Showing posts with label planets. Show all posts
Showing posts with label planets. Show all posts

Planet - Neptune

Neptune





                              Mass                            :                 1.0243×1026 kg
                              Distance from Sun         :                 4,503,000,000 km
                              Orbital period               :                 165 years
                               Length of day               :                 0d 16h 6m
                              Gravity                         :                  11.15 m/s²
                              Discovery date             :                  23 September 1846
                              Discovered by              :                   Urbain Le Verrier
                                                                                      John Couch Adams
                                                                                      Johann Galle

 
( Urbain Le Verrier)

( Johann Galle)

(John Couch Adams)
                                       Neptune is the eighth planet from the Sun and the fourth largest (by diameter). Neptune is smaller in diameter but larger in mass than Uranus.In Roman mythology Neptune was the God of Sea
                                      After the discovery of Uranus, it was noticed that its orbit was not as it should be in accordance with Newton's laws. It was therefore predicted that another more distant planet must be perturbing Uranus' orbit. Neptune was first observed by Galle and d'Arrest on 1846 Sept 23 very near to the locations independently predicted by Adams and Le Verrier from calculations based on the observed positions of Jupiter, Saturn and Uranus. An international dispute arose between the English and French (though not, apparently between Adams and Le Verrier personally) over priority and the right to name the new planet; they are now jointly credited with Neptune's discovery. Subsequent observations have shown that the orbits calculated by Adams and Le Verrier diverge from Neptune's actual orbit fairly quickly. Had the search for the planet taken place a few years earlier or later it would not have been found anywhere near the predicted location.
                                   More than two centuries earlier, in 1613, Galileo observed Neptune when it happened to be very near Jupiter, but he thought it was just a star. On two successive nights he actually noticed that it moved slightly with respect to another nearby star. But on the subsequent nights it was out of his field of view. Had he seen it on the previous few nights Neptune's motion would have been obvious to him. But, alas, cloudy skies prevented obsevations on those few critical days.

 Physical Characteristics : 
                                          
                                   Neptune’s cloud cover has an especially vivid blue tint that is partly due to an as-yet-unidentified compound and the result of the absorption of red light by methane in the planets mostly hydrogen-helium atmosphere. Photos of Neptune reveal a blue planet, and it is often dubbed an ice giant, since it possesses a thick, slushy fluid mix of water, ammonia and methane ices under its atmosphere and is roughly 17 times Earth's mass and nearly 58 times its volume. Neptune's rocky core alone is thought to be roughly equal to Earth's mass.
                                   Despite its great distance from the sun, which means it gets little sunlight to help warm and drive its atmosphere, Neptune's winds can reach up to 1,500 miles per hour (2,400 kilometers per hour), the fastest detected yet in the solar system. These winds were linked with a large dark storm that Voyager 2 tracked in Neptune's southern hemisphere in 1989. This oval-shaped, counterclockwise-spinning "Great Dark Spot" was large enough to contain the entire Earth, and moved westward at nearly 750 miles per hour (1,200 kilometers per hour). This storm seemed to have vanished when the Hubble Space Telescope later searched for it. Hubble has also revealed the appearance and then fading of two other Great Dark Spots over the last decade.

( dark spot)

 Orbital Characteristics : 
                  
                                    Neptune is the eighth and most distant planet from the sun. Its elliptical, oval-shaped orbit makes it keep an average distance from the sun of almost 2.8 billion miles (4.5 billion kilometers), or roughly 30 times as far away as Earth, making it invisible to the naked eye. Neptune goes around the sun once roughly every 165 Earth years, and will complete its first orbit, since being discovered, in 2011.
                                    Every 248 years, Pluto moves inside Neptune's orbit for 20 years or so, during which time it is closer to the sun than Neptune. Nevertheless, Neptune remains the farthest planet from the sun, since Pluto was reclassified as a dwarf planet in 2006.

