Over the past few weeks the Professional High School CTS's Astronomy Team have been researching the biggest and may be the most interesting planet in the Solar System. We've conducted two experiments that include:
We have conducted experiments into these issues: we have tested the durability of diferent plants in hot liquid, some poison gasses, frozen and cold conditions.
But before we could perform these experiments we have carried out some background research into Jupiter, its moons, history and near future. All the research is listed in report.
Jupiter (a.k.a. Jove, Zeus) was the King of the Gods, the ruler of Olympus and the patron of the Roman state.Zeus was the son of Cronus (Saturn).
- Even seen through a small telescope or pair of binoculars, Jupiter looks like a real world, displaying a faintly banded disk quite unlike the tiny, brilliant image of a star. It also reveals the brightest members of its satellite family as star-like points spread out along a straight line extended east-west through the planet. There are four of these planet-sized moons; with their orbits seen edge-on from Earth, they seem to move constantly back and forth, changing their configuration hourly.
- Jupiter has been known since prehistoric times as a bright "wandering star". But in 1610 when Galileo first pointed a telescope at the sky he discovered Jupiter's four large moons Io, Europa, Ganymede and Callisto (now known as the Galilean moons) and recorded their motions back and forth around Jupiter. This was the first discovery of a center of motion not apparently centered on the Earth.It was a major point in favor of Copernicus's heliocentric theory of the motions of the planets (along with other new evidence from his telescope: the phases of Venus and the mountains on the Moon).Galileo's outspoken support of the Copernican theory got him in trouble with the Inquisition.
- A few decades later the satellites of Jupiter were used to make the first measurement of the speed of light. Observers following their motions had learned that the satellite clock seemed to run slow when Jupiter was far from Earth and to speed up when the two planets were closer together. In 1675 the Danish astronomer, Ole Roemer, explained that this change was due to the finite velocity of light.
- Jupiter was first visited by Pioneer 10 in 1973 and later by Pioneer 11, Voyager 1, Voyager 2 and Ulysses. The spacecraft Galileo orbited Jupiter for eight years. It is still regularly observed by the Hubble Space Telescope.
Jupiter impact with Comet Shoemaker-Levy 9:
*Comet Shoemaker-Levy 9 is so-named because it was the ninth short-period comet discovered by Carolyn and Eugene Shoemaker and David Levy.
*More details on: http://www.cox-internet.com/ast305/sl9.html
Galileo Galilei 1564-1642 Italian astronomer and physicist. The first to use a telescope to study the stars. Discoverer of the first moons of an extraterrestrial body (see above). Galileo was an outspoken supporter of Copernicus's heliocentric theory. In reaction to Galileo, the Church declared it heresy to teach that the Earth moved and silenced him. The Church clung to this position for 350 years; Galileo was not formally exonerated until 1992.
Jupiter is the fifth planet from the Sun and by far the largest and the fourth brightest object in the sky (after the Sun, the Moon and Venus). Jupiter is more than twice as massive as all the other planets combined (318 times Earth).
- Core : Probably of rocky material amounting to something like 10 to 15 Earth-masses.
- Above the core : There is the main bulk of the planet in the form of liquid metallic hydrogen. This exotic form of the most common of elements is possible only at pressures exceeding 4 million bars, as is the case in the interior of Jupiter (and Saturn). Liquid metallic hydrogen consists of ionized protons and electrons (like the interior of the Sun but at a far lower temperature). At the temperature and pressure of Jupiter's interior hydrogen is a liquid, not a gas. It is an electrical conductor and the source of Jupiter's magnetic field. This layer probably also contains some helium and traces of various "ices".
- The outermost layer : Composed primarily of ordinary molecular hydrogen and helium which is liquid in the interior and gaseous further out. The atmosphere we see is just the very top of this deep layer. Water, carbon dioxide, methane and other simple molecules are also present in tiny amounts. Recent experiments have shown that hydrogen does not change phase suddenly. Therefore the interiors of the jovian planets probably have indistinct boundaries between their various interior layers.
GRS has been seen by Earthly observers for more than 300 years (its discovery is usually attributed to Cassini, or Robert Hooke in the 17th century). The GRS is an oval about 12,000 by 25,000 km, big enough to hold two Earths. Other smaller but similar spots have been known for decades. Infrared observations and the direction of its rotation indicate that the GRS is a high-pressure region whose cloud tops are significantly higher and colder than the surrounding regions. Similar structures have been seen on Saturn and Neptune. It is not known how such structures can persist for so long.
False color representation of Jupiter's Great Red Spot (GRS) taken through three different near-infrared filters of the Galileo imaging system and processed to reveal cloud top height. Images taken through Galileo's near-infrared filters record sunlight beyond the visible range that penetrates to different depths in Jupiter's atmosphere before being reflected by clouds. The Great Red Spot appears pink and the surrounding region blue because of the particular color coding used in this representation. Light reflected by Jupiter at a wavelength (886 nm) where methane strongly absorbs is shown in red. Due to this absorption, only high clouds can reflect sunlight in this wavelength. Reflected light at a wavelength (732 nm) where methane absorbs less strongly is shown in green. Lower clouds can reflect sunlight in this wavelength. Reflected light at a wavelength (757 nm) where there are essentially no absorbers in the Jovian atmosphere is shown in blue: This light is reflected from the deepest clouds. Thus, the color of a cloud in this image indicates its height. Blue or black areas are deep clouds; pink areas are high, thin hazes; white areas are high, thick clouds. This image shows the Great Red Spot to be relatively high, as are some smaller clouds to the northeast and northwest that are surprisingly like towering thunderstorms found on Earth. The deepest clouds are in the collar surrounding the Great Red Spot, and also just to the northwest of the high (bright) cloud in the northwest corner of the image. Preliminary modelling shows these cloud heights vary over 30 km in altitude. This mosaic, of eighteen images (6 in each filter) taken over a 6 minute interval during the second GRS observing sequence on June 26, 1996, has been map-projected to a uniform grid of latitude and longitude. North is at the top.
