Astronomy Third Test Flashcards
19- a) Write “Bode’s Law”, and indicate the location of each planet in the scheme.
Bode’s law states that if you take the number sequence 0,3 and from there double it, then add four then divide each number by 10, you get the approximate distance of each planet from the sun in AU.
b) State where the law originally appeared not to be accurate.
The law appeared to break down when no planet was found at 2.8AU between Mars and Jupiter. The dwarf planet Ceres was eventually found there, followed by the discovery of the rest of the asteroids that make up the Asteroid belt between Mars and Jupiter. It is thought that these would have formed a planet except for the effects of Jupiter’s gravity.
20- a) Why were astronomers not able to measure the rotation rate of Venus until the middle of the 20th century?
Venus’s incredibly thick atmosphere blocks wavelengths of light that are normally used to calculate the rotation of bodies by measuring their doppler shift.
b) Describe and name the method used in 1960, including a diagram.
In the 1960s radar was used to measure Venus’ rotation rate. Radar is bouncing radio waves off of an object and measuring time it takes to bounce back. Venus’ atmosphere is transparent to radio waves so the doppler method of measuring rotation can be used here.
21- a) Name 2 major features on the surface of Mars, and compare each in size to a familiar feature on Earth.
a) Two major features on the surface of Mars are Olympus Mons, an extinct mountain volcano that is four times as tall as Mt. Everest and the tallest mountain in the solar system. Another is the Valles Marinaris, an ancient canyon carved by water that is as long as the United States is wide.
21- a) Name 2 major features on the surface of Mars, and compare each in size to a familiar feature on Earth.
a) Two major features on the surface of Mars are Olympus Mons, an extinct mountain volcano that is four times as tall as Mt. Everest and the tallest mountain in the solar system. Another is the Valles Maranes, an ancient canyon carved by water that is as long as the United States is wide.
21b) Name 4 of the probes (rovers etc.) that were soft-landed on Mars before 2012.
b) Viking 1 and 2, Sojourner+Pathfinder, Spirit, Opportunity.
22- a)You are in a spacecraft that can somehow withstand the pressures and temperatures in the body of Jupiter. You fly into the planet along its equatorial plane, and descend all the way to very near the center. Describe 3 distinctly different layers that you encounter, including the major chemical components, a rough idea of temperature, and phase state (solid, liquid or gas) of each, and the nature of the transition zone from one layer to the next.
a) The first layer of Jupiter you encounter is water clouds, followed by clouds of ammonium and ammonium nitrate. After that, it gradually transitions into a layer of liquid hydrogen followed by liquid metallic hydrogen. It is thought that Jupiter has a rocky core made of heavier elements. The transitions between each phase are gradual, in kind of a soupy state.
23- Astronomers are particularly interested in Io, Europa, Titan and Enceladus.
a) With one sentence for each, what makes each so interesting and what planet does each one orbit?
a) Io- a volcanic moon of jupiter. Volcanic due to stresses of Jupiter’s tidal forces.
Europa- ice moon of jupiter. Thougth that there are liquid oceans under the ice, possibly harbors life?
Titan- has a thich atmosphere. lakes of liquid nitrogen.
Encladus- covered in water ice. “tiger stripes” of geysers near south pole spray water ice out. something must be keeping it warm.
- b) Draw a picture showing the four bodies (Io, europa, titan, enceladus and Mercury roughly to scale, lined up in a row from smallest to largest.
Enceladus, Europa, Io, Mercury, Titan!
24- a) There are several strange things about Neptune, one of its moons, and Pluto. Briefly describe 3 of those things. One sentence for each is enough, but draw a diagram to illustrate at least one of them.
Neptune doesn’t fit bode’s law. Its moon Triton has a retrograde (backwards) orbit compared to almost everything else in solar system. Pluto’s highly elliptical orbit crosses Neptune’s.
24b) State the current definition of a planet.
- Must be in orbit around sun
- Must spherical shape, have shaped itself by gravity
- Must have cleared its orbital path of debris
26- a) Draw a diagram of a comet, showing the various parts or regions, and including the approximate size of each in km.
10km across nucleas, 100k. ionized trail away from sun, blown by solar wind, another dust trail following comet. 100k thing is called.
26 b) How are comet orbits different from planetary orbits?
Comet orbits are much more eccentric ellipses, and then are often not at all on the same plane as the rest of the solar system. These are both because comets originate in a spherical body of small rocky objects.
