In today's image, we see small spherules of hematite on the Martian surface as discovered by the Opportunity Rover back on 2004. These are another one of the pieces of evidence that liquid water once existed on Mars in the past.

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This Podcast is an authorized New Media Mirror Site for APOD. You can access the image and website directly at: Astronomy Picture of the Day. You can use the archive link below the image to select the photo corresponding to the date of this podcast.

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