4. Bronnen

Link 1: Info over NASA

National Aeronautics and Space Administration

Link 2: OfficiĆ«le website NASA 

National Aeronautics and Space Administration

Link 3: Afbeelding

https://www.google.nl/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjSsfy8lZ3NAhVPFMAKHS1XAuEQjRwIBw&url=http%3A%2F%2Fwww.tijdgeest.eu%2Fastrologie%2Fplaneten&bvm=bv.124272578,d.d2s&psig=AFQjCNEJn8Jwe6_C7d_Z8abqqabdr2A6Ag&ust=1465638071427625

Link 4: Lichtjaren

http://www.sterrenkunde.nl/index/encyclopedie/lichtjaar.html

Link 5: Filmpjes zoeken

YouTube