Taking a Look into the Jupiter's Dangerous Atmosphere Ever


A Journey without return in the hellish atmosphere of Jupiter Mysterious, imposing, and austere, Jupiter is the largest and most massive planet in the entire Solar System. It is so large (140 thousand kilometers in diameter) that if we put together all the other planets, including Saturn, we would be able to equal only half of its mass. It is difficult to describe in words the fascination that this cosmic giant has exerted over the centuries on entire generations of astronomers, enthusiasts, and simply curious. On Jupiter, everything is out of scale, starting from its best-known feature, the Great Red Spot, a huge cyclone that rages in the atmosphere of the planet for at least 350 years. Like Saturn, Uranus, and Neptune, Jupiter is mostly composed of gas especially hydrogen and helium and therefore has no defined surface on which to land. A hypothetical descent into its atmosphere would look very much like a very long dive into the depths of the ocean. Although we do not know all the secrets of Jupiter yet, we know just enough to imagine the wonderful and terrible spectacle that a hypothetical astronaut would see if he tried to venture into its turbulent atmosphere. Alien colors, clouds as big as mountains, immense columns of gas in continuous movement, lightning so powerful that an entire ocean evaporates in the space of an instant: on Jupiter every atmospheric phenomenon is taken to the extreme, to characterize one of the most hostile environments of the Solar System. An environment that few remember we began to explore a quarter of a century ago. So much time has in fact passed since the day the Galileo probe arrived on Jupiter after a six-year journey. Among the main objectives of that mission, in addition to the study of the Medicean satellites and the Jovian magnetic field, there was also the analysis of the atmosphere, for which was designed a small probe (called "atmospheric")that would measure pressure, temperature and chemical composition. Galileo released the atmospheric probe five months before meeting Jupiter, in July 1995, and on December 7, 1995, the two ships reached the gas giant together. The "mother probe" entered into orbit around the planet, while the little one penetrated its atmosphere at a speed of 48 kilometers per second, after which, in little more than two minutes it was slowed down to subsonic speed by the density of the air. The descent lasted a total of 58 minutes, and the connection was interrupted when the probe, arrived at 150 km of "depth", reached conditions of temperature and pressure so high that it dissolved in the atmosphere of the planet. The data collected along the way proved to be of fundamental importance to understand the dynamics and chemical composition of the upper layers of the Jovian atmosphere but did not provide any clue as to what lies deeper. However, nothing prevents us from putting together what little we know with a bit of imagination, and fantasize about what we might see as we descend towards the core, obviously protected by a super pressurized suit. A dive that will allow us to discover the secrets of one of the most extreme environments of the Solar System. Are you ready? En route to Jupiter! We are half a million kilometers away from Jupiter, aboard our ship, and the approach phase is much longer than expected: we are navigating at the maximum speed allowed by our propulsion system, yet it seems that the planet is not approaching one meter! The outermost layers of its atmosphere begin to occupy the entire field of view only after several hours of travel, when we are still 200,000 kilometers away from the apparent surface of the planet, that is, from the top of its highest clouds. Now the entire disc of the planet extends into the sky for about 40 degrees of apparent diameter. Finally, we see in detail the dense clouds of ammonia and hydrogen that rotate in parallel around the equator forming the characteristic white, red, and orange bands. Jupiter, as well as the Sun and Saturn, is in fact subject to a differential rotation phenomenon. Because of its high speed of rotation (9.9 hours), the gases that make up the upper layers of the atmosphere mainly hydrogen, helium, and ammonia move at different speeds depending on their position with respect to the equator, creating the characteristic horizontal bands of a different color. Usually, the red ones, called "zones", correspond to atmospheric depressions caused by descending cold air, while the lighter ones, the "bands", are cloudy reliefs formed by rising hot air. The Great Red Spot, so clean and geometric if seen from a distance, slowly begins to transform, so that after a few hours we find it hard to distinguish the contours. The enormous vortex, which from space seemed to us a single structure, now appears as a chaotic set of smaller vortexes, whose circumstance reveal new and unexpected details about the extreme turbulence of the atmosphere. The mighty columns of gas emerging from the deepest layers of the planet make Jupiter resemble a huge pot full of bubbling water. Arrived at 100 thousand kilometers from the surface the electromagnetic bombardment caused by the Jovian magnetosphere is so intense that we are forced to activate the special protections of our ship. If we did not, we would die of radiation poisoning within minutes. Jupiter is in fact like a giant dynamo: because of its fast rotation period the speed with which the metallic hydrogen "slides" on the inner core of the planet generates strong electric currents that give rise to a magnetosphere 20 thousand times more powerful than the Earth. The magnetosphere then traps solar emissions in huge bands of radiation, generating a radioactive environment that is a deadly risk both for probes, whose instrumentation must be adequately shielded and for astronauts. 0 km. The descent begins! Continuing our journey we finally reach the edge of the troposphere, the zero limit from which we begin to measure the descent, as we would do with the depths of an oceanic trench. The long descent to the innermost layers of the gas giant begins here: we disengage from the spacecraft, protected by our magical spacesuit, and let gravity drag us towards the core. Because of its enormous mass, at this height Jupiter generates a gravitational acceleration 2.6 times higher than the Earth, so if we want to avoid burning like a meteor we have to open a parachute to slow the fall. We do it, and in a few minutes, our speed goes from 3200 to 360 kilometers per hour, with a deceleration that allows us to avoid any risk of supersonic compression or overheating due to friction. -10 km. Among the mists of the Great Red Spot. Looking around we notice an unusual landscape: the colors vary from bright red to brown and there is a thick layer of mist that prevents us from pushing our gaze further than a few hundred meters. But if we could do it we would see a spectacle