Here you can find information about the position,size,mass and other basic characteristics of the planet and it's moons in the Solar System.
Here you can watch Jupiter in real time
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
| Ring | Distance(000 km) | Width (km) |
| Halo | 100 | 22800 |
| Main | 123 | 6400 |
| Gossamer | 129 | 214200 |
More Statistics ... Distance from the Sun to Jupiter
Metric: 778,412,020 km
English: 483,682,810 miles
Scientific Notation: 7.7841202 x 108 km (5.20336 A.U.)
By Comparison: 5.023 x Earth
Mass
Metric: 1,898,700,000,000,000,000,000,000,000 kg
Scientific Notation: 1.8987 x 1027 kg
By Comparison: 317.82 x Earth
Equatorial Radius & Circumference Radius
Metric: 71,492 km
English: 44,423 miles
Scientific Notation: 7.1492 x 104 km
By Comparison: 11.209 x Earth
Circumference
Metric: 449,197 km
English: 279,118 miles
Scientific Notation: 4.49197 x 105 km
Volume
Metric: 1,425,500,000,000,000 km3
English: 342,000,000,000,000 mi3
Scientific Notation: 1.4255 x 1015 km3
By Comparison: 1316 x Earth
Density
Metric: 1.33 g/cm3
By Comparison: 0.241 x Earth
Surface Area
Metric: 62,179,600,000 km2
English: 24,007,700,000 square miles
Scientific Notation: 6.21796 x 1010 km2
By Comparison: 121.9 x Earth
Sidereal Rotation Period (Length of Day)
Hours: 9.925
Earth days: 0.41354
By Comparison: 0.4147 x Earth
Sidereal Orbit Period (Length of Year)
Earth years: 11.8565
Earth days: 4330.6
Jupiter’s planet configuration toward Sun:
| Opposition | Conection | ||||||||||||
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OCCULTATIONS: If the orbits of the all planets are on one flat surface, the backing of the planets will be without interruption. This backings happen rarely, and they are called occultations The most interesting occultation is when you can seethe disks of the two planets with the telescope. That is quite interesting picture. On fig. is the occultation from the 4th of January, year 1818.
Not less interesting was the occulation with Mars 2 years B.C. in 13.09.1170 :
Venus covers the disks of Jupiter. That connection will happen in 2.12.2223 :
*The planet Mars pass by the disk of Jupiter. If you look an occultation for a long you will observe the movement of the planets and you could feel the majesty of the Universe.
*More detiles on : http://moscowaleks.narod.ru/galaxy001.html
Planet’s parade on the 27.04.2022year:
*An impressive arrangment of the planets Jupiter, Venus, Neptun, Mars, Saturn and the Moon can be seen on the 27th of April, year 2022. It is called the planet's parade
Jupiter’s occultation – past and future:
| Data | Time | Front Planet | Back Planet | Calendar |
| 2.05.1570 | 7:47 | Venus | Jupiter | Julian |
| 1.04.1613 | 2:08 | Jupiter | Neptune | GREGORIAN |
| 7.15.1623 | 17:03 | Jupiter | Uranus | GREGORIAN |
| 9.19.1702 | 13:26 | Jupiter | Neptune | GREGORIAN |
| 10.04.1708 | 12:46 | Mercury | Jupiter | GREGORIAN |
| 1.03.1818 | 21:51 | Venus | Jupiter | GREGORIAN |
| 11.22.2065 | 12:47 | Venus | Jupiter | GREGORIAN |
| 10.27.2088 | 13:46 | Mercury | Jupiter | GREGORIAN |
| 4.07.2094 | 10:46 | Mercury | Jupiter | GREGORIAN |
| 9.14.2123 | 15:26 | Venus | Jupiter | GREGORIAN |
| 12.02.2223 | 12:39 | Mars | Jupiter | GREGORIAN |
It's best to observ the planets when you know their connections with the moon.
Jupiter’s connection with the moon:
| Date | Hour | Direction |
| 12.01.2004 | 12,8 | 3°S |
| 8.02.2004 | 15,6 | 3°S |
| 6.03.2004 | 17,6 | 3°S |
| 2.04.2004 | 22,3 | 3°S |
| 27.05.2004 | 14,5 | 4°S |
| 24.06.2004 | 2,2 | 3°S |
| 21.07.2004 | 16,3 | 3°S |
| 18.08.2004 | 8,3 | 3°S |
| 12.10.2004 | 22,2 | 2°S |
| 9.11.2004 | 17,7 | 1°S |
| 7.12 2004 | 12,7 | 3°S |
| 4.01.2005 | 3,6 | 0,4°N |
| 31.01.2005 | 12,8 | 0,9°N |
| 27.02.2005 | 16,6 | 1°N |
| 26.03.2005 | 17,7 | 1°N |
| 22.04.2005 | 20,5 | 0,6°N |
"Astronomical calendar", BAS-BG-2005
Jupiters occultation with the star.
October 10, 1999 Occultation of a star by Jupiter:
*More detiles on: http://www.lpl.arizona.edu/~rhill/planocc/Oct15.html
The Future of Extra-solar Planetary Exploration
Finding Jupiters is 1000 times "easier" than finding Earth .
Like the goal of sending humans to the Moon in the 1960's, the current NASA administrator has set a grand goal of detecting and imaging other Earth-like planets by the mid-21st century.
Like the Moon missions, much of the technology is only in the conceptual phase at present, but there is a clear path to the goal Take a census of the prevalence of other solar systems around nearby stars -- we are doing this now.
Detect Earth-sized planets -- requires refining techniques to avoid the glare of the star and see planets directly -- 2006.
Detect life on Earth-sized planets -- requires building several space telescopes, launching them beyond the orbit of Jupiter and precisely combining the light they collect -- 2012.
Main goal: detect oxygen in the atmosphere of distant earth-like planets.
Significant oxygen in a planetary atmosphere is produced and maintained by life. Remove life from the Earth and the oxygen goes away in a very short time.
Take a picture of a distant Earth -- 2030?
