Radiation Questions

• Can you make a shock wave of light by breaking the light barrier just like supersonic airplanes break the sound barrier?
• Did cancer exist before man-made chemicals were around to create it?
• Do humans give off radiation?
• How bright is a laser beam when viewed from the side?
• How do 5G cell phone signals harm humans?
• How does a microwave oven heat up food even though it emits no thermal radiation?
• How long can you use a cell phone before getting a brain tumor?
• How much extra radiation am I exposed to if I stick my hand in the microwave right after it turns off?
• Is ionizing radiation always harmful?
• What keeps space empty?
• What makes heat rise?
• When I sit by a campfire, how does its hot air heat me?
• Why doesn't my laptop emit radiation?