Infrared Waves - NASA Science

Introduction to Infrared Waves

• Infrared waves are part of the electromagnetic spectrum, not visible to the human eye but detectable as heat.
• Everyday encounters: Used in remote controls to change TV channels; divided into near-, mid-, and far-infrared.
• Thermal infrared (8 to 15 microns) is useful for studying Earth's thermal energy.

Discovery of Infrared

• Discovered by William Herschel in 1800.
• Experiment showed temperature increase from blue to red in the visible spectrum, with even higher temperatures beyond red, indicating infrared light.

Applications of Thermal Imaging

• Infrared energy can be sensed as heat, emitted by warm objects like humans and animals.
• Instruments like night-vision goggles and infrared cameras can "see" infrared waves.

Astronomy and Infrared

• Infrared helps detect cooler and faint objects in the universe, e.g., planets, cool stars, nebulae.
• Cassini spacecraft used infrared to capture images of Saturn's aurora.

Seeing Through Dust

• Infrared waves pass through gas and dust with less scattering and absorption compared to visible light.
• James Webb Space Telescope uses infrared to study galaxy, star, and planet formation.

Monitoring the Earth

• Infrared used to detect thermal emissions from Earth, helpful for studying land and sea surface temperatures.
• Used in monitoring natural phenomena like lava flows and forest fires through satellites like MODIS.

Infrared Imaging

• Provides detailed cloud structures and distinctions between clouds and land.
• Reveals multiple cloud layers and temperature variations in the atmosphere.

Key Takeaways

• Infrared technology enhances our understanding of both terrestrial and astronomical phenomena.
• Offers capabilities for thermal imaging, environmental monitoring, and astronomical observations.
• Infrared imagery provides unique insights not available through visible light.

Visual and Practical Examples

• Remote Controls: Use infrared at ~940 nanometers, detectable by some cameras.
• Heat Lamps: Emit both visible and infrared energy (500nm to 3000nm), used for heating and keeping food or animals warm.

Notable Instruments

• Cassini Spacecraft: Detected Saturn's aurora in infrared.
• James Webb Space Telescope: Uses infrared to reveal unseen celestial objects.
• MODIS (Aqua and Terra satellites): Monitors Earth's surface temperature and detects forest fires.

Additional Resources

• Tour of the Electromagnetic Spectrum
• Exploring Remote Sensing Activity
• Diagram of the Electromagnetic Spectrum