 Neptune’s Moons : 
                     
                                 Neptune has 13 known moons, named after lesser sea gods and nymphs from Greek mythology, just as Neptune itself was named after the Roman god of the sea. The largest by far is Triton, whose discovery on Oct. 10, 1846 was in a sense enabled by beer — amateur astronomer William Lassell used the fortune he made as a brewer to finance his telescopes.
                                 Triton is unique in being the only large moon in the solar system to circle its planet in a direction opposite to its planet's rotation — this "retrograde orbit" suggests that Triton may once have been a dwarf planet that Neptune captured rather than forming in place. Neptune's gravity is dragging Triton closer to the planet, meaning that millions of years from now, Triton will come close enough for gravitational forces to rip it apart.
                               Triton is extremely cold, with temperatures on its surface reaching about minus 391 degrees F (minus 235 degrees C), making it one of the coldest places in the solar system. Nevertheless, Voyager 2 detected geysers spewing icy matter upward more than 5 miles (8 kilometers), showing its interior appears warm. Recently, seasons have been discovered on Triton.
Triton is the only spherical moon of Neptune — the planet’s other twelve moons are irregularly shaped.

(Triton)

 Rings of Neptune :
                          Neptune's unusual rings are not uniform, but possess bright thick clumps of dust called arcs. The rings are thought to be relatively young and short-lived. Earth-based observations announced in 2005 found that Neptune's rings are apparently far more unstable than previously thought, with some dwindling away rapidly. Neptune has six rings which circle the planet. Neptune's rings have been given names: the outermost is Adams (which contains three prominent arcs now named Liberty, Equality and Fraternity), next is an unnamed ring co-orbital with Galatea, then Leverrier (whose outer extensions are called Lassell and Arago) and finally the faint but broad Galle. 

 Exploration 
                        NASA's Voyager 2 space satellite was the first and as yet only spacecraft to visit Neptune on Aug. 25, 1989. The satellite discovered Neptune's rings and six of the planet's moons





After the discovery of Uranus, it was noticed that its orbit was not as it should be in accordance with Newton's laws. It was therefore predicted that another more distant planet must be perturbing Uranus' orbit. Neptune was first observed by Galle and d'Arrest on 1846 Sept 23 very near to the locations independently predicted by Adams and Le Verrier from calculations based on the observed positions of Jupiter, Saturn and Uranus. An international dispute arose between the English and French (though not, apparently between Adams and Le Verrier personally) over priority and the right to name the new planet; they are now jointly credited with Neptune's discovery. Subsequent observations have shown that the orbits calculated by Adams and Le Verrier diverge from Neptune's actual orbit fairly quickly. Had the search for the planet taken place a few years earlier or later it would not have been found anywhere near the predicted location.
More than two centuries earlier, in 1613, Galileo observed Neptune when it happened to be very near Jupiter, but he thought it was just a star. On two successive nights he actually noticed that it moved slightly with respect to another nearby star. But on the subsequent nights it was out of his field of view. Had he seen it on the previous few nights Neptune's motion would have been obvious to him. But, alas, cloudy skies prevented obsevations on those few critical days.

 In Roman mythology Neptune (Greek: Poseidon) was the god of the Sea.


In Roman mythology Neptune (Greek: Poseidon) was the god of the Sea.

Posted by Unknown | at 20:10 | 0 comments

Planet Uranus

Uranus





                          Mass                            :     86.81E24 kg
                          Volume                       :     6.833×1013                                                                             
                          Distance from Sun        :    2,877,000,000 km
                          Orbital period              :     84 years
                          Gravity                        :      8.69 m/s²
                          Lenght of Day               :      17 h 14 min 24
                          Discovered                  :     March 13, 1781
                          Discovered by              :    William Herschel 


(William Herschel)

                                             Uranus is the ancient Greek deity of the Heavens, the earliest supreme god. Uranus was the son and mate of Gaia the father of Cronus (Saturn) and of the Cyclopes and Titans (predecessors of the Olympian gods).
                                            Uranus, the first planet discovered in modern times, was discovered by William Herschel while systematically searching the sky with his telescope on March 13, 1781. It had actually been seen many times before but ignored as simply another star (the earliest recorded sighting was in 1690 when John Flamsteed cataloged it as 34 Tauri). Herschel named it "the Georgium Sidus" (the Georgian Planet) in honor of his patron, the infamous (to Americans) King George III of England; others called it "Herschel". The name "Uranus" was first proposed by Bode in conformity with the other planetary names from classical mythology but didn't come into common use until 1850.