Coming Soon: "Good" Jupiters
We tend to think of Earth as the most important planet in our solar system. But if you were to eavesdrop on a group of astronomers from a distant world, discussing their initial investigation of our sun and its planets, Earth might not even be on the agenda. More likely, they'd be talking about Jupiter.
Jupiter is huge. Its mass is 318 times that of the Earth. All of the planets in our solar system, even puny Pluto, do a gravitational dance with the sun, tugging the star this way and that as they sweep through their orbits. But Jupiter's effect is by far the greatest.
It is this wobble, the sun's change in radial velocity caused by the tug of Jupiter's gravity, that would offer astronomers on faraway worlds the most obvious evidence that there are planets orbiting our sun. Indeed, it is the gravitational effect of giant planets on other stars that has enabled astronomers on Earth to find more than 130 extrasolar planets. Most of these planets are Jupiter-sized or larger.
Planets that orbit close to their stars also have a detectability advantage. The closer in a planet is, the more quickly it completes a full orbit, so astronomers don't have to wait long to see a pattern emerge in its star's wobble. Some extrasolar planets complete their orbits in just a few days. These close-in giant planets have come to be known as "hot Jupiters." They comprise one of the two major groups of extrasolar planets discovered so far.
Planets in the second group are known as "eccentric Jupiters." These massive worlds have elongated orbits that, like comets, dip in close to their stars and then swing out to great distances. "Between half and 1 percent of the stars are showing hot Jupiters. And then about another 7 percent are showing eccentric giant planets," says Greg Laughlin, a UC Santa Cruz astronomer who works with the UC Berkeley-based planet-hunting team headed by Geoff Marcy.
The discovery of both hot Jupiters and eccentric Jupiters surprised astronomers. Work is ongoing to understand how solar systems so unlike our own could have formed. There is also debate about whether systems like those discovered so far can host habitable planets like Earth.
What planet hunters would really like to find, though, is a third group of Jupiters, so-called "good Jupiters." Planets that orbit their stars in circular orbits at roughly the same distance that Jupiter orbits our sun, about 5 times the Earth-sun distance.
The "good" thing about a solar system that contained a good Jupiter is that it might also harbor an Earth-like - and possibly life-bearing - planet. In our solar system, Jupiter plays two roles believed to be important to life on Earth.
It helps to stabilize the orbits of the inner planets, which in turn helps to stabilize Earth's climate. And it keeps the inner solar system relatively free of comets and asteroids that could cause devastating impacts. Planetary systems that contain good Jupiters, therefore, will make excellent targets for future missions, such as Kepler, Darwin and the Terrestrial Planet Finder, that will be designed to hunt for Earth-sized planets.
Why the delay in finding good Jupiters? Because planets so far from their stars take many years to complete an orbit. Jupiter, for example, takes nearly 12 Earth years to make a full trip around the sun. And astronomers need to observe a complete orbit to be confident that they have found a planet. "It's easy to get fooled if you don't see a full [orbital] period," Laughlin says.
Planet hunting began in earnest only about 10 years ago. So it wasn't until 2002 that the first good Jupiter was found. The planet, slightly more massive than Jupiter, takes about 7 years to orbit its star, Gliese 777A. It is about 3.5 times as far from its star as Earth is from the sun.
But astronomers are studying a number of other stars that also hold the promise of hosting good Jupiters. Over the next few years, we can expect to see the announcement of such planets to become commonplace. "Within 5 years," Laughlin says, "the announcement of a Jupiter-like planet on a truly Jovian orbit [won't even be reason to call a press conference."
Only Solar Systems With Jupiters May Harbor Life
The search for Earth-like life on other worlds should focus on solar systems with Jupiter-like planets, a University of Arizona scientist reports today in the Jan. 30th issue of the Proceedings of the National Academy of Sciences.
Jupiter-like planets flinging Mars-sized objects toward their sun-like stars would deliver the water needed for carbon-based terrestrial life, said Professor Jonathan I. Lunine of the Lunar and Planetary Laboratory, chair of the UA Theoretical Astrophysics Program.
That, evidence says, is what happened in our solar system, Lunine concludes.
"The bottom line is, the asteroid belt certainly had much more material when the solar system was forming than it does today, and Jupiter was responsible for clearing most of that material out," he said.
As the solar system formed, Jupiter's powerful gravity perturbed asteroids to accrete into larger and larger objects - terrestrial "embyros" as big as Mars or bigger - then tossed them into very unstable elliptical orbits. Those that hit Earth when flung toward the inner solar system delivered the water that now fills Earth's oceans. That happened when Earth was about half its present size.
Lunine and Italian and French colleagues published in the November 2000 Meteoritics and Planetary Science their model of how planetary embryos supplied most of the Earth's ocean water. Authors on the article are Alessandro Morbidelli and Jean Petit of the Observatory de la Cote d'Azur, John Chambers of NASA Ames, Lunine of the UA, Francois Robert of the Paris Museum of Natural History, Giovanni Valsecchi of the Institute for Space Astrophysics (Rome), and Kim Cyr of NASA Johnson Space Center.
A solar system with water-bearing asteroids but no giant planets might not evolve habitable worlds with oceans, they conclude.
The deuterium-to-hydrogen ratio in Earth's seawater is the key clue as to the source of the oceans. Seawater contains 150 ppm deuterium, or heavy hydrogen. That's about five or six times the deuterium-to-hydrogen ratio found in the sun and in the solar nebula gas, known from measurements made at Jupiter. But it's only about a third of the deuterium-to-hydrogen ratio measured in comets Halley, Hyakutake, and Hale-Bopp,. The findings contradict the popular idea that comets supplied the Earth with oceans.
"If deuterium abundances in the asteroid belt are correctly reflected by the meteorites, planetary embryos sent careening by Jupiter into the Earth are by far and away the biggest contribution to Earth's water,'" Lunine said.
That Mars meteorites are richer in deuterium than Earth's seawater is consistent with the model. Lunine said. So is the scenario that Earth's moon was created when a Mars-sized object slammed into proto-Earth, an idea developed by UA planetary sciences Professor Jay Melosh and others, Lunine noted.
