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CHAPTER 1

INTRODUCTION

1.1 Jovian Planetary System

Some of the most prolific and profound objects in our solar system are the Jovian gas

giants. These massive swirling bodies of gas and ice have been the fascination of the ancient star

gazers to today’s well renowned astronomers and astrophysicists. Our own solar system is

comprised of four of its own gas giants: Neptune, Uranus, Saturn and Jupiter.

In our solar system these four Jovian planets all lie on the outer edges of the solar system

past the asteroid belt with the closest, Jupiter, lying 5.2 astronomical units (4.836 x 108 miles)

and the furthest, Neptune lying 30.1 astronomical units (2.7993 x 109 miles) away. The

characteristics making these planets so different from the other four terrestrial planets are two

basic facts:

1.) Immense size difference.

2.) Gas composition with liquid inner layer.

When studied these differences become extremely clear with hundreds of earth-sized

planets being able to fit into their Jovian counterparts. Part of the reason for this is the material

they are made out of. Typical terrestrial planets have thin crusts of a silicate mineral

composition with very dense metallic cores mostly composed of iron, nickel and several other

heavy metals. Some may wonder why the gas giants are all on the outer reaches of the solar

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system and all the terrestrial bodies are inward closer to the Sun. Astronomers have developed a

widely accepted theory accurately telling why this is.

In the early solar system, “Gravity from our young star pulled in much of the free-

floating gas… while the solar wind of particles streaming from the Sun also swept the gas

outward” (Sparrow 52). When the Sun was younger, it produced much more heat and energy as

it developed. It created massive solar winds that pushed the lighter elements like hydrogen and

helium, the main components of the gas giants Jupiter and Saturn, back to the further reaches of

the solar system. As a result of this the heavier particles of rock and metal were left and

influenced by the Sun’s gravitational force and began to grow larger and accumulated more

particles and mass to create the rocky and dense planetesimals that would be the base for the

terrestrial inner planets. Figure 1.1

However, the lighter elements were

pushed back by these solar winds and were

joined together rather quickly due to

gravitational forces.

There are two debated models upon

which astronomers and astrophysicists

believe the Jovian planets formed, the core

accretion model or the gravitational

instability model (Metchev). The first and

more widely accepted model, the core accretion

model, shown in Figure 1.1, states once a

planetesimal has formed, it would then have

As the planetesimal forms, it gathers mass at an exponential rate once it reaches its runaway point.

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sufficient gravitational influence on the surrounding gas to begin rapidly gaining mass due to the

accretion of gas molecules blown away from a star’s initial releases of solar winds. This process

continues in the gas-rich outer edges of a solar system until there is no longer any more gas to

pull in, resulting in the final planet.

The second model for the creation of gas giants is the gravitational instability model.

This model states huge clouds of gasses detached from the initial star forming nebula, began to

rapidly spin under their own angular velocity and eventually begin falling in on themselves

creating the planet (Sparrow 52). These two theories are at odds as the core accretion model

only explains how planets of this nature form within the confines of a 30 AU orbital radius form

its parent star and gravitational instability is only effective at explaining planets around

extremely massive parent stars, nothing comparable to a star like GJ 504 or our Sun.

Nonetheless, when they came together, the Jovian gas giants were formed with masses of

Uranus’s 8.86 x 1025 kilograms to Jupiter’s 1.90 x 1027 kilograms although giant gas planets as a

whole are not limited to these parameters and can exceed or deceed them. Due to the great mass

of the accumulated gas clouds that surround the rocky inner cores, the pressures and

temperatures greatly increase as you travel further into the atmosphere. Chris Impey states,

“Data shows (of Voyager and Galileo probes), the upper atmospheres are cold, but below the

cloud layers, their lower atmospheres are hot and have high air pressure.”

1.2 GJ 504 b and Its Parent Star

In the constellation Virgo lies a star named GJ 504. GJ 504 is G0 type main-sequence

star that lies approximately 57 light years away and is believed to be around 160 million years

old (Reddy). It has a mass of about 1.2 solar masses and has a rotational period of about 3.33

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days (Kuzuhara). This star is not really out of the ordinary and actually often compared to the

Sun, resembling size and temperature. It is a fairly common star with no notable anomalies

about it. In Table 1.1 is a fact table of GJ 504.

Table 1.1

The strange thing about this star is its one identified planet, GJ 504 b. This star gets its

name from its parent star GJ 504 where “b” stands for the planet’s position as the second object

in the system while GJ 504 would be considered first. The planet was discovered in 2013 by the

Strategic Exploration of Exoplanets and Disks with Subaru or SEEDS (Kuzuhara). “GJ 504 b is

about four times as massive as Jupiter and is about 460 degrees Fahrenheit (511 K)”

(Westerholm). A planet four times the mass of Jupiter would equate to 7.6 x 1027 kilograms or

approximately 1,300 times the mass of the Earth. This planet is quite peculiar and according to

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accepted scientific models of how gas giants form, shouldn’t exist based on its mass and distance

from GJ 504.

Like Jupiter, GJ 504 b is also a gas giant. This planet, unlike Jupiter’s rusted red color, is

a very deep swirling purple or magenta color. However, this isn’t a typical gas giant planet.

There are certain aspects of this planet that have astrophysicists perplexed. These aspects will be

viewed in greater depth in the next section.

1.3 Discovery of GJ 504 b and Its Significance

Like previously stated, GJ 504 b was discovered in 2013 by the Strategic Exploration of

Exoplanets and Disks with Subaru (SEEDS) program. The SEEDS team comprised of 120

members, led by Motohide Tamura of the University of Japan, has been utilizing the Subaru

Telescope since 2009 to view approximately 500 stars in an effort to find new exoplanets

(Subaru). GJ 504 b is a product of this ongoing search. The team took a direct-imaging

approach in order to photograph this planet by fixing the Subaru Telescope on GJ 504 in order to

see what it could find. Below is the first direct-imaging result the SEEDS team took:

Figure 1.2

This was the one of the first published photos produced by the SEEDS team and the Subaru Telescope. Directly centered is the parent star GJ 504 with GJ 504 b to the top right. An outline of Neptune’s orbit is given for scale.

