...es about 26 days for the sun to spin one time. The suns outer atmosphere is called the corona. Its inner atmosphere is called the chromosphere. Belo the photosphere are the convective zone, the radiative zone, and the core. The suns core converts 700 million tons of hydrogen gas into 695 million tons of helium gas every second. The remaining 5 million tons of matter is converted to pure energy. That 5 million tons is about 600 times the amount of ater floing over Niagara Falls in one second. The temperature at the suns core is 15 million degrees K. Although sunspots are very hot, they are slightly cooler than the rest of the photosphere so they look darker. Sunspots have a dark center called the Umbra and a lighter ring around the outside called the Penumbra. It takes 50 million years for the energy formed deep inside the sun to reach Earth. Earth only gets one-billionth of the total energy produced by the sun. Light, traveling at 186 thousand miles per second, takes just over 8 minutes to reach Earth from the sun. Apollo as both the Greek and Roman god of the sun. He brought life-giving heat and light to Earth and as the patron god of musicians and poets.3. Planets3.1 MercuryMercury is the closest planet to the sun. Its average distance from the sun is 36 million miles. Mercury is about 3,030 miles 4,878 km across. That makes it the second-smallest planet in the solar system only Pluto is smaller. In fact, Mercury is just a little bigger than Earths moon. Its also covered ith craters just like the moon. Mercurys year the time it takes to orbit the sun one time is 88 Earth days long, but one day the time it takes to rotate from sunrise to sunrise is 176 Earth days long. Because Mercury is so close to the sun, it has the smallest orbit of all the planets. That means it goes around the sun very quickly 88 Earth days or about 3 Earth months. Although Mercury goes around the sun quickly, it spins very sloly on its axis. For every year on Mercury, the planet spins 1 12 times about 59 Earth Days or 2 Earth months. But hile Mercury is sloly spinning, it is still speeding its ay around the sun. Mercury has to spin another 1 12 times for the sun to rise over the same spot. That means one day sunrise to sunrise on Mercury is about 6 Earth months long, and thats tice as long as Mercurys year! So every day on Mercury means 2 years! Mercury has a very, very thin atmosphere of helium and hydrogen. On Mercury you ould either freeze or roast. The highest surface temperature is 870F, hile the loest temperature is 300F. Scientists ho study the planets have found ice at Mercurys poles. Like Earths moon, Mercury is covered ith craters. At one time, Mercury may have had volcanoes. Scientists believe that Mercury has a very thin crust, folloed by a rocky layer, ith a metallic core, probably made of iron, at its center. To escape Mercurys gravity you have to travel at 9,600 miles per hour. Because Mercury moves so fast around the sun, early Roman sky atchers named it after their speedy-messenger god. To the ancient Greeks, Mercury is identified ith the god Hermes..2 VenusVenus is the second planet from the sun. Its average distance from the sun is 67 million miles. Sometimes called Earths sister planet, Venus is slightly smaller than Earth. Its also our closest neighbor at about 25 million miles aay from Earth. Venus is hot enough to melt lead. Its surface temperature can get close to 900F. This makes Venus the hottest place in the solar system after the sun. After the sun and moon, Venus is the brightest object in the sky. Because its thick clouds reflect most of the light Venus gets from the sun, the planet looks like a very bright star in the morning just before sunrise or evening just after sunset sky. The surface of Venus is covered ith craters, mountains, volcanoes, and lava plains. Maxell Montes is the highest point on Venus. It is more than 7 miles high. Standing on Venus ould be like standing in a shallo bol. The atmosphere is so thick and heavy that it bends light, making the ground appear to curve upard in all directions. The planets atmosphere is 90 times heavier than Earths. Venus has sulfuric acid clouds. Its atmosphere is mostly carbon dioxide 96, nitrogen 3.5, and carbon monoxide, argon, sulfur dioxide, and ater vapor all less than 1. It takes 225 Earth days for Venus to go around the sun one time. Venus spins on its axis once every 243 Earth days, but it spins in the opposite direction of Earth. On Venus, the sun rises in the est and sets in the east. To escape Venuss gravity you have to travel at 23,300 miles per hour. Venus as identified ith the Roman goddess Aphrodite, the goddess of love and beauty. To the ancient Mayans, Venus as the patron planet of arfare called Kukulcan.3.3 EarthEarth is the third planet from the sun, hich is about 93 million miles aay. From space, Earth looks like the blue ater orld it is. About 70 of Earths surface is covered ith ater, and 97 of all that ater is in the salty oceans. Only 3 of Earths ater is freshater, the ater e drink. Earths atmosphere is a mixture of gasses that become thinner as e move aay from the planet toard space. Most of the atmosphere is nitrogen 78, oxygen 21, argon and other gases 1. Some of the oxygen in Earths atmosphere has changed over time to form ozone. Earths high ozone layer filters out the suns harmful ultraviolet rays, protecting the creatures living on the surface. But too much ozone helps trap the suns infrared rays. Infrared radiation is heat radiation. It is the armth you feel hen the sun shines on you. If too much heat is trapped in Earths atmosphere, surface temperatures ill rise. This is called the greenhouse effect and its hat makes Venus so hot. Earth goes around the sun in 365 and 14 days. Every 4 years that 14 day adds up to one hole day and e add a day to the end of February, creating a leap year. It takes only 24 hours 1 day for Earth to spin on its axis one time. Earth is covered ith mountains, volcanoes, lakes, rivers, and oceans. Most of the surface material is made of rocks high in silica, iron, and magnesium. The highest point on Earths surface is Mount Everest on the border of Nepal and China at 29,035 feet 8,850 meters. Earths average surface temperature is 45F. To escape Earths gravity you have to travel at 25,000 miles per hour. Earth has a diameter of 7,926 miles.3.4 MarsMars is the fourth planet from the sun. Its orbit is roughly 142 million miles from the sun. The planets reddish color is caused by rust iron oxide in the soil. Mars is the planet most like Earth. It takes 687 Earth days about 2 Earth years for Mars to go around the sun one time, and Mars spins on its axis at about the same speed as Earth does. It takes 24 hours and 37 minutes about 1 Earth day for Mars to rotate one time. Mars has the largest canyon Valles Marineris, and the highest volcano Olympus Mons in the solar system. If Valles Marineris ere on Earth, it ould span the United States, from Ne York on the East C...
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