Andres Deleon
Phys. 121
HW 11
4. What are the seasons like on Jupiter?
Jupiter’s seasons are very mild and almost nonexistent. This is because Jupiter has a very
small axial tilt of about 3 degrees, meaning the Sun's position in the sky doesn't change much
throughout its orbit. As a result, there is little variation in sunlight at different latitudes over the
course of a Jovian year, and the planet experiences no significant seasonal changes like Earth
does.
6. Describe the seasons on the planet Uranus.
Uranus has the most extreme seasons in the solar system due to its extreme axial tilt of about
98 degrees. Essentially, Uranus orbits the Sun on its side. Each pole spends about 42 years in
continuous sunlight followed by 42 years of darkness. This unique tilt causes very long and
unusual seasonal cycles, with one hemisphere being completely lit or completely dark for
decades at a time.
13. What are the visible clouds on the four giant planets composed of, and why are they
different from each other?
The visible clouds on the four giant planets are composed of different substances based on
temperature and atmospheric composition. On Jupiter and Saturn, the upper clouds are mostly
made of ammonia ice. Below that, there are clouds of ammonium hydrosulfide and water. On
Uranus and Neptune, which are colder, the visible clouds are composed of methane ice. These
differences occur because the temperatures at which different gases condense into clouds vary,
and each planet has different temperatures and chemical abundances.
21. Would you expect to find free oxygen gas in the atmospheres of the giant planets?
Why or why not?
We would not expect to find free oxygen gas (O₂) in the atmospheres of the giant planets. Free
oxygen is highly reactive and would quickly combine with other elements like hydrogen to form
compounds such as water. On Earth, free oxygen is only abundant because it is continuously
produced by photosynthetic life. Since the giant planets do not have known life forms to
replenish it, free oxygen is not expected to accumulate there.
24. Describe the different processes that lead to substantial internal heat sources for
Jupiter and Saturn. Since
Jupiter and Saturn have substantial internal heat sources due to different processes. Jupiter
generates heat primarily through the slow gravitational compression of its massive interior, a
process known as Kelvin-Helmholtz contraction. Saturn, in addition to gravitational contraction,
is thought to generate extra heat by the slow settling of helium droplets in its interior, which
releases energy as helium separates from hydrogen and sinks toward the core. These
processes keep both planets warmer than what sunlight alone would account for.
29. As the Voyager spacecraft penetrated into the outer solar system, the illumination
from the Sun declined. Relative to the situation at Earth, how bright is the sunlight at
each of the jovian planets?
As the Voyager spacecraft traveled farther from the Sun, sunlight became significantly dimmer.
The brightness of sunlight decreases with the square of the distance from the Sun. Compared to
Earth:
At Jupiter (about 5 AU), sunlight is about 1/25 as bright.
At Saturn (about 9.5 AU), sunlight is about 1/90 as bright.
At Uranus (about 19 AU), sunlight is about 1/360 as bright.
At Neptune (about 30 AU), sunlight is about 1/900 as bright.
This rapid drop in brightness explains why the outer solar system is so cold and why spacecraft
there need alternative power sources like nuclear batteries instead of solar panels.