Photo Credit: Sci.News.com and Subaru Telescope

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The photo in Figure 1.3 is what perplexed the SEEDS team. Upon comparing the orbit of GJ

504 b to that of Neptune’s they realized the problems the planet itself was posing. According to

current accepted models, mainly the core accretion model, this planet should not have been able

to form.

The core accretion model only complies with planets within 30 AUs of their planet star.

GJ 504 b lies about 50 AUs away. GJ 504 b far exceeds that boundary as the model states there

would not have been a sufficient amount of material for a planet of that size and mass to form.

At this point some astronomers and astrophysicists would argue the gravitational instability

model could easily be applied. However, GJ 504 is a medium sized main-sequence star born out

of a smaller nebula, a situation that would have nowhere near enough mass to allow the

collapsing in of the gas molecules from the clouds angular velocity alone.

This predicament is what is making GJ 504 b such a special case. As of now, science has

no sound way of explaining why and how this planet was able to form. It completely contradicts

everything astronomers know about how Jovian gas giants form. Because of this, there is no

doubt this planet will continue to be scrutinized and studied to see what researchers can further

unlock about this planet and what exactly caused it to form in such different circumstances.

Directly comparing GJ 504 b to a standard cookie cutter gas giant like Jupiter will hopefully

bring about new thoughts onto why this planet is so different.

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CHAPTER 2

PHYISCAL CHARACTERISTICS

2.1 Appearance

When it comes to appearances, Jupiter could be considered one of the most dazzling to

look at, and for good reason. Its deep rusted red and blaze orange atmosphere dance in stratified

lines across the planet’s atmosphere. These lines and colors are not just by coincidence though.

There is a major connection of atmospheric pressures, chemical presence, and movement

resulting in the outer appearance of Jupiter. Likewise, GJ 504 b is also believed to have

stratified layers of alternating colored lines but in deep purples and bright fuchsias. GJ 504 b’s

color is direct result of the mass amounts of methane that comprise a large majority of its

atmosphere (Kuzuhara). Jupiter’s orange and reddish colors are a result of the chemical

reactions taken place in its atmosphere. However, more of what gives each planet their colors

will be looked at in greater depth in Chapter 3.1.

Gas giants like Jupiter and GJ 504 b tend to have much larger sizes compared to their

terrestrial counterparts. Part of the reason for this is their very low densities. Gas giants usually

possess a much greater amount of mass, but spread out over a much greater sphere. Rocky

terrestrial planets like Earth have much less matter comprising their makeup but it is crammed

into much smaller sphere resulting a significantly higher density, as seen below:

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Volume= 4/3πr3

Earth Jupiter

V=4/3π(6,378 km.3) V=4/3π(71,492km.3)

V=1.087 x 1012 km.3 or 1.087 x 1027 cm.3 V=1.531 x 1015 km.3 or 1.531 x 1030 cm.3

Density=Mass/Volume

Earth Jupiter

D=5.98 x 1024 kg. / 1.087 x 1027 cm.3 D= 1.90 x 1030 g. / 1.531 x 1030 cm.3

Density = 5.5 g /cm.3 Density = 1.2 g./cm.3

As you can see from the calculations above, terrestrial planets, like Earth, are

substantially denser than their Jovian counterparts. While there will obviously be variations in

the densities of all planets, it can be concluded terrestrials have a much higher density. The

densities among gas giants also vary greatly. However, since GJ 504 b is roughly four times the

mass of Jupiter (7.6 x 1027 kilograms), its true density is open to interpretation and further study

as there have been no conclusive tests that would have led to figuring out the exact radius of GJ

504 b; a variable needed to find its volume and consequently its density. The average density of

our solar system’s Jovian planets is 1.232 g./cm.3, an average which Jupiter lies extremely close

to. Based on these observations, it would not be crazy to speculate GJ 504 b’s average density

lies near our solar system’s Jovians’ average density. Unfortunately, the actual number will not

be able to come to fruition until more research is done by the SEEDS team. Simply finding the

planet’s linear diameter would give us the ability to calculate GJ 504 b’s actual density.

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2.2 Moons

Comparison of Jupiter’s Galilean Moo

Moon Radius Mass (kg.) Distance from Jupiter

Io 1821.6 km. 8.932 x 1022 kg. 4.216 x 105 km.

Europa 1560.8 km. 4.800 x 1022 kg. 6.709 x 105 km.

Ganymede 2631.2 km. 1.482 x 1022 kg. 1.070 x 106 km.

Callisto 2410.3 km. 1.076 x 1023 kg. 1.883 x 106 km.

One of Jupiter’s most notable characteristics is its moons. Jupiter’s immense mass acts like a

gravitational magnet for all sorts of space debris and rock. Although the number frequently

changes, at the time of the publication of this paper, Jupiter is believed to have 67 recognized

moons. These moons vary greatly in size and shape. Some are so large that they are spherical

due to their own gravity and others that are just smaller asteroid shaped objects of rock, ice, and

metal. The four largest moons, referred to as Galilean moons, after their discoverer Galileo

Galilei, are Io, Europa, Ganymede, and Callisto. These four moons have been a great wonder to

astronomers ever since Galileo first discovered them with his homemade telescope in the 1600s.

Residing in orbital distances (closest to further away from Jupiter) in the same order as listed

above, they can be seen with only a moderately powered telescope, a testament to the size of the

moons. As you can see in Table 2.1, the moons are fairly substantial in size and

Mercury 2240 km. 3.30 x 1023 kg.

mass, even rivaling the planet Mercury in certain dimensions such Ganymede having a greater

diameter and Callisto only being slightly less massive than Mercury.

