#249# Nebula. #700# Sequence illustrating the probable origin of the solar system starting from a cloud of gas and rotating gas. In the frames: aggregation of planets. #529# The Earth and the Moon. #603# In 1986 Voyager 2 flew by Uranus, transmitting pictures and scientific information to the Earth. #504# Jupiter's ring taken by Voyager 2. #247# The great surprise of Neptune's atmosphere are these high-altitude cirrus clouds made of frozen methane. #550# Iapetus, Saturn's farthest moon. #526# The pressure in Titan's atmosphere is 60% greater than on the surface of the Earth. #554# Titan is Saturn's largest moon and the only one in the solar system that has a stable atmosphere, consisting mainly of nitrogen. #555# Voyager's instruments to measure plasma, cosmic rays and low-energy particles. #556# Voyager's infrared and ultraviolet instruments and photopolarimeter. #557# Jupiter and the four Galilean Satellites: Io, Europa, Ganymede and Callisto. Photomontage. #558# Saturn and its major satellites: Titan, Iapetus, Tethys, Mimas, Enceladus, Dione and Rhea. Photomontage. #522# From a geological point of view, Enceladus is Saturn's most highly evolved moon. #552# The satellite Mimas has a huge crater that encircles an icy peak higher than Mount Everest. #524#553# The moon Dione. #525# The moon Rhea has lighter streaks which might have been created by recent flows of ice from under the surface. #523# The moon Tethys has a vast canyon (Ithaca Chasma) that extends for three quarters of its circumference. #551# Some small nameless satellites of Saturn. #534# Volcanic eruption on Io. Nine volcanoes were erupting while the Voyager 1 probe flew by the moon. #543# An illuminated half of Iapetus (northern hemisphere), Saturn's moon. #539# Titan, Saturn's largest moon. #506# Titan has a dense atmosphere consisting of nitrogen and methane. #521# Mimas, one of Saturn's frozen satellites. #549# Satellite 1980S26 of Saturn. #536# The surface of Ganymede, consisting of iced water and rocks. #537# Callisto is the second largest Galilean satellite with a diameter of 4 820 Km. and is bigger than Mercury and Pluto. #566# The 27 antennas near Socorro in New Mexico ready to receive data transmitted from Voyager. #501# Three large antennas located in three different points around the world tracked the Voyager missions. This one, 64 meters high, is located in the California desert. #567# Parkes Radio Observatory near Tidbinbilla, Australia. #568# Pictures of Neptune taken over a 5-hour period in July 1988 from the Mauna Kea Observatory. #602# Voyager. #601# One hour before Voyager 2 moves alongside Triton at its closest rendez-vous point. #600# The Voyager 2 probe facing Neptune. #561# Neptune seen from Triton (National Geographic Magazine). #581# Uranus' ring system consists of dust, large chunks of rock and ice. #580# This photograph was taken with a wide-angle exposure of 96 seconds while Voyager was in Uranus' shadow. #578# The photograph of the delta ring was taken during the passage of the star Sigma Sagittarius behind it. #576# Surface of Miranda, Uranus' moon, with real and reprocessed colors. #586# Ariel, Uranus' moon. #575# Dawn on Uranus taken from a distance of 600 000 miles. #573# The axis of Uranus' magnetic fields. #572# Uranus' molten core is surrounded by an atmosphere of hydrogen and helium. #571# To eliminate disturbances during data transmissions from the probes, and especially during explorations of Uranus, an electronic link was created among the largest antennas in the world (Deep Space Network). #570# The DSN antennas (Deep Space Network) in Camberra, Australia, were of primary importance during Voyager 2's approach to Uranus. #569# Photomontage showing Voyager 2 close to Uranus. #293# The Viking launch. #288# Challenger photographed by Bruce McCandless during the tenth Shuttle mission in February 1984. #287# Launch of a Space Shuttle. #349# Eta Carinae Nebula. #381# The Rose nebula in Monoceros shows a central area in which the interstellar matter was used to create new stars. #663# This X-ray image taken from Nasa's HEAO-2 Astronomical Observatory shows a recently discovered object (top left): it is the only quasar ever observed that emits X-rays. #645# Space Shuttle 35 Columbia takes off from Pad.39-B on December 2, 1990. #644# The components of the payload Astro 1 against the backdrop of the Earth photographed from the stern of the Space Shuttle 35 Columbia. #643# View of the Earth (France and England) from the Space Shuttle 41-G. #642# Space Shuttle 38 Atlantis flies off into the night. #640# Photo taken by the crew of Space Shuttle 31 showing the Space Telescope opened on April 25, 1990. #641# Space Shuttle 35 Columbia rises from Pad.38-B on December 2, 1990. #636#637#638#639# The Discovery control system lifts the Space Telescope above the Earth's horizon before opening the antennas and the solar panels. #635# The Space Telescope pointing towards Cuba and the Bahamas. #634# The Space Shuttle Discovery rises into the Florida sky carrying the Space Telescope (Hubble Space Telescope). #633# January 9, 1980: the Space Shuttle Columbia takes off from the Kennedy Space Center Pad.39-A into the Florida sky. #630# Aldrin poses for a photograph next to the USA flag during the Apollo 11 Eva. #664# New view of the Milky Way obtained from the DIRBE experiment on the COBE satellite (Cosmic Background Explorer). #613# Reconstruction of the main space explorations. #564# Five hours after its encounter with Neptune, Voyager 2 passes by the moon Triton. #563#562# It is believed that Neptune's interior consists of melted ice and rock. #574# Uranus' atmosphere consists of various layers of clouds. #240# Triton's thin methane atmosphere. #239# Triton, Neptune's largest moon: it rotates in the opposite direction of the planet, indicating that it is a wandering body that was probably captured by a comet. #241# The southern hemisphere of Triton with a rough frozen surface. #242# Neptune's system contains two moons, Triton