Category: Planets

Jupiter, a failed star?

Well, Jupiter shares some similarities to stars but its fundamental nature and formation, set it apart as a gas giant planet rather than a failed star.

Jupiter, the largest planet in our solar system, has long captured the fascination of scientists and stargazers alike.

With its immense size and swirling storms, some have wondered if Jupiter could have been a failed star.

To reveal the truth, we have to move back in time and investigate the planet and star formation of our solar system.

We will consider the exact moment when our sun was a protostar (a borning star) yet.

Jupiter, the similarities to Stars

Jupiter does possess a few similarities to stars, such as its composition.

Both stars and Jupiter are primarily made up of hydrogen (90%) and helium (10%), the two lightest elements in the universe.

If you wish to deepen Jupiter atmosphere topic, you could give a read to our article Jupiter, Rock or Gas Planet?.

Considering the radius, Jupiter is about ten times smaller than the Sun.

You could fit, insted, about 900 Jupiters within our Sun.

However, there exist stars, in the outer space, which are smaller than Jupiter.

For this reason we can state that Jupiter has compatible dimensions to stars’ one.

Additionally, Jupiter emits more energy than it receives from the Sun, a characteristic shared with stars.

Energy is produced as internal heat and released as X-Rays.

NuSTAR telescope detected high-energy X-rays in the auroras near the northern and southern poles of Jupiter.

NuSTAR cannot locate the light source with great accuracy, but can only find that the light comes from somewhere in the purple coloured regions.

Jupiter, the differences to Stars

However, the key distinction lies in the formation process.

Stars are formed when large amounts of gas collapse under gravity.

This usually leads to the ignition of nuclear fusion at their cores, due to high pressure and temperature values.

Jupiter, on the other hand, formed from the gas and dust swirling around the early Sun but did not accumulate enough mass to ignite fusion.

This is, actually, the main reason why our father planet, Jupiter, did not become a star.

No ignition, no stars.

Jupiter, failed Star or gas giant Planet?

To be classified as a star, an object must reach a critical mass known as the “minimum mass for sustained hydrogen fusion“.

Jupiter falls well short of this threshold, with only about 0.1% of the mass required for fusion.

Without the sustained nuclear reactions that define stars, Jupiter cannot produce its own energy and instead primarily reflects the Sun’s light.

Its gaseous nature, lack of internal heat, and absence of a solid surface further reinforce its classification as a gas giant planet rather than a failed star.

Jupiter’s Role and Significance

While Jupiter may not be a failed star, its role in our solar system is still significant.

It plays a crucial role in shaping the dynamics of the solar system, influencing the orbits of other planets and protecting Earth from potential impacts by attracting and capturing asteroids and comets.

Jupiter’s iconic storms, such as the Great Red Spot, showcase the planet’s complex atmospheric dynamics and provide valuable insights into atmospheric processes on both Jupiter and Earth.

By studying Jupiter, scientists can gain a better understanding of planetary formation and evolution, further deepening our knowledge of the universe we inhabit.

In conclusion, while Jupiter shares some similarities with stars in terms of composition and energy emissions, its formation, mass, and inability to sustain nuclear fusion distinguish it as a gas giant planet rather than a failed star.

Despite this distinction, Jupiter’s presence in our solar system remains of great importance for its significant influence on planetary dynamics and its role in protecting Earth.

The study of Jupiter continues to provide valuable insights into the workings of our universe and contributes to our understanding of planetary science.

It seems you have reached the end of this article. You deserve a prize!

Enjoy this incredible pictures of Voyager 1 approaching Jupiter in 1979! 
Credits: NASA/JPL-Caltech

https://www.astronomy.wtf/wp-content/uploads/2023/05/jupiter-voyager-1-approaching.mp4

Jupiter, biggest Planet?

Yes, having a radius of 43,441 miles (or 69.911 km), Jupiter is the biggest planet of our solar system. It is not, however, the biggest planet we have ever discovered outside this system.

If you wish to compare it to the Earth, Jupiter radius is almost 11 times bigger, since our planet radius is about 3,959 miles (6.311 km).

Considering the volume, it is 3.434×10¹⁴  mi³ (1,431×10¹⁵ km³) meaning that it is 1,321 times bigger (one thousand, three hundreds, twenty one) than Earth’s,  which is 2.599×10¹¹ mi³ (1.08321×10¹² km³ ).

In other words 1,321 Earths would fit within Jupiter’s volume.

However, Saturn is the second biggest one, having a radius of  37,449 miles (60.268 km), the 86.32% of Jupiter one, and a volume of  1.967×10¹⁴  mi³ (0,827x 10¹⁵ km³), corresponding to the 57.28% of Jupiter planet’s volume.

Are you thinking that Jupiter is huge?

Well, surely you are not wrong, we can not say it is tiny. 

It has to be said, anyway, that there exist, out there, planets which are way larger than it.

