Layered hills like time capsules help unlock the secrets of Mars’ past

On January 29, 2025, thousands of mysterious hills on Mars hold valuable information, believed to have been shaped by ancient water on the red planet. The NASA has gathered evidence of potential past life on Mars and is currently planning new missions in the region. Robots will explore to determine if there were oceans in the past and if there could have been life.

CNN reports that there are over 15,000 hills standing in the Chryse Planitia, located between the northern and southern halves of Mars. These geological features have fascinated scientists as they serve as time capsules that could help unravel the mysteries of Mars’ past.

Images captured by orbiting spacecraft around the red planet show that these formations cover an area as large as the state of Texas. These unusual features are reminiscent of the famous lone peaks and mesas in Monument Valley at the Arizona and Utah border.

The hills on Mars, towering at 1,800 feet (550 meters) and spanning an area 2,000 times larger than Monument Valley, are much older, existing for billions of years rather than millions.

Analyzing the images and data collected by the orbiting spacecraft, scientists revealed in a new analysis published in the journal ‘Nature Geoscience’ on January 20 that these hills originated from erosion caused by water between 4 to 3.8 billion years ago.

“Each hill is composed of layers of rocks, each layer recording past events,” said Dr. Joe McNeil, a planetary scientist and researcher at the Natural History Museum in London. “The oldest hills are at the bottom, made up of rocks from around 4 billion years ago. For geologists, looking at these layers is like reading pages of a book—each page tells a story!”

Although evidence suggests Mars might have had fast-flowing rivers and lakes in the past, it’s challenging to determine the type of water that led to the erosion.

Dr. McNeil and his colleagues are exploring the possibility of an ancient northern ocean on Mars causing erosion and shaping the planet’s geology.

The boundary line dividing Mars into the northern plains and southern highlands remains a mystery. The appearance of this boundary varies, with some areas appearing to directly connect lowlands to highlands, while others have steep cliffs dividing the hemispheres.

A study published on January 16 in ‘Geophysical Research Letters’ suggests that seismic activities detected by the retired NASA InSight lander indicate that convection within Mars is responsible for creating these boundaries.

Areas near the hills, such as Oxia Planum and Mawrth Vallis, have piqued scientists’ interest as they might preserve traces of past life on Mars.

According to the European Space Agency (ESA), Oxia Planum is the predicted landing site for the Rosalind Franklin Mars rover in 2028.

“This is very exciting because it means that by exploring these plains, the rover will provide us with a lot of information about a larger area and possibly tell us about the environment there and whether it could have been habitable,” said Dr. McNeil.