Ancient Mars was warm and wet, not cold and icy
A recent study showed that Mars was warm and wet billions of years ago. The finding contrasts with another theory that this era was mainly cold and icy. The result has implications for the idea that life could have developed on the planet at this time.
Whether Mars was once habitable is a fascinating and intensely researched topic of interest over many decades. Mars, like the Earth, is about 4.5 billion years old and its geological history is divided into different epochs of time.
The latest paper relates to Mars during a time called the Noachian epoch, which extended from about 4.1 to 3.7 billion years ago. This was during a stage in solar system history called the Late Heavy Bombardment (LHB). Evidence for truly cataclysmic meteorite impacts during the LHB are found on many bodies throughout the solar system.