and Nereide: the first satellite rotates clockwise very close to the planet, while the second one follows an elongated orbit in the opposite direction. #243# A picture of Neptune's rings, obtained with a long exposure: the irregular distribution of dust in the rings had made its seem that these were incomplete arcs. #244# While the Voyager probe moves away, it takes this interesting picture of Neptune (at the top) and Triton. #246# Perspective view of Neptune from the south pole: the black spot can also be seen. #5650# The main instruments on board the Voyager 2 probe. #655#233#245# Neptune: the enormous black spot is visible just below the equator, a gigantic cyclone rotating around itself in a counterclockwise direction. Photo using three filters: blue, green and a filter that is absorbed by the methane gas. (Voyager 2) #7120# This is how Neptune, with the large moon Triton, appears from Earth telescopes. #585# Drawing illustrating the arrangement of Uranus' moons and satellites. #229# Picture of Uranus taken with blue, green and orange filters. #5280# Oblique view of the plane of the rings taken from Voyager 2. #5270# Saturn's F ring. #704# The Earth and the Moon: September 18, 1977 (11.66 million Km.) #87# View of the crater Golubkina (Russian sculpture). #82# A structure that is difficult to interpret: there are two sets of parallel lines which intersect almost at a right angle. Faults in the crust or other volcanic formations? Similar structures have never been seen before in the solar system. #725# The Pioneer Venus probe made it possible to create the first altimetric map of the planet: light-blue represents the depressed areas, green the lowlands and so on, yellows, browns and reds for the higher areas. #93# It was decided that the feminine planet par excellence would not have any masculine names: the crater Julia Ward Hove (English feminist). #117# The solar system in a photomontage: Venus and the Earth are visible. #76# Alpha Regio. Seven volcanic domes, with a height of 750 m. and a width of 25 Km., which have been given the name "pancake": perhaps they were formed following an eruption of very dense lava from a reservoir of magma near the surface. #84# Detail of the surface of Venus. #81# This nameless asymmetrical crater was perhaps produced by the impact with a large meteorite. It has a very particular shape: the celestial body probably broke apart when it came in contact with the atmosphere. #73#74#75#85#83#86#88#89#90#91#92#94#95#96#97#98#99# Mapping the surface of Venus indicates the presence of a wide range of geological features. #80# Launched on May 4, 1989, Magellan entered orbit around Venus one year later and begin transmitting data to the Earth starting on September 15, 1990. #78# Magellan is equipped with radar that measures the altitude of the ground calculating the echo time of the waves emitted vertically towards the planet: because it can distinguish objects with dimensions of just 130 m., it was used to obtain a precise map of 84% of the planet. #79# Completing hundreds of revolutions around Venus, Magellan can observe the same point several times from different angles. #713# Hypothetical representation of Pluto-Charon: the planet (in the close-up) and its satellite are two cold worlds that receive very weak sunlight. #617# Classification diagram of the main types of galaxies, called the "diapason". #616# Schematic diagram of the Big Bang: in the beginning, all matter was concentrated in a single point; then expansion produced a set of reactions which led to the formation of the chemical elements, clouds of incandescent gas and finally stars and galaxies. #608#609# The American Pioneer Venus missions had been designed to use probes that could orbit around the planet but also to collect data during the descent. This is why they were equipped with parachutes to slow them down and allow the vehicles to land. #623# The Humason comet photographed as it approached the Earth. #624# This series of photographs of the comet Kohoutek was taken between December 18, 1973 and January 5, 1974. It is possible to see how the direction of the tail prior to the passage around the Sun reverses once it "rounded" our star. #625#628# The nucleus of Halley's comet photographed in ultraviolet by the Pioneer Venus television cameras in orbit around Venus: the various levels of luminosity are very evident. #627# The Giotto probe rendez-vousing with Halley's comet. #626# Pictures of the Vega probe were used to study the nucleus of Halley's comet: it emits real jets of gas. #650# The Pioneer Venus Orbiter was placed in orbit in 1986. The space vehicle completed one orbit a day, the clouds rotated around the planet every 4 hours. #651# The atmosphere on Venus circulates mainly through currents which move from the equator to the pole and vice versa. The temperature difference between the illuminated side and the shadow side generates strong winds moving to the west (Pioneer Venus Orbiter). #711# Saturn with its moons is a kind of planetary system that has many bodies in all different sizes. This photomontage shows a close up of Dione. #657# Saturn and two of its moons: Tethys (above) and Dione (Voyager 1). #724# The asteroid 1989 PB was discovered in August 1989 by E.F.Helin at the Palomar observatory in California. It appears to consist of two distinct bodies which are in contact and is the first recognized case of a solid double in astronomy. #614# Recent pictures of the asteroid 4179 Toutatis, taken in December 1992 at a distance of about 4 million Km. from the Earth. #615# Gaspra asteroids. #707# The asteroids have very different shapes and surface features. #176# The largest of Mars' two moons: Phobos ("fear") photographed by Mariner 9. The other moon was called Deimos ("terror"). Their irregular shape is caused by the fact that they were captured by the planets. #175# They called it Olympus like the sacred mountain of the gods, because it is the largest volcano in the entire solar system: 