Io-moon of Jupiter, summary of findings - part XNUMX

Io is the first extraterrestrial body to have real-time volcanic eruptions observed by any spacecraft observing it. An island is a living geological body. Some of the volcanic eruptions were more powerful than any known volcanic eruption on Earth.

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FEATHERS

As we mentioned earlier, the plumes are material emitted from the volcanic sources of Io. The spatial distribution of this material when it reaches the heights is usually umbrella-shaped, which means that the movement of the volcanic material is ballistic. In the case of the Pele volcanic source, the first eruption observed by Voyager 1 from the plume reached a height of 300 km and a diameter of 1400 km. In some of the photographs of this volcanic source, the plume moves in a swirling motion. It is assumed that this movement is related to some kind of interaction of the emitted material with gases.

Voyager 1 at least observed the plume when it began observing the Moon. Some of them were active for several days at the time of Galileo's arrival and are found in low latitudes, their geographical distribution is 30° from the equator. 8 were active months later when Voyager 2 began observing them. Two of the plume-creating volcanic sources each created pairs of plumes.

Any model that tries to explain the mechanism that creates the plumes must take into account the high speeds of the movement of the material in them, which is between 500-1000 meters per second. According to one low-energy explanation, volcanic eruptions start when liquid SO2 comes into contact with hot liquid sulfur. At this time the liquid SO2 begins to boil and the result is a mixture of liquid and gas that begins to spread towards the surface. In this place, still below the surface, the residual liquid freezes and the expansion of the SO2 is limited by the condensation of the SO2 vapor into ice of solid particles. According to an explanation, after the high energy starts with SO2 vapor at very high temperatures. In this case the spread towards the surface is accompanied at first by the condensations of the liquid and then comes the freezing and the snow. In any case, the combination of accumulation modes of the SO2 is accelerated within the lava conductor until the flow reaches the speed of sound (between this). At this point the speed can no longer increase (speed of hundreds of meters per second). Near the surface the lava-carrying factor can expand. Moreover, upon reaching the surface the current can spread through the thin atmosphere of the moon. For this reason the current can increase its speed above the exit opening. According to calculations made, the speed can be higher than 1 km/h(1). In the polar regions, the frequency of plumes is low and the lifespan of each of them is short(44). It seems that the plumes (the materials that reach the ground) have a short life span. They disappear within a few years, unless a new supply arrives. Most of the activity is limited to changing the surface of calderas and emplacement of lava flows that cover a small part of the surface of Io (40).

Ultraviolet photo analysis of plumes using the Hubble Space Telescope also revealed a strong signature of diatomic sulfur (2S). S and probably cause the formation of more stable 153S and 2S molecules. The result is a more solid and hot material, so the SO3 gas is the important factor in the formation of the red-orange ring surrounding Pele. Similar although smaller and more diffuse halos surround other volcanic sources such as Cullan Patera. Although the 4S and 2S molecules are more stable in the end they also break down. Their life span is several years and until they disintegrate they rearrange themselves in the structure of 3 S, the most stable form of sulfur and is probably the reason for the yellow color of most of Io's surface. This is probably also the explanation why most of the volcanic sources of the island have a red halo which turns yellow over the years(4).

chemical elements

As we have seen the dominant elements in the lava erupting from the volcanic sources of Io are mainly sulphur, SO2 and silica. The highest concentration of frost deposits of SO2 is found in large basins in the equatorial region. About 30% of the island's surface, excluding the basins, is covered by SO2 frost. Inside the basins, the frost covers more than half of their area (38). The sulfur and its compounds reach a depth of at least several millimeters below the surface. At the beginning of the observation of the Vigers, there were estimates that the soil also contains compounds of sodium, potassium and cations of other alkaline elements(54). Galileo's findings showed that potassium and sodium are emitted from the atmosphere of Io. The presence of chlorine in the atmosphere is higher than in any other body in the solar system. Chlorine is also found in the torus ring that surrounds Jupiter. Hydrogen chloride (HCl) is also found on the moon.