Astronomers in the past half decade have discovered that there are more planets outside our solar system than in it. They have found what may be giant gas planets at least as massive as Jupiter in orbit around 50 nearby stars. All of the newly found gas giants are closer to their stars than Jupiter is to the sun - some as close to their parent stars as Mercury is to the sun.
That giant gas planets exist in the inner solar system "has enormous implications for the frequency of habitable Earth-like planets in the galaxy," Lunine said.
The radial velocity observing technique used in the discoveries reveals planets by the Dopper effect of starlight. But the technique is blind to planets that may be farther out in their solar systems. Lunine has found in research he did with David Trilling of the University of Pennsylvania and Willy Benz, University of Bern, Switzerland, that for every giant planet detected close to a parent star, two or three giant planets orbit farther out, waiting to be discovered.
With no plausible theory of how objects more massive than Jupiter can form so close to their parent stars, theorists like Lunine have modeled the complicated story of how Jupiter-like planets might form far out in the solar system and migrate inward. The gist of the story is that some planets migrate all the way in and transfer all their mass to the sun and disappear. Others migrate only partway in before the gaseous disk disappears, at which time inward migration stops and terrestrial planets form from leftover rocky debris.
Jupiter, at about 5 astronomical units (AU) from the sun, is well beyond the "habitable zone," the region where liquid water is stable. (Earth is one astronomical unit from the sun.)
"If giant planets existed closer to a star than 5 AU - say, at 3 AU - there would still be terrestrial planets in stable orbits," Lunine said. "But they could well be dry because the giant planet would have tossed water-bearing material away from the habitable zone."
Or, if the giant gas planet were very distant in the outer solar system, it likely would fling water bound in planetary embryos to a region too cold for life. And it would send too few water-bearing embryos in toward terrestrial planets at 1 AU, Lunine added.
"In that case, you might end up with a big but icy terrestrial planet at 4 or 5 AU - too cold to support life as we know it," he said.
Lunine is a member of a key project for a future space astrometry mission called SIM.
Astrometry, a technique that measures the motions of stars with extreme precision, will do a better job in finding Jupiter-like planets that are moderately distant from their parent stars than does the radial velocity technique. Astrometry will also give actual rather than minimum planet masses, unlike the radial velocity method.
Direct imaging is the ultimate technique for planet searches, however, because the spectra, or colors of light, from a planet reveal planetary atmospheres and history.
The UA-led Large Binocular Telescope consortium, the California-led Keck Telescope consortium, and Europe's impressive national giant telescopes are developing adaptive optics for the direct detection of extra-solar planets. Future space-based, very long baseline interferometers called Terrestrial Planet Finder and Darwin promise to be more powerful tools in planet searches.
"If you really want to discover another Earth, you've got to understand where the Jupiters are and what they've done to their solar systems over time," Lunine said. "You might find water vapor in the atmosphere of that second Earth, but you don't know if that water vapor is supported by an ocean that is a kilometer, 10 kilometers or 5 meters deep."
Lunine recently argued the case at a workshop for participants in the Terrestrial Planet Finder (TPF) project. UA collaborates with Lockheed Martin to develop a winning design for TPF, a space observatory that NASA plans to launch in 2012 as part of Origins Program.
Lunine and other UA scientists working on TPF, including Nick Woolf and Roger Angel of Steward Observatory, propose a precursor project to TPF for direct mapping of Jupiter-like planets.
Are our nearest living neighbours on one of Jupiter's Moons?
Introduction.
Mankind has for centuries debated on whether it is possible for life to exist somewhere in the universe other than on Earth. Although our eyes are now turned to the possibility of planets similar to the earth existing elsewhere in the cosmos, discoveries made over the past few decades make it likely that we may find life in some form much nearer home, within our own solar system. Current research indicates that perhaps the most likely place to find living organisms within our solar system may be on Jupiter's moon Europa.
Composition of Europa.
Europa is a satellite of Jupiter just slightly smaller than our own moon. The photographs and measurements taken by the Galileo and Voyager spacecraft show that Europa seems to be covered with ice, and spectroscopic analysis indicates that this ice has a significant pure water content (various NASA announcements). The density of Europa has been measured as being far greater than that of pure water, and therefore the whole satellite must have some sort of heavier core overladen with water or ice.
Either the moon has a solid core with a large area of water topped by a thick layer of ice or the core is overlaid with a convecting layer of molten or slushy ice topped by a surface of brittle ice. These are the only two scenarios that would seem to explain the surface markings photographed by NASA spacecraft. The Galileo images appear to show evidence of "near surface" areas of melting ice, plus movements of large blocks of icy crusts very similar to those observed on the earth's ocean ice sheets.
Although Europa is cold, with a surface temperature of only 110 degrees Kelvin (110 degrees centigrade above absolute zero) the moon may be internally heated from two possible heat sources. It may be partially warmed, as is the earth, by the decay of radioisotopes in the core. Much more likely is the heat provided by the "tidal heating" provided by the gravitational pull of its parent body Jupiter (Barry 2001).
As well as ice movement occurring due to core heat sources, it also occurs because of Jupiter's pull on Europa's sub surface ocean. Scientists have discovered that the satellite surface is covered in unique cycloidal (curved) cracks and ridges, running through the entire lunar surface. Each arc segment in a cycloidal crack seems to form in 85 hours - the time it takes Europa to complete an orbit of Jupiter. This hints at the near certainty of a totally liquid ocean beneath the icy crust.
As Europa has a slightly non elliptical orbit around Jupiter (plus its gravitational interaction with it's companion moons Gannymede, Callisto and Io) its fabric is likely to be subject to considerable geological and tectonic activities due to both the radioactive and the tidal heating. The sister satellite Io exhibits this type of heating in the form of continuous volcanic activity.
The Surface of Europa.
