In August 1972, NASA's Mariner 9 arrived at Mars and snapped one of the first close-up pictures of the planet. The image showed a landscape of craters and channels that resembled a dry desert in the American southwest. Scientists soon noticed something odd: a bright streak crossing the face of the planet.

The streak appeared as a thin, white line, stretching from the top right to the bottom left of the image. At first, scientists thought the streak might be a cloud or a dust storm. But further observations revealed that the streak was not moving, and it did not appear to be affected by the atmosphere.

Eventually, scientists determined that the streak was a meteor impact. The impact of the meteor had created a crater about 1 km in diameter, and the streak was a trail of ejecta that had been thrown out of the crater by the impact.

The Mariner 9 meteor streak is just one of many examples of how meteor impacts have shaped the surface of Mars. Meteor impacts are a common occurrence on Mars, and they have played a significant role in the planet's evolution.