ASTRO 101 FINAL EXAM PREP 2025/2026 COMPLETE QUESTIONS WITH CORRECT DETAILED ANSWERS || 100% GUARANTEED PASS <BRAND NEW VERSION>

ASTRO 101 FINAL EXAM PREP 2025/2026 COMPLETE QUESTIONS WITH CORRECT DETAILED ANSWERS || 100% GUARANTEED PASS &lt;BRAND NEW VERSION&gt; 1. What do astronomers think is the origin of the many irregular moons around the outer planets (irregular meaning they are orbiting backwards and/or have eccentric orbits)? - ANSWER These moons were likely formed elsewhere and captured by the giant planets 2. Ninety percent of all stars (if plotted on an H-R diagram) would fall into a region astronomers call: - ANSWER The main sequence 3. Why are astronomers much more interested in the luminosity of a star than its apparent brightness? - ANSWER Because the luminosity tells us how bright a star really is, while apparent brightness only tells us how bright it happens to look from Earth 4. Measurements show a certain star has a very high luminosity (100,000 x the Sun's) while its temperature is quite cool (3500o K). How can this be? - ANSWER It must be quite large in size 5. Stars that lie in different places on the main sequence of the H-R diagram differ from each other mainly by having different: - ANSWER Masses 6. In an H-R diagram, where can you see the spectral type of a star (whether it is an O type star or a G type star, for example)? - ANSWER Along the bottom (the horizontal axis) 7. Where on the H-R Diagram would we find stars that look red when seen through a telescope? - ANSWER Only on the right side of the diagram and never on the left 8. The telescope in space that allowed astronomers to find thousands of exoplanets and exoplanet candidates by making very careful measurements during a planet transit was called: - ANSWER Kepler 9. A type of planet that our surveys of exoplanets are revealing around other stars, but we don't have any examples of around the Sun are: - ANSWER Super-Earth's 10. The first ordinary star (other than our own Sun) around which planets were definitely discovered was: - ANSWER 51 Pegasi 11. What observations about disks of dusty material around young stars suggest that planets may be forming in such disks? - ANSWER The disks show lanes that are empty of dust within them 12. Planets in the habitable zone of their stars: - ANSWER Are at a temperature where water can exist as a liquid 13. The first (living) star other than our own Sun found to have more than one planet orbiting it is called - ANSWER Upsilon Andromedae 14. With our current techniques, astronomers can typically only measure the minimum mass of a planet orbiting another star. To know the precise mass of the planet, they must also be able to determine - ANSWER The angle at which the planet's orbit is tilted relative to us 15. The fact that each type of atom has a unique pattern of electron orbits helps explain why - ANSWER Each type of atom shows different absorption or emission spectra 16. The ground state in an atom is - ANSWER The electron orbit with the lowest possible amount of energy 17. What technique did astronomers use to make the first confirmed discovery of a planet around another star like the Sun? - ANSWER Measure the Doppler shift of the lines in the star's spectrum and look for periodic changes in this shift due to the pull of the planet as it orbits the star 18. We observe a glowing cloud of gas in space with a spectroscope. We note that many of the familiar lines of hydrogen that we know on Earth seem to be in a different place. They are shifted toward the blue or violet end of the spectrum compared to their positions in the spectrum of glowing hydrogen gas on Earth. From this we can conclude that: - ANSWER The cloud is moving toward us 19. Why is an absorption spectrum especially useful for astronomers? - ANSWER It has dark lines in it that allow astronomers to determine what elements are in the star 20. An astronomer whose secret hobby is riding merry-go-rounds has dedicated his career to finding the stars that rotate the most rapidly. But the stars are all very far away, so none of them can be seen to spin even when he looks through the largest telescopes. How then can he identify the stars that rotate rapidly? - ANSWER Stars that rotate have much wider lines in their spectra than stars that do not 21. Geometry of the Earth-Moon-Sun, and how that gives the Moon's phase. - ANSWER Since the Moon is tidally locked, we always see the same side from Earth, but there's no permanent "dark side of the Moon." The Sun lights up different sides of the Moonas it orbits around Earth - it's the fraction of the Moon from which we see reflected sunlight that determines the lunar phase. 