In the early 2000s, various models proposed that Mars had undergone many rounds of ice ages in the past. Now an analysis of radar data collected by NASA’s Mars Reconnaissance Orbiter (MRO) has confirmed that the red planet is just coming out of an ice age. It offers evidence that climate is still actively changing on Mars. Findings of the study were published Friday in the Science journal.
The red planet’s ice started its retreat 370,000 years ago
The radar data was analyzed by Isaac Smith and his colleagues at the Southwest Research Institute. Smith said in a statement that they found an “accelerated accumulation rate of ice in the uppermost 100 to 300 meters of the polar cap.” Surprisingly, both the thickness and volume of ice matches model predictions made decades ago. The findings will provide important data for human exploration on Mars, besides helping us understand the Earth’s climate better.
Researchers confirmed that the Martian ice age ended only about 400,000 years ago. And the ice began its retreat 370,000 years ago. That may seem like a long time ago, but 400,000 years is pretty recent in cosmic terms. Scientists found that about 87,000 cubic kilometers of ice had accumulated at the red planet’s poles since the end of the ice age. Most of the ice accumulated in the northern polar cap.
What causes ice age on Mars?
The amount of ice accumulated is so huge that if it were spread throughout the red planet, the entire Mars would be covered with a 2-foot thick ice layer. Smith said understanding the ice ages will help NASA understand how ice and water behaved over time on Mars. It will help them figure out how the red planet turned into a frigid, barren land. Ice ages on both Earth and Mars are caused by similar factors – long-term changes and tilt of the planet.
Mars’ axis is currently tilted 25 degrees, but it changes wildly. The red planet’s tilt ranges between 10 degrees and 60 degrees on the scale of hundreds of thousands of years. By comparison, our Earth’s axis is tilted 23.5 degrees, and it changes only about 2 degrees over the same time period. Wild changes in Mars’ tilt could be explained by the fact that it doesn’t have a large moon like Earth to stabilize its orbit. Also, Jupiter’s gravity might be affecting the red planet’s rotation.