Photographs of Europa show a heavily cracked surface as if the ice has been continuously moving, perhaps partially re-melting then re-freezing again (Pappalardo 1999). For a moon so near to Jupiter, there are surprisingly few impact craters. This indicates that the ice surface has either been recently renewed, or is in a state of constant renewal, such as would occur if the water were to "well up" before flowing over the surface ice before re-freezing. Some photographs indicate that perhaps "hot spots" melt specific areas of the ice sheet, before again re-freezing .Because Io, Jupiter's innermost satellite, supports highly active volcanic systems driven by internal tidal friction, the suspicion must be that perhaps similar - although less intense activity - may exist in the sub surface of Europa which would explain the apparent "new" nature of the moons icy surface.
How can life exist on Europa?
Although initially it appears as if Europa is a most unlikely place to find any form of life, over the last decade people are beginning to think the seemingly impossible. Recently, planet scientist Richard Green from University of Arizona said "I'd bet there's life on Europa - I wouldn't bet there's life on Mars (April 2000 Wired magazine). Until recently we thought that "life" was impossible in some of the most inhospitable parts of our own planet and that without light for photosynthesis, liquid water and oxygen nothing could survive. Since then, we have discovered places on earth where life is sustained in the dark, and without oxygen using instead the heat and thermal energy from volcanic fluids and water. Does this sound a bit like Europa?
What type of life might be possible on Europa?
If life of some sort were to exist under the ice of Europa due to thermic activity, it is likely be of a fairly basic form such as thermophillic (or heat loving) bacteria such as occurs on earth. Many scientists now speculate that life may have originally arisen in such circumstances here on earth. The ice in some areas of Europa is thought to be fairly thin, and in these places, the liquid water beneath may be close enough to the surface for photosynthesis to occur. Due to this, it may even be possible for algae or other similar forms of life to exist fairly near the surface.
On Europa we believe that the ice is torn apart by some sort of thermic or seismic activity. The resultant crustal movements, may allow material from below the surface to well up and fill the gaps in the ice floes, as can be seen in colouration exhibited in the ice cracks on some Galileo photographs (web site 1).
The infilling material may be warmer, softer ice from below the surface, or water from a subsurface ocean. It is possible for material from the core to be vented to the surface via the cracks or gaps in the surface ice. This shows on Galileo images as reddish brown colouring near some of the cracks. Although life is unlikely to exist on the surface of Europa due to the low temperature, future research may prove that even this is possible under certain circumstances especially as recent observations have shown that Europa has a tenuous atmosphere composed mainly of oxygen. Traces of sulphuric acid have also been discovered on Europa and even though one may imagine that its presence might lessen the chances of life, it should not be forgotten that sulphur and sulphuric acid act as oxidants (energy sources) for some living organisms.
On Earth, all living organisms existed originally only in the oceans and it was not until the end of the Silurian period some 440 million years ago that living creatures ventured onto dry land. Primordial life has had plenty of time to develop under the ice of Europa and it has even been suggested (Hoagland 1980) that the equivalent of Plesiosaurus could be swimming under Europa's ice! However later research (Gaidos 1999) has shown that perhaps Europa lacks the heat sources needed to provide the energy required for the development of complex forms of mulicelular life forms.
How do we find this "life"?
It will be extremely difficult to discover whether life forms exist on Europa for not only has a craft to get to the moon but a lander will also have to be sent to the surface. Estimates for the ice thickness vary from a few kilometers to 200 kilometers. The task of searching beneath the ice poses problems, which are as yet, unanswerable. Initially, an orbiter will be needed to gather more data about the moon, perhaps equipped with laser altimetry equipment (to measure small changes in the moon's shape as it orbits Jupiter). Alternatively, a radar imager could also be used to look through the ice to determine how the crust changes with depth. As the orbiter flies overhead, it might measure how much Europa is "pulling" on the spacecraft at different locations, the amount of pull at each place being dependent on the mass between the centre and the surface of the moon. Using this data from different locations would provide a 3D image of the interior of the moon. The orbiter could also carry an infrared spectrometer to provide information about the chemical composition of Europa's surface, including the presence of organic molecules. The decision, on which instruments will be carried on an orbiter is difficult, as the craft will be limited to a very small payload of perhaps only 20 kilograms (Chyba 1998). The low payload is due to the propulsion problems involved in firstly getting a craft into Jupiter orbit, then braking itself into a low circular orbit of Europa. The craft would also require heavy shielding in order to survive the very high radiation levels from the radiation belts around Jupiter.
The orbiter missions would be followed by craft landing on Europa. These would be used to probe through the ice crust and sample the possible liquid beneath, to determine amongst other things, the temperature, pH levels etc. at different depths. The problem with any search beneath the surface ice would be to avoid contamination of Europa by outside influences. Many scientists feel that full under ice exploration of Europa is decades away (Moonaw 2001).
Current research.
As well as research taking place for future space missions to Europa, investigations into the possibilities of life on Europa and in other inhospitable habitats continue apace here on earth. We already know that simple organisms can live and flourish in the darkness of the deep oceans near to undersea volcanic vents, in the blistering heat of hot springs and now we even read (Parkes 1998) of lowly bacteria existing to a great depth in the earth's rocky crust.
The "test bed" for future Europa exploration is now taking place under the earth's ice sheets by NASA with a great deal of work being done at Lake Vostok in Antarctica. This lake is a body of water the size of Lake Ontario deep under the ice - which acts as a shield and protects the lake from the cold on the surface. Cores taken from the ice above the lake have shown the presence of bacteria, fungi, spores, diatoms plus other organisms which have not yet been recognised. Investigation of the lake itself is delayed because as yet, methods of exploration without contaminating the water have not yet been perfected.
It is thought that Europa and Lake Vostok could be very alike in their condition and anything learned from Vostok will undoubtedly have an effect on future Europa exploration.
The future.
Is life possible on Europa? Well, we're hardly likely to find a humanoid in an aqualung swimming along under the ice crust, but there now appears to be more than a fighting chance that some form of living organisms could survive on Europa if a liquid ocean really does exist below the ice. Our nearest living "relatives" really could be living on one of Jupiter's moons.
The Experiments:
1) To observe a plant in hot liquid.
For our first experiment we put some seaweed in boiling water
to observe what will happen and how the high temperatures will
affect the plants.