For example, TrES-4b, extrasolar planet orbiting in 31 hours the star GSC 03089-00929 (Hercules constellation) 1,430 light years away, has a radius of 143,000 miles (230.000 km) which is the 330% of the biggest planet of our system.

Is Jupiter bigger than Sun?

No way!

Sun radius is 432,686 miles (696.340 km) while Jupiter is 43,441 miles (69.911 km), meaning that gas giant radius is 10 times smaller than our star’s.

Comparing, instead, the volume, our shiny star value is 3.38 ×10¹⁷mi³ (1,41×10¹⁸ km³) while, as said above, Jupiter’s one is 3.434×10¹⁴  mi³ (1,431×10¹⁵ km³).

Comparing the volume values, you can fit about 1,000 Jupiters inside our energy source,  the sun.

Such a big amount of space, isn’t it?

Well, it depends.

There are celestial corps that are way bigger than our sun, even up to a thousand times (e.g. Antares, Betelgeuse giant red stars).  

This leads to the conclusion that they are, consequently, up to 1,000,000 times corps greater than Jupiter, which makes our lovely father planet, Jupiter, not soo big, in the end.

Is Jupiter bigger than Earth?

Absolutely yes!

As computed above, Jupiter is 1,321 times greater in volume than Earth and it has a radius which is 11 times longer; this makes Jupiter bigger than our home, the Earth.

The numbers should explain why you could potentially fit an entire Earth within Jupiter Great Red Spot, and there would be even some free space!

If you are already preparing the luggages, calm down.

Have a look to the below picture and then decide if you still wish live in Jupiter planet’s Great Red Spot.

Is Jupiter the largest Planet?

Jupiter, with his greatest volume of 3.434×10¹⁴  mi³ (1,431×10¹⁵ km³) and his longest radius of 43,441 miles (or 69.911 km), can be considered the largest planet of our solar system.

Starting from the tiniest planet, the order in size of our system planets and the comparison with Jupiter and Earth, assuming the radius as parameter, are:

• Mercury (1,516 miles/2.440 km) – 3.45% of Jupiter’s – 38.29% of Earth one
• Mars (2,460 miles/3.390 km) – 5.66% of Jupiter’s – 62.14% of Earth one
• Venus (3,761 miles/6.052 km) – 8.66% of Jupiter’s – 95.76% of Earth one
• Earth ( 3,959 miles/6.311 km) – 9.11% of Jupiter’s
• Neptune (15,299 miles/ 24.622 km) –  35.22% of Jupiter’s – 388.44% of Earth one
• Uranus ( 15,759 miles/ 25.362 km) – 36.28% of Jupiter’s – 398.06% of Earth one
• Saturn ( 36,184 miles/58.232 km ) – 83.29% of Jupiter’s – 913.97% of Earth one
• Jupiter (43,441 miles/69.911 km ) – 1,097.27% of Earth one 

With this data, we can conclude that Jupiter, alone, has the 35.5% of the total of solar system planets radius.

Joint with Saturn, they make the 65.07%. 

The volume is, so, heterogeneous, in our system.

The remaining 34.93% is shared between the other 6 planets, Uranus, Neptune, Earth, Venus, Mars and Mercury.

Anyway, we can surely conclude that Jupiter is the largest and biggest planet of our solar system.

If you are now wondering about the composition and phenomena of Jupiter atmosphere, you might be interested in reading our article Jupiter, Rock or Gas Planet?.

Jupiter, Rock or Gas Planet? 

Jupiter, the fifth planet from the Sun and the biggest in our system, is often also known as the “Gas Giant“, since it is composed by liquid hydrogen and its atmosphere is made up of hydrogen (90%), helium (10%) and traces of other gases; for this reason Jupiter can be defined a gas planet and it is not characterised by any rocky surface.

Its gaseous condition can be related to the fact that the planet was not able to reach the critical mass to become a star.

Did you know that the majority of solar systems, in the outer space, are usually made of two stars instead of a single one?

However, some theories currently being verified by NASA Mission Juno, hypothesize the posibility, for Jupiter to have, or have had in the past, a solid core.

The presence and the extent of the magnetic and gravitational fields, will bring new data into this debate.

The shape is related to the gas planet rotation speed of one complete round in about 10 hours, meaning that in a Earth Day it is involved in 2,5 rotations.

This high speed makes Jupiter, and its gases, take the shape of an oblate spheroid.

Does Jupiter have an atmposphere?

Yes, even if there is not a precise separation like on Earth, Jupiter’s atmosphere has been defined by scientists as the layer above the point where the pressure measures the same as on Earth’s surface, 14.50 psi (1 bar or 0.9869 atm). 

It is composed by four sections: troposphere , stratosphere, thermosphere and exosphere; each one has been identified by specific pressure and temperature configuration.

