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Why Is the Planet Mercury Orange?

Mercury, the Roman name for the Greek god Hermes, is the closest planet to the sun in the solar system. Between Mercury and Earth is Venus. We can see Mercury and Venus without a telescope when their orbital paths make them visible. While some areas on Mercury are orange in color, the major part of the planet's surface is gray. Occasionally, though, it looks like some of the planet is pink.

Identification
- Go to the StarDate website if you want to know when and where to look for Mercury in the night sky. The website also explains how to recognize Mercury. Even though Mercury is visible from Earth, discerning the true color of any celestial body is difficult because we have to factor in the visual distortions caused by our atmosphere. Mercury does not have its own atmosphere which, if it did, would also effect how we perceived its color.
History
- While the first astronomer to draw a detailed map of the surface of Mercury was Eugenios Antoniadi in 1933, the first close-up photographs were not made until Mariner 10 orbited the planet in 1974-75. These pictures verified the planet is gray, pocked with craters on its surface like the moon.
Considerations
- Messenger returned to Mercury with a wide-angle camera on Jan. 14, 2008. These photographs returned color images that included some small bright blue spots. Astronomers concluded these spots are the most recently formed craters.
Theories/Speculation
- Messenger's camera also captured images that are bright orange on Mercury. They were in the region known as the Caloris Basin. No one knows why there are places on the planet that are orange, but the astronomers speculate they might be live volcanoes.
Effects
- Like Earth, the core of Mercury is made of molten iron. Solid iron ore has an orange hue, so some of the pinkish color that can be visible on Mercury could be from that. Suffice to say, Mercury has some orange, but it is mostly gray.

Astronomy