Concept explainers
What evidence can you give that we live in a galaxy?
The evidence that life exists in a galaxy.
Answer to Problem 1RQ
The living organisms of the Milky Way galaxy are made up of the same constituents as the living organisms on earth are made up of. Hence, the life exists in a Milky Way galaxy.
Explanation of Solution
The galaxy in which life exists is the Milky Way Galaxy, the diameter of this galaxy is more than
The Milky Way Galaxy in which the life exists and which the living organisms live in has millions of stars, these stars are made up of the same basic constituents that the living organisms of the Earth and most of the atoms are made up of.
Therefore, the life exists in Milky Way galaxy.
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Chapter 15 Solutions
Foundations of Astronomy (MindTap Course List)
- Stars form in the Milky Way at a rate of about 1 solar mass per year. At this rate, how long would it take for all the interstellar gas in the Milky Way to be turned into stars if there were no fresh gas coming in from outside? How does this compare to the estimated age of the universe, 14 billion years? What do you conclude from this?arrow_forwardIf the diameter of the Milky Way Galaxys visible disk, 80,000 ly, is represented in a model by a dinner plate with a diameter of 10 inches, what is the model distance to galaxy M31, 2.6 millionly away? What is the model distance to the Virgo galaxy cluster, 16 Mpc away? (Convert answers to feet.)arrow_forwardIf you could search for life in the galaxy shown in this image, would you look among stars in the disk, in the central bulge, in the halo, or in all of those places? Discuss the factors that influence your decision.arrow_forward
- Suppose no stars more massive than about 2 MSunhad ever formed. Would life as we know it have been able to develop? Why or why not?arrow_forwardSuppose the average mass of a star in the Galaxy is one-third of a solar mass. Use the value for the mass of the Galaxy that we calculated in Exercise 25.19, and estimate how many stars are in the Milky Way. Give some reasons it is reasonable to assume that the mass of an average star is less than the mass of the Sun.arrow_forwardWhat is the evidence that star formation began when the universe was only a few hundred million years old?arrow_forward
- Assume that the average galaxy contains 1011MSunand that the average distance between galaxies is 10 million light-years. Calculate the average density of matter (mass per unit volume) in galaxies. What fraction is this of the critical density we calculated in the chapter?arrow_forwardThe nearest galaxy to our home galaxy is about 2.5 million light- years away. How many meters is that?arrow_forwardWhat are some answers to the Fermi paradox? Can you think of some that are not discussed in this chapter?arrow_forward
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