Mercury Images

Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green Bay First-time Visitors: Please visit Site Map and Disclaimer. Use "Back" to return here.

General Views

	Because of its rotational resonance, Mercury has two "hot poles" where the sun shines straight down when Mercury is closest to the Sun. This radio map shows them clearly.
	A Mariner 10 mosaic of Mercury

The Caloris Basin

Chaotic Terrain

	Directly opposite the Caloris basin is the chaotic terrain, a jumble of hills and valleys. Many planetary geologists suspect the shock from the Caloris impact was focused by Mercury's large core and fractured the crust on the other side of the planet. Note the smooth floor of one crater from lava that clearly post-dates the chaotic terrain.
	Detail of chaotic terrain.

Scarps

The numerous scarps on Mercury seem to be thrust faults and suggest the radius of the planet has decreased by a few kilometers, possibly from cooling and shrinkage of its core

Intercrater Plains

Most of Mercury has fairly wide plains between craters. These intercrater plains indicate that Mercury was resurfaced after most of its early impact bombardment, probably by volcanism.

The Snowball in Hell

	Radar images of Mercury reveal a bright reflection at the poles, matching the radar signature of ice. The sun's powerful tidal effects keep Mercury's equator locked on the sun and ensure that the poles never receive more than grazing illumination. Deep craters never get sunlight at all.
	Left: both poles show reflections. Bottom: detailed maps show the reflections match craters exactly once a slight correction to Mercury's poles is applied (red). Some researchers suggest that sulfur compounds rather than ice could produce the echoes.

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Created 6 April 1999, Last Update 6 April 1999

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