A new study suggests that Mars and Earth had very different atmospheres 4.6 billion years ago. This conclusion was made after analyzing 40 meteorites from Mars, which can also reveal if life did exist on the Red planet.

Researchers from the University of Maryland, led by former research associate Heather Franz, analyzed the chemical signatures of 40 meteorites that are believed to be from Mars's surface. Scientists believed that the meteorites were thrown into Earth after an asteroid or comet impact.

They specifically looked for the sulfur level of the ancient rocks since Mars is known for its volcanic activities. The oldest rock they have is about 4.1 billion years old while the youngest is 200 million years old.

Curiosity, a car-sized robotic rover, has been exploring Mars for evidence that it once supported life. In September 2013, it has made a soil sample analysis which revealed that it contains two percent of water. The surface soil was collected from the Gale Crater, which scientists believed to be a region where water flowed billions of years ago.

Scientists are convinced that Mars and Earth share the same basic element for life-water. However, others are still contemplating on the possibility of life existing because of the difference of the atmospheres. The Red planet has a harsh atmospheric condition due to the greenhouse gases emitted by the volcanoes which makes human life impossible.

During the meteorite chemical signature analysis, researchers searched for the sulfur level of each ancient rock. They also categorized each rock based on its source-from deep below the volcanic surface, from the atmosphere, or from biological activity.

Their analysis revealed that the majority of the meteorites sulphur content was from the atmosphere. This finding suggests that Mars and Earth are really different since humans live through oxygen while Mars organisms breathe sulfur dioxide.

"Climate models show that a moderate abundance of sulfur dioxide in the atmosphere after volcanic episodes, which have occurred throughout Mars' history, could have produced a warming effect which may have allowed liquid water to exist at the surface for extended periods," Franz said in a university news release. "Our measurements of sulfur in Martian meteorites narrow the range of possible atmospheric compositions, since the pattern of isotopes that we observe points to a distinctive type of photochemical activity on Mars, different from that on early Earth."

Further details of the study can be read on the April 17 issue of Nature.