Naap atmospheric retention answers

TA: Keslo Estil SEC#: Name: Atmospheric Retention Lab Projectile Motion 1. Imagine that asteroid A that has an escape velocity of 50 m/s. If asteroid B has twice the mass and twice the radius, it would have an escape velocity ………. the escape velocity of asteroid A. a) 4 times b) Twice c) the same as d) half e) one-fourth 2. Complete the table below by using the Projectile Simulation to determine the escape velocities for the following objects. Since the masses and radii are given in term of the Earth’s, you can easily check your values by using the mathematical formula for escape velocity. Object Mass (𝑴𝒆𝒂𝒓𝒕𝒉 ) Radius (𝑹𝒆𝒂𝒓𝒕𝒉 ) 𝑽𝒆𝒔𝒄 (𝒌𝒎/𝒔) Mercury 0.055 0.38 4.3 km/s Uranus Io Vesta Krypton 15 0.015 0.00005 100 4.0 0.30 0.083 10 𝑽𝒆𝒔𝒄 (𝒌𝒎/𝒔) calculation √ 0.055 𝑘𝑚 𝑘𝑚 (11.2 ) = 4.3 0.38 𝑠 𝑠 NAAP – Atmospheric Retention TA: Keslo Estil SEC#: Name: Gas Retention Plot This simulator presents an interactive plot summarizing the interplay between escape velocities of large bodies in our solar system and the Maxwell distribution for common gases. The plot has velocity on the y-axis and temperature on the x-axis. Two types of plotting are possible: ▪ A point on the graph represents a large body with that particular escape velocity and outer atmosphere temperature. An active (red) point can be dragged or controlled with sliders. Realize that the escape velocity of a body depends on both the density (or mass) and the radius of an object. ▪ A line on the graph represents 10 times the average velocity (10×vavg) for a particular gas and its variation with temperature. This region is shaded with a unique color for each gas. o If a body has an escape velocity vesc over 10×vavg of a gas, it will certainly retain that gas over time intervals on the order of the age of our solar system. o If vesc is roughly 5 to 9 times vavg, the gas will be partially retained and the color fades into white over this parameter range. o If vesc < 5 vavg, the gas will escape into space quickly. • Begin experimenting with all boxes unchecked in both the gasses and plot options. 3. Plot the retention curves for hydrogen, helium, ammonia, nitrogen, carbon dioxide, and xenon gases. Explain the appearance of these curves on the retention plot. ANS: • Check show gas giants in the plot options panel. 4. Discuss the capability of our solar system’s gas giants to retain particular gases among those shown. ANS: NAAP – Atmospheric Retention TA: Keslo Estil SEC#: Name: 5. Drag the active point to the location (comparable with the escape speed and temperature) of Mercury. The gases hydrogen, helium, methane, ammonia, nitrogen, and carbon dioxide were common in the early solar system. Which of these gases would Mercury be able to retain? ANS: 6. Most nitrogen atoms have a mass of 14u (hence 28u for N2), but a small percentage of nitrogen atoms have an extra neutron and thus an atomic mass of 15u. (We refer to atoms of the same element but with different masses as isotopes of that element.) Recently, scientists studying isotope data from the Cassini spacecraft have noticed that the ratio of 15u nitrogen to 14u nitrogen is much larger than it is here on earth. Assuming that Titan and the earth originally had the same isotope ratios, explain why the ratios might be different today. ANS: 7. Other observations by the Cassini probe have confirmed that Titan has a thick atmosphere of nitrogen and methane with a density of about 10 times that of the Earth’s atmosphere.