Universe at a glance (part 1): 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 hugeexplosions 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. •Earthatmosphere 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. Jupitar •Jupiter, the largest planet in our solar system, is 318 times larger than Earth. •The orbital speed of Jupiter is 13.1 km/sec •A year on Jupiter is equal to 11.9 Earth Years •Jupiter has 67 natural satellites.[105] Of these, 51 are less than 10 kilometres in diameter and have only been discovered since 1975. •Galileo Galileihad discovered Jupiter's four largest moons, now called Io, Europa, Ganymede, and Callisto. These four moons are known today as the Galilean satellites. •In 1610, Galileo Galilei makes the first detailed observations of Jupiter. •Jupiter's moon Ganymede is the biggest satellite in solar system •Jupiter has rings, the third planet discovered to have a ring system in our Solar System. •Jupiter’s rings are identified as: Halo ring, Main ring, Amalthea gossamer ring, and Thebe gossamer ring. •Jupiter’s rings were discovered by Voyager 1 in 1979.