Seti-telescopes-Landmark-missions

Seti 

  Astronomers involved in the Series project use powerful radio telescope to scan the skies in search of artificial radio signals broadcast by alien civilizations. The Estimate project has been running since 1960, but it has so far found no conclusive evidence of alien signals, despite some false alarm 

 Is there anybody out there? 

  One of the biggest questions in science is whether life is unique to Earth or arisen on other worlds. And if life has appeared elsewhere, could intelligent beings have evolved? Scientists have set up projects to watch and listen for singnals form extraterrestrials, and messages have been sent to the stars to infrom any aliens out there of our existence. 

Arecibo message 

  In 1974,scientists used the giant Arecibo radio telescope in puerto Rico to broadcast a radio message towards the star cluster M13.The message contains symbols (right) that represent human beings, ourbase-10 counting system,the DNA molecule, and the Solar system.More a publicity stunt than a serious attempt to contact aliens, the broadcast willtake 25,000 years to return. 

Pioneer plaque 

  The robotic spacecraft pioneer 10 and pioneer 11 visited the planets Jupiter and saturn in 1973-74 and then flew off into deep space. if aliens ever discover either craft drifting through interstellar space, they will find a gold-plated plaque engraved with a message from Earth. 

How telescopes work 

 The invention of the telescope revolutionized astronomy. A telescope collects more light from an object than a human eye can.It uses this light to forma magnifide image.There are two basic types of telecope: refracting and reflecting. The refracting telescope has a large convex (outward-curving) lens light.The reflecting telescope uses a curver mirror instead. 

Refracting telescope 

  A convex lens bends light entering the telescope to focus it, forming an image. At the other end of the telescop,a smaller lens called the eyepiece magnifies the image. 

Reflecting telescope 

 A concave (inward-curving) main mirror reflects light on to a smaller, flat mirror. The resulting image is magnified by an eyepiece lens. 

Landmark missions 

 Since the first spacecraft to visit a planet was launched in 1962,abut 200 craft have explored the solar system. Some of the most famous mission are shown hear. 

Venera 7 

 The first craft to touch down on another planet, venera 7 landed on venus in 1970. It lasted 23 minutes before the searing heat destoryed it. 

Lunokhod 1 

 Russian-built Lunokhod 1 was the first luner rover. It landed on the Moon in 1970 and spent 322 days exploring,travelling a total 10.5 km (6.5 miles). 

Voyager 1

  Launched in 1977 and still operational, voyager 1 is the furthest manmade object from Erath. It visited jupiter in 1979 and saturn in 1980.