Planets

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As the furthest orbiting planet in the Solar System, Neptune has the longest year, taking 164.8 Earth years to complete a single orbit of the Sun. Prior to its reclassification as a dwarf planet in 2006, Pluto was the planet with the longest year, equal to about 248 Earth years.

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  • What are the diameters of the planets?

    Q: What are the diameters of the planets?

    A: The diameters of the planets are as follows: Mercury is 3,032 miles; Venus is 7,521 miles; Earth is 7,926 miles; Mars is 4,222 miles; Jupiter is 88,846 miles; Saturn is 74,898 miles; Uranus is 31,763 miles; Neptune is 30,778 miles. As a result, the largest planet by diameter is Jupiter and the smallest is Mercury.
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  • Who discovered Mars?

    Q: Who discovered Mars?

    A: Because Mars with its famous red coloration is readily visible from Earth, it is unknown who first discovered it; NASA lists the planet as "known by the ancients." There are records of its existence as far back as ancient Egypt.
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  • Why is Pluto not a planet?

    Q: Why is Pluto not a planet?

    A: In 2006, the International Astronomical Union changed Pluto's classification from a planet to a dwarf planet because the planet has not cleared its orbit of other objects. When a planet clears its orbit, all other objects on the orbital path are either drawn into the planet's gravitational pull or flung away from it and out of the orbit.
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  • How many satellites does Mercury have?

    Q: How many satellites does Mercury have?

    A: The planet Mercury does not have any known moons (natural satellites) as of 2014. There has been one known artificial satellite orbiting Mercury, known as Messenger.
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  • How did Mars get its name?

    Q: How did Mars get its name?

    A: Because of their militant nature, the Romans named the brightest red point of light in the night sky after their patron god of war. It only makes sense to give him a place of honor then, but Mars has had many names throughout the course of human civilization.
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  • How many satellites does Mars have?

    Q: How many satellites does Mars have?

    A: Mars has two very small satellites orbiting it, Phobos and Deimos. Scientists believe that both moons are actually asteroids captured via Mars's gravitational field. Made of dark rock that includes a great deal of carbon, both satellites have many craters due to collisions with debris.
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  • What type of planet is Mercury?

    Q: What type of planet is Mercury?

    A: Like Earth, Mercury is one of four terrestrial planets. It is known as a terrestrial planet because it has a solid ground surface made up of rock and metal. This surface makes Mercury's density very similar to that of the Earth and denser than gas planets, according to Universe Today.
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  • Can you see Saturn from Earth?

    Q: Can you see Saturn from Earth?

    A: Saturn is frequently visible from Earth's surface. Space.com describes it as resembling a bright star when viewed by the unaided human eye. Owing to the planet's size and proximity, however, it usually doesn't twinkle the way stars do.
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  • What is the composition of Mars' atmosphere?

    Q: What is the composition of Mars' atmosphere?

    A: The composition of Mars' atmosphere is 95.32 percent carbon dioxide, 2.7 percent nitrogen, 1.6 percent oxygen and 0.08 percent carbon monoxide. The remaining 0.3 percent is made up of various trace elements.
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  • What is the hottest planet in the solar system?

    Q: What is the hottest planet in the solar system?

    A: Venus, the second planet from the sun, is the hottest planet in the solar system, with surface temperatures of around 864 degrees Fahrenheit, and there is no difference between day and night temperatures on Venus, so there is no time of day where temperatures tend to dip. This high temperature, which is hot enough to melt tin and lead, is due in part to the planet's proximity to the sun, though Venus manages to be much hotter than Mercury, which is the closest planet to the sun. Venus' extreme heat can be attributed mostly to its extremely thick atmosphere, which is 93 times thicker than Earth's atmosphere and composed mainly of carbon dioxide.
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  • How would a human being fare on Mars?

    Q: How would a human being fare on Mars?

    A: Low pressures, a lack of oxygen and cold weather on Mars would force humans to remain confined to spacecrafts and vehicles, according to physics.org. Astronauts could occasionally walk around in the open, but only if they wore spacesuits. Settlers would risk dying if their spacesuits became seriously damage. Underground shelter would be an ideal scenario. As of 2014, no settlement on Mars has been established.
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  • Is Saturn hot or cold?

    Q: Is Saturn hot or cold?

    A: Saturn is a mostly cold planet, with areas that reach temperatures as low as minus 270 F. There are some regions of the planet that feature temperatures of 80 F, but these remain unfriendly, having an extremely high atmospheric pressure.
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  • What are the nine planets in order?

    Q: What are the nine planets in order?

    A: The nine planets in order are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and, if it's still considered the ninth planet, Pluto. However, not only has Pluto been demoted to a dwarf planet by some astronomers, but its orbit is so eccentric that there are times when it's closer to the sun than Neptune.
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  • How much would a 100 pound person weigh on Neptune?

    Q: How much would a 100 pound person weigh on Neptune?

    A: A 100-pound person who stood, or floated, on the surface of Neptune would weigh 114 pounds. Although Neptune is much more massive than Earth, it's far less dense, so the acceleration of gravity at its surface is weaker than expected for a planet that is 17 times Earth's mass.
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  • What color is Saturn?

    Q: What color is Saturn?

    A: Saturn is described as having a yellowish-brown color. This is due to the presence of trace amounts of ammonia, hydrocarbons, water vapor and phosphine in its atmosphere.
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  • How many miles is Jupiter from the sun?

    Q: How many miles is Jupiter from the sun?

    A: Jupiter is located an average of 483.64 million miles from the sun. The exact distance between Jupiter and the sun varies depending on the location of Jupiter along its orbit.
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  • What is the weather like on Jupiter?

    Q: What is the weather like on Jupiter?

    A: Jupiter has a dry, thick atmosphere; high-speed winds, turbulence and long-lasting storms are common. The weather on Jupiter is much different from that found on a rocky planet such as the Earth.
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  • Who discovered that the Earth was round?

    Q: Who discovered that the Earth was round?

    A: The discovery that the Earth is round is most commonly ascribed to the ancient Greek philosopher Pythagoras, while the credit for proving it is usually given to Aristotle. It appears that most ancient Greek philosophers that followed him believed in a round Earth. Since the records from that time are not perfect, it is quite possible that someone before him was aware of the Earth's round shape.
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  • What is the surface temperature on planets?

    Q: What is the surface temperature on planets?

    A: The surface temperatures of the solar system's planets are dependent on how close each planet is to the sun. Planets that have atmospheres are better able to retain heat from the sun, affecting the planet's surface temperature.
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  • When is the next time all the planets will align?

    Q: When is the next time all the planets will align?

    A: The next planetary alignment will not occur until the year 2854. According to astronomers, such alignment typically occurs every 1500 years, with the last phenomenon appearing in 561 B.C.
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  • What are the special features of Mars?

    Q: What are the special features of Mars?

    A: Mars has a number of interesting features that make it one of the most studied planets in the solar system. One of the most often noted features of Mars is its reddish color, which earned it the nickname the Red Planet. The reddish hue results from iron oxide, or rust, in the soil.
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