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Learning objectives

By the end of this section, you will be able to:

  • Discuss the atmospheric composition of the giant planets
  • Describe the cloud formation and atmospheric structure of the gas giants
  • Characterize the giant planets’ wind and weather patterns
  • Understand the scale and longevity of storms on the giant planets

The atmosphere s of the jovian planets are the parts we can observe or measure directly. Since these planets have no solid surfaces, their atmospheres are more representative of their general compositions than is the case with the terrestrial planets. These atmospheres also present us with some of the most dramatic examples of weather patterns in the solar system. As we will see, storms on these planets can grow bigger than the entire planet Earth.

Atmospheric composition

When sunlight reflects from the atmospheres of the giant planets, the atmospheric gases leave their “fingerprints” in the spectrum of light. Spectroscopic observations of the jovian planets began in the nineteenth century, but for a long time, astronomers were not able to interpret the spectra they observed. As late as the 1930s, the most prominent features photographed in these spectra remained unidentified. Then better spectra revealed the presence of molecules of methane (CH 4 ) and ammonia (NH 3 ) in the atmospheres of Jupiter and Saturn.

At first astronomers thought that methane and ammonia might be the main constituents of these atmospheres, but now we know that hydrogen and helium are actually the dominant gases. The confusion arose because neither hydrogen nor helium possesses easily detected spectral features in the visible spectrum. It was not until the Voyager spacecraft measured the far-infrared spectra of Jupiter and Saturn that a reliable abundance for the elusive helium could be found.

The compositions of the two atmospheres are generally similar, except that on Saturn there is less helium as the result of the precipitation of helium that contributes to Saturn’s internal energy source. The most precise measurements of composition were made on Jupiter by the Galileo entry probe in 1995; as a result, we know the abundances of some elements in the jovian atmosphere even better than we know those in the Sun.

James van allen: several planets under his belt

The career of physicist James Van Allen spanned the birth and growth of the space age, and he played a major role in its development. Born in Iowa in 1914, Van Allen received his PhD from the University of Iowa. He then worked for several research institutions and served in the Navy during World War II.

After the war, Van Allen ( [link] ) was appointed Professor of Physics at the University of Iowa. He and his collaborators began using rockets to explore cosmic radiation in Earth’s outer atmosphere. To reach extremely high altitudes, Van Allen designed a technique in which a balloon lifts and then launches a small rocket (the rocket is nicknamed “the rockoon”).

James van allen (1914–2006).

Photograph of James Van Allen holding a small rocket, which was part of a “rockoon”.
In this 1950s photograph, Van Allen holds a “rockoon.” (credit: modification of work by Frederick W. Kent Collection, University of Iowa Archives)

Over dinner one night in 1950, Van Allen and several colleagues came up with the idea of the International Geophysical Year (IGY), an opportunity for scientists around the world to coordinate their investigations of the physics of Earth, especially research done at high altitudes. In 1955, the United States and the Soviet Union each committed themselves to launching an Earth-orbiting satellite during IGY, a competition that began what came to be known as the space race. The IGY (stretched to 18 months) took place between July 1957 and December 1958.

The Soviet Union won the first lap of the race by launching Sputnik 1 in October 1957. The US government spurred its scientists and engineers to even greater efforts to get something into space to maintain the country’s prestige. However, the primary US satellite program, Vanguard, ran into difficulties: each of its early launches crashed or exploded. Simultaneously, a second team of rocket engineers and scientists had quietly been working on a military launch vehicle called Jupiter-C. Van Allen spearheaded the design of the instruments aboard a small satellite that this vehicle would carry. On January 31, 1958, Van Allen’s Explorer 1 became the first US satellite in space.

Unlike Sputnik, Explorer 1 was equipped to make scientific measurements of high-energy charged particles above the atmosphere. Van Allen and his team discovered a belt of highly charged particles surrounding Earth, and these belts now bear his name. This first scientific discovery of the space program made Van Allen’s name known around the world.

Van Allen and his colleagues continued to measure the magnetic and particle environment around planets with increasingly sophisticated spacecraft, including Pioneers 10 and 11, which made exploratory surveys of the environments of Jupiter and Saturn. Some scientists refer to the charged-particle zones around those planets as Van Allen belt s as well. (Once, when Van Allen was giving a lecture at the University of Arizona, the graduate students in planetary science asked him if he would leave his belt at the school. It is now proudly displayed as the university’s “Van Allen belt.”)

Van Allen was a strong supporter of space science and an eloquent senior spokesperson for the American scientific community, warning NASA not to put all its efforts into human spaceflight, but to also use robotic spacecraft as productive tools for space exploration.