17 000 m. high, it has a diameter of 500 Km. However, now it is inactive. #174# A strange feature: what seems to be a footprint is really an area with a length of 200 Km., called the "giant's footprint"; it is formed by two craters produced by two large meteorites that fell next to each other. #108# A tropical island in which the submerged part, which is always covered with vegetation, is red, while the sandy bottoms project like veins on the dark blue of the ocean. #109# This is how a portion of the Antarctic pack-ice nearing thawing appears from the satellite, with a thousand cracks running throughout the area, the definite origin of dozens and dozens of icebergs which will detach from its edge. #110# The water on our planet is a basic element for life. It may flow in the most arid regions, fertilizing those areas just like large rivers: the Nile delta seen from the satellite. #112# A part of a desert furrowed by a myriad of dunes and where an active oil well can be seen thanks to the long plume of smoke produced by combustion. #113# The Earth seen from space. An infinite variety of forms can be observed, all the result of the reshaping by air, water, volcanic activity and the life that developed. The island of Hawaii, with a large volcanic cone in the center. #621# The Earth is a geologically alive planet and its continents move a few centimeters each year. Over the last 180 million years, their shape and position have continuously changed until reaching the configuration we know today. #622# The interior of the Earth is still a mystery that geologists continue to study. For example, it is believed that the inner core is rigid and compact, while the outer core is fluid but very dense and viscous. #142# The lunar disk pock-marked with craters as it appears from the Earth during a full Moon: a desolate world that however is still the key to understanding our planet. #143# Another moment during the exploration of the Moon by the Apollo missions: an astronaut gets close to a large rocky formation to examine its geological composition. #145# The first space missions were designed to study the closest celestial body to our planet - the Moon. Some of the most spectacular explorations were carried out by the American Apollo missions, which between 1969 and 1972 sent 12 men to the Moon. #146#363# The lunar crater 308 Ian photographed from Apollo on the dark side of the Moon: the maximum bombardment by meteorites on the Moon and the other planets of the solar system took place during the first hundreds of millions of years after their formation. #147#149# The space missions on our satellite allowed us to see the Earth for the first time as it rose above the lunar horizon. #148# The seas (in the photo the Plain of Aristarchus) are wide, approximately circular plains and are probably the remains of the impact with large asteroids: the remains of the bodies that produced the impact might be found under the surface, which consists of molten lava that then solidified. #151#368# The Apollo 17 astronauts used an all-terrain vehicle to explore the lunar surface. #152# Another crater photographed from space: this is Schmidts' crater, in the Sea of Tranquility. #278# The historical moment of the first human landing on the Moon, on July 20, 1969 and transmitted live to televisions around the world (Apollo 11). #279# The astronaut Armstrong reflected on Aldrin's helmet (Apollo 11). #280# The lunar globe. #281# The first human footprint on the Moon (Apollo 11). #282# Total eclipse of the Moon. #284# Nebula M-20 Trifid. #288# The Challenger Shuttle photographed by Bruce McCandless. #289# The astronaut Bruce McCandless photographed from Shuttle 10 on February 7, 1984. #290# The Challenger Shuttle and the astronaut Bruce McCandless. #3560#610# The Apollo missions landed on the Moon thanks to the LEM, a module that detached from the orbiter and descended gently to the surface. #359# The Moon, here photographed from the Earth during an eclipse, always turns the same face to the Earth, apart from what seem to be changing shapes during the alternating phases in the four weeks of the lunar month. #3570# One of the most important results of the manned lunar missions was the collection of rock samples. In one of the tests performed on the Earth, very thin cross-sections were cut and were then illuminated with polarized light to highlight the various types of crystals. #155# A picture of Argyre's basin taken by Viking while a dust storm was raging. These types of storms sometimes cover the entire planet with an impenetrable blanket of minuscule solid particles. #156# Valles Marineris. Viking detected the presence of these clouds of ice that fill the canyons: they are more heavily concentrated during the first few hours of the morning. #158# At the present time, only glacial caps of solidified carbon dioxide, or "dry ice", cover the polar regions of Mars. One of the caps, the North Martian pole, was repeatedly photographed by Viking to obtain this incredible mosaic. #165# According to some astronomers, Phobos and Deimos are two asteroids captured by the gravitational field. Their surface is pock-marked with craters and streaks due to impacts with other celestial bodies. #166# This exceptional sunset on Mars was photographed from the Viking 1 landing module, a part of which can be seen in the foreground. The ringed halo around the Sun is caused by the fact that the probes cannot record continuous graduations of light. #167#706# The Viking landing module was equipped with special mechanical arms that could collect samples from the ground and insert them into special micro-laboratories for chemical and physical analysis. #168# One of the largest structures not only on Mars but in the entire solar system is the so-called Mount Olympus, an enormous volcano three times higher than Everest. Its complex caldera, located at the peak of the mountain, is sixty kilometers wide and is pock-marked with smaller and more recent craters. #171#173# The