Mars Rover Curiosity Dates Rocks on Red Planet

Determining the age of rocks is an important part of finding out more about a planet. That's why researchers have determined ages of rocks from planetary bodies in the past. Yet these experiments have always been conducted on Earth. Now, researchers have successfully determined the age of a Martian rock with experiments performed on Mars.

In March, Mars rover Curiosity drilled holes into the mudstone of Yellowknife Bay, an expanse of bare bedrock in Gale Crater about 500 meters from the rover's landing site. The rover collected powdered rock samples from two locations and once the rock samples were dripped, Curiosity's robotic arm delivered the rock powder to the Sample Analysis on Mars (SAM) instrument. This tool can perform a variety of chemical analyses, including rock dating techniques.

So what did they find? The age of the mudstone was about 3.86 to 4.56 billion years old, which is essentially the number everyone expected. Yet there were some surprises--even if it wasn't the actual age.

"What was surprising was that our result--from a technique that was implemented on Mars with little planning on Earth--got a number that is exactly what crater counting predicted," said Ken Farley, one of the researchers, in a news release. "MSL instruments weren't designed for this purpose, and we weren't sure if the experiment was going to work, but the fact that our number is consistent with previous estimates suggests that the technique works, and it works quite well."

However, there is some uncertainty in the measurement. One reason for this uncertainty is that mudstone is a sedimentary rock, which means that it's formed in layers over a span of millions of years from material that eroded off of the crater walls. This means that the sample really represents the combined age of those bits and pieces.

The findings reveal a little bit more about the rocks of Mars. In addition, it shows that this technique can be used remotely to tell scientists more about certain areas. The information could also be important for researchers who are looking for evidence of past life on Mars.