A section of Mars' Utopia Planitia, covered in dark volcanic materials, is expanding across the Red Planet's surface, with new photos revealing this phenomenon. Scientists are unsure why this phenomenon is occurring. The feature was first spotted by NASA's Viking probes in 1976 and is believed to be expanding by around 4 miles per year. It is unclear how large the feature is. However, sections of the patch's southern boundary have moved farther south by at least 200 miles (320 km). This suggests that Martian winds may be responsible for the movement of the dark patch. The region of Mars has been a focus of interest for scientists over the past half century.