The smallest parallax angle that Hipparcos will be able to detect is 0.002 arcsecond. In lecture you were given the mass of the sun, which is symbolized by the solar mass. Convert the mass of the earth first to grams, and then give its mass in solar masses. The hydrogen atom has a mass of kg. Express the mass of a hydrogen atom in grams.
Stars radiate away enormous amounts of energy in the form of electromagnetic radiation.
The estimated lifetime of the sun is about years. In a short paragraph, explain what the ultimate source of a star's energy is. As discussed in lecture, there is a lower limit and an upper limit to the mass of stars. Give the mass of the lightest and heaviest possible stars in kilograms. Explain why there exist lower and upper limits to the masses of stars.