 Like on Earth, the temperature decreases with the increase of height, to a minimum point; this particular value separates the troposphere from the stratosphere.

This boundary is also called tropopause and it is located about 30 miles (50 km) from the “surface”.

As we move out to the outer space, the pressure decreases its value as the layer of gases gets thinner; temperature, instead, slightly increases again until the height of about 200 miles (320 km).

Here, the temperature reaches the -99.67 °F (200 K, -73,15 °C) and this is defined stratosphere-thermosphere boundary.

Above this point, in the thermosphere, temperature grows and reaches its highest value of 1340.33 °F (1000 K, 726,85 °C) at an altitude of 621.37 miles (1000 km).

This is the boundary which defines the external section called exosphere.

The bottom parts of atmosphere, troposphere and stratosphere, host the famous Jupiter clouds and an haze layer.

The troposphere has an heterogeneous chemical composition and three clouds sections, with increasing pression and density values as we drop the considered height.

First, the upper clouds made of ammonia ice, located at the pressure range of 0.6 – 0.9 bar (8.70 – 13.05 psi); below this, at the pressure layer of  1 – 2 bar (14.50 – 29 psi), denser clouds made of ammonium hydrosulfide, (NH₄)HS, or ammonium sulfide, (NH₄)₂S; at the pressure of 3 – 7 bar (43.51 – 101.53 psi) , also water clouds are thought to exist.

There are no methane clouds as the temperature is too high for it to condense.

The water ones are the densest, having the biggest influence on the atmosphere turbulent dynamic: this is the result of the higher condensation heat and abundance of water, compared to ammonia and hydrogen sulfide.

In other words, oxygen is a more abundant chemical element than either nitrogen or sulfur in this gas planet.

Regarding the stratospheric haze layers, they reside above the main cloud layers.

They are made from condensed heavy polycyclic aromatic hydrocarbons or hydrazine; these are generated in the upper stratosphere from methane, under the influence of the ultraviolet radiation of the sun.

Jupiter’s thermosphere is located where pressures is lower than 14.50 psi (1 μbar) and demonstrates such phenomena as airglow, polar aurorae (below image) and X-ray emissions.

Ionosphere is formed by the layers of increased electron and ion density that exist whithin it.

The thermosphere and the exosphere at the poles emit X-rays.

From Jupiter’s magnetosphere arrive energetic particles that create bright auroral ovals, as you can see in the image above.

Jupiter aurorae are permanent in the atmosphere, while on Earth can be seen only during magnetic storms.

Does Jupiter have a surface?

Being a gaseous mass, scientists think that Jupiter does not own a solid surface, even if nobody actually ever verified by trying to walk there!

If you are really looking for a rocky surface, the core of the gas planet, whose existence is still in doubt, could be made of solid matter where you could try to have an exciting walk.

 

However, it is assumed that under the atmosphere made of 30 miles (or 50 km) cloud barrier, there are hydrogen and helium.

These ones are constantly liquefying, as pressure increases while moving in the direction of the center of Jupiter.

Under that layer, it is supposed to exist liquid metallic hydrogen and the thickness of this section should be about 25,000 miles or 40.000 km.

Going deeper, we could probably find the core, the innermost part of the gas planet.

Scientists are still trying to figure out its existence, as you will read below.

Does Jupiter have a core?

According to the majority of theories, Jupiter has a solid dense core composed of ice, rock and metal, aggregated at the beginning of our solar system by the gravity force, joining together asteroids and comets surfing in the area at the perfect moment, billion years in the past.

 The nucleus is made of diffuse core mixed into its mantle; its dimension is significant as it is characterised by a radius value between the 30% – 50% of the planet’s one.

An impact by a 10 times Earth trump planet or some particular conditions arisen during Jupiter formation in the surrounding nebula, could have led to the this nucleus condition.

After the formation of the core, due to its gravity, all the gases that we are able to see now have been captured in Jupiter’s atmosphere and still are prisoner of planet’s gravity (2.5 times stronger than Earth’s, local g=24.79m/s).

The temperature there would be 55,000 Fahrenheit (30.000 Celsius) and the pressure would reach out of mind values, because of the heavy layer of gases floating above.

However, according to a minority theory, the planet could have no core at all.

The hydrogen and the helium cooled and condensed from the large cloud in which the sun was born, in a heterogeneous way: some regions were denser and able to pull more matter until the planet was born.

This doubt is going to be solved by Juno Mission which will measure Jupiter’s gravitational and magnetic fields, revealing wheter the gas planet has a core.

By that measurement, and having eventually the knowledge of fields size, one theory will prevail on the other one.

To clear the situation, some scientists suggested another possibility considering that the core could have gone through time and now it is not there anymore.

It looks like you have reached the end of the article and you deserve a prize!

Have a look at these pictures of Jupiter.

Astronomy.wtf encourage all kind of amateur work considering those of inestimable value.