                                     Uranus is blue-green in color, the result of methane in its mostly hydrogen-helium atmosphere. The planet is often dubbed an ice giant, since 80 percent or more of its mass is made up of a fluid mix of water, methane, and ammonia ices.Unlike the other planets of the solar system, Uranus is tilted so far that it essentially orbits the sun on its side, with the axis of its spin nearly pointing at the star. This unusual orientation might be due to a collision with a planet-sized body soon after it was formed.
This unusual tilt gives rise to extreme seasons roughly 20 years long, meaning that for nearly a quarter of the Uranian year, equal to 84 Earth years, the sun shines directly over each pole, leaving the other half of the planet to experience a long, dark, cold winter.
                                   A planet's magnetic poles are typically lined up with the poles along which it rotates, but Uranus' magnetic field is tilted, with its magnetic axis tipped over nearly 60 degrees from the planet's axis of rotation. This leads to a strangely lopsided magnetic field for Uranus, with the strength of the field at the northern hemisphere's surface being up to more than 10 times that of the strength at the southern hemisphere's surface.

 Uranus's Moons :
                                       
                                 Uranus has 27 known moons. Instead of being named after figures from Greek or Roman mythology, its first four moons were named after magical spirits in English literature, such as William Shakespeare's "A Midsummer Night's Dream" and Alexander Pope's "The Rape of the Lock." Since then, astronomers have continued this tradition, drawing names for the moons from the works of Shakespeare or Pope.Oberon and Titania are the largest Uranian moons, and were the first to be discovered, by William Herschel in 1787. William Lassell, who was the first to see a moon orbiting Neptune, discovered the next two, Ariel and Umbriel. Nearly a century then passed before Miranda was found in 1948.
                                 Then Voyager 2 visited the Uranian system in 1986 and found an additional 10, all just 16 to 96 miles (26-154 kilometers) in diameter — Juliet, Puck, Cordelia, Ophelia, Bianca, Desdemona, Portia, Rosalind, Cressida and Belinda — and each roughly made half of water ice and half of rock. Since then, astronomers using the Hubble Space Telescope and ground-based observatories have raised the total to 27 known moons, and spotting these was tricky — they are as little as 8 to 10 miles (12 to 16 km) across, blacker than asphalt, and nearly 3 billion miles (4.8 billion kilometers) away.
                                 Between Cordelia, Ophelia and Miranda is a swarm of eight small satellites crowded together so tightly that astronomers don't yet understand how the little moons have managed to avoid crashing into each other. Scientists suspect there might still be more moons, closer to Uranus than any known.


 

 The Rings of Uranus : 
    
                                  The rings of Uranus were the first to be seen after Saturn's. They were a significant discovery, since it helped astronomers understand that rings are a common feature of planets, not merely a peculiarity of Saturn.Uranus possesses two sets of rings. The inner system of rings consists mostly of narrow, dark rings, while an outer system of two more-distant rings, discovered by the Hubble Space Telescope, are brightly colored, one red, one blue. Scientists have now identified 13 known rings around Uranus.















Atmospheric Composition  :
               82.5 percent hydrogen, 15.2 percent helium, 2.3 percent methane.

Research & Exploration : 
                                In 1986, NASA's Voyager 2 interplanetary probe encountered Uranus. This flyby remains the only investigation of the planet carried out from a short distance, and no other visits are currently planned. Launched in 1977, Voyager 2 made its closest approach to Uranus on January 24, 1986, coming within 81,500 kilometers of the planet's cloudtops, before continuing its journey to Neptune. Voyager 2 studied the structure and chemical composition of Uranus's atmosphere including the planet's unique weather, caused by its axial tilt of 97.77°. It made the first detailed investigations of its five largest moons, and discovered 10 new moons. It examined all nine of the system's known rings and discovered two new ones . It also studied the magnetic field, its irregular structure, its tilt and its unique corkscrew magnetotail caused by Uranus's sideways orientation


(Voyager2)
                   

Posted by Unknown | at 19:04 | 0 comments

Planet Saturn

Saturn



               Mass                          :    568.3E24 kg
               Volume                       :    8.2713×1014 km3
                   Gravity                       :    10.44 m/s²
              Distance from Sun       :   1,433,000,000 km
              Orbital period             :    29 years
              Length of day              :   0d 10h 39m
               