We heated the water up to 100°C and put the seaweed in the boiling
water. After 5-6 minutes we place the plants in an aquarium with water with
normal temperature. On the next day the seaweed had yellow color - the 'hlorophil'
in these plants were gone into the water so they were dead /they can not photosyntesise/.
We conduct these experiment to see how the hot liquid gasses will affect to
normal plants
from the Earth. In our lab we were allowed to use only water but we think that
this is quite
a good proof that normal organisms can not survive on Jupiter. May be except
some strange crabs
and fishes living around active underwater volcanos.
2) To observe a plant in icy environment.
In this experiment that we performed we examined whether plants
could survive in sub zero temperatures. We researched the growth of
seaweed, which could be measured easily at school.
We measured the rate of growth of seaweed at
temperatures of 22°C, 3°C and -11°C, to compare warm, cold and frozen
conditions, in water. Growth continued in warm conditions and,
to a lesser extent in cold conditions, although in an etiolated
state. Prolonged etiolation resulted in the formation of mould.
With the frozen samples we found that these living organisms
can survive at cold temperatures but then enter a type of
state where growth does not occur.
We think that the ice on Europa could preserve life,
bacterial or otherwise. Perhaps life on meteorites or
comets could be preserved in the frozen material in the
moon’s surface.
If ‘undersea’ convection currents are generated from heat nearer
to the moon’s core, then it is possible that the liquid material
could provide an environment in which this life could develop.
Conclusion:
We have enjoyed our study of Jupiter but, as with most studies,
there are still many questions to answer.
Why Jupiter doesn't became a star?
What would happen if Jupiter explodes in cause of some kind of inner activity?
Is there liquid water below the icy surface of Europa? The proposed Europa Orbiter
spacecraft might find out.
Why is the surface of Europa so smooth?
Perhaps with more exploration and information in the future these questions will be answered.
Jupiter has 63 known satellites (as of Feb 2004): the four large Galilean moons, 34 smaller named ones, plus many more small ones discovered recently but not yet named.
- Galilean Satellites
On January 7, 1610, while skygazing from his garden in Padua, Italy, astronomer Galileo Galilei was surprised to see four small "stars" near Jupiter. He had discovered Jupiter's four largest moons, now called Io, Europa, Ganymede, and Callisto. Collectively, these four moons are known today as the Galilean satellites(moons). Jupiter is very gradually slowing down due to the tidal drag produced by the Galilean satellites. Also, the same tidal forces are changing the orbits of the moons, very slowly forcing them farther from Jupiter.Jupiter's satellites are named for other figures in the life of Zeus (mostly his numerous lovers).
| Satellite | Distance (km) | Radius (km) | Mass (kg) | Discovered by | Date |
| Io | 422 | 1815 | 8.94e22 | Galileo | 1610 |
| Europa | 671 | 1569 | 4.80e22 | Galileo | 1610 |
| Ganymede | 1070 | 2631 | 1.48e23 | Galileo | 1610 |
| Callisto | 1883 | 2400 | 1.08e23 | Galileo | 1610 |
| Amalthea | 181 | 98 | 7.17e18 | Barnard | 1892 |
| Himalia | 11480 | 93 | 9.56e18 | Perrine | 1904 |
| Elara | 11737 | 38 | 7.77e17 | Perrine | 1905 |
| Pasiphae | 23500 | 25 | 1.91e17 | Melotte | 1908 |
| Sinope | 23700 | 18 | 7.77e16 | Nicholson | 1914 |
| Carme | 22600 | 20 | 9.56e16 | Nicholson | 1938 |
| Lysithea | 11720 | 18 | 7.77e16 | Nicholson | 1938 |
| Ananke | 21200 | 15 | 3.82e16 | Nicholson | 1951 |
| Leda | 11094 | 8 | 5.68e15 | Kowal | 1974 |
| Adrastea | 129 | 10 | 1.91e16 | Jewitt | 1979 |
| Thebe | 222 | 50 | 7.77e17 | Synnott | 1979 |
| Metis | 128 | 20 | 9.56e16 | Synnott | 1979 |
This is a list of some satellites that we found most important, sorted by the year of discovering. The values are approximate.
This is the full list of the Satellites of Jupiter until now(The end of 2004)
| 1. Metis | 26. Kalyke | 51. S/2003 J11 | |
| 2. Adrastea | 27. Magaclite | 52. S/2003 J12 | |
| 3. Amalthea | 28. Sinope | 53. S/2003 J13 | |
| 4. Thebe | 29. Callirrhoe | 53. S/2003 J13 | |
| 5. Io | 30. Euporie | 54. S/2003 J14 | |
| 6. Europa | 31. Kale | 55. S/2003 J15 | |
| 7. Ganymede | 32. Orthosie | 56. S/2003 J16 | |
| 8. Callisto | 33. Thyone | 57. S/2003 J17 | |
| 9. Themisto | 34. Euanthe | 58. S/2003 J18 | |
| 10. Leda | 35. Hermippe | 59. S/2003 J19 | |
| 11. Himalia | 36. Pasithee | 60. S/2003 J20 | |
| 12. Lysithea | 37. Eurydome | 61. S/2003 J21 | |
| 13. Elara | 38. Aitne | 62. S/2003 J22 | |
| 14. S/2000 J11 | 39. Sponde | 63. S/2003 J23 | |
| 15. Iocaste | 40. Autonoe | ||
| 16. Praxidike | 41. S/2003 J1 | ||
| 17. Harpalyke | 42. S/2003 J2 | ||
| 18. Ananke | 43. S/2003 J3 | ||
| 19. Isonoe | 44. S/2003 J4 | ||
| 20. Erinome | 45. S/2003 J5 | ||
| 21. Taygete | 46. S/2003 J6 | ||
| 22. Chaldene | 47. S/2003 J7 | ||
| 23. Carme | 48. S/2003 J8 | ||
| 24. Pasiphae | 49. S/2003 J9 | ||
| 25. S/2002 J1 | 50. S/2003 J10 | ||
Orbit : 422,000 km from Jupiter
Diameter : 3630 km
Mass : 8.93e22 kg
Io was a maiden who was loved by Zeus (Jupiter) and transformed into a heifer in a vain attempt to hide her from the jealous Hera .
