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This Hubble Space Telescope composite view of the gorgeous island universe is one of the largest Hubble images ever made of a complete galaxy.

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Image credit: Hubble Heritage Team, ESA, NASA

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Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away. Also known as M42, the nebula is visible to the unaided eye, but this stunning infrared view from the Spitzer Space Telescope penetrates the turbulent cosmic gas and dust clouds to explore the region in unprecedented detail.

Image credit: Thomas Megeath (Univ. Toledo) et al., JPL, Caltech, NASA

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Every spring, strange dark spots appear near the Martian poles, and then vanish a few months later. A hypothesis has been suggested where the spots are caused by explosive jets of sand-laden CO2. As a pole warms up in the spring, frozen CO2 on the surface thins, perforates, and begins to vent gaseous CO2 held underneath.