                                                    In Roman mythology, Saturn is the god of agriculture. The associated Greek god, Cronus, was the son of Uranus and Gaia and the father of Zeus (Jupiter). Saturn is the root of the English word "Saturday" . Saturn has been known since prehistoric times. Galileo was the first to observe it with a telescope in 1610; he noted its odd appearance but was confused by it. Early observations of Saturn were complicated by the fact that the Earth passes through the plane of Saturn's rings every few years as Saturn moves in its orbit. A low resolution image of Saturn therefore changes drastically. It was not until 1659 that Christiaan Huygens correctly inferred the geometry of the rings. Saturn's rings remained unique in the known solar system until 1977 when very faint rings were discovered around Uranus (and shortly thereafter around Jupiter and Neptune).
                                                    Saturn is a gas giant made up mostly of hydrogen and helium. Saturn is the second largest planet, big enough to hold more than 760 Earths, and is more massive than any other planet except  Jupiter, roughly 95 times Earth's mass. However, Saturn has the lowest density of all the planets, and is the only one less dense than water — if there were a bathtub big enough to hold it, Saturn would float on top.
                                                  Saturn is the farthest planet from Earth visible to the naked human eye. The yellow and gold bands seen in the planet's atmosphere are the result of super-fast winds in the upper atmosphere, which can reach up to 1,100 miles per hour (1,800 kilometers per hour) around its equator, combined with heat rising from the planet's interior.Saturn spins faster than any other planet except Jupiter, completing a rotation roughly every 10-and-a-half hours. This rapid spinning causes Saturn to bulge at its equator and flatten at its poles — the planet is 8,000 miles (13,000 kilometers) wider at its equator than
between the poles.Saturn occasionally has storms on its surface, similar to those of Jupiter. The Great White Spot is a massive storm in the planet's northern hemisphere that has been observed about once every Saturnian year since 1876. 

(Great white spot in Saturn)



Chemical composition :
                                              Saturn seems to have a hot solid inner core of iron and rocky material surrounded by an outer core probably composed of ammonia, methane, and water. Next is a layer of highly compressed, liquid metallic hydrogen, followed by a region of viscous hydrogen and helium. This hydrogen and helium becomes gaseous near the planet's surface and merges with its atmosphere.

 Saturn's Moons :
                                 
                                             Saturn has at least 62 moons. Since the planet was named after Cronus, lord of the titans in Greek mythology, most of Saturn's moons are named after other titans, their descendants, as well as after giants from Gallic, Inuit and Norse myths.
                                             Saturn's largest moon, Titan, is slightly larger than Mercury, and is the second-largest moon in the solar system behind Jupiter's moon Ganymede. Titan is veiled under a very thick, nitrogen-rich atmosphere that might be like what Earth's was long ago, before life. While the Earth's atmosphere extends only about 37 miles (60 kilometers) into space, Titan's reaches nearly 10 times as far.

Saturn's Rings : 
                                           Galileo was the first to see Saturn's rings in 1610, although from his telescope they resembled handles or arms. It took Dutch astronomer Christiaan Huygens, who had a more powerful telescope, to propose that Saturn had a thin, flat ring.
                                           Saturn actually has many rings made of billions of particles of ice and rock, ranging in size from a grain of sugar to the size of a house. The rings are believe to be debris left over from comets, asteroids or shattered moons. Although they extend thousands of miles from the planet, the main rings are typically only about 30 feet thick. Cassini revealed vertical formations in some of the rings, with particles piling up in bumps and ridges more than 2 miles (3 kilometers) high.
                                          The rings are generally named alphabetically in the order they were discovered. They are usually relatively close to each other, with one key exception caused by the Cassini Division, a gap some 2,920 miles (4,700 kilometers) wide. The main rings, working out from the planet, are known as C, B and A, with the Cassini Division separating B and A. The innermost is the extremely faint D ring, while the outermost to date, revealed in 2009, could fit a billion Earths within it.




 Magnetic Field :
                               Saturn has a magnetic field about 578 times more powerful than Earth's.

Saturn Space Probes:   
                           
                               Saturn has been visited in flybys in the 1970s by NASA's Pioneer 11 and in 1980-81 by the Voyager 1 and 2 spacecraft. The Cassini spacecraft, launched in 1997 arrived at Saturn in July 2004. The Huygens probe explored the moon -Titan.

