pogoda: Life on Mars

Evidence: 45 • authority: 72

The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no conclusive evidence of past or present life has been found on Mars. Cumulative evidence suggests that during the ancient Noachian time period, the surface environment of Mars had liquid water and may have been habitable for microorganisms, but habitable conditions do not necessarily indicate life. Scientific investigations for potential life on Mars began in the 19th century and continue today with telescopes and robotic probes searching for water, chemical biosignatures in the soil and rocks at the planet's surface, and biomarker gases in the atmosph…

Evidence: 41 • authority: 80

Why more than two-thirds of Australians think no news is good news (at least some of the time)

Evidence: 41 • authority: 92

Water Versus Land on Temperate Rocky Planets.. Water and land surfaces on a planet interact in particular ways with gases in the atmosphere and with radiation from the star. These interactions define the environments that prevail on the planet, some of which may be more amenable to prebiotic chemistry, some to the evolution of more complex life. This review article covers (i) the physical conditions that determine the ratio of land to sea on a rocky planet, (ii) how this ratio would affect climatic and biologic processes, and (iii) whether future astronomical observations might constrain this ratio on exoplanets. Water can be delivered in multiple ways to a growing rocky planet - and althou…

Evidence: 41 • authority: 92

What the Solar System Can Teach Us About Rocky Exoplanets.. The number of rocky extrasolar planets being discovered continues to increase, but so too does the apparent diversity of such worlds. As we work to understand the likely bulk properties and thermal, geological, and climatological attributes we might expect of rocky exoplanets, we can look to the Solar System for guidance. Here, we review the interior, surface, and atmospheric characteristics of modern Earth, and discuss how our homeworld has changed through Solar System history. We then visit in turn Venus, Mars, Mercury and Earth's Moon, and Io, noting how these terrestrial planets are alike, how they are different, and how they h…

Evidence: 41 • authority: 72

The gravity of Mars is a natural phenomenon, due to the law of gravity, or gravitation, by which all things with mass around the planet Mars are brought towards it. It is weaker than Earth's gravity due to the planet's smaller mass. The average gravitational acceleration on Mars is 3.721 m/s2 (about 38% of the gravity of Earth), with a global variation range of ~0.059 m/s2. In general, topography-controlled isostasy drives the short wavelength free-air gravity anomalies. At the same time, convective flow and finite strength of the mantle lead to long-wavelength planetary-scale free-air gravity anomalies over the entire planet. Variation in crustal thickness, magmatic and volcanic activities…

Evidence: 41 • authority: 72

Mars 2020 is a NASA mission that includes the rover Perseverance, the now-grounded small robotic helicopter Ingenuity, and associated delivery systems, as part of the Mars Exploration Program. Mars 2020 was launched on an Atlas V rocket at 11:50:01 UTC on July 30, 2020, and landed in the Martian crater Jezero on February 18, 2021, with confirmation received at 20:55 UTC. On March 5, 2021, NASA named the landing site Octavia E. Butler Landing. As of 18 October 2026, Perseverance has been on Mars for 2013 sols (2068 total days; 5 years, 242 days). Ingenuity operated on Mars for 1042 sols (1071 total days; 2 years, 341 days) before sustaining serious damage to its rotor blades, possibly all fo…

Evidence: 41 • authority: 72

The climate of Mars has been a topic of scientific curiosity for centuries, in part because it is the only terrestrial planet whose surface can be easily observed in detail from Earth using a telescope. Although Mars is smaller than Earth, with only one-tenth of Earth's mass, and is 50% farther from the Sun than Earth, its climate has important similarities with Earth's, such as the presence of polar ice caps, seasonal changes, and observable weather patterns. It has attracted sustained study from planetologists and climatologists. While Mars' climate has similarities to Earth's, including periodic ice ages, there are also important differences, such as much lower thermal inertia. Mars' atm…

Evidence: 41 • authority: 72

Mars is the fourth planet from the Sun. It is also known as the "Red Planet", for its orange-red appearance. Mars is a desert-like rocky planet with a tenuous atmosphere that is primarily carbon dioxide (CO2). At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from −153 to 20 °C (−243 to 68 °F), and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, fog, frost, larger polar regions of permafrost and ice caps (with seasonal CO2 snow), but no bodies of liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. Its…