Related papers: The Climate of Early Mars
The deuterium-to-hydrogen (D/H or 2H/1H) ratio of Martian atmospheric water (~6x standard mean ocean water, SMOW) is higher than that of known sources, requiring planetary enrichment. A recent measurement by NASA's Mars Science Laboratory…
Recent findings suggest Mars may have been a clement environment for the emergence of life, and may even have compared favorably to Earth in this regard. These findings have revived interest in the hypothesis that prebiotically important…
Carbon dioxide (CO$_2$) ice clouds have been routinely observed in the middle atmosphere of Mars. However, there are still uncertainties concerning physical mechanisms that control their altitude, geographical, and seasonal distributions.…
Despite a fainter Sun, the surface of the early Earth was mostly ice-free. Proposed solutions to this so-called "faint young Sun problem" have usually involved higher amounts of greenhouse gases than present in the modern-day atmosphere.…
The layered polar caps of Mars have long been thought to be related to variations in orbit and axial tilt. We dynamically link Mars's past climate variations with the stratigraphy and isotopic composition of its ice by modeling the exchange…
In this Letter, we make use of sophisticated 3D numerical simulations to assess the extent of atmospheric ion and photochemical losses from Mars over time. We demonstrate that the atmospheric ion escape rates were significantly higher (by…
In this paper, we analyze water ice occurrences at the surface of Mars using near-infrared observations, and we study their distribution with a climate model. Latitudes between 45{\deg}S and 50{\deg}N are considered. Data from the…
Characterizing the Martian atmosphere is an essential objective to understand its meteorology and its climate. The lower atmosphere (< 40 km) and middle atmosphere (40-80 km) of Mars appear dynamically coupled at much higher levels than in…
Mars is believed to have had a substantial atmosphere in the past. Atmospheric loss led to depressurization and cooling, and is thought to be the primary driving force responsible for the loss of liquid water from its surface. Recently,…
Planet Mars past environmental conditions were similar to the early Earth, but nowadays they are similar to those of a very cold desert, irradiated by intense solar UV light. However, some terrestrial lifeform showed the capability to adapt…
Little is known about the early evolution of Venus and a potential habitable period during the first one billion years. In particular, it remains unclear whether or not plate tectonics and an active carbonate-silicate cycle were present. In…
A 54-km diameter Noachian-aged crater in the southern highlands of Mars contains unusually well-preserved inverted fluvial channel networks and lacustrine deposits, all of which formed completely inside the crater. This closed-source…
Mars shares many similarities and characteristics to Earth including various geological features and planetary structure. The remarkable bimodal distribution of elevations in both planets is one of the most striking global features…
Ozone is an important radiative trace gas in the Earth's atmosphere. The presence of ozone can significantly influence the thermal structure of an atmosphere, and by this e.g. cloud formation. Photochemical studies suggest that ozone can…
We extracted a Martian water-ice cloud climatology from OMEGA data covering 7 Martian years (MY 26-32). We derived two products, the Reversed Ice Cloud Index (ICIR) and the Percentage of Cloudy Pixels (PCP), indicating the mean cloud…
Global climate evolution models for habitable earthlike planets do not consider the effect of ocean salinity on land ice formation through the hydrological cycle. We consider two categories of such planets: planets with deep oceans, but…
The existence of possible early oceans in the northern hemisphere of Mars has been researched and debated for decades. The nature of the early martian climate is still somewhat mysterious, but evidence for one or more early oceans implies…
The atmospheres of the terrestrial planets are known to have been modified as a consequence of the impact degassing and atmospheric erosion during the late accretion. Despite the commonality of these processes, there are distinct gaps --…
The history of the Earth has been marked by major ecological transitions, driven by metabolic innovation, that radically reshaped the composition of the oceans and atmosphere. The nature and magnitude of the earliest transitions, hundreds…
The composition of an atmosphere has integrated the geological history of the entire planetary body. However, the long-term evolutions of the atmospheres of the terrestrial planets are not well documented. For Earth, there were until…