Table 2.1*

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Scientists have been studying these moons for good reason. An ocean of liquid water is

believed to exist under the outer ice layer surrounding the moon Europa. Astronomers and

astrobiologists have good reason to believe that this life giving water could be a great contender

for containing extraterrestrial life. However, further tests and perhaps probing missions will

have to be done in order to conclude whether life not only lives there, but has the potential to live

there.

In regards to the moons of GJ 504 b, there has not been enough research on the planet to

produce a definitive answer as to whether or not the gas giant possesses any. Based on the

immense mass of the planet however, roughly 7.6 x 1027 kilograms, it is pretty clear that there

should be some moons gravitationally attracted to it. It would make sense and be logical to think

though that due to the planet’s mass, it would easily surpass the amount of moons Jupiter has.

Four times the mass could roughly equal four times the gravitational influence on the space

around it.

The presence of at least one moon is extremely plausible and more than likely the case.

However, being able to find these exoplanets like GJ 504 b is hard enough. Therefore, the idea

of imaging a moon of some sort is almost inconceivable based on their predicted size and the fact

that they would not give off any form of radiation of their own.

Mass is not the only factor when speaking of moons. One huge variable surrounding the

formation and acquisition of moons is the amount of debris that was present around the planet

when it formed. It is believed that through an idea called the Giant Impact Theory, our own

moon was a left over remnant of an asteroid impact in Earth’s early stages of life. This asteroid

became gravitationally locked and continued to form and accrete more and more space debris

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floating around the Earth, rounding out as a result of its own gravity pulling inward, and

eventually forming the moon we have today.

2.2 Other Satellite Systems

A satellite like system GJ 504 b could very well possess is a ring system. Saturn and

Uranus are known for their rins systems that are as beautiful as they are intricate. However,

these are not the only ones as all Jovian planets have rings, as seen in Figure 2.1. Jupiter also has

a small series of rings only 30 km. thick; merely a plane of dust particles orbing its equator

(Sparrow 55). Rings systems actually tend to be a fairly common occurrence amongst high mass

planets, typically gas giants.

This leads no reason to believe that GJ 504 b, a planet roughly four times the mass of

Jupiter, wouldn’t be a suitable contender for a ring system. This could especially be the case if

the GJ 504 system possesses a Kuiper belt-like structure. This could have the potential to be a

Figure 2.1*

*Figure provided by University of Oregon Astronomy Department

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prime location for picking up pieces and fragments or rocks and icy bodies capable of venturing

too close the gravitational pull of GJ 504 b.

As I stated in Chapter I, gas giants form so far out because only the lighter gas molecules

could be pushed by the sun’s radiation, approximately five AU’s out. These are the molecules

having formed together in order to create these types of planets. GJ 504 b sits 50 AU’s away

from GJ 504 b, 20 more than Neptune does from our own sun. At these distances, rocky and icy

bodies may become less and less easier to come by.

There is a high possibility that the GJ 504 system contains an asteroid belt-like

component, or perhaps a Kuiper belt component. Within our own solar system, the Kuiper Belt

spans from the edge of Neptune’s orbit all the way out to about 80 AUs from the sun, or 1.2 x

1010 kilometers. This span of roughly 50 AUs is an immense debris rich field. Remembering GJ

504 is similar to our sun in mass, the presence of a Kuiper belt-like feature could be

hypothesized to be at a similar distance. If so, GJ 504 b would be placed very closely, if not

directly in GJ 504’s debris field. These could very well aid to a possible “trapping” of any debris

or body of rock would happen to float too closely into GJ 504 b’s field of gravitational influence.

One could calculate a rough estimate of what GJ 504 b’s surface gravity is, reflecting the

pull it would extend to a passing object or moon. Based on two rough estimates, the mass of GJ

504 b and its density, an idea of its gravity can be calculated.

Using an average of the densities of all of our solar system’s Jovian planets and GJ 504

b’s estimated mass, we can come to a final number. Remembering that volume is equal to 4/3π

times the radius of the object cubed, we can rearrange the equation basing our volume off of our

Jovian planet’s average density (1.233 g./cm3) to find a rough estimation of GJ 504 b’s radius.

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Then using the formula for calculating the acceleration due to gravity, we can come up with a

very rough number to put on GJ 504 b’s gravitational influence, and then compare it to Jupiter.

Volume

V = mD

V = 7.6 x 1030 g .

1.233 g .cm .3

V = 6.164 x 1030 cm.3

After I found the volume by simply dividing the estimated mass of GJ 504 b by the

average density of our solar system’s Jovian planets to get a volume of 6.164 x 1030 cm.3. I can

then plug it into my new and rearranged formula for the volume of a sphere in order to find an

estimated radius of GJ 504 b.

Volume of a Sphere

V = 43 πr3

r= 3√ V43

π

r = 3√ 6.164 x 1030 cm .3

43

π

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r = 1.13 x 1010 cm. or 1.13 x 108 m. or 1.13 x 105 km.

As you can see, based upon my calculations and using an estimated average density of

1.233 g. /cm.3, I was able to hypothesize a potential radius for GJ 504 b. However, the margin

for error is great as the number used for density is only an average and not a legitimate

calculation of its density. Next, I calculated GJ 504 b’s surface gravity by using the value for

radius above.

Acceleration due to Gravity

g =Gmr2

g = (6.67 x 10−11 m3

kg . s .2 )(7.6 x 1027 kg .)

(1.13 x108 m. )2

g = 39.699 m/s2

According to my a calculations, the surface acceleration due to gravity can be concluded,

based on rough averages, to be 39.699 meters per second per second. This is an extremely

substantial gravitational influence.

In order to gauge the strength of this gravitational acceleration, take our Earth’s surface

acceleration due to gravity: 9.81 meters per second per second. GJ 504 b’s acceleration to due to

gravity is just barely over four times stronger. Earth has the greatest acceleration due to gravity

of all the terrestrial planets. When compared, GJ 504 b’s gravity dwarfs Jupiter’s 24.8 meters per

second per second (based upon my values and calculations). GJ 504 b’s surface gravity is almost

1.6 times stronger that Jupiter’s.