Viking landing module was also equipped with a television camera that photographed the surrounding area up to the horizon. The data was then transmitted to the Earth to be studied by Nasa geologists and biologists. #172# Valles Marineris. Faults which extend from the equator up to a latitude of about 30 degrees North of the planet, appear to have been shaped by phenomena related to the presence of water and wind. #292# This exceptional sunset on Mars was photographed from the Viking 1 landing module, a part of which can be seen in the foreground. The ringed halo around the Sun is caused by the fact that the probes cannot record continuous graduations of light. #611#612# The Viking space mission supplied the greatest amount of information about Mars. After having taken beautiful photographs of the planet, the probe separated into two modules: an orbiter that photographed the underlying ground and a landing module to descend to the surface and perform a series of experiments. #179# Callisto is a body studded with craters that are distributed uniformly over the surface. But the most interesting structure, which can be clearly seen in the detail, is Valhalla, concentric rings that extend over a radius of 1 500 kilometers and are perhaps the result of an impact with a gigantic meteorite. #180##202#203# This is how Io appeared as the Voyager probe approached: a body teeming with activity and where real volcanic eruptions occur. The plumes launched by the volcanoes had a height ranging from 70 to 300 kilometers. #181#208##207#209#199#345# A shining and streaked disk with large colored bands: this is how Jupiter appeared to the Voyager probe on February 1, 1979, with the Great Red Spot and the moons Io (on the disk of the planet) and Europa. #182# Io is the only satellite in the solar system where volcanic activity has been observed. In this picture taken by Voyager at a distance of about 900 000 kilometers, we can see gigantic wounds produced by the eruptions and the color red makes it seem to be gigantic "pizza with tomato sauce". #183##200# Up to 1973 it was believed that only Saturn was surrounded by rings. In that year the Pioneer 10 probe sent to Earth the first faint picture of a ring also around Jupiter. With a width of 6 000 kilometers, the ring encircles Jupiter at a distance of 58 000 kilometers from the height of the clouds. #184# Callisto. #185# The four Galilean satellites of Jupiter photographed by Voyager at a distance of one million kilometers. #186# Europa is about the same size as our own Moon, but its surface is much more uniform because the satellite is almost completely made of ice. #187#206#535# Ganymede is Jupiter's largest satellite. The interior is probably a mix of rock and ice. This is demonstrated by the white streaks that run along the surface produced by the impact with meteorites which must have caused the ice to melt and then re-solidify. #44# A solar eruption on June 10, 1973 that extends for more than a third of the radius of the Sun. #47# Solar eruption photographed by Skylab in 1973. The colors are not real, but obtained through computer enhancement. #46# Solar eruption photographed by the Skylab laboratory in 1973 (picture in the ultraviolet spectrum). #45# Solar eruption on June 10, 1973 photographed by the Skylab laboratory. #118# Sometimes the aurora borealis is so intense that it may cover a vast area, like the exceptional aurora and ring photographed above the north pole by a satellite. #119# Fire-red auroras are the rarest of these phenomena and occur only at a height of between 250 and 500 Km., where atomic oxygen is more abundant. #123# The Aurora borealis (purple color) photographed on the northern hemisphere of the Earth by the Dynamics Explorer satellite in a polar orbit around our planet. Computer enhancement. #121# Common aurora borealis. #122# If the particles of the solar wind collide with nitrogen, the color of the aurora will be blue violet. This depends on the presence of such substances according to the height from the Earth. #120# Formation of the polar lights. #129#124# Aurora borealis with multiple bands. #130# Aurora borealis with bands. #131# Aurora borealis and Ursa Major. #136#135#134#133#132# Aurora borealis photographed from Spacelab 3. #137# Aurora borealis above Alaska. #138#139#140#141#125#126#127#128# Aurora borealis. #65# The Alpha region of Venus photographed on November 7, 1990 by the Magellan probe (reconstruction with computer graphics). These formations have a diameter of about 25 kilometers and a height of 750 meters. #48# Computerized graphic simulation of the Gula volcano of Venus with overflowing lava (view from 110 kilometers at a horizontal distance). #49# Gula Mons, the name of the Assyrian mother-goddess, is a volcano that stands out on this Venusian horizon (3 000 meters high and 200 Km. at the base). The Cunitz crater is in the foreground, with a diameter of 48 km., caused by a recent impact with a meteorite #50# Two volcanic formations on the surface of Venus photographed by the Magellan probe (reconstruction with computer graphics). #51# Detail of the Alpha region of Venus (reconstruction with computer graphics): mountains of lava belonging to the chain of the "seven pancakes" (seen from 2 400 m). #52# Three craters on the surface of Venus (reconstruction with computer graphics): the Julia Ward Hove crater in the foreground; Danilova (Russian dancer) in the background on the left; Aglaonice (astronomer of ancient Greece) on the right. #53# Detail of the Eistla Western region of Venus (reconstruction with computer graphics), seen from 700 km. south-east of Mount Gula. #66#55# Mount Maat of Venus seen from a horizontal distance of 560 kilometers (reconstruction with computer graphics). #58#60#61# Detail of the surface of Venus photographed with radar scanning by the Magellan probe. #1790# The large rock in the background could have been fatal for Lander 1 and was nicknamed "Big Joe": this rock, along with others, shows