Universe at a glance ...... Sun • The Sun is a star that is in the center of the Solar System • The Sun is recognized as having the largest mass in our Solar System. • It has a diameter of about 1,392,684 km, about 109 times that of Earth • The sun is the closest star to Earth, at a mean distance from our planet of 149.60 million km • Sun fuses 620 million metric tons of hydrogen each second. • At the core, the temperature is about 27 million degrees Fahrenheit (15 million degrees Celsius) • In February 1974, Skylab was the first manned spacecraft to study the Sun. • Solar flares occur when magnetic fields of the Sun come together and cause huge explosions on the Sun’s surface. • Solar flares produce bursts of electromagnetic radiation, x-rays, ultraviolet radiation, visible light, and radio waves. Mercury • Mercury is the closest and second smallest in the Solar System. • Mercury is the second densest planet after Earth. • The only visit to Mercury was a flyby made by the Mariner 10 spacecraft in 1974. • Mercury speeds around the sun every 88 days, traveling through space at nearly 50 km (31 miles) per second • Galileo first observed Mercury during the 17th century. Venus • Venus is the second closest and sixth largest planet in the Solar System • The orbital speed of Venus is 35 km per second. • Venus is the hottest planet in the Solar System. • Venus appears to be the brightest planet in the sky. • It takes 244.7 days for Venus to rotate on its axis. • The first robotic space probe mission to Venus, and the first to any planet, began on 12 February 1961, with the launch of the Venera 1 probe. Earth • Earth formed approximately 4.54 billion years ago, and life appeared on its surface within one billion years. • The Earth is the densest planet in the Solar System. • Earth is the fifth largest planet in the Solar System. • The Diameter of the Earth is 12,756 km (7,926 miles) • The earth’s orbital speed is 29.8 km per second. • Earth atmosphere consists of 78 percent nitrogen, 21 percent oxygen and 1 percent other ingredients.. • Earth rotates about its own axis 366.26 times, creating 365.26 solar days Moon • The Moon is Earth’s lone natural satellite. • In 1610, Galileo Galilei is the first to use a telescope to make scientific observations of the Moon. • The Moon is the fifth largest satellite in our Solar System. • The Moon’s diameter is 2160 miles (3476 km) • Average distance between the Earth and the Moon is about 239,000 miles. Actual distance varies from 221,457 to 252,712 miles. • The Moon’s gravity is 1/6 that of Earth. • The Moon does not have an atmosphere; there is no wind on the Moon. • Apollo 11 was the American space mission to first reach and land on the moon. • The first human landing on the Moon was on 20 July 1969. • The Moon orbits around the Earth every 29 days. Mars • Mars is the fourth planet from the Sun and the second smallest planet in the Solar System. • iron oxide prevalent on its surface gives it a reddish appearance, often described as “ Red Planet” • A Mars year is equal to 686.98 Earth Days • A day in Mars is equal to 24.6 Earth Hours • Like Earth, Mars experiences seasons because of the tilt of its rotational axis • Asaph Hall discovered both of Mars’ moons, Phobos and Deimos, in August 1877. • Mariner 4 – first successful flyby mission to Mars. Launched on November 28, 1964 and arrived at Mars on July 14, 1965. • Viking 1 – Successful orbit and landing on surface of Mars. Launched August 20, 1975 and arrived at Mars July 20, 1976
Posted on: Sun, 21 Dec 2014 19:51:44 +0000
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