22. What causes a lunar eclipse? What is the Moon's phase? - ANSWER An event that occurs when the moon passes through earth's shadow, which can occur only at full moon. 23. What causes a solar eclipse? What is the Moon's phase? - ANSWER An event that occurs when the moon's shadow falls on earth, which occurs only at the new moon 24. Difference between bound and unbound orbits. - ANSWER Bound orbits - orbits on which an object travels repeatedly around another object ; elliptical in shape Unbound - orbits on which an object comes in toward a large body only once, never to return ; unbound orbits may be parabolic or hyperbolic in shape 25. What is the significance of the semi-major axis of an elliptical orbit? - ANSWER The semi-major axis is the mean value of the maximum and minimum distances and of the ellipsefrom a focus — that is, of the distances from a focus to the endpoints of the major axis. In astronomy these extreme points are called apsides. 26. Retrograde motion- ANSWER Every so often a planet moves from east to west against the background of stars. This is called retrograde motion. 27. Direct motion- ANSWER The planets move through the constellations of the zodiac, primarily from west to east. This is called direct motion. 28. Epicycles- ANSWER a small circle in which a planet moves while simultaneously going around a larger circle (the deferent) around Earth in the Ptolemaic model of the universe. 29. Deferents- ANSWER The large circle upon which a planet follows its circle-upon-circle path around the earth in the Ptolemaic model of the universe 30. Difference between scalars and vectors (give examples) - ANSWER Scalars - quantities that are fully described by a magnitude (or numerical value) alone. (speed) Vectors - quantities that are fully described by both a magnitude and a direction. (weight) 31. Mass- ANSWER Amount of matter in your body 32. Speed- ANSWER The rate at which an object moves 33. Velocity- ANSWER Velocity is the directed change of position (measured in some unit of distance per unit time) Tells us both speed and direction (v = acceleration X time) 34. Put the steps of the Sun's evolution in chronological order from 1 to 3 - ANSWER 1) fuse hydrogen into helium at its core 2) run out of hydrogen and become a red giant 3) shed outer layers in a nebula and become a white dwarf 35. What stops a white dwarf from collapsing? - ANSWER Electrons in the core producing degeneracy pressure that stops the white dwarf from collapsing 36. What causes a white dwarf to collapse, releasing the energy to explode in a Type Ia supernova? - ANSWER 37. What causes a core-collapse supernova? - ANSWER A core-collapse supernova is caused by the collapse of a star with a high enough mass that it forms an iron core 38. What can be produced when a high-mass star dies by core-collapse supernova? - ANSWER A black hole, A neutron star, A nebula 39. What is degeneracy pressure? - ANSWER Degeneracy pressure is the resistance of certain particles to being in the same place and energy state 40. what are characteristic of neutron stars? - ANSWER 1) Supported by degeneracy pressure 2) Primarily comprised of densely packed neutrons 3) Formed by core-collapse supernova 41. What is entropy? - ANSWER Entropy is a measurement of disorder in a system. 42. What is the relationship between the temperatures of a small and large black hole? - ANSWER The small black hole is hotter than the large black hole. 43. If a black hole increases in mass, what happens to its entropy? - ANSWER Its entropy increases. 44. What are the first three laws of black hole thermodynamics? - ANSWER 0) the surface gravity of a black hole is the same across its surface 1) changes to a black hole depend on the mass and energy consumed by it 2) the sum of the entropies of the black hole and the emitted Hawking radiation always increases 45. When a black hole increases in mass by a factor of two, what happens to its temperature? - ANSWER Its temperature decreases by a factor of two. 46. As a black hole gets hotter, what happens to its Hawking radiation? - ANSWER The peak wavelength of its Hawking radiation shifts to bluer wavelengths. 47. What happens to a black hole when its energy emission due to Hawking radiation is faster than its mass accretion. - ANSWER The black hole begins to evaporate, steadily losing mass. 48. Which black holes are the most likely to evaporate? - ANSWER Primordial, or super-tiny black holes, because of their low mass. 49. Which black holes have been observed emitting Hawking radiation? - ANSWER Hawking radiation has not been observed from black holes. 50. What theory are physicists looking for that would help them understand quantum mechanics in black holes? - ANSWER A quantum theory of gravity. 51. What would we call a piece of quantum information? - ANSWER A qubit.