Examples of Wien’s Displacement Law in Real Life and Space

Wien’s Displacement Law helps us understand how temperature changes the color of light objects give off. We see this in glowing metal, shining stars, and even leftover light from the Big Bang. Iron glows red, yellow, and blue as it heats up. Stars like Rigel and Betelgeuse show different colors because they are different temperatures. The cosmic microwave background is cold, but still shines in microwaves. These examples make the law easy to understand.

Wien’s Displacement Law Examples

Wien’s Displacement Law shows that hotter objects shine with shorter wavelengths, which means the color of their light changes as they get hotter. Here are some Examples of Wien’s Displacement Law in Real Life and Space:

1: Heating Objects

When an object is cool, it does not glow in visible light. It only gives off invisible infrared radiation. This is why things at room temperature don’t glow.

As the object gets hotter, its radiation moves into the visible part of the spectrum. First, it begins to glow red. This happens around 800 to 1,000 Kelvin. Red light has a longer wavelength, so it appears first when objects heat up.

As the heat increases, the object shines orange and then yellow. These colors mean the peak wavelength is getting shorter.

If the object becomes extremely hot, it starts to shine white. This white light is a mix of many wavelengths across the visible spectrum. It means the object is so hot that it gives off many colors at once.

At even higher temperatures, the object glows blue. Blue light has a shorter wavelength than red or yellow. This is a clear sign that the object is now very hot.

This change in color with heat is an everyday example of Wien’s Displacement Law.

2: Stars and Stellar Colors

Stars are giant balls of hot gases. They glow because they are very hot. Their color tells us how hot they are. This is one of the best examples of Wien’s Law in space.

The star Rigel, found in the Orion constellation, has a surface temperature of about 11,000 Kelvin. It looks bluish-white in the night sky. This color means it gives off short wavelengths. Because it is very hot, its peak radiation is in the ultraviolet and blue part of the spectrum.

On the other hand, the star Betelgeuse, also in Orion, is much cooler. Its temperature is around 3,500 Kelvin. It appears red in the sky. That red color shows it gives off longer wavelengths. Betelgeuse is cooler than Rigel, so its light follows the same law — cooler means longer wavelengths.

3: Heating Iron

Iron is a metal that glows when heated. This change in color is easy to observe in a fire or furnace.

At first, cold iron is dark and does not glow. As it heats up to around 900 Kelvin, it begins to shine red. This red glow shows its peak emission has moved into the visible light range.

As the iron gets hotter, it turns orange, then yellow. These color changes happen because the peak wavelength keeps moving toward the shorter end of the spectrum.

If the iron is heated to extreme temperatures — above 10,000 Kelvin — it begins to glow blue. It might even give off ultraviolet radiation, which we cannot see.

This shows how heat and light color are linked. The hotter the iron, the shorter the wavelength of light it gives off. This follows Wien’s Displacement Law perfectly.

4: Cosmic Microwave Background (CMB)

The cosmic microwave background is light left over from the early universe. It fills space and gives us clues about the universe’s age and temperature.

This radiation comes from a time when the universe was just 380,000 years old. Now, after billions of years, the temperature of this light is only about 2.7 Kelvin. That is very cold.

At this low temperature, the light’s peak wavelength is in the microwave range — around 1 millimeter. We cannot see this light, but scientists detect it using special telescopes.

Even though the temperature is low, it still follows Wien’s Law. Cold objects give off long wavelengths. Hotter ones give off shorter ones. This example proves that the law works not just for hot objects, but even for cold ones in space.