the effects on the ground due to impacts with meteorites. #177# This picture was taken in 1976 in the Cydonia region, in the northern hemisphere of Mars and shows a face with a length of 2 500 m., width of 2 050 and height of 420. Studies have excluded the possibility of an optical elusion. #178# Mars once had an abundant amount of water; the dry beds are what remains today of its large rivers: a part of the water evaporated and another part ended up in the subsoil and the ice caps at the poles of the planet. #283#154#366#361#367# Detail of the lunar soil. #648# The planet photographed by Apollo 13 during its return home. #647# Irwin is next to the Rover parked near the Lunar Module. Mount Hadley is in the background (Apollo 15). #632# The view of the full moon photographed by Apollo 11 during its mission beyond the Earth. #631# The second lunar landing of the American mission produced this beautiful lunar photograph. #150# During the Apollo 17 mission, the astronaut Harrison Schmidt collects fragments of rocks. #286# The lunar car can transport two astronauts and their equipment; it was powered by electric motors, one for each wheel. It was used in the Apollo 15, 16 and 17 missions. #646# The space missions on our satellite allowed us to see the Earth rise for the first time above the lunar horizon (Apollo 10). #649# One of the most beautiful scenes of the Moon above the Earth's horizon photographed by the crew of Space-Shuttle 41-D in August 1984. #619# Picture of the surface of Mercury pock-marked with craters. The temperature on the illuminated side reaches 500 degrees above zero, while the temperature on the dark side reaches 170 degrees below zero. #620# The surface of Mercury, photographed by the Mariner 10 probe, shows the signs of an intense bombardment of meteorites that made it resemble the Moon. #654# The temperature on the illuminated side of the planet reaches 500 degrees above zero, while the temperature on the dark side reaches 170 degrees below zero (Mariner 10). #721# The magnetosphere protects the Earth like a shield that the solar wind compresses on one side and elongates on the other like a comet's tail. The plasma particles enter only at the poles, ionizing the atmosphere and generating the aurora. #333# Theoretical shield for solar wind. #999# Probable creation of a black hole: A= gravitational collapse; B = during rotation the star irradiates energy into space; C = it may undergo further contraction becoming a black hole. #722# The color spectrum of the polar lights. #723# Shapes and colors of the polar lights at night: homogeneous arc (before 10 p.m.); spoked band (from 10 p.m. to 1 a.m.); corona (from 1 a.m. to 3 a.m.); folded band (from 1 a.m. to 3 a.m.); scattered spots (from 3 a.m. to 6 a.m.). #888# An X-ray picture which highlights the areas with higher temperatures such as spots which appear with intense colors. #606# Here are the components (to scale) of the extraordinary family of planets in our solar system. The respective planets are next to each one. #718# The Earth rises behind the Moon covering the Sun. The background of this photomontage shows Venus, Mercury, Jupiter, Mars and Saturn. #395# This is the first infrared photograph taken by the Explorer mission in 1978. The area is about 700 km from Cape Hatteras at the Great Lake of Ontario. #397# Radar image with artificial colors of the coast of New Guinea taken by the Columbia Shuttle. #398# The Hubble orbiting telescope can see as far as 14 billion light years away. #396# Sea dynamic effects. The reflection of the sunlight creates these spirals with a diameter of about 15 kilometers (Mediterranean Sea off of Libya). #360# The Gassendi Crater on Kepler. #399# Aurora borealis photographed by Skylab. #400# Stars in the constellation of Aquarius photographed by Skylab. #405#406# Study of the temperatures at the Earth's South pole (microwave image taken by the Nimbus satellite). #404# Study of the temperatures at the Earth's North pole (microwave image taken by the Nimbus satellite). #402# The well-known picture of the Earth from space. #401# This might be another "solar system" with planets. In Beta-Pictoris there is a system around which, for a radius of 60 billion kilometers, there is ice, organic and silicated substances which are very similar to the elements in our system. #387# The Large Magellanic Cloud. #388# The Small Magellanic Cloud is globular cluster Tucanae 47. #389# The Trifid (above) and Lagoon nebulae in Sagittarius. #390# The California nebula in Perseus. #352#353#354#355# Dawn on the Earth. #375# Galaxy NGC 253 in Sculptor. #376# Galaxy NGC 598 M-33 in Triangulum. #356#357#358# The Flagstaff observatory in Arizona. #374#326# The Dumbbell nebula in Vulpecula. #327# Spiral galaxy NGC 4736 in Canes Venatici. #328# Aurora borealis. #369#329# North America nebula NGC 7000 in Cygnus. #330# Spiral galaxy NGC 6946 in Cepheus. #384#379#372#347#331# Lagoon Nebula NGC 6523 M-8 in Sagittarius. #385# Nebula NGC 7293 in Aquarius. #386# Galaxy NGC 7331 in Pegasus. #370#332# The Veil nebula in Cygnus. #346#334#373# The great nebula NGC 1976 M-42 in Orion. #335# Nucleus of the Andromeda galaxy. #336# The Nebel Galaxy. #391#371#337# A ring nebula in Lyra. #382# Galaxy NGC 3034 M-82 in Ursa Major. #338# Irregular galaxy in Ursa Major. #383# Nebula NGC 6611 M-16 in Serpens. #339# Spiral galaxy in Coma Berenices. #340# Spiral galaxy in Draco. #380#341# The horsehead nebula NGC 2024 in Orion. #342# Galaxy in Canes Venatici. #377#348# The Trifid nebula NGC 6514 M-20 in Sagittarius. #350# Nebula M27. #392# Nebula Eta Carinae. #378# The Pleiades NGC 1432 M-45 in Taurus. #314# The solar system. #318# Even Venus has phases just like our Moon; the picture shows the crescent phase of Venus. #317# The whirlwinds in Venus' atmosphere can only be seen with an ultraviolet filter, as shown in this photograph taken by the Pioneer Venus probe. #319# Equatorial view of Saturn. #344#3180# Saturn and its rings. #322# Uranus and