 (Pioneer 11)

 
 (Cassini)


 ( Huygens at an altitude of 30 km above the surface of Titan)


Posted by Unknown | at 21:36 | 0 comments

Planet Jupiter

Jupiter



          
              Mass                                  :                          1.8986×1027 kg
                  Volume                               :                           1.4313×1015 km3
                  Gravity                               :                            24.79 m/s²
              Distance from Sun              :                           778,500,000 km
             Orbital period                    :                            12 years
              Length of day                    :                            0d 9h 56m
              Satellites                           :                            67


                                                                    Jupiter was the king of the gods in Roman mythology — a fitting name for the largest of the planets. In a similar manner, the ancient Greeks named the planet after Zeus, the king of the Greek pantheon.
                                                                Jupiter helped revolutionize the way we saw the universe and ourselves in 1610, when Galileo discovered Jupiter's four large moons — Io, Europa, Ganymede and Callisto, now known as the Galilean moons. This was the first time celestial bodies were not seen circling the Earth, major support of the Copernican view that Earth was not the center of the universe.
                                                              Jupiter is the most massive planet in our solar system, more than twice as massive as all the other planets combined, and had it been about 80 times more massive, it would have actually become a star instead of a planet. Its atmosphere resembles that of the sun, made up mostly of hydrogen and helium, and with four large moons and many smaller moons in orbit around it, Jupiter by itself forms a kind of miniature solar system. All told, the immense volume of Jupiter could hold more than 1,300 Earths.
                                                           The colorful bands of Jupiter are arranged in dark belts and light zones created by strong east-west winds in the planet's upper atmosphere traveling more than 400 miles per hour (640 kilometers per hour). The white clouds in the zones are made of crystals of frozen ammonia, while darker clouds of other chemicals are found in the belts. At the deepest visible levels are blue clouds.
                                                         The most extraordinary feature on Jupiter is undoubtedly the Great Red Spot, a giant hurricane-like storm seen for more than 300 years. At its widest, the Great Red Spot is three times the diameter of the Earth, and its edge spins counterclockwise around its center at a speed of about 225 miles (360 kilometers) per hour. The color of the storm, which usually varies from brick red to slightly brown, may come from small amounts of sulfur and phosphorus in the ammonia crystals in Jupiter's clouds. Every now and again, the Great Red Spot seems to fade entirely.

  • Magnetic Field :
                         Jupiter’s magnetic field is 14 times as strong as Earth

  • Rings  :
                     Jupiter has three thin rings around its equator. They are much fainter than the rings of Saturn.
 



      
  • Gravity  :
                        Because of the giant size of Jupiter, the gravity there is 2.4 times more than on Earth. If you weigh 200lbs on Earth, you would feel like you weighed 480lbs on Jupiter
  • Comet Shoemaker-Levy 9  :
                          In March 1993, astronomers Eugene Shoemaker, Carolyn Shoemaker, and David H. Levy discovered a comet near Jupiter. Astronomers witnessed a spectacular event when 21 fragments of a comet named Shoemaker-Levy 9 crashed into Jupiter's atmosphere. The impacts caused tremendous explosions, some scattering debris over areas larger than the diameter of Earth.
  • Jupiter related Spacecraft: 
                       The United States has sent six space probes to Jupiter: (1) Pioneer 10 (December 1973) (2) Pioneer 11 (December 1974) (3) Voyager 1 (1979) (4) Voyager 2  (1979) (5) Ulysses (February 1992) and (6) Galileo.
In December 1995, NASA's Galileo spacecraft dropped a probe into Jupiter's atmosphere, which collected the first direct measurements of the atmosphere.
Cassini made a flyby in 2000 on its way to Saturn. NASA’s New Horizons spacecraft made its flyby in 2007.


 (ulysses)

( New Horizons )

Posted by Unknown | at 20:02 | 0 comments

Planet - Mars

Mars




              Mass                   :                       6.4185×1023 kg
              Density                :                       3.93 g/cm³
              Length of day       :                      1d 5h 5m
              Gravity                :                       3.711 m/s²
              Distance from Sun:                      227,900,000 km
              Orbital period       :                      687 days

                                   

