Time is running out to get a look at Mercury, at least for a while. The best time to look is just as the sky is getting dark. Look towards the setting sun (wait until it is below the horizon!). That little speck of light will be Mercury. March 1^st will be a nice sight as the crescent moon will move past the planet; should be a nice pairing.

Mercury is normally hidden in the glare of the sun and every now and then moves into a position where it is visible to us. While everybody most people know Mercury is the closest planet to the Sun, not many know the planet is likely shrinking. Shrinking? In 1974, NASA’s Mariner 10 spacecraft flew by Mercury and took some images of the surface. Among the features that were imaged were what planetary geologists call “lobate scarps” – those are wrinkles to the rest of us. The “wrinkle” in the image to the right are named Discovery Rupe. It is thought Mercury has an oversized iron core that is shrinking due to cooling and as the core shrinks so does the rest of the planet. Picture the wrinkles on a raisin, you get the idea.

Nobody knows what is behind the wrinkles for sure, just like nobody knows for sure what the “mystery-substance” is at the planets poles. Based on the Mariner’s images whatever the substance is, it is bright. Even more bizarre as a shrinking iron core, among the favorites is ice. You wouldn’t think ice would be on a planet where the temperature exceeds 700 F (400 C), but in places the sun doesn’t ever shine the temperature is lower than -212 F (-350 C), or so researchers believe.

We may learn more about these oddities when the Messenger space probe arrives in 2008.

Mercury is a planet not many people have seen or knew they were looking at it. Pity, we’re so busy with the hustle and bustle of our everyday lives we don’t even take the time to look around, be different – check it out.

Image Credit: NASA, Mark Robinson, Northwestern University via Science@NASA, Arecibo Radar (J. Harmon, P. Perrilat, and M. Slade).

[tags]Mercury, NASA, Messenger[/tags]