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With these values, and again the values for radius and mass in my calculations were

averages and estimations, respectively, it is clear to see that GJ 504 b is not lacking in the

gravitational influence department. A force like this would easily accommodate a multitude of

moons, natural satellites, and perhaps even a rings system. Based on my calculations, GJ 504 b

has significantly more gravitational pull, and has presented no reason to believe it would not

have a similar moon system.

Chapter III

Atmospheric Characteristics

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3.1 Chemical Makeup

In order to fully grasp just what a planet is made of, the planet’s chemical composition is

extremely important to examine. The planet’s chemical makeup leads to a lot factors. A planet’s

density, mass, coloration, and atmosphere can all be related to just what is making the planet tick

and what makes the planet unique. They are massive bodies of large amounts of gas that swirl

and react together to work in unison to create a final planet. In order to perform a proper

analysis of two massive gas giant planets, the examination of their atmospheric characteristics

need to be looked at.

First we will look at the chemical characteristics of the atmosphere of Jupiter. “Jupiter

boasts an enormous supply of hydrogen and helium that make it the most massive planet in the

solar system” (Redd). Close to 90% of Jupiter’s atmosphere is comprised of hydrogen, about

10% of the atmosphere is hydrogen, and there are small trace amounts of other gasses commonly

found in gas giants like compounds such as ammonia, sulfur, methane, and water vapor (Redd).

The majority of this hydrogen is all hydrogen leftover from the creation of the sun. When the

sun formed the massive accretion disk, it began to fall in on itself over time eventually becoming

massive and hot enough to ignite thermonuclear fusion in the sun’s core, beginning its energy

producing life.

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However, not all the hydrogen was able to fall in. Here is again where the two disputing

theories mentioned in Chapter I come into play, the core accretion model and the gravitational

instability model. To recap, the core accretion model, postulates that a small rocky and/or icy

body was able to form a planetesimal. This planetesimal then had a sufficient amount of

gravitational influence to begin collecting and pulling in the left over hydrogen, helium, and

other gas molecules. These molecular clouds left over eventually swarmed the planetesimal

forming the gas giant, as seen in Figure 3.1. This is the model that is more widely accepted by

scientists in the field of astronomy and more frequently referred to when speaking of Jovian

planetary formation.

The second model is the gravitational

instability model which states that gas

giants are created from a cloud of gas

detached from the initial formation of

the planet’s parent star. A molecular

cloud would have to detach itself from

the main protostar, obtain a sufficient

angular velocity, collapse in on itself,

and stabilize into the final planet.

These two debated models put

forth depend on different factors in

*Figure 3.1 courtesy of John Schombert, University of Oregon

Figure 3.1*

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order to operate efficiently, however there is a main similarity. Both the core accretion model

and gravitational instability disk model depend on an inner core for which the immense

atmosphere can gravitationally link on to. Unfortunately scientists have yet to provide proof of

an “Earth sized” rock, metallic, or icy core in the center of the planet. The atmospheres of gas

giants obviously vary in size and mass depending on the planet.

When studying the outer layer of Jupiter, the most prominent feature of the atmosphere

are the alternating layers of orange and white layers running parallel to the equator. What causes

Figure 3.2

The figure adjacent represents the chemicals that comprise the outer surface layer of Jupiter’s atmosphere. The outer clouds are comprised of NH3, or ammonia, that give way to ammonium hydrosulfide, then to basic water vapor clouds, before taking on a more crystallic nature of those chemicals.

Credit to John Schombert, University of Oregon

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these bands to show are alternating areas of high and low pressures that dance across the

atmosphere. The whiter and lighter bands are called zones. “The lighter clouds found in the

zones are dominated by ammonia crystals, which condense at lower temperatures than the

ammonium hydrosulphide…” (Sparrow 55). Similar to Earth, the further out you travel out of

Jupiter’s atmosphere the colder the temperature gets. The outer colder layer is where the lighter

zones reside.

The orange and brown darker bands are referred to as belts. These are the lower lying

bands that are results from higher pressure systems. Like previously stated, 90% of Jupiter is

comprised of hydrogen, about 9% helium, and the rest are a mixture of more complex ammonias

and similar chemicals. This 1% of other chemicals is what comprises a majority of the outer

layers as seen in Figure 3.2. These are all contained in the part of Jupiter’s atmosphere known as

the troposphere which is about 50 km. thick.

Scientists have a fairly good idea of what the chemical makeup of GJ 504 b is. Based on

direct imaging testing of GJ 504 b, Markus Jason concluded that the gas giant’s atmosphere

contains mass amounts of CH4S, a methane based organic compound called methanethiol. The

methane absorption test conducted by Jason confirmed the belief that CH4S was the dominant

methane based compound in the planet’s atmosphere, along with traces of another, less abundant

methane compound, CH4L (Jason).

For GJ 504 b to be so far away, it coordinates with the behaviors seen in our own solar

system. GJ 504 b’s orbit may be 20 AU’s larger in radius than Neptune’s, but they still have

similar chemical makeup. Uranus and Neptune are known for having methane rich atmospheres.

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With the uncertainty of 20 AU’s and based on these two systems, the matching compositions of

these three planets cannot go unnoticed, based on their distance form their stars.

Jupiter and GJ 504 b have fairly different chemical makeups. However, the reason for

this could be largely due to GJ 504 b’s extreme distance from its parent star. A location where

methane compounds where abundant, formed together via one of the two planetary models, and

created the new methaneiol rich planet.

3.2 Meteorological Conditions

Another very important aspect of the atmospheres of Jovian planets is what the gas

compounds that comprise it are doing. The weather of gas giants can be looked at almost the

same way they are on Earth. Our own Earth has an atmosphere where we can measure pressures,

precipitation, temperatures, and storms. Giants have these same features, the only difference is

that theirs are much, much larger compared to Earths and countless times thicker.