Neptune. #323# In the telescope, Pluto appears as a luminous point that moves against the fixed stars. #343# Aurora borealis. #324# The comet Ikeya-Seki. #1# A splendid eclipse studied by the McMath solar observatory in Arizona: the luminous segments of the corona irradiate from the disk of the sun (in the middle). #2# An exceptional picture of the solar corona taken by Skylab and computer processed to highlight its composition: each color corresponds to a different temperature level. #661#291# Photo taken on December 19, 1974 by Skylab 4; it shows one of the most spectacular solar flares ever recorded: it expands more than 588 000 Km. through the solar surface. #3#10#11#21#22#23#24#31#29#30#35#351#28# Solar prominences are one example of the activity of our star. They are jets of hydrogen at very high temperatures which have very different shapes, from jets to plumes, and even complex arcs. #4#5#6#7#27# Solar prominences studied by Skylab and computer processed to highlight the various temperature using different colors. Their presence and intensity are related to the periods of activity of the star. #8# The solar regions with the most intense activity are surrounded by two parallel strips at the equator of the star, as shown in an X-ray image which highlights the areas with greater temperatures, such as spots which appear with intense colors. #9# The solar regions with the most intense activity are surrounded by two parallel strips at the equator of the star, as shown by a magnetic map of the Sun in which the magnetic fields are represented in red and in blue. #12#13#14# An exceptional picture of the solar corona taken by Skylab and computer processed to highlight its composition: each color corresponds to a different temperature level. #15# Total eclipses are of fundamental importance to study the outer atmosphere of the Sun. Here, the disk of the Moon has not completely covered the Sun, which is about to glitter in all of its splendor. #16# A camera with three different filters to study its behavior. #17# This is how a sunspot appears as photographed from an Earth observatory. These structures are colder regions in the photosphere, the visible surface of the star, where matter is trapped by gigantic magnetic fields. #18# Sunspots are distributed in approximately two strips along the equator and they vary according to 11-year cycles. It is easy to note the difference between the almost without and with many sunspots. #19# This is how the Sun appears when it is quiet and when it is very active. #20#31# It was unusual solar activity that made the Skylab probe, which had been designed to study the Sun, fall out of orbit prior to schedule and disintegrate in the atmosphere. #25#32#33# Solar activity. #26# Sequence of X-ray images of the Sun. On the surface there is a type of dark "hole" that moves from left to right: this is a corona hole, which turns together with the Sun, whose temperature and density are lower than the surrounding areas. #34# X-ray images of solar flares. #36# Solar passage. #37#38#393#394# Eclipses. #39# Chromosphere. #40#41#42# Solar eruption. #43# Corona hole. #67#68#69# The temperature difference between the illuminated and dark side of Venus generates strong winds which drag the blanket of clouds, as shown in this sequence of photographs taken by the Pioneer Venus probe at an interval of only one day. #70#77# The Soviet probe, Venus 13, finally transmitted two detailed color pictures to the Earth: they show scattered rocks, a portion of the probe (that looks like a gear) and a yellow-orange sky. #71# The Pioneer Venus probe made it possible to develop the first altimetric map of Venus: the light-blue indicates the lower areas, green the plains, yellow, brown and red the higher elevations. #325# The surface of Mercury, photographed by the Mariner 10 probe, shows the signs of the intense bombardment of meteorites which has made it closely resemble the Moon. However, the craters are smaller. #618# The Caloris Basin of Mercury, a gigantic structure with a diameter of 1 400 kilometers produced by the impact with a gigantic meteorite. The concentric rings are the result of a violent side movement of the planet's crust. #50# The surface of Mercury pock-marked with craters. The temperature on the illuminated side of the planet reaches 500 degrees above zero, while the temperature of the dark side reaches 170 degrees below zero. #100#315# This is the historical photograph of the Earth taken by the Apollo 14 astronauts at a distance of 40 000 kilometers during their return trip from the lunar mission: Africa and the Antarctic are clearly visible. #101# Water, which is the basic element for life, is concentrated in the large ice masses in the polar zones. #102# Weather satellites like Meteosat can transmit pictures of the planet at various wavelengths. After being processed by a computer, they provide colored images to highlight the distribution of the cloud systems. #103#111# Cyclone. #104# The Earth is enveloped by an atmosphere whose composition is continuously modified by the geological activity of the planet. The general phenomena of the atmospheric circulation are emphasized by the presence of clouds (here seen from a satellite). #105# The flow of the Brahamaputra into the Ganges, in India, in a picture in which the vegetation is shown with red. #106# Movement of the continents: the lithosphere, including the Earth's crust and part of the upper mantle, is divided into a series of "plates" which tend to move away from each other due to the flow of material which, rising from the oceanic ridges, pushes them laterally. #107# Weather satellites, such as Meteosat, have been put into orbit around the Earth to monitor the evolution of atmospheric weather and to develop forecasts which are as precise as possible regarding the movement of the air masses.. #59# Detail of the Eistla region of Venus, photographed with radar scanning by the Magellan probe: a volcano with a width of 66 Km. that