It is not clear where the salt comes from. The moon does not have oceans in which part of them evaporates, the salt in them sinks. It is possible that underground there are rivers or aquifers that feed the volcanic sources and in which there is dissolved salt. The salt can also be formed during reactions in the atmosphere. It is possible that the chlorine was emitted from the volcanic sources or during the decomposition of chlorine on the surface following charged particles from the torus, which regularly bombard the ground(14).

Temperatures

The temperatures in the volcanic sources when a volcanic eruption occurs can reach hundreds of degrees or more. According to one of the models proposed to explain the temperature differences in different places, a distinction must be made between two systems of volcanic sources driven by different types of volatile substances. A factor that must be taken into account is different relationships within the sulfur, it is temperature and viscosity. When sulfur heats up and passes the melting point it undergoes several changes. The sulfur, starts as a yellow solid, at a temperature of C ° 127 it melts and turns into a yellow and viscous liquid with low viscosity. With the increase in temperature its color becomes orange and at a temperature of 157 °C its color changes to pink. In the next step its color changes to dark red and it becomes thick. At a temperature of C ° 227 its color turns to black tar. At a temperature of C ° 327 the viscosity begins to decrease and at C ° 377 it becomes a liquid again. In the final stage where the temperature depends on the pressure it evaporates. Low-viscosity molten sulfur can transfer heat in two forms. Red sulfur at a temperature of C ° 157 - C ° 127 gets a dull black color (black opaque). At a temperature exceeding C ° 377 it is estimated that in small plumes such as in Prometheus are driven by liquid and brown sulfur coming into contact with liquid and brown SO2, causing the SO2 to evaporate and spread and in a large plume such as in Pele rise when hot silicates in the crust of Mars island volatilize sulfur At temperatures of C ° 927 – C ° 477 (1).

Infrared measurements made by Galileo show that in at least 12 volcanic sources, lava eruptions are probably hotter than the highest temperatures in basaltic eruptions on Earth today. In at least one case at Pillan Patera, two different instruments in the spacecraft showed that the temperature of the lava was higher than 1427°C and probably reached 1727°C. The explanation for this is that the lavas are ultramafic siliceous (rich in magnesium). This assessment is supported by the measurement of magnesium-rich orthopyroxene in the lava flows associated with Hot Spots at high temperatures(55). When the Ulysses spacecraft passed by Jupiter on its way to the Sun, its instruments measured a temperature range of C ° 427 - C ° 27, although it should be noted that this observation did not include all types of volcanic activity of the moon(9). In testing the ground temperature, which is not related to volcanic activity, it became clear that at night at the equator the temperature is the same as at the poles(56).

Based on the measurement of the vignettes, the plumes are divided into two types. The most common plumes are thrown upwards at a speed of 500 meters per second, reaching a height of 100 km. The eruption of the plumes lasts several months. Infrared temperature measurements showed that the temperature above the volcanic vents is 127 °C. Pele belongs to the second type. The duration of the eruption was shorter than the time interval between Voyager 1 and Voyager 2. When they passed by, the temperature measured at the entrance of Pele was 327 °C and the velocity of the material being thrown into the air was 1 km per second(2).

In Pillan Patera, which was photographed on 28.6.1997, a temperature higher than C ° 1427 was measured and probably reached C ° 1727 (57). In October 1999, a temperature of -73°C was measured in this volcanic source. Although in a number of Hot Spots a temperature of 107 °C was probably measured, probably due to a lot of heat emitted from lava flows that came out of several fissures (40). The volcanic source Zamama was created during the 1979 Voyager flyby and the 1996 Galileo photographs of Io. Based on photographs of the place taken in 3.1998 and 7.1999, it is estimated that in these places a temperature of 83°C (47) was measured. In a photograph taken in the Southern Hemisphere, at night in an area near Pele, a temperature lower than -186 °C was measured. At another point, a temperature of -168°C was measured (58).

erosion

Evidence of weathering was also found in the photographs. Areas defined each as a "lying flat unit".
(Units Layered Plains) are characterized as wide-dimensional plains which are bounded by steeps whose height can range from 150 to 1700 meters. Grabens parallel these slopes or the latter cross them. The steeps represent erosion caused by normal faults and grabens. These plains probably present the geographical limits of the erosion produced by collapses due to the release of volatile substances(54). A possible explanation for the occurrence of this erosion is SO2. White nodules associated with the emanation of the SO2 liquid are common around these plains. They are the ones who cut the rocks and created the Arouzia (25).

