IF a particular galaxys has a total mass of 10 to the 56 grams and the average star in that galaxy has a mass of 10 to the 35 grams, approximately how many stars are there in that galaxy? Give your answer to the nearest whole power of 10 by entering the exponent only.
A certain spacecraft is 3.3 AU (Astronomical Units) from Earth. How long in seconds does it take for a signal to reach the Earth after it is transmitted from the spacecraft? Hint: An AU is about 149.9 Million Km, and light moves at 299,800 Km/s. {Indicate your answer to the nearest whole second).
If a hypothetical planet in our Solar System had a sidereal period of 11.1 Earth years and a circular orbit, how far from the Sun in Astronomical Units would it be? Enter your answer to the nearest 0.01 AU.
A particular spiral galaxy can be approximated by a thin disk-like volume 35 Thousand Light Years in radius and 8 Hundred Light Years thick. If this Galaxy contains 790 Billion stars, estimate the average distance between the stars in this galaxy. Hint: calculate the average volume per star in cubic Light Years, and then estimate the approximate linear dimension across such a volume. (Indicate your answer to one decimal place.)
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2 answers
2. d = 3.3AU * 1.499*10^8km/AU =
d = V*t, V = 3*10^5 km/s, t = ?.