In section 3.1, it was already explained how the different zones and belts interact witch

each other due to different pressures to create the stratified groups of bands running latitudinal

across Jupiter. These could be encompassed into meteorological conditions as well based on

how they work. However, not only Jupiter, but gas giants in general have much more to look at

in their thick blankets of gas. Author of the book Cosmos, Giles Sparrow states:

“Along the boundaries between belts and zones, complex and beautiful cloud patterns

called festoons frequently appear, and the movement of different air masses can set up rotating

cells that develop into vast storms” (Sparrow 55).

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These festoons Sparrow talks about are a frequent feature within Jupiter’s atmosphere.

The belts and zones travel around the planet in opposite directions. Therefore, just like when the

pressure systems and cells on Earth meet, they collide and swirl creating vast storms. Upon an

examination of the atmosphere of Jupiter in a photo, these festoons become extremely clear and

are found all over the planet’s outer layer of clouds. These storms can create tremendous winds.

As seen in Figure 3.3, both Cassini and Voyager missions were able to detect great wind speeds

at consistent rates twenty years apart.

Figure 3.3

Festoons really can grow to immense sizes. One perfect example is Jupiter’s famous

Great Red Spot. The Great Red Spot really is just a case of a festoon becoming so large and

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spinning so rapidly it was able to stabilize into a raging storm easily larger than two Earths that

has been raging ever since its discovery.

Astronomers believe another part of the reason that the Great Red Spot has been so

persistent is that it is not like hurricanes here on Earth. Terrestrial hurricanes travel over ground

and lose their energy source, a.k.a. warm ocean water. In Jupiter’s case the Great Red Spot

never really loses its energy. It is believed to be powered by the great heat created from the

immense pressures experienced as you travel deeper into the planet. The rival rotations of the

bands aid in the creating of cyclones as seen Figure 3.4. In addition, since there is no land for

the Great Red Spot to travel on, it wouldn’t lose energy over it, rather than being continuously

powered in the gaseous atmosphere (The Atmosphere).

The Great Red Spot has become one of the most widely studies aspects of Jupiter’s

atmosphere. Writer Jerry Coffey states:

Figure 3.4

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The Great Red Spot on Jupiter is one of the best known features in the Solar System. The

storm is located 22° south of the equator and is larger in diameter than Earth. It is thought

to have been in existence when Giovanni Cassini observed the planet in the 1600s. The

storm rotates in a counter-clockwise motion (See Figure 3.4 as to how these counter-

clockwise motions begin). It has been known to shrink and grow. It has been as large as

40,000 km in diameter. It rotates differentially than the rest of the atmosphere: sometimes

faster and sometimes slower. During its recorded history it has traveled several times

around the planet relative to any fixed position below it (Coffey).

It is completely possible for another gas giant like GJ 504 b to have these same similar

features found on Jupiter. Unfortunately for astronomers, not much is necessarily known about

what sort of weather conditions can be found on GJ 504 b. The planet is believed to have vague

stratified bands like both Saturn and Jupiter. These pressurized systems could almost certainly

have the potential to create great storms and festoons like found on Jupiter.

The different chemical compositions may also play a role in what the meteorological

conditions do. The ammonia compounds in Jupiter’s troposphere may react and move

differently than the mainly methane based compounds of GJ 504 b. One factor GJ 504 b has in

common with Jupiter is the heat is still there. Jupiter gets a majority of its heat from lighting

created from the discharging of ammonia crystals in the troposphere and the heat produced in the

planets inner layers due to the great pressure. However, GJ 504 b is still young and carries a lot

of heat with it. Dr. Michael McElwain, member of NASA’s Goddard Space Flight Center team

stated: "If we could travel to this giant planet, we would see a world still glowing from the heat

of its formation with a color reminiscent of a dark cherry blossom, a dull magenta. Our near-

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infrared camera reveals that its color is much more blue than other imaged planets, which may

indicate that its atmosphere has fewer clouds” (Reddy).

According to astronomers, GJ 504 b has the heat to move clouds and gasses in intricate

storms like Jupiter, but the fewer clouds believed to be lack thereof in the atmosphere may bring

about problems. Jupiter is rich and dense in its cloud structure but GJ 504 b may be much less,

thereby not providing a sufficient amount of gas in order to create effects found in atmospheres

like Jupiter.

3.3 Notable Anomalies

When it comes to studying the heavens, one thing is for certain and it is that nothing is

certain. From the ancient stargazers of the past to the modern accredited astronomers of the day

there have always perplexing questions with unfindable answers. In this day of modern

astronomy, this principle still applies.

Jupiter is one of the most studied planets, outside of Earth, but yet there are still aspects

of it we don’t fully comprehend. Like stated in Chapter 3.2, it is believed Jupiter’s Great Red

Spot is powered by residual heat emitting from the planet’s core, powering the large festoon.

However, this has never been proven. This theory is merely one of the best supported and

accepted. Like Jerry Coffey stated in Chapter 3.1, the Great Red Spot goes through phases of

growth and shrinkage.

On 15 May 2014, NASA released a statement saying the Great Red Spot is actually

believed to be at its smallest size every observed. Ever since the astronomers first attempted to

calculate its size, the measurements have become smaller and smaller. Astronomers believe they

may know of a reason for such a change in a storm hundreds of years old. Amy Simon from the

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NASA Goddard Space Flight Center said, “In our new observations it is apparent very small

eddies are feeding into the storm… We hypothesized these may be responsible for the

accelerated change by altering the internal dynamics and energy of the Great Red Spot.”

The Goddard team plans to continue research in to the storm to confirm their beliefs

(Phillips).

In addition to the phenomena of the Great Red Spot, one mystery that has baffled

astronomers for a long time is the state of Jupiter’s core. Scientists have no idea what is actually

at the center of Jupiter, and have only postulated theories as to what it may. More information

regarding just what the core could be made of can be found in Chapter IV.

Another mystery that astronomers are stumped on is what powers Jupiter’s immense

electromagnetic field. Jupiter’s magnetic field is the largest planetary energy field in the solar

system as seen in Figure 3.5. It takes the tapered shape seen due to the charged particles of the

Sun’s rays, just like Earth’s.