tectonics

The tectonics of Io is different from that of the Earth and is characterized by vertical movements. Lava rises from the depths and spreads over the ground. Older lava sinks and compresses until it breaks and at the same time fragments push up high mountains. These fractures open new openings for other lava flows and it is possible to observe complex relationships between mountains and volcanic sources such as Tohil (59). The tectonic stresses caused many fractures and the formation of the mountains of Ayo. Exposure of each of them caused the formation of straight sets of cracks that cause the irregular configuration of the topography. The grabens show a reticular pattern probably caused by tidal forces(54).

Poles

When Galileo passed near the North Pole in August 2001 and over the South Pole in October of the same year, the density of charged particles that the spacecraft passed through suddenly increased 10 times. This occurred when the spacecraft was in the transition of the magnetic field connecting Io and Jupiter. The waves indicating the density passed through the plasma of charged particles. When these waves were translated into sound waves, one could hear hissing sounds from Jupiter's radio wave emission and when passing over the pole one could hear a tremendous roar that starts suddenly and stops suddenly, similar to the noise of a powerful electric generator. The place where the particle density is where electrons and ions come from Io's atmosphere and follow into a "flux tube", a place where Jupiter's magnetic field lines cross Io. In a transit flight made in 1999, the Galileo discovered something regarding the high density above the poles. On the 2001 flyby, the spacecraft's findings clearly indicated that dense regions collide with the flux of Jupiter's magnetic field. Measuring the magnetic field also taught something new about the plumes erupting from Io's volcanic origins and in relation to the Moon's core. Galileo discovered that electric currents moving along magnetic field lines over two volcanically active regions. Materials that reach high altitudes following volcanic eruptions affect the electrical conductivity at a height of 100 km above the surface(60).

In one of the photographs from 31.5.1998 we see a lunar eclipse (from the point of view of the one on Jupiter). The moon was in Jupiter's shadow. Gases above ground created a glow that could be seen in red, green and blue visible light. The colors created by the collision between Io's atmospheric gases and energetic particles trapped in Jupiter's magnetic field have not been seen before. The green and red colors are created by a mechanism similar to that created at the Earth's poles that create the aurora borealis. The blue color indicates the places of dense volcanic plumes and probably also places where Io is electrically connected to Jupiter(61).

Internal structure

It has 3 parts. A metallic core probably made of iron and iron sulphide with a diameter of 896 km and above it a shell made of molten metal and above it a crust. The core was probably created by heating the interior of the moon when it was originally formed or due to long-lived tides that heated and moved the volcanic sources(18). No internal field has been found on the moon. This means that its molten inner core does not have the same type of convective overturning that the Earth's molten core creates the magnetic field. This lack is consistent with a model according to which the core of an island is heated from the outside by tides bending the layers around it, more than heating coming from the center(60).

magnetic field

Galileo discovered a "hole" in Jupiter's magnetic field near Io. This phenomenon was discovered when the spacecraft passed by Io on its way to Jupiter. The magnetic field should increase as you get closer to Jupiter. Instead, near Io, the field strength suddenly decreased by 30%. It is estimated that there is some unknown factor that creates this phenomenon. It could be that the moon has its own magnetic field that creates this phenomenon(18), which can strengthen the assessment that the moon has its own field. The ionosphere and the presence of sodium in the atmosphere. These are not supposed to withstand the plasmatic pressure of justice operating in their environment. Only the moon's magnetic field can protect them from Jupiter's plasma pressure. Such a magnetic field is supposed to interact with Jupiter's magnetic field and tilt it to the side(17). To date, no evidence has been found that the moon does have its own magnetic field.

