Jupiter is the fifth planet in the solar system. The first 4 planets in the solar system are rocky planets. On planets ahead of these first four planets, things change a lot. The first of these planets, called gas giants, is Jupiter, the solar system’s largest planet in both size and mass.
The planet’s equatorial diameter, which has a mass of almost 320 times that of Earth, is 12 Earth-wide.One of the most characteristic features of the giant planet is its Red Spot, which is almost 2 times the size of Earth. This structure, a storm known as the Big Red Spot, has been turning Jupiter upside down for more than a century.
The planet is home to 4 moons discovered by Galileo Galilei. These are of great importance in the history of astronomy, as they were the first satellites discovered beyond Earth. The number of moons of Jupiter, consisting mainly of hydrogen and helium, is over 75!
One of the most characteristic features of the giant planet is its Red Spot, which is almost 2 times the size of Earth. This structure, a storm known as the Big Red Spot, has been turning Jupiter upside down for more than a century.
After the moon and Venus, Jupiter, the brightest celestial body in the sky, has features quite different from the inner planets Mercury, Venus, Earth and Mars.
In 1610, thanks to astronomers studying the movement of 4 satellites discovered by Galileo Galilei, we are able to know the mass of Jupiter with a fairly high sensitivity. At about 1.9×1027 kilograms, this giant planet has a mass of more than the sum of the mass of all the remaining planets, although its mass is only one thousandth of the mass of the Sun.
If Jupiter’s mass was 80 times its current mass, it would be a candidate to become a star!
We can find it using the planet’s radius, its distance to Earth, and its angular size. As a result of this process, which corresponds to a simple ratio ratio, the radius of Jupiter can be found to be about 71,500 km. Since we know the mass and radius, we can also calculate its density quite easily.
If you remember from our article on Venus, we said that the density of Venus is about 5500 kg/m3. When we do this calculation for Jupiter, we see that its density is only 1300 kg/m3. Even this difference alone (the density of other rocky planets is also quite close to the density of Venus) is enough to say that there is something different about Jupiter.
If Jupiter were the size of a basketball, Earth would be about the size of a grape seed.
Studies have shown that the reason for this density difference is that 90% of the planet consists of hydrogen, the simplest atom in the universe, and the remaining 10% consists of helium.
It may come to mind that the density of these two elements at sea level on earth is much lower than the density of Jupiter that we have calculated. The density of hydrogen and helium at sea level is approximately 0.08 km/m3 and 0.16 km/m3, respectively. What increases the density of Jupiter by almost 10,000 times formed by these two elements is the incredible gravity of the planet and the pressure force generated by it.
As with rock planets, for gas giants, we can determine the speed of rotation around their axes. But since gas giants do not have a surface, this calculation is quite difficult compared to rock planets. The biggest reason for this is that certain parts of the atmosphere rotate at different speeds compared to other regions.
Observations have shown that, as predicted, the rotation speed of the planet in the equatorial region is greater than at high latitudes. The period of rotation at the equator is 9 hours 50 minutes, while when you go to the poles, this time increases to 9 hours 55 minutes. Although the difference seems to be “only” 5 minutes, you can estimate how high the rotation speed at the equator is if you take into account that as latitude increases, the path that needs to be taken for one full lap decreases.
For sharper measurements, astronomers studying the period of the change of the planet’s magnetic field found the period of the change to be 9 hours and 55 minutes. Based on this information, it can be said that the rotation period of the planet’s core is 9 hours and 55 minutes. Given that this time for Earth is 24 hours, it can be easily said that the planet rotates around itself at a fairly high speed.
To understand the atmospheric structure of planets, we either look at the spectrum of sunlight it reflects, or we resort to the help of radio waves. These two measurements in question, as we mentioned above, showed us that hydrogen (in H2 form) and helium make up 99% of the planet’s atmosphere. In addition to these two elements, methane, ammonia and water are also known to be present in the planet’s atmosphere.
Although all of this data provides information about Jupiter’s outer layers, it is thought that its core structure also bears similarities to the outer layers.
Like many sky enthusiasts, if you turn your telescope into the sky and look at Jupiter, just like in the image above, you will see stripes running parallel to its equator and undoubtedly the “Big Red Spot.“ These stripes (or bands) and the red stain tell us a lot about the planet’s atmospheric structure.