Nasa has called the "tick" because of its resemblance to that insect. #57# Reconstruction with computer graphics of the Northern hemisphere of Venus. North is in the center of the picture. #56# Reconstruction with computer graphics of Venus. #62# Two graphic reconstructions of the Golubkina crater of Venus with the data received in August 1990 and April 1991. #63#72# Detail of the Golubkina crater of Venus: it has a diameter of 34 Km. (Magellan). #64# Reconstruction of the surface of Venus with the radar data transmitted from the Magellan probe. #114# Satellite view. #115#116# Satellite view of the Hawaiian islands. #153# Multiple view of the solar eclipse. #144# August 11, 1971: astronaut Irwin salutes the American flag. At the back of the Rover vehicle, at a distance of about 5 kilometers, the lunar crater San Giorgio. #164#162#163#161#160# The surface of Mars. #159# This is the first color photograph of Mars taken by the Viking probe (June 1976). The Viking probe made it possible to see details of the features that were first discovered by Mariner 9. #157# Views of Phobos, one of Mars' moons. #170# Detail of the Marineris Valley on Mars. #169# Mars seen from the Viking 2 probe (August 1976). It is possible to see Mount Acreasus with a cloud formation; the great canyon system called Valle Marineris, in the center ( 4 800 km in length) and the Argyre basin, one of the largest craters on Mars. #189# Volcanoes on Io, one of Jupiter's moons. #190# Jupiter's satellite Io, seen from the Voyager probe. #193# One of the most spectacular pictures of Jupiter taken by Voyager 1 at a distance of 20 million Km. from the planet. The innermost Galilean satellites can be seen on the disk: Io on the left and Europa on the right, as a whitish spot. #2100# Another detail of the complex convolutions in Jupiter's atmosphere: the clouds of the gas giant have spiral shapes which resemble those of the hurricanes on Earth, but whose dimensions are absolutely enormous. #191#653# View of the Great Red Spot with enhanced colors which do not correspond to those in Jupiter's atmosphere, but are the result of special computer enhancement (Voyager 2). #192# A beautiful picture of the Great Red Spot and the turbulent whirlwinds that surround it. This gigantic hurricane, that has been raging on the planet for 300 years, covers an area of 30 000 Km. #302#303#304# Jupiter's Great Red Spot (Voyager 1 mission). #652# This view of Jupiter shows details that have never been seen before (Pioneer 10). #194# Unlike the Great Red Spot, the large dark ovals that stand out on Jupiter's disk are special types of "holes" which open in the atmosphere and may even last up to two years. #204# Polar view of Jupiter. #195# The four Galilean satellites of Jupiter compared to the Moon and Mercury. #205#201# Io, one of Jupiter's satellites. #188#197# Amalthea, the largest of the swarms of small Jovian satellites. #196# The convolutions in Jupiter's atmosphere. #198# Jupiter's satellite Europa, totally covered with cracks. #540# Saturn glitters behind its rings. Voyager took this photograph as it moved away from the planet. #510# False-color photograph of the B and C rings of Saturn. #511# Images from the photopolarimeter show that even ring F of Saturn consists of various thinner levels. #211#217#218#507#508#544# Saturn and its rings. #658# This false-color picture of ring A of Saturn was taken with a field of 2.8 million Km. (Voyager 2). #659# This image focuses on ring C of Saturn and is the result of three photographs taken with three separate filters (Voyager 2). #660# The rings of Saturn are seen from the south at a distance of 6.5 million Km. (Voyager 2). #527# Each Voyager probe carries a recorded disk with sounds and information about the Earth in the form of drawings. #528# Voyager 2's route around Jupiter. #515# Saturn's three largest rings (A, B, C starting from the outermost region) have different colors which presumably indicate a difference in the chemical composition, even though it is believed that the most prevalent component is ice. #518# Detail of ring B of Saturn. #516# Starting from the outermost region: ring F; ring A; Cassini Division; ring B; ring C. #548# An effect similar to the spokes of a wheel due to minuscule particles in ring B. #519# The rings appear very different when seen from the dark side: ring C and the Cassini Division seem to be more brilliant since the solar light can penetrate. #520# Details of Saturn's rings B and C. #513#545#514#546#94a# Close-up picture of the surface of Saturn, taken by Voyager and computer processed: there are cloud formations which are similar to those observed on Jupiter. #512# Saturn with processed colors; the shadow of the rings can be seen on the planet. #509#542# Large storms and high-speed winds (1 700 Km/h) were recorded in Saturn's atmosphere. #505#210# Saturn, here photographed by Voyager at a distance of 34 million Km., is mainly composed of liquid hydrogen that surrounds a rocky core. But its most outstanding feature is the system of rings which wraps around the equatorial plane. #219# Close-up picture of the surface of Saturn: the black ring is the shadow projected of the satellite Dione. #213#214# The surface of Saturn. #212#2120# Detail of the surface of Saturn showing vortexes and cloud formations similar to those observed on Jupiter. #215# Enceladus is the lightest and brightest of Saturn's satellites. #216# Hyperion is Saturn's most irregular satellite due to the large impact craters. #236# View in natural colors of Triton, Neptune's satellite, taken by the Voyager 2 probe on August 25, 1989. #238# The Great Black Spot of Neptune photographed by the Voyager 2 probe at a distance of 2.8 million Km. #234#656# Picture of Neptune with false colors taken by the Voyager 2 probe: the areas which appear white or red are those which reflect the sunlight before it passes through the layer of methane gas. #235# False-color picture of the surface of Neptune's satellite, Triton, taken