe to recollapse.
C) The acceleration probably is not real, and what we attribute to acceleration is probably just a misinterpretation of the data.
D) We have moderately strong evidence that the acceleration is real, but essentially no idea what is causing it.
Balmer Lines in the Spectrum of a Star
The Solar Corona
Change in Bone Mass over Time In your early years, more bone mass is added than lost in your body
Relationship of Sun Angle and Solar Radiation
What is the isotopic atomic mass of an isotope if 9.7023 1022 atoms weighs 4.0256 g?