According to the beliefs of modern geology, a liquid metallic core is necessary for the

presence of an electromagnetic field. The composition of Jupiter’s inner core is currently

unknown. There are several proposed theories as to what type of core is hidden under Jupiter’s

clouds. The most widely accepted theory, based upon Jupiter’s very own electromagnetic field,

will be further looked at in Chapter IV.

Electromagnetic fields are also responsible for auroras. Auroras are a fairly common

occurrence on Earth, but they are also commonly found on Jupiter. When charged particles from

the Sun hit the weaker portions of Jupiter’s magnetosphere, they get trapped and spin creating

energy, become excited, and release the energy in the form of visible and ultraviolet wavelengths

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creating a phenomena similar to our own Northern Lights here on Earth (Garrity). Jupiter,

having the largest electromagnetic field of all the planets in our solar system, is also responsible

for creating the largest planetary auroras in the solar system. They have been photographed and

studied by numerous NASA missions.

Figure 3.5*

*Credit by Peter J. Garrity of StarMariner.net

Being so far away and not as extensively studied as other exoplanets, GJ 504 b has not

had much time to really be looked at closely for any unusual anomaly. However, one aspect of it

is its nonconformity with the recognized models of how gas giants formed, as mention in

Chapter I. Both the core accretion model and gravitational instability model only work for

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planets hovering around 30 AU’s from its parent star. Because of this, it is possible to see new

propositions on how gas giants form. There is a good chance of seeing tweaks and adjustments

on our two contending models. Further research may even prove that the gravitational instability

model has been right all along, discrediting the more favored core accretion model. Or perhaps

we may see both models completely rejected based on new developments in the field of

astrophysics with GJ 504 b being the catalyst for a new age of study in the field of planetary and

gas giant formation.

GJ 504 b is significant because it reverberates the old idea that only one thing is for

certain and that is nothing is certain. Discoveries like GJ 504 b are what propel the fields of

astronomy and astrophysics because they cause us to rethink theories we thought to be correct

and cause to constantly have to adapt with each and every new discovery.

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Chapter IV

The Core and Inner Layers

4.1 Under the Troposphere

Gas giants are known for not having a definitive surface. To the less informed, one

would imagine a gas giant’s atmosphere is static and remains as cloud-like formations up until

the theorized core is reached.

However, this is not the case. If you could travel through a gas giant’s atmosphere, you

would not see a stagnant cloud cover of gasses. The deeper you go the physics of the planet

begin to take shape and really have an influence on just what the planet is doing. Great pressures

and heat begin to alter the matter that comprises these atmospheres and transform them into

peculiar forms.

Recall that the composition of Jupiter is almost all hydrogen. The majority of this

hydrogen lies under the belts and zones of its outer atmosphere. Jupiter is large and possesses

great amounts of gas. When small amounts of gas join even larger amounts of gas, they begin to

make a difference in a planet’s composition.

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On Earth, we have a liquid molten outer core and a solid inner core comprised of heavy

elements, mainly iron and nickel. Contrary to what most may logic, the inner core is actually

hotter but remains a solid. This is due to the amount of pressure it is under. The inner core has

almost all of Earth’s mass, 5.98 x 1024 kilograms, pressing down on it. An amount of pressure

like this is so great it will actually force a change in its state of matter. If a metal or rock heats

up to a high temperature, it will begin to melt. The pressure on Earth’s core is so great that it

actually inhibits molecular movement, forcing it to remain in a solid state, as the molecules and

atoms cannot move as freely, yet the outer core remains liquid because there is not enough to

pressure force a change in state of matter.

A similar process is taking place within Jupiter. However, rather than forcing a liquid

state of matter to a solid state of matter, Jupiter’s pressure forces its gaseous hydrogen

atmosphere into the form of a liquid. Despite hydrogen naturally occurring as a gas, Jupiter’s

pressure within its inner layers is so great that it restricts atomic movement, thus forcing it into a

liquid as in Figure 4.1

Figure 4.1*

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…The interior of the planet is mostly liquid hydrogen containing small amounts of

heavier elements. The pressure and temperature are higher than the critical point for

hydrogen, and that means there is no difference between gaseous hydrogen and liquid

hydrogen. If you parachuted into Jupiter, you would fall through the gaseous atmosphere

and notice the density of the surrounding fluid gradually increasing until you were in a

liquid… (Seeds 505).

The actual size and depth of the liquid hydrogen layer is debated. As with most of

Jupiter’s inner layers, it remains a mystery to modern astronomy. Knowing that Jupiter is made

of about 90% hydrogen, astronomers hypothesize the hydrogen layers would become so

compressed as to turn into a liquid form of H2, the hydrogen compound comprising Jupiter.

The possibility of an extremely similar composition may exist within GJ 504 b. GJ 504 b

does have higher amounts of methane compounds as detected by its direct imaging, but what lies

underneath is a mystery. The more methane based Jovian planets, Uranus and Neptune, which

are more similar to GJ 504 b with respect to their semimajor axis and known composition, could

provide a better forecast of what could be inside of GJ 504 b. Uranus and Neptune are still

mainly comprised of hydrogen and helium despite the strong presence of methane compounds,

so perhaps GJ 504 b could be hiding a large layer of hydrogen or H2 underneath its methane

outer shell.

4.2 Further Down

*Figure credit to Nick Strobel

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The further down we venture into the atmosphere of Jupiter, the less certainty there is.

Pressures increase, temperatures, increase, and exotic changes start to happen to the hydrogen

compounds.

The smoking gun for the possibilities of what is this deep in the atmosphere lies in

Jupiter’s giant electromagnetic field. A liquid metal core is necessary for the stabilization of an

electromagnetic field. This comes from the dynamo effect theory that states a rotating body with

a metallic core of convecting matter is necessary for the creation and stabilization of a magnetic

field (Strobel).

The question astronomers might ask would be, if Jupiter is made of mainly hydrogen, a

gaseous and non-metallic element, what is creating the electromagnetic field that requires a

convecting metal?