by the Voyager 2 probe on August 25, 1989 at a distance of 18 000 Km. (violet, green and ultraviolet filters). #237# Picture of the Southern hemisphere of Neptune taken by the Voyager 2 probe at a distance of 4.2 million Km. #224# The Voyager probe discovered that there are several smaller bodies among Uranus' rings, called "shepherd moons", which prevent the rings from dissipating. #225# One of Uranus' rings. #231# Umbriel, Uranus' satellite. #223# Titania, Uranus' satellite. #221# Oberon, Uranus' satellite. #220#230# Two pictures of Uranus: one with real uniform colors and the other with electronic colors. #227#228# Electronic picture of Uranus obtained from the data transmitted by the Voyager probe. #226# One of the first pictures of Uranus obtained with a long exposure where the rings can be seen. #587# Nine pictures were combined to create the mosaic of the surface of Miranda. #579# The rings of Uranus. #222# Miranda, Uranus' satellite. #232# As Uranus would be seen by a visitor on Miranda (photomontage of pictures from the Voyager 2 probe). #248# The comet West as it appeared in 1976. #250# The famous Adoration of the Magi by Giotto which shows what was probably Halley's comet. #251# Computer enhancement of the comet Kohoutek. #252# Computer enhancement of a famous black and white photograph of Halley's comet. #254# Front view of the spiral galaxy NGC 5457 in the Ursa constellation (computer enhanced image). #255# Perspective view of spiral galaxy NGC 5457 in the Ursa constellation (computer enhanced image). #253# Trifid Nebula; the brightness is generated by a central star, whose veils of gas have an almost fluorescent appearance. #258# Galaxy in the Andromeda constellation. #257# Computer-enhanced image of spiral galaxy NGC 4321. #256# The Crab Nebula. #277# Saturn. #276# Storm on Saturn. #275# Picture of Jupiter with real colors. #274# South-East Quadrant of Jupiter. #273# Syrtis Major region of Mars. #272# Pluto and Charon. #271# The Orion Nebula. #2700# Jet-like structure in the Orion nebula. #270# Symbiotic star (R Aquarii). #269# Supernova ring (SN 1987A). #268# Erupting star (Eta Carinae). #267# Slow gravitational effect (Galaxy 2237+0305). #266#265# Center of globular cluster (Tucano 47). #264#263# Globular cluster. #262# Extragalactic jet (Galaxy 3C66B). #261# Spectrum of quasar UM675. #259#260# Beta Pictoris. #605# The planets of the solar system move in orbits which are almost all in the same plane except for Pluto whose orbit is inclined by 17 degrees. #719# The McMath solar observatory in Arizona. Revolving mirrors at the top of the tower track the Sun and reflect its rays into the long underlying tunnel. #701# The density of Venus' atmosphere is so high that the rays from the sun can barely reach the surface of the planet. This imaginative drawing shows how an observer would see the surface of Venus with greatly deflected rays. #702# Drawing which shows the Pioneer Venus probe after a soft landing on Venus. #703# Detail of the radar map of Venus. The average radius of 6 051 kilometers is used as the sea level reference. The areas under this level are represented in light blue. #705# Drawings of Mars by the astronomer Pietro Secchi. The changing aspect of the planet led to the conviction that Mars had criss-crossing canals. #708# The huge meteorite exhibited at the Museum of Natural History in New York. Meteorites may be simple grains, but also masses weighing dozens of tons. #709# Ancient crater formed by a falling meteorite (Manicougan Crater in Canada). The diameter is about 65 kilometers. #7090# Sectioned and polished meteorites. Studies on these objects make it possible to trace the primeval origins of the solar system. #710# In one Nasa project, asteroids would be mined after they are placed in orbit around the Earth. #712# Studies of Saturn in the seventeenth century, the age in which astronomers did not know that the rings created the strange side bulges. In the upper left, the interpretation by Galileo. #720# Spectacular picture of the nine rings of Uranus taken by Voyager at a distance of 4 million kilometers. #7120# Neptune seen by an Earth telescope. Next to its satellite, Triton. #714# Trees knocked down in the Tunguska area of Siberia due to the effect of a huge meteorite which fell on June 30, 1921. #715# Halley's comet photographed during its passage in 1986. #716#717# The nucleus of Halley's comet (from photographs taken by the Vega probe) in the form of an irregular figure "8". #362# Astronaut Aldrin next to the American flag on the Moon (Apollo 11). #365# Astronaut Irwin on the Moon next to the lunar module and the Rover vehicle (Apollo 15). #364# Lunar module and Rover vehicle. #3580# Samples of lunar soil brought back to the Earth by the Apollo 14 mission. #294# The Viking 2 probe. #295#296#297#298#299# The Martian ground (Viking missions). #316# Mount Olympus on Mars (Mariner mission). #502#300# Departure of a Voyager probe carried into space by the space rocket Titan Centauro (summer 1977). #301# One of the first pictures of Jupiter taken by the Voyager 1 probe. #305# Cloud formations on Jupiter. #530# Ganymede (on the left) and Callisto (on the right) are Jupiter's largest satellites. #307# Ganymede is Jupiter's largest satellite. Its internal structure is probably a mix of ice and rock. #306# Ganymede, Jupiter's satellite. #308# Europa, one of Jupiter's satellites, is about the same size as our Moon, but its surface is much more uniform because the satellite is almost completely made of ice. #309# Jupiter's satellite, Amalthea, the largest of the swarm of smaller satellites. #310# The surface of Jupiter's moon, Io, showing very active volcanoes. #503# View of Jupiter from the Voyager probe. #311#312#313#532#533# Io is the first celestial body other than the Earth where scientists have seen volcanic activity in progress. #320# Jupiter and its satellites. #321# The Great Red Spot of Jupiter. #500# Two identical Voyager probes explored Jupiter and Saturn. # #