What would if the sun dissapered and the earth was still here.

  Well first of all we need plants to survive.  Without sun light plants will not be able to do photosynthesis because sunlight helps make photosynthesis.  As soon the sun disappears the photosynthesis would stop immediately.  Without photosynthesis the plants won't be able to make food for people and soon everybody would starve to death and photosynthesis makes air for us to breathe.All 8 billion of us humans on earth breath in 6,000,000,000 kg. But our atmosphere has 1,000,000,000,000,000,000 kg of air so it will take  millions of years for the earth to run out of air.Trees or bigger plants would survive longer because they have saved sugars so the trees would last for a years.  The only problem for the trees or big plants would that it will be very cold.  The earth will become very cold in the first year it would be -73 degrees Celsius. The best ways to survive the cold is too live near warm places like yellow stone or Iceland.  These places would be the few safe havens for humans life after the sun disappears.  Nearly all life on earth exists because of, and is dependent upon, the sun.  But the earth produces its own heat. Despite floating in the coldness of space for billions of years.Down below the crust the earth is quite warm.  To survive the cold we would have to live close to warm places(as i said before) and underground since it would be extremely cold. Also when the sun disappears the earth won't be orbiting in a circle anymore after the sun disappears the earth will go in a straight line forever.  our only source of light would be man-made electronics and stars