caption: From Nebula to Star A passing shock wave triggers a part of a cloud to begin to contract. Shock waves come from four processes:
exif: {"Image DocumentName": "From Nebula to Star A passing shock wave triggers a part of a cloud to begin to contract. Shock waves come from four processes:", "Image ImageDescription": "Nearby supernovae. Ignition of a nearby star. Collision between molecular clouds. Rotation of a galaxy. As the cloud contracts atoms gather speed as they fall in a stage called free-fall contraction. Gravitational energy is converted into thermal energy and the gas grows hotter. if temperatures reach about 7 million K, nuclear fusion starts. A star is born.", "Image XResolution": "200", "Image YResolution": "200", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}