Astronomers and astrophysicists believe they may have the answer. They believe the

liquid hydrogen from the previous layer gets compressed even further to create a strange

substance known as liquid metallic hydrogen. Planetary formation expert of the California

Institute of Technology, David Stevenson said, “Liquid metallic hydrogen has low viscosity, like

water, and it's a good electrical and thermal conductor… like a mirror, it reflects light, so if you

were immersed in it, you wouldn't be able to see anything” (Coulter).

Refer back to Figure 4.1 to see how compression creates liquid metallic hydrogen. The

pressure is so great it has enough power to overcome the forces holding the electron into the

atom. When the electron is released, it establishes a pool of electrons surrounding all the

hydrogen atoms. This pool of electrons becomes a great conductor of electricity. Astronomers

believe this metallic form of hydrogen is what is generating all of Jupiter’s electromagnetic field

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and satisfies the problem of not having a suitable electric conductor as presented by the dynamo

effect theory.

It is fairly hard to determine just exactly what liquid metallic hydrogen is and how it acts,

despite our basic understanding of it based on our knowledge of physics. Scientists have never

been able to study it in hand as it does not occur naturally on Earth and attempts to create it in a

lab are futile. Under lab conditions, scientists can only mimic the pressures needed to create

liquid-metallic hydrogen for only a short amount of time. Consequently, the amount of time

their hydrogen samples occupy their liquid metallic state is extremely small, less than a second,

which is not a sufficient amount of time in order to study and observe. For now, the

characteristics behind liquid metallic hydrogen largely remain a mystery, despite the wide

presence of it on worlds outside our own.

No one is sure exactly what portion of the inner layers is liquid hydrogen and how much

is liquid metallic hydrogen. One estimation can be found in Figure 4.2, presented by the

Kapteyn Astronomical Institute, however the debate goes on.

Figure 4.2

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There is an extremely high probably of GJ 504 b having a similar inner content as Jupiter.

More than likely, GJ 504 b has inner layer composition of mainly hydrogen (H2), helium,

methane compounds, and other heavier gasses like oxygen, nitrogen, etc.. Should the SEEDS

team further their research into GJ 504 b, we may see a firm establishment of what exactly it is

made of beneath the calm magenta methane troposphere.

However, for the time being, a mainly hydrogen composition is more than likely the case.

Based on the mass and size of GJ 504 b, and provided there was a hydrogen center, the presence

of liquid metallic hydrogen inside of it would almost certainly be guaranteed. Recalling the mass

of GJ 504 b to be roughly four times the mass of Jupiter, or 7.6 x 1027 kilograms, it can easily be

concluded that there would be enough pressure to squeeze out its hydrogen atoms’ electrons to

form the liquid metallic hydrogen soup. According to Figure 4.2, once the inner mantle reached

11,000o Kelvin and experiences pressures of three million standard atmospheres (atm).

With respect GJ 504 b’s inner layers, it can be concluded that it is similar to not only

Jupiter, but all other high mass, high density, hydrogen rich planets.

4.3 Core

Astronomers possess a great deal of certainty on the content of Jupiter’s inner and outer

mantles. There is a firm belief of the liquid hydrogen layer and the following liquid metallic

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hydrogen based on the pressures, temperatures, and the cause for its massive electromagnetic

field.

One thing still eluding astronomers is what makes up the core, or lack thereof, of gas

giants like Jupiter and GJ 504 b. This debate stems back to the argument of which form

planetary creation is responsible for gas giants, the gravitational instability model or core

accretion model. Astronomers are fairly certain the smaller terrestrial planets formed by means

of the core accretion model, or a similar process. There is not much of a debate on those

grounds. Neither of the models are perfect and they both have their problems.

The core accretion model, again, the more widely accepted model in today’s modern

astronomy, argues on the platform based on its namesake. It states a solid core of either rock,

ice, heavy metals, or a composition of all three, formed together to attract and pull in the

hydrogen and helium gasses from the planetary disk left over from the initial formation of the

sun. This model presents strong evidence for a solid core, more than likely of rock and ammonia

or methane ices. Despite the heat, possibly 40,000 degrees Kelvin, according to Figure 4.2, the

ice remains as it is based on the pressure at the center. The ice formations cannot melt, taking

the form of a liquid, because of the pressures pushing down the atoms, restricting entropy in the

core.

Believers in the gravitational instability model would more than likely argue there is a

core of super condensed hydrogen, ices, or other heavier gasses, but not necessarily taking the

shape of solid. A rocky or metallic based core would be out of the question. Since the

gravitational instability model concludes the planet’s disk of material spun rapidly to eventually

fall in on itself due to its own gravity while all the heavier and denser elements sank to the

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bottom. This “bottom” of the planet would be its core. Nonetheless, the idea of a solid core is

nonexistent. A “soup” of elements condensed down and extremely hot is more favorable under

this model. Gemma Lavender of All About Space stated: “A theory surrounding the formation

of giant planets of gas suggests that there is almost definitely a core. This idea is called the

bottom-up theory or core-accretion model. Here, a ten Earth-mass protoplanet formed, which

quickly swept up gas from the primordial disk that formed our Solar System to develop a

massive atmosphere around it and become the gas giant Jupiter (Lavender).”

While the core accretion model recognizes the need for a solid core, even under the

temperatures and pressures of Jupiter’s atmosphere, solids aren’t necessarily solid. The metallic

hydrogen compounds, ices, molten metals, and other varying materials and combine together to

create a somewhat slushy core (Lavener).

Therefore, even as these two models stand differently, they both possess similar

components in the fact that even though the core is “solid” in the core accretion model, it still

possesses semi-liquid traits in certain aspects.

GJ 504 b is a planetary outcast, not clearly fitting into or only fitting certain pieces of

each model. Its mass is sufficient enough to be labeled as a win for the gravitational instability

model, but this model is a requiring millions of years to create planets. Based on the estimates of

GJ 504 b’s age and the times it takes the gravitational instability model to apply to planets, the

numbers would not add up.