Formation Of Strips
If we look at the stripes in detail, we can see that some are light and some are dark. This color difference is caused by convection currents. Research conducted with the Voyager spacecraft has shown that light strips are the result of an upward convection current, while dark strips are the result of a convection current directed at the core. On the surface of the bands formed by these convection currents, there are currents (zonal wind pattern) that are directed in the East and west directions.
Big Red Stain
In addition to the light and dark stripes on it, Jupiter also has a fairly large storm system. This storm system, known as the big red blotch, was discovered in the 1600s. This storm is big enough to engulf the Earth.
During the Voyager crossings in 1979, the storm measured 23,300 kilometers in length and 13,000 kilometers in width. Hubble observations in 1995 showed a decrease to 20,950 kilometers, and observations in 2009 showed a decrease to 17,910 kilometers. In observations in 2015, it was observed that it measured 16,500 е 10,940 kilometers and shortened by 930 kilometers per year (from in length).
The chemical process that caused the color of this storm system, which completed its rotation around itself in 6 days, is not yet known. According to recent studies, the stain is shrinking every day.
Atmospheric structure of Jupiter
The first problem encountered when studying the structure of the atmosphere is that there is no zero point to reference for altitude. For this reason, as a reference, the troposphere, where all weather events occur, is taken as zero km. For this reason, all cloud systems on the planet are located below this zero km point.
Just below the troposphere, at a depth of about 40 km, is a cloud layer of ammonia ice. The temperature of this region is between 125-150 K. As we descend below this region, the temperature begins to increase faster.
Just below the cloud layer consisting of ammonia ice is a cloud layer consisting of ammonium hydrosulfide ice formed by the chemical reaction of ammonia and hydrogen sulfate.
After ammonium hydrosulfide clouds, clouds consisting of residual water begin to appear at a depth of about 80 kilometers. Because the color of many compounds associated with sulfur can be associated with red, brown, and Yesil, the color of the stripes on Jupiter is thought to be formed by compounds containing sulfur and phosphorus.
As we cross the region of solid and liquid water, the residual temperature begins to approach 400 kelvins and we encounter gaseous hydrogen, helium, methane and ammonia.
Inner Structure Of Jupiter
Given the planet’s distance to The Sun, temperature measurements were expected to show a temperature of about 105 K. But looking at the spectrum of Jupiter, the calculated temperature was exactly 20 K more than that. Although this seems to be a small difference, it corresponds to exactly 4×1017 Watts more energy than it should be.
Astronomers have realized that what is responsible for this energy difference is gravitational energy that accumulates in the planet’s core and turns into heat as Jupiter forms. The energy accumulated in the core first leaked into the upper layers of the atmosphere and from there to the outside with the help of various mechanisms. This energy output was also enough to make Jupiter’s average temperature higher than expected.
As we descend deeper from the troposphere, both temperature and density increase. As we descend a few thousand kilometers, the elements and compounds in the gas structure begin to liquefy due to increased pressure. When we reach the core, the total pressure reaches 30 million times that of the Earth’s surface. For this reason, the core has an extremely high density. The temperature of the core, which is thought to have a diameter of approximately 20,000 km, is approximately 25,000 K (increasing to 35,000 K levels in some sources).
Because of this pressure and temperature, hydrogen, whose metallic properties predominate, behaves just like liquid metals found in the Earth’s core. This structure, which becomes an extremely good conductor, contributes to the formation of Jupiter’s magnetic field.
If you remember, stars also have hydrogen-rich nuclei with fairly high temperature and pressure. If Jupiter had 80 times more mass than its current mass, Jupiter’s core would also be capable of nuclear fusion. In other words, Jupiter would also become a star (albeit dim and small).
Jupiter’s Magnetic Field
As a result of radio telescope observations, space probes that we sent, and approaches made by various satellites, we received data on Jupiter’s magnetic field. This data showed us that Jupiter has a magnetic field just like Earth (but much wider). The tail of this magnetic field is so long that it extends almost to the orbit of Saturn. Moreover, as in the Earth’s magnetic field (the Van Allen Belts), Jupiter is also surrounded by high-energy particles due to its magnetic field!
Measurements showed us that Jupiter’s magnetic field is about 20,000 times larger than Earth’s magnetic field. This magnetic field is undoubtedly formed when its internal structure in the liquid state becomes a dynamo due to Jupiter’s fairly high rotation speed.