Sources

1. Torrence VJ Soderblom LA – “Io”  Scientific American 12 12.1983 pp. 60-71

2. Morrison D. – “The enigma called Io”  Sky and Telescope 3.1995 pp. 198-205

3. "Pele's plume" - Sky and Telescope 9.1997 p. 17

4. "Glileo spots dramatic volcanic activity on Io" - Astronomy Now 12.1997 p. 6

5. "Galileo sees dazzling lava fountain on Io" 17.12.1999

http://galileo.jpl.nasa.gov/news/release/press991217.html

6."NASA's Galileo sees volcanic displays on Jupiter's moon Io" 19.5.2000

http://www.spaceflightnow.com/news/n005/19galileoimages/index.html

7. PIA02588: Galileo and Cassini image two giant plumes on Io

http://photojournal.jpl.nasa.gov/catalog/PIA02588

8. "Pluto probe's amazing view of the volcanic moon Io" 1.3.2007

http://www.spaceflightnow.com/news/n0703/ 01io/

9. Spencer JR et al – “Volcanic activity on Io at the time of Ulisses encounter” – Science

Vol. 257 11.9.1992 pp. 1507-1510

10. "Beware: Io dust" 15.9.2004

http://www.spacedaily.com/news/jupiter-moons-04c.html

11. "Researches produce images of gases escaping from Jupiter moon Io" 21.7.2007

http://www.spacedaily.com/reports/ Researches_ Produce_ Images _Of_ Gases_ Escaping_ From _Jupiter_ Moon _Io_999.html

12. McCauley JF et al – “Erosional scraps on Io”  Nature Vol. 280 30.8.1979 pp. 736-738

13. Spencer J. _ “Galileo's closest look at Io”  Sky and Telescope 5.2001 pp. 41-46

14. "Salty Io" - 2.2. 1999

http://exosci.com/news/160.html

15. "Volcanoes on Jovian moon spew salt into atmosphere" 1.1.2003

http://www.spaceflightnow.com/news/n0301/ 02iol

16. "Aurora lights on Io reveal secrets of Jovian moon's atmosphere" 5.8.1999

http://www.jpl.nasa.gov/galileo/press990805.html

17. Barbats JP et al – Atmospheres Pergumon Press Inc. 1981 260 pp.

18. "Galileo finds giant iron core in Jupiter's moon Io"

http//www.spaceart.com/solar/eng/galp/4htm

19. "Beware: Io Dust" 15.9. 2004

http://www.spacedaily.com/news/jupiter-moons-04c.html

20. "Jupiter's moon produces lots of dust" 4.5.2000

http://www.discoveries.com/news/briefs/20000504/space_galileo.html

21. "Io's volcanoes vent far from Jupiter" 4.3.2002

http://www.spaceflightnow.com/news/jupiter-10-12a.html

22. "Taking the science route to Io" 30.6.1999

http://science.nasa,gov/newhome/headlines/ast30jun99-1.htm

23. Sagan C. "Sulfur flows on Io"  Nature Vol. 280 30.8. 1979 pp. 750-753

24. Rogers JH – The giant planet Jupiter Cambridge University Press 1995

25. PIA02536: 1997 Lava flows near Pillan Patera Io

http://photojournal.jpl.nasa.gov/catalog/ PIA02536

26. PIA03528: Collapsing cliff at Telegonus Mensa, Io

http://photojournal.jpl.nasa.gov/catalog/ PIA03528

27. PIA02557: Lava flows and ridge plains at Prometheus' Io

http://photojournal.jpl.nasa.gov/catalog/ PIA02557

28. "Galileo finds big changes on Jupiter's volcanic moon Io" 16.7.1996

http://www.jpl.nasa.gov/

29. Bond P. - "Galileo survives closest Io flyby"  Astronomy Now 1.2000 p. 8

30. Stockton TC - "Io mountains maybe not volcanoes" 26.2. 2001

http://www.spacedaily.com/news/galileo-01a.html

31. Schenk PM Bulmer M. - "Origin of mountains on Io by thrust faulting and large scale mass movements"   Science Vol. 279 6.3.1998 pp. 1514-1517