                                                           Mars is a small rocky body once thought to be very Earthlike. Like the other terrestrial planet—Mercury, Venus, and Earth—its surface has been changed by volcanism, impacts from other bodies, movements of its crust, and atmospheric effects such as dust storms. It has polar ice caps that grow and recede with the change of seasons; areas of layered soils near the Martian poles suggest that the planet's climate has changed more than once, perhaps caused by a regular change in the planet's orbit.
                                                          Martian tectonism, the formation and change of a planet's crust, differs from Earth's. Where Earth tectonics involve sliding plates that grind against each other or spread apart in the seafloors, Martian tectonics seem to be vertical, with hot lava pushing upwards through the crust to the surface.
                                                          Periodically, great dust storms engulf the entire planet. The effects of these storms are dramatic, including giant dunes, wind streaks, and wind-carved features.
                                                         Mars has some remarkable geological characteristics, including the largest volcanic mountain in the solar system, Olympus Mons; volcanoes in the northern Tharsis region that are so huge they deform the planet's roundness; and a gigantic equatorial rift valley, the Valles Marineris. This canyon system stretches a distance equivalent to the distance from New York to Los Angeles; Arizona's Grand Canyon could easily fit into one of the side canyons of this great chasm.
                                                        Mars also has two small moons, Phobos and Deimos. Although no one knows how they formed, they may be asteroids snared by Mars's gravity.
                                                        Some of the latest Mars information comes from five active probes on or in orbit around Mars including three orbiters and two rovers. This includes 2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, Opportunity rover, and Curiosity rover.Dozens of unmanned spacecraft, including orbiters, landers, and rovers, have been sent to Mars by the Soviet Union, the United States, Europe, and Japan to study the planet's surface, climate, and geology. The public can request images of Mars via the HiWish program.. The Mars Science Laboratory, named Curiosity, launched on November 26, 2011, reached Mars on August 6, 2012 UTC.




  •  The tallest mountain in the Solar System is the mighty Olympus Mons on Mars. It rises up 27 kilometers above the surrounding plains. Olympus Mons is a shield volcano, like Hawaii’s Mauna Kea, and formed gradually over billions of years. Some lava flows on the volcano are so young that planetary scientists think that it might still be active.
(Olympus Mons)

  •  One of the most distinct features on the surface of Mars is the Valles Marineris canyon. It stretches 4,000 km along the equator of Mars, and can be as deep as 7 km in places. If you could move the Valles Marineris to Earth, it would stretch right across the United States. 
( Valles Marineris)

  • Mars has two, tiny asteroid-sized moons called Phobos and Deimos. Phobos orbits the planet at such a low altitude that it’s going to eventually be torn apart by the gravity of Mars. It will survive as a ring for a few years, and then the debris will rain down on Mars. Scientists disagree on when this will happen. It could happen as soon as 10 million years from now, and no later than 50 million years
     
    .
     
     
     
     
     
     
     


Posted by Unknown | at 21:36 | 0 comments

Planet Facts

Venus

 
Transit of Venus (Venus in black spot)



                                                             Venus is the second planet from the sun and the closest planet to Earth. It is named after The Roman Goddess of love and beauty, but it's extremely hot and deadly atmosphere makes it impossible for any human astronaut to explore it's surface. The diameter of Venus is about 7,520 miles which is about 400 miles smaller than that of Earth. 

  •  Venus is known as Earths' twin sister because of its similar size and proximity to each other.
  •  Venus rotates so slowly that it orbits the sun faster than it can make one whole rotation on its axis. In other words, Venus has a longer day than year. 
  •  And it takes 224 days for Venus to orbit around the sun.
  •  It takes 243 days for Venus to make a rotation.
  •  It is believed that Venus used to have bodies of water similar to Earth, but dried up over a period of 300 million years when the sun began admitting more solar energy after the sun's infancy stage.
  •  The clouds of Venus is filled with sulfuric acid.
  •  Venus has mountains that are higher than Earth. Maat Mons is more than 5 miles high.
  •  Venus is the brightest planet viewed from Earth.
  •  Its atmosphere is made up mostly of carbon dioxide.
  •  Venus is the most widely explored planet aside from our own Earth. Numerous space probes have been sent to Venus to gather data and some have landed on the surface. The first spacecraft to visit Venus was Mariner 2 in 1962. It was subsequently visited by many others , including Pioneer Venus and the Soviet Venera 7 the first spacecraft to land on another planet, and Venera 9 which returned the first photographs of the surface. Most recently, the orbiting US spacecraft Magellan produced detailed maps of Venus' surface using radar.

Posted by Unknown | at 19:08 | 0 comments

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