Discovered by Galileo and Marius in 1610.
I n contrast to most of the moons in the outer solar system, Io and Europa may be somewhat similar in bulk composition to the terrestrial planets, primarily composed of molten silicate rock. Recent data from Galileo indicates that Io has a core of iron (perhaps mixed with iron sulfide) with a radius of at least 900 km.
Io's surface is radically different from any other body in the solar system. It came as a very big surprise to the Voyager scientists on the first encounter. They had expected to see impact craters like those on the other terrestrial bodies and from their number per unit area to estimate the age of Io's surface. But there are very few, if any, impact craters on Io (left). Therefore, the surface is very young .
Instead of craters, Voyager 1 found hundreds of volcanic calderas . Some of the volcanoes are active ! Striking photos of actual eruptions with plumes 300 km high were sent back by both Voyagers (right) and by Galileo (bottom left image on this page) This may have been the most important single discovery of the Voyager missions; it was the first real proof that the interiors of other "terrestrial" bodies are actually hot and active. The material erupting from Io's vents appears to be some form of sulfur or sulfur dioxide. The volcanic eruptions change rapidly. In just four months between the arrivals of Voyager 1 and Voyager 2 some of them stopped and others started up. The deposits surrounding the vents also changed visibly.
Recent images taken with NASA's Infrared Telescope Facility on Mauna Kea, Hawaii show a new and very large eruption (right). A large new feature near Ra Patera has also been seen by HST . Images from Galileo also show many changes from the time of Voyager's encounter. These observations confirm that Io's surface is very active indeed.
Io has an amazing variety of terrains: calderas up to several kilometers deep, lakes of molten sulfur (below right), mountains which are apparently NOT volcanoes (left), extensive flows hundreds of kilometers long of some low viscosity fluid (some form of sulfur?), and volcanic vents. Sulfur and its compounds take on a wide range of colors which are responsible for Io's variegated appearance.
Analysis of the Voyager images led scientists to believe that the lava flows on Io's surface were composed mostly of various compounds of molten sulfur. However, subsequent ground-based infra-red studies indicate that they are too hot for liquid sulfur. One current idea is that Io's lavas are molten silicate rock. Recent HST observations indicate that the material may be rich in sodium. Or there may be a variety of different materials in different locations.
Some of the hottest spots on Io may reach temperatures as high as 2000 K though the average is much lower, about 130 K. These hot spots are the principal mechanism by which Io loses its heat.
The energy for all this activity probably derives from tidal interactions between Io, Europa, Ganymede and Jupiter. These three moons are locked into resonant orbits such that Io orbits twice for each orbit of Europa which in turn orbits twice for each orbit of Ganymede. Though Io, like Earth's Moon always faces the same side toward its planet, the effects of Europa and Ganymede cause it to wobble a bit. This wobbling stretches and bends Io by as much as 100 meters (a 100 meter tide!) and generates heat the same way a coat hanger heats up when bent back and forth. (Lacking another body to perturb it, the Moon is not heated by Earth in this way.)
Io also cuts across Jupiter's magnetic field lines, generating an electric current. Though small compared to the tidal heating, this current may carry more than 1 trillion watts. It also strips some material away from Io which forms a torus of intense radiation around Jupiter. Particles escaping from this torus are partially responsible for Jupiter's unusually large magnetosphere .
Recent data from Galileo indicate that Io may have its own magnetic field as does Ganymede.
Io has a thin atmosphere composed of sulfur dioxide and perhaps some other gases.
Unlike the other Galilean satellites, Io has little or no water. This is probably because Jupiter was hot enough early in the evolution of the solar system to drive off the volatile elements in the vicinity of Io but not so hot to do so farther out
orbit : 670,900 km from Jupiter
diameter : 3138 km
mass : 4.80e22 kg
Europa was a Phoenician princess abducted to Crete by Zeus, who had assumed the form of a white bull, and by him the mother of Minos.
Discovered by Galileo and Marius in 1610.
Europa and Io are somewhat similar in bulk composition to the terrestrial planets: primarily composed of silicate rock. Unlike Io, however, Europa has a thin outer layer of ice. Recent data from Galileo indicate that Europa has a layered internal structure perhaps with a small metallic core.
But Europa's surface is not at all like anything in the inner solar system. It is exceedingly smooth : few features more than a few hundred meters high have been seen. The prominent markings seem to be only albedo features with very low relief.
There are very few craters on Europa; only three craters larger than 5 km in diameter have been found. This would seem to indicate a young and active surface. However, the Voyagers mapped only a fraction of the surface at high resolution . The precise age of Europa's surface is an open question.
The images of Europa's surface strongly resemble images of sea ice on Earth. It is possible that beneath Europa's surface ice there is a layer of liquid water , perhaps as much as 50 km deep, kept liquid by tidally generated heat. If so, it would be the only place in the solar system besides Earth where liquid water exists in significant quantities.
Europa's most striking aspect is a series of dark streaks crisscrossing the entire globe. The larger ones are roughly 20 km across with diffuse outer edges and a central band of lighter material. The latest theory of their origin is that they are produced by a series of volcanic eruptions or geysers.
Recent observations with HST reveal that Europa has a very tenuous atmosphere (1e-11 bar) composed of oxygen. Of the 61 moons in the solar system only four others ( Io , Ganymede , Titan and Triton ) are known to have atmospheres. Unlike the oxygen in Earth's atmosphere, Europa's is almost certainly not of biologic origin. It is most likely generated by sunlight and charged particles hitting Europa's icy surface producing water vapor which is subsequently split into hydrogen and oxygen. The hydrogen escapes leaving the oxygen.
