kosmos: Titan (moon)

Evidence: 100 • authority: 72

Titan is the largest moon of Saturn and the second largest in the Solar System. It is the only moon that is known to have a dense atmosphere (denser than that of Earth), and is the only known object in the Solar System besides Earth with clear evidence of stable bodies of surface liquid. Titan is one of seven gravitationally rounded moons of Saturn, and is the second-most distant among them. Frequently described as a planet-like moon, Titan is 48.16% larger in diameter than Earth's moon, and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's Ganymede, and is larger than Mercury, and yet Titan is only 40% as massive as Mercury, because Mercury is mainly iron…

Evidence: 45 • authority: 72

Saturn has 293 moons with confirmed orbits as of June 2026, the most of any planet in the Solar System. Saturn's moons are diverse in size, ranging from tiny moonlets to Titan, which is larger than the planet Mercury and the second largest moon in the Solar System. Three of these moons possess particularly notable features: Titan has a nitrogen-rich atmosphere and a landscape featuring river networks and hydrocarbon lakes; Enceladus emits jets of ice from its south-polar region and is covered in a deep layer of snow; and Iapetus has contrasting black and white hemispheres as well as an extensive ridge of equatorial mountains which are among the tallest in the Solar System. Twenty-five of th…

Evidence: 42 • authority: 72

Iapetus () is the outermost of Saturn's large moons. With an estimated diameter of 1,469 km (913 mi), it is the third-largest moon of Saturn and the eleventh-largest in the Solar System. Named after the Titan Iapetus from Greek mythology, the moon was discovered in 1671 by Giovanni Domenico Cassini. A relatively low-density body composed mostly of ice, Iapetus is home to several distinctive and unusual features, such as a striking difference in coloration between its dark leading hemisphere and its bright trailing hemisphere, as well as a massive equatorial ridge that runs three-quarters of the way around the moon.

Evidence: 37 • authority: 72

Rhea () is the second-largest natural satellite of Saturn and the ninth-largest moon in the Solar System, with a diameter of 1,528 kilometres (949 mi). Rhea is the smallest body in the Solar System that is confirmed to be in hydrostatic equilibrium. It has a nearly circular orbit around Saturn, but it is also tidally locked, like Saturn's other major moons. It rotates with the same period it revolves or orbits. Thus, one hemisphere always faces towards the planet. The moon has a fairly low density, composed of roughly three-quarters ice and only one-quarter rock. The surface of Rhea is heavily cratered, with distinct leading and trailing hemispheres. Like the moon Dione, it has high-albedo…

Evidence: 34 • authority: 92

ShortSCOPE: An Optical Short-Period Seismic Sensor for Planetary Exploration.. Seismology offers a window into the formation, structure, and dynamical processes of solar system bodies. Seismic data from Earth, the near side of the Moon, and Elysium Planitia on Mars have transformed our understanding of planetary interiors. Expanding these insights to new targets-such as ocean worlds and asteroids-requires seismometers with enhanced sensitivity, low power consumption, and robustness in extreme environments. We present the performance and environmental qualification of the Short-Period Seismic Characterization using Optics for Planetary Exploration ("ShortSCOPE") sensor, a novel force-balance…

Evidence: 27 • authority: 92

The chemistry of habitable oceans in the Solar system.. Liquid water exists on the Earth and several other planetary bodies in our solar system. The chemical character of these aqueous reservoirs is central to evaluating their habitability. Here, we synthesize the chemical features of water reservoirs and their biological implications on the modern Earth. We then outline constraints on the evolutionary history of Earth's ocean chemistry and discuss its interplay with the biosphere. Furthermore, we examine the inferred chemical environments of water bodies on early Mars, dwarf planet Ceres, Jupiter's moon Europa and Saturn's moons Enceladus and Titan. We conclude by outlining priority questi…

Evidence: 27 • authority: 72

This article includes a list of the most massive known objects of the Solar System and partial lists of smaller objects by observed mean radius. These lists can be sorted according to an object's radius and mass and, for the most massive objects, volume, density, and surface gravity, if these values are available. These lists contain the Sun, the planets, dwarf planets, many of the larger small Solar System bodies (which includes the asteroids), all named natural satellites, and a number of smaller objects of historical or scientific interest, such as comets and near-Earth objects. Many trans-Neptunian objects (TNOs) have been discovered; in many cases their positions in this list are appro…

Evidence: 27 • authority: 72

Of the Solar System's eight planets and its nine most likely dwarf planets, six planets and seven dwarf planets are known to be orbited by at least 468 natural satellites, or moons. At least 19 of them are large enough to be gravitationally rounded; of these, all are covered by a crust of ice except for Earth's Moon and Jupiter's Io. Several of the largest ones are in hydrostatic equilibrium and would therefore be considered dwarf planets or planets if they were in direct orbit around the Sun and not in their current states (orbiting planets or dwarf planets).

Evidence: 21 • authority: 92

Ammonia as a parameter shaping habitability on icy moons.. The search for life now extends beyond the traditional habitable zone to include the icy moons of Jupiter and Saturn. These moons feature ice-covered surfaces overlying substantial oceans formed primarily of liquid water and other potential constituents, such as ammonia. On Earth, ammonia supports biochemistry at low concentrations by providing nitrogen but becomes disruptive at higher concentrations. Ammonia could therefore influence the habitability of extraterrestrial oceans, yet this topic has received limited attention in the literature. This review synthesises current research on ammonia in Saturn's icy moons, Enceladus and Ti…

Evidence: 21 • authority: 92

Titan's strong tidal dissipation precludes a subsurface ocean.. The Cassini mission provided unprecedented insights into Saturn's largest moon, Titan, from its atmosphere to the deep interior 1 . The moon's large measured response to the tides exerted by Saturn was interpreted as evidence of the existence of a subsurface ocean 2,3 . This response, twice the value predicted in pre-Cassini studies, has escaped complete explanation. Here we show that the signature of tidal dissipation in Titan's gravity field is not consistent with the presence of an ocean. Our results arise from the detection of this signature through a reanalysis of the radiometric data acquired by Cassini with improved tech…