continuous spectra
Human body (really anything on Earth)
- T about 98 F= 37 C ~ 300 K
- peak wavelength 10,000 nm
- infrared, not visible to eye
- rattlesnake can detect infrared radiation
- decides what to strike at (i.e. heated sandbag)
- wear down parka to foil rattlesnakes
- military (i.e. Desert Storm, etc.) uses infrared
- hot things glow even in total visual darkness
- tanks easily visible at night (hot engines)
- naked human body radiates ~700 W
- need to stay indoors (warm room) or wear clothes
- Other planets will also radiate
- hottest Mercury 600 K, coldest Pluto 60 K
- All will radiate in the infrared