Questions & Answers

what is time
Abdul Reply
Time is relative
mrunal
pls elaborate
sakshi
the clear defination.I know that.
Abdul
In planet mars there the life exits or not and is there water there
Eshwarsa Reply
see till now nothing can be found as u know that the curiosity rover has struck in mars
Maya
what is your opinion about the theory of Vedas about modern physics..
Manish Reply
i think in some ways vedas are also correct but not everytime
Maya
I agree
sakshi
hmm even I agree
Samuel
Is there any patened theory about time relativitg in growth and development?
donot Reply
some astronomer's says that there is no alien exist but why search for extra terrestrial intelligence center is established
Eshwarsa Reply
No One Knows That For Absolute Fact, The Universe Is Too Huge To Have Any Type Of Idea About What Exist In The Far Reaches Of Our Universe.....
Adam
Check Out The Drake Equation.....
Adam
their should be aliens as like ours there would be another planet
Maya
which could have existed life on it
Maya
adam i want to ask a question
Maya
can kepler 1st law be applied on all the planets of the universe
Maya
hello, anyone home?
Denise
sjskskfhjkkktewqqw and try?
Lanika Reply
what is this ?
Samuel
hi I am Samuel from India mumbai
Samuel
nice to meet you
Samuel
thats my question, what is this?
penzias and wilson's a discovery of the cosmic microwave background is a nice example of scientific serendipity-something that is found by chance but turns out to have a positive outcome
Jacqueline Reply
how should I make my carrier in astronomy
Ayush Reply
I think that Newton's third law is not appropriate if any also thinks like this please reply me
Ayush
Can you explain your reasoning
Huh
why u think so
joseph
yes Ayush u are right
Yoganshu
I think when we apply force to a object it start moving but , a/c to Newton's third law every action has equal and opposite reaction,so object should also exert equal force on us and it should not move due to balanced force
Ayush
if I am not right then reply me
Ayush
no
Zack
because of friction that opposes that force and help us to move ahead
Manish
but this is not satisfied as third law say another thing
Ayush
you are telling why object moves
Ayush
you have to think a/c to third law
Ayush
its because of its mass
Maya
because it is applying equal and opposite force but also our mass is also less in comparison to the object
Maya
which is why we cant move the object but it can make move us
Maya
manish is too correct in his place because we need to apply force which would overcome the frictional force
Maya
My dear friends, can u plz tell me that among u guys who are in the field of cosmology
Madhav Reply
😢I am not there in cosmology
Samuel
Just A Science Fan.....
Adam
Adam even I am 😥😅😅😂😂
Samuel
I am also not in cosmology but I am just a fan or we can say science and part of NASA is my dream
Yoganshu
yoganshu Arya same here
Samuel
you are from which country
Yoganshu
hi yoganshu
Samuel
India
Samuel
which state
Samuel
I am also from India
Yoganshu
from delhi
Yoganshu
and u...?
Yoganshu
I am from Maharashtra
Samuel
from which state?
Yoganshu
You are a ASTRONOMER ...
Yoganshu
or a scientist..
Yoganshu
or just a member
Yoganshu
What is time...? not about Newton= time is constant..... that all scientists openions n point of view I m knowing. . what can be the Perfect Definition of Time
Madhav Reply
time is what clock reads
Ayush
Who is the best astronomer of India at present time
Gian Reply
Jayant Narlikar, Proponent Of Steady State Cosmology.....
Adam
What is the real colour of sun rays
Gian Reply
white.. so white it becomes violet.. so violet it become ultraviolet
Tom
white and red and yellow
Bianca
Vibgyor
Samuel
the real colour of sunlight is White
Madhav
the Sun's has a variety of waves all throughout the elextromagnetic spectrum.
Jacie
we only see it as a few bc of how some of them get redshifted (? can that term be applied for something so local?) by some particles in our upper atmosphere
Jacie
Vibgyor will be when, the white light will pass through the clouds ( prism ) then Refraction phenomenon leads us to 7 colours splitting from a single colour "White " light
Madhav
so the sun rays r of White colour
Madhav
Taurus in astronomy and horoscope?
Yasser Reply
how to put E=MC2
Gospel Reply
What Do You Mean By How To Put?
Adam
What Do You Mean By How To Put?
Adam
What Do You Mean By "How To Put E=MC2?
Adam
yep
Gospel
Hi guys
Samuel
i mean how NASA came to know the mass and diameters of Stars.how?
Gospel
how did they do using E=MC2
Gospel
thats my questioning
Gospel
that's easy formula's derivation
Madhav
why all planets revolving orbits are nearly in equal inclination?
Kartik Reply
***medium.com/starts-with-a-bang/ask-ethan-82-why-are-the-planets-all-in-the-same-plane-4470245c8743
rishabh
dependent on the mass
Madhav
no
Janak
I think because of the Suns gravity pull ,😕😕
Samuel
Samuel,. it's but obvious
Madhav

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Source:  OpenStax, Astronomy. OpenStax CNX. Apr 12, 2017 Download for free at http://cnx.org/content/col11992/1.13
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