Daily Earth Science Pictures

here.

Examples include frost on a blade of grass:

The caption reads:

The spectacular image above shows morning frost on a blade of grass as imaged using a low temperature scanning electron microscope (SEM). This grass fragment was held in liquid nitrogen (-196 degrees C or -320 F), to keep the frost crystals from melting, before it was imaged at the Scanning Electron Microscopy Laboratory in Beltsville, Maryland. Frost crystals form perpendicular to individual blades of grass. Note that although these plate type crystals are hexagonal, a number of them appear to be square-shaped.

http://epod.usra.edu/archive/epodviewer.php3?oid=180832

The Southern Cross:

The caption reads:

This photo, taken in late February, shows the constellation of the Southern Cross (Crux), at the top center of the image, as viewed from Gramado Town in southern Brazil. The night sky was clear and moonless. Stars down to a magnitude 9 or so are shown, including some deep sky nebulosity. Crux is a southern circumpolar constellation -- comparable in declination or latitude to Ursa Major (Big Dipper) in the Northern Hemisphere.

The Southern Cross is indeed a brilliant constellation, consisting of several bright gems in the shape of a cross -- more or less. The brightest is Alpha Crucis (magnitude of 1.1), which is actually a triple star system. One of the stars is about 650 times as bright as our Sun and another is almost 1,000 times as bright. Beta Crusis (magnitude 1.5) is a blue star, and Gamma Crusis, at the head of the cross, is an orange colored second magnitude star. The star denoting the right-most corner on the cross (Delta Crusis) is the faintest of the four (third magnitude). Perhaps only the magnificent Orion has three bright stars that appear to be so close to each other.

http://epod.usra.edu/archive/epodviewer.php3?oid=185888