The Voyagers didn't get a very good look at Europa. But it is a principal focus of the Galileo mission. Images from Galileo's first two close encounters with Europa seem to confirm earlier theories that Europa's surface is very young: very few craters are seen, some sort of activity is obviously occurring. There are regions that look very much like pack-ice on polar seas during spring thaws on Earth. The exact nature of Europa's surface and interior is not yet clear but the evidence is now strong for a subsurface 'ocean'.
Galileo has found that Europa has a weak magnetic field (perhaps 1/4 of the strength of Ganymede's). And most interestingly, it varies periodically as it passes thru Jupiter's massive magnetic field. This is very strong evidence that there is a conducting material beneath Europa's surface, most likely a salty ocean.
Open Issues
- How thick is the surface ice? Is there liquid water below? The proposed Europa Orbiter spacecraft might find out.
- What are the surface streaks? How were they formed?
- Why is the surface so smooth?
- Is Europa being heated by tidal friction like Io? How much? Is there any volcanism, perhaps hidden beneath the ice?
- The possible presence of liquid water and volcanism on Europa puts it on my list of possible life-bearing bodies , though, of course, the probability is very low.
- Galileo's extended mission has been approved. If all goes well, it will spend another two years focusing primarily on Europa.
orbit : 1,070,000 km from Jupiter
diameter : 5262 km
mass : 1.48e23 kg
Ganymede was a Trojan boy of great beauty whom Zeus carried away to be cup bearer to the gods.
D iscovered by Galileo and Marius in 1610.
Ganymede is the largest satellite in the solar system. It is larger in diameter than Mercury but only about half its mass. Ganymede is much larger than Pluto .
Before the Galileo encounters with Ganymede it was thought that Ganymede and Callisto were composed of a rocky core surrounded by a large mantle of water or water ice with an ice surface (and that Titan and Triton were similar). Preliminary indications from the Galileo data now suggest that Callisto has a uniform composition while Ganymede is differentiated into a three layer structure: a small molten iron or iron/sulfur core surrounded by a rocky silicate mantle with a icy shell on top. In fact, Ganymede may be similar to Io with an additional outer layer of ice.
Ganymede's surface is a roughly equal mix of two types of terrain: very old , highly cratered dark regions (left), and somewhat younger (but still ancient) lighter regions marked with an extensive array of grooves and ridges (right). Their origin is clearly of a tectonic nature, but the details are unknown. In this respect, Ganymede may more similar to the Earth than either Venus or Mars (though there is no evidence of recent tectonic activity).
Evidence for a tenuous oxygen atmosphere on Ganymede, very similar to the one found on Europa , has been found recently by HST (note that this is definitely NOT evidence of life).
Similar ridge and groove terrain is seen on Enceladus , Miranda and Ariel . The dark regions are similar to the surface of Callisto.
Extensive cratering is seen on both types of terrain. The density of cratering indicates an age of 3 to 3.5 billion years, similar to the Moon . Craters both overlay and are cross cut by the groove systems indicating the the grooves are quite ancient, too. Relatively young craters with rays of ejecta are also visible (left).
Unlike the Moon, however, the craters are quite flat, lacking the ring mountains and central depressions common to craters on the Moon and Mercury . This is probably due to the relatively weak nature of Ganymede's icy crust which can flow over geologic time and thereby soften the relief. Ancient craters whose relief has disappeared leaving only a "ghost" of a crater are known as palimpsests (right).
Galileo's first flyby of Ganymede discovered that Ganymede has its own magnetosphere field embedded inside Jupiter's huge one. This is probably generated in a similar fashion to the Earth's: as a result of motion of conducting material in the interior.
Orbit : 1,883,000 km from Jupiter
Diameter : 4800 km
Mass : 1.08e23 kg
Callisto was a nymph, beloved of Zeus and hated by Hera. Hera changed her into a bear and Zeus then placed her in the sky as the constellation Ursa Major.
Callisto is only slightly smaller than Mercury but only a third of its mass.
Unlike Ganymede , Callisto seems to have little internal structure; however there are signs from recent Galileo data that the interior materials have settled partially, with the percentage of rock increasing toward the center. Callisto is about 40% ice and 60% rock/iron. Titan and Triton are probably similar.
Callisto's surface is covered entirely with craters. The surface is very old , like the highlands of the Moon and Mars . Callisto has the oldest, most cratered surface of any body yet observed in the solar system; having undergone little change other than the occasional impact for 4 billion years.
The largest craters are surrounded by a series of concentric rings which look like huge cracks but which have been smoothed out by eons of slow movement of the ice. The largest of these has been named Valhalla (right). Nearly 3000 km in diameter, Valhalla is a dramatic example of a multi-ring basin , the result of a massive impact. Other examples are Callisto's Asgard (left), Mare Orientale on the Moon and Caloris Basin on Mercury .
Like Ganymede, Callisto's ancient craters have collapsed. They lack the high ring mountains, radial rays and central depressions common to craters on the Moon and Mercury . Detailed images from Galileo (left) show that, in some areas at least, small craters have mostly been obliterated. This suggests that some processes have been at work more recently, even if its just slumping.
A nother interesting feature is Gipul Catena , a long series of impact craters lined up in a straight line (right). This was probably caused by an object that was tidally disrupted as it passed close to Jupiter (much like Comet SL 9 ) and then impacted on Callisto.
Callisto has a very tenuous atmosphere composed of carbon dioxide.
Galileo has detected no evidence of a magnetic field.
Unlike Ganymede, with its complex terrains, there is little evidence of tectonic activity on Callisto. While Callisto is very similar in bulk properties to Ganymede, it apparently has a much simpler geologic history. The different geologic histories of the two has been an important problem for planetary scientists; (it may be related to the orbital and tidal evolution of Ganymede). "Simple" Callisto is a good reference for comparison with other more complex worlds and it may represent what the other Galilean moons were like early in their history.
Sources of Information:
http://stardate.org
http://www.astronomytoday.com
http://www.u-piter.info/article/art/upiter.htm
http://www.zvezdi-oriona.ru/86828.htm
http://www.meo.ru/data/out/371/74339.zip <-- .ZIP file in russian
"Encyclopedia of Astronomy & Astrology" .PDF file
Images - google images search engine
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