With respect to the core accretion model, GJ 504 b is much too massive and much too far

away from its parent star for it to be an effective model of creation. Because of this, it is fairly

hard to determine what is at the center of GJ 504 b. Until further research is done, astronomers

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are sort of left to apply what we know about other gas giants to GJ 504 b. Those applications

being the chances of a similar liquid metallic core or possibly a rocky and/or heavy metal and ice

core must reside there.

Until we can discover what is actually inside the core of at least one Jovian planet, we

may never know. Even at that point, no one can say if the same core characteristics apply to all

other gas giants.

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Chapter V

Conclusion

The discovery of GJ 504 b back in 2013 by the SEEDS team was a groundbreaking

discovery. It shattered the previous belief of how a gas giant like Jupiter and itself could have

formed. I initially set forth to find out what helped to make this planets so different by covering

every possible aspect of this planet. I took into consideration how all these aspects compared to

Jupiter, a standard, well-known, and well-studied Jovian planet. I analyzed the different

characteristics and aspects of each to see what possibilities of differences are hidden.

The first aspect covered was each planet’s appearance. It was clear from the beginning

that these planets differ greatly here. Jupiter is known for its white, brown, and rusted red

appearance while GJ 504 b is making headlines in the astronomical community as the “bubble

gum” planet based on its magenta, purplish color. These color differences are attributed to the

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different chemical compounds found in their outer troposphere. It is clear to see a concurrence

in their chemical makeup, based purely on the visible wavelengths of their outer troposphere is

nonexistent.

I concluded in my research into GJ 504 b’s potential density that it would lay very close

to Jupiter’s. Based on pure speculation and averages, I would personally feel that GJ 504 b

would extremely similar to Jupiter in respect to its mass and volume.

The possibility of a satellite system, either being a moon, ring system or bath, is an

extreme and more than likely possibility. Based on observations of other gas giants, namely our

local Jovian gas giants, the potential for moons becomes clear. GJ 504 b has a mass four times

greater than the most massive planet in our solar system. It would be a spectacle to see a planet

this size with no means.

In addition, along with all having moons, all Jovian planets have a ring system of some

as shown by Figure 2.1. Further extending this logic, a ring system similar to Jupiter’s is again

an almost certainty, especially if GJ 504 has an outer debris field. To conclude, moons and other

similar satellites are an almost guarantee, however, further research an observation can be the

only final say.

In my attempt to pin a number on GJ 504 b’s gravitation pull, I averaged out the densities

of our Jovian planets an assigned it to GJ 504 b, a value I found applicable based on previous

reasoning. Through my calculations I was able to determine that GJ 504 b has an acceleration

due to gravity of 39 meters per second per second, almost 1.6 times more greater than Jupiter. It

is necessary to note these values are built upon reasoning and averages so the actual value may

and more than likely will vary from my produced value.

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I was able to determine there are actually big differences in the chemical makeup

between Jupiter and GJ 504 b based purely on their color. My research produced that the

chemical makeup of each planet’s troposphere is believed to have a large role in the planet’s

visible color. It is known that GJ 504 b was imaged to be a planet largely comprised of methane

compounds, with respect to the troposphere. Jupiter’s hydrogen rich troposphere is what dictates

its well-known color. Based on this reasoning alone it can be easily conclude that GJ 504 b

shares very few similarities with Jupiter’s outer layer. It may however prove to be a better match

to other methane rich planets like Uranus and Neptune.

When looking at atmospheric conditions, there are differences and possibilities for

similarities. Jupiter is a ravenous world of high speed winds, varying pressure zones, and great

storms. GJ 504 b more than likely has similar characteristics but it is believed to be much

calmer. Movement of gas isn’t as active, but the possibility is still largely there for great storms

based upon the heat the planet is putting out. This heat is pure fuel for moving pressure systems

that use heat to create storms like Jupiter’s Great Red Spot.

In Chapter III, I also looked at the possibility of GJ 504 b possessing an electromagnetic

field. The chance of this happening almost independently revolves around the presence of liquid

metallic hydrogen in its inner layers. The liquid metallic hydrogen is solely responsible for

Jupiter’s and all other Jovian planets’. It seems that any planet with a majority composition of

hydrogen (H2) would possess an electromagnetic field proportionally equal to the amount of

liquid metallic H2 present inside of it. More than likely, GJ 504 b would be a mainly hydrogen

body, based on other gas giants, so there is no reason to believe an on ocean of liquid and liquid

metallic hydrogen, and by extent and electromagnetic field, would be present.

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One aspect of not only GJ 504 b, but all gas giant and Jovian planets, that is still a

mystery is their core composition. Astronomers have yet to perform a conclusive test to find out

just what exactly lies at these planets’ centers. There are different beliefs based on different

models of creation, but no one knows for sure. The two current possibilities that exist are a

dense gas and liquid core and a solid, slushy core of a mixture of rock, compressed gasses and

ices.

I originally set out to find out if GJ 504 b shares a sufficient amount of characteristics

that would allow me to determine if GJ 504 b and Jupiter could be the same type of gas giant.

Unfortunately, based upon all my research and findings, I believe they are not similarly sufficient

enough to be thrown into the same category. Although research is still young for GJ 504 b, the

facts presenting themselves now tell me they are very different. The share very different

tropospheric compositions, their size and mass do rival each other, but not close enough to allow

a good comparison, the probable origins of their creations are far too different based upon their

distance from their stars and meteorological conditions are polar opposites in terms of gas giants.

The only aspects concurring with each other like the potential for an electromagnetic field and

believed hydrogen inner composition are common among too many other gas giants to really be

point out as significant.

Jupiter and GJ 504 b are two ends of the same stick. They are two amazing celestial

bodies that are unique in their own ways, but unique and unalike is how I believe they should

remain based upon my research and conclusions.

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Coulter, Dauna. “A Freaky Fluid Inside Jupiter?.” NASA Science. 9 Aug. 2011. NASA. Ed. Dr.

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