32. "Haemus Mons"

http://www.spaceart.com/solar/cap/jup/iomoon.htm

33. PIA02534: Terrain near Io's south pole in color

http://photojournal.jpl.nasa.gov/catalog/ PIA02534

34. PIA03600 : Tall mountain, Tohil Mons' on Io

http://photojournal.jpl.nasa.gov/catalog/ PIA03600

35. "Final looks at Jupiter's moon Io-big picture view" 28.5.2002

http://www.jpl.nasa.gov/releases/2002/releases_2002-120.html

36. "New Galileo images reveal Hawaiian style volcano on Io" 4.11.1999

http://galileo.jpl.nasa.gov/news/release/press991104.html

37. "Galileo images of Io"

http://.spaceart.com/solar/eng/galileo.htm

38. McEwen A. S- “SO2 rich equatorial basins and epeirogeny of Io”  Icarus 1995 pp. 415-422

39. "Jupiter's moon Io covered with volcanoes galore" 1.6.2000

http://www.spaceflightnow.com/ news/n0006/01galileo.index.html

40. Ashley GD – “Volcanism on Io: The view from Galileo”  Astronomy and Geophysics Vol. 42 4.2001 pp. 2.10-2.15

41. PIA02533 : Highest resolution of lava flows on Io

http://photojournal.jpl.nasa.gov/catalog/ PIA02533

42. "Galileo dedicated to returning science data stored in onboard type recorded" 10-16.4.2000

http://www.jpl.nasa.gov/galileo/news/thiswk/today000410.html

43. "Io's fountain of fire" - Sky and telescope 4.2000 pp. 18-19

44. "Spacecraft to fly over source of recent polar eruption on Io"

http://www.jpl.nasa.gov/galileo/news/release/press010802.html

45. PIA03529 : Galileo's last view of Jupiter, Io

http://photojournal.jpl.nasa.gov/catalog/ PIA03529

46. ​​PIA09354 : Io in eclipse 2

http://photojournal.jpl.nasa.gov/catalog/ PIA09354

47. PIA02504 : Close up of Zamama Io(color)

http://photojournal.jpl.nasa.gov/catalog/ PIA02504

48. PIA02506 : Amirani-Maui : longest known active lava flow in the solar system

http://photojournal.jpl.nasa.gov/catalog/ PIA02506

49. PIA02539 : Bright lava flows at Emakong Patera : Io

http://photojournal.jpl.nasa.gov/catalog/ PIA02539

50. PIA02563: Camaxtli Patera, an active volcanic crater on Io

http://photojournal.jpl.nasa.gov/catalog/ PIA02563

51. PIA03885 : Io's Cullann – Tohil region in color

http://photojournal.jpl.nasa.gov/catalog/ PIA03885

52. PIA09355 : Io surface changes

http://photojournal.jpl.nasa.gov/catalog/ PIA09355

53. Carr MH et al - "Volcanic features of Io"  Nature Vol. 280 30.8.1979 pp.. 729-733

54. Schaber G. G.- "the surface of Io: Geologic units, morphology and tectonics"  Icarus 43 1980 pp. 302-333

55. McEven A. S.- “high temperature silicate volcanism on Jupiter's moon Io” Science Vol. 281 3.7.1998 pp. 87-90

56."Temperature map of volcanic moon on Io presents a puzzle" 24.6.2001

http://www.spaceflightnow.com/news/n0106/24iomap

57. PIA01635 : Io in eclipse reveals high temperature hot spot

http://photojournal.jpl.nasa.gov/catalog/ PIA01635

58. PIA03603 : Nighttime temperature on southern Io

http://photojournal.jpl.nasa.gov/catalog/ PIA03603

59. "Final looks at Jupiter's moon Io aid big-picture view" 28.2.2002

http://www.jpl.nasa.gov/releases/2002/release-2002-20-html

60. "Jupiter's Io generates power and noise 'but no magnetic field" 10.12.2001

http://www.jpl.nasa.gov/galileo/news/release/presso011210.html

61. PIA01637 : Io's arrora

http://photojournal.jpl.nasa.gov/catalog/ PIA01637

More of the topic in Hayadan:

• Io-moon of Jupiter, summary of findings - part I
• Rings of Saturn - new discoveries
• Titan - the lunar soil
• Things that Yaorim know: where does the compass needle point?
• The Earth's Moon - Summary of Findings Part 3