without equality: the clouds that surround us, up to 45 km high and composed mainly of hydrocarbons, hydrogen, methane, and ammonia crystals, would look like huge mountains. We would immediately notice that ammonia covers the upper surface of the clouds like an oil film on the water, adding a hue of white to the dominant red color. Pushing our eyes even further in the direction of the Great Red Spot, we would see a huge column of turbulent gas soaring over the surrounding clouds, almost as if it were floating above the troposphere. -50 km. Lightning and turbulence. At the height at which we are now, about -50 km from the beginning of the troposphere, the conditions of pressure and temperature are similar to those detectable on the surface of the Earth, but the winds raging around us are dragging us at a speed of over 560 kilometers per hour and the intensity of radiation generated by the Jovian magnetic field could still kill us in a few minutes, in the absence of protection. The noise generated by the turbulence is deafening because here the speed of sound is four times higher than we are used to. The sky is continuously crossed by violent lightning tens of kilometers long, thousands of times more powerful than those generated on Earth. The lightning is mainly caused by rains of water, sulfuric acid, and ammonia, which due to the gravitational attraction of Jupiter fall at a speed three times faster than the Earth's rains, creating a huge difference in potential. -100 km. Goodbye to the light. After another five minutes of descent, the atmospheric pressure rises to 2 bar and we begin to cross a new layer of clouds, this time composed of ammonium sulphite and ammonium hydrosulphide. The conditions of the environment around us are quite extreme, but at this moment we do not need any additional protection other than good radiation shielding. Although the weight of the air above us starts to grow following an exponential curve, the relatively low fall rate allows the cavities of our body to equalize their internal pressure without generating undesirable effects. Another 10 minutes pass and the pressure reaches 4 bar, a value corresponding to what we would experience on Earth by diving into the water at a depth of 30 meters, while the temperature drops to -40 degrees. We begin to encounter the first clouds of frozen water and in the meantime, the ambient brightness continues to decrease. The speed of the winds rises to 720 kilometers per hour but we barely notice it, because the level of turbulence in the atmosphere gradually decreases. Another 15 minutes of fall and the pressure rises to 10 bar. At this point, to avoid harmful effects on the body, we have to modify the air mixture supplied by the suit's respirator: if we do not do it in a few minutes we would encounter oxygen poisoning, or nitrogen narcosis because under pressure the two gases become toxic. Let's take a last look above us, just in time to see the weak disk of the Sun disappearing in the orange fog. Another 25 minutes pass and the situation begins to get complicated. The special protective suit with which we are equipped must withstand a temperature above 100 degrees Celsius, continuously and constantly increasing, accompanied by enough atmospheric pressure to crumple a car. We find ourselves suddenly immersed in darkness and we can no longer distinguish anything. The absence of light is due to the density and chemical composition of air: around us now there are only hydrogen, helium, ammonium sulfide, and traces of water vapor, compressed to the point of absorbing all the electromagnetic radiation coming from the Sun. Our journey has turned into a slow fall into darkness. -20,000 km. Gases become liquid. We continue to slow down due to the increasing atmospheric density, while incandescent helium is raining around us. The gases compress more and more, starting to behave like liquids: if we had to leave our protective suit we would be crushed and vaporized in a split second. Now we are no longer even able to determine where we are in relation to Jupiter's core because the transition between gas and liquid is so gradual that we can not realize the change in density. Below us, at an unspecified distance, we notice a faint luminescence caused by the energy radiating from the nucleus. The Atmosphere is now almost completely formed by liquid hydrogen that boils at thousands of degrees centigrade, as on the surface of the Sun. The pressure rises rapidly from one thousand to two million bar and the atmospheric density has exceeded the water density by a while, reaching even one thousand kilograms per cubic cm. At this point, the fall stops, because our body, being less dense than the matter around it, once exhausted the kinetic energy of the fall can no longer sink. If we want to continue we need a push, so we turn on the propellers of the suit, and start to descend slowly again. - 30,000 km. An ocean of liquid metal. From here on, and for several hours, the journey is particularly boring: darkness and silence dominate the monotony is interrupted only by the imperceptible flashes that emanate from the deepest regions of the planet. Continuing becomes more and more difficult. After a time that seems endless, however, something unexpected happens: the darkness is torn by a web of lightning that vaguely resembles a spider's web. This network of lightning branches out following a very particular geometry, which closely resembles the way electricity propagates in the water. We are sailing in a vast ocean of metallic liquid hydrogen! Under normal conditions of pressure and temperature, hydrogen is a gas, but if its density exceeds a certain critical point it turns into something different, a substance that flows like a viscous liquid and conducts electricity like a metal. The lightning we saw in the troposphere are nothing compared to those that cross this boundless ocean. Where we are now, pressure and temperature have reached such high levels that they escape any attempt at understanding. -60,000 km. The core! No matter how hard we try, we can't go any further. Below us now is the core of Jupiter, an extremely dense and warm core with a mass between 12 and 45 times the Earth's one: astronomers believe that it is mostly solid and contains most of the heaviest elements of the planet, such as ice, rock, iron and other heavy components, with a considerable amount of hydrogen. 

To be able to walk on its surface we should be able to survive pressures four million times higher than the Earth's surface and temperatures of over 35 thousand degrees: a bit too much even for our imagination! After all, it is only thanks to the latter that we can bear the idea of being forced to stay here forever, held as we are by a gravity force equal to 130 times that of the Earth. A well from which no means of propulsion, no matter how powerful, would ever be able to pull us out.

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