What is the Mars Climate Like?

The climate of Mars, researchers from the University of California, said that the change in Mars climate is caused by the inclination of Mars as it orbits the sun. Simply put, when Mars orbits the sun, its position toward the sun changes slightly. This process has occurred many times in the history of the Earth's orbit around the sun, and has induced global climate change.

Mars climate

Mars has a harsh climate but may have had life

The two Mars rover "Courage" and "Opportunity" on Mars have found more evidence that despite the wet historical environment on Mars, there have also been hot and violent periods, with dry and dry climate There are often volcanic eruptions and celestial collisions. Scientists said at the annual meeting of the American Geological Association that the evidence showed that the Martian environment had historical moments suitable for life, but most of the time was not suitable for life development.

So far, the "Courage" Mars rover has landed on Mars for 708 Earth Days, more than one Mars year (the Mars year is equivalent to 687 Earth Days), it has traveled 5.5 km on Mars; and in the other hemisphere of Mars Opportunity will also usher in a new year of Mars after landing on the 11th of this month, and it traveled 6.4 kilometers. The two Mars vehicles returned 130,000 photos of Mars to Earth.

Project scientists report that the "Courage" is exploring the "Hesband" in the Gusev crater region. The "Courage" has recently climbed to the summit and is currently descending the slope. During this approximately 1-kilometer journey, Courage explored the nearby desert, gravel, and bedrock formations. Squares, chief scientist of the Mars Rover Exploration Project and a professor at Cornell University, said that the Courage inspected a total of six types of rocks. From these rock formations, it can be inferred that the climate near the "Hesband Mountain" in history was very hot and violent, with volcanic eruption and celestial collisions, and water may only exist in the hot springs once, or in trace amounts in the rock formations. in.

The Opportunity cruised near the Martian Meridian plane also received more evidence. Project scientists say that Opportunity has explored the two craters Patience and Victoria, and the bedrock structure of the ground between them. Scientists have found that the structure of these bedrocks is similar to "sandwich biscuits", that is, one layer is a sedimentary rock layer, and the other is a rock layer petrified by sand piles, which are repeatedly stacked. This shows that the climate near the Meridian plane has experienced repeated cycles of drought and wetness from 3 billion to 4 billion years, and that the topmost rock formation is sandstone, indicating that the most recent climate change was a drought cycle. In addition, although the iron oxide particles formed under the influence of water flow are present in all rock formations, they are rarer in younger rock formations, indicating that the recent wetting cycle was shorter or that these iron oxide particles were formed for other reasons. Squills said the evidence gathered by the two Mars rover shows that the historical environment of Mars may be the "forbidden zone" for most life forms, especially during its hot and dry cycle. The results published by other scientists at the conference also support this hypothesis.

Neukum of the Free University of Berlin believes that there may be a large number of water bodies on Mars until 3 billion years ago, and the climate is suitable, but a large-scale volcanic eruption 2.6 billion years ago suddenly heated Mars, melted the glaciers, and evaporated water. Since then, Mars has entered a long dry and hot period, during which the wet period has become shorter and shorter, which has caused Mars to lose most of its atmosphere and water.

At the same time, scientists found evidence of methanogenic archaea living in Greenland's underground ice cores. This microorganism, which can survive in extremely harsh conditions, is likely to survive on Mars. Methanogenic archaea are an extremely ancient microorganism that is more primitive than bacteria. They can survive in the absence of oxygen and sunlight, relying on the energy of chemical reactions or metabolism such as geothermal, methane is its metabolite. Price and others analyzed the bottom of the ice core sample collected from more than 3,000 meters underground in Greenland and found that the methane concentration was abnormally high, while only a small amount of methanogenic archaea survived around the same depth. Researchers believe that the high concentration of methane in ice cores should be the metabolites of methanogenic archaea accumulated over a long period of time.

After analyzing the metabolic rate of these methanogens, they found that the archaea have survived underground for 100,000 years. Under the harsh environment of more than 3,000 meters underground, the metabolism of methanogens was extremely slow. In 100,000 years The energy produced by their metabolism can only be used to repair the damage to their genes caused by the environment, not to mention the development of reproduction. At the same time, the methane they produce has gradually accumulated. Researchers believe that methanogenic archaea are likely to exist on Mars and are a source of methane in Mars' atmosphere. The concentration of methane in Mars' atmosphere is about one part per billion, but methane cannot exist stably in the environment of Mars, because sunlight can easily combine methane with hydroxyl groups to form water and carbon dioxide, and there is currently no evidence that Mars has sustained The chemical process of methane production, so methane is likely to be produced by biological processes.

Price et al. Calculated based on the rate of methane loss in the atmosphere of Mars and the metabolic rate of methanogens near the ice core. If the methanogens are the source of methane in the atmosphere of Mars, it is assumed that they are 10 meters thick at zero degrees Celsius. It is evenly distributed in the stratum, so as long as the archaea concentration reaches 1 archaea per milliliter volume, the methane concentration in the atmosphere of Mars can be stably maintained. In order to verify this idea, they are currently manufacturing a fluorescence detector to detect the weak fluorescence generated by the metabolism of methanogenic archaea. This instrument can detect one archaea per milliliter of soil or stratum. In the future, It can also be installed on a new Mars rover to find life on Mars.

Modern Martian climate is warmer than previously thought

According to a report by the US Space Network, according to a recent scientist's survey of certain terrain on the surface of Mars, the climate of modern Mars is warmer than previously believed by scientists. This finding suggests that there may be Martian life.

Matthew Balme of the Open University of Great Britain has studied images of the Martian equatorial topography taken by NASA s Mars Reconnaissance Orbiter (MRO) high-resolution imaging scientific experimental instrument (HiRISE). The surface of Mars was covered with liquid water 100 million years ago. Although several studies in recent years have shown that liquid water flows on the surface of modern Mars, the tangible evidence of liquid water flowing on the surface of modern Mars has not been confirmed, and it has become quite concerned by scientists. hot spot.

For example, the ditch topography suggests that liquid water still flowed on the surface of Mars 1.25 million years ago, and another recent study found that rivers may exist on the surface of Mars 1 billion years ago. Bam's analysis shows that some topography of the equator was formed by melting ice-bearing soil during the "icing-thawing" cycle of 2 million years ago. The images taken by HiRISE show the presence of hemispherical polygonal blocky soil, multi-branched ditch topography, mottled soil fragments, and conical mound structures near the equator. This topography is very similar to the situation after the permafrost in the polar regions of the earth has melted. Permafrost has been frozen for many years, even thousands of years, and most of it exists in the Arctic. If the climate changes, the permafrost will eventually melt.

"Previously, scientists thought that such terrain near the equator might have been caused by volcanic activity. Amazing images taken by HiRISE at the moment show that the terrain is formed by the expansion and contraction of ice layers, and the ice-rich ground soil Melting. This implies that the climate of Mars before was very different from today. "

The observed terrain of Mars is an outflowing canal. From 2 million to 8 million years ago, such liquid water still existed on the surface of Mars. "Observations confirm that not only did ice exist on the equator of Mars millions of years ago, but also that these ice-water substances formed liquid water from the topographical characteristics, but then frozen and went through many cycles," Bam said.

It is reported that Bam's research was supported by a grant from the British Science and Technology Facilities Research Council, and the research will be published in the recently published Earth and Planetary Science Letters. Modern Mars water activity will help find life that Mars once or currently exists. Perhaps the earliest life on Mars is earlier than life on Earth.

"Liquid water is an essential condition for the existence of life, such as the currently observed Martian equator, which will help find evidence of past life on Mars," Bam said.