Space: 1889

Space 1889Space 1889'' audio dramas
By the time of the game's setting in 1889, the great powers have used Edison's invention to extend their colonies and interests to the inner planets of the solar system. Venus and Mars have been colonized by the United Kingdom, Germany, France, and Russia. Belgium has only colonized Mars and Italy has only colonized Venus whilst Japan and the United States maintain economic and scientific enclaves on Mars. There are no colonies or bases on the Moon. Only the United Kingdom maintains a (scientific) base on Mercury. The inner planets reflect an evolutionary progression, the planets nearest to the sun being younger than those farther out.

Astrological sign

zodiac signzodiac signssign
Nevertheless, some researches say that there is an obvious relationship between the Chinese 12-year cycle and zodiac constellations: each year of the cycle corresponds to a certain disposal of Jupiter. For example, in the year of Snake Jupiter is in the Sign of Gemini, in the year of Horse Jupiter is in the Sign of Cancer and so on. So the Chinese 12-year calendar is a solar-lunar-jovian calendar. The following table shows the twelve signs and their attributes. In Chinese astrology, the zodiac of twelve animal sign represents twelve different types of personality.

Late Heavy Bombardment

heavy bombardmentintense early bombardmentEarliest evidence for life
The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, at a time corresponding to the Neohadean and Eoarchean eras on Earth. During this interval, a disproportionately large number of asteroids are theorized to have collided with the early terrestrial planets in the inner Solar System, including Mercury, Venus, Earth, and Mars. Since 2018, the existence of the Late Heavy Bombardment has been questioned. Evidence for the LHB derives from lunar samples brought back by the Apollo astronauts. Isotopic dating of Moon rocks implies that most impact melts occurred in a rather narrow interval of time.

Night sky

night skiessky''' of the Earthsky of Earth
Mercury, Mars, Jupiter and Saturn are also visible to the naked eye. Earth's Moon is a grey disc in the sky with cratering visible to the naked eye. It spans, depending on its exact location, 29-33 arcminutes - which is about the size of a thumbnail at arm's length, and is readily identified. Over 27.3 days, the moon goes through a full cycle of lunar phases. People can generally identify phases within a few days by looking at the moon. Unlike stars and most planets, the light reflected from the moon is bright enough to be seen during the day. (Venus can sometimes be seen even after sunrise.) Some of the most spectacular moons come during the full moon phase near sunset or sunrise.

Moons of Uranus

Uranus' natural satellites27Uranian moons
Indeed, the combined mass of the five major satellites is less than half that of Triton (the seventh-largest moon in the Solar System) alone. The largest of the satellites, Titania, has a radius of 788.9 km, or less than half that of the Moon, but slightly more than that of Rhea, the second-largest moon of Saturn, making Titania the eighth-largest moon in the Solar System. Uranus is about 10,000 times more massive than its moons. As of 2016, Uranus is known to have 13 inner moons. Their orbits lie inside that of Miranda. All inner moons are intimately connected with the rings of Uranus, which probably resulted from the fragmentation of one or several small inner moons.

Amalthea (moon)

AmaltheaJupiter Vmoons of Jupiter
Galileo made its final satellite fly-by at a distance of approximately 244 km from Amalthea's center (at a height of about 160–170 km) on 5 November 2002, permitting the moon's mass to be accurately determined, while changing Galileo's trajectory so that it would plunge into Jupiter in September 2003 at the end of its mission. In 2006, Amalthea's orbit was refined with measurements from New Horizons. Amalthea is the setting of several works of science fiction, including stories by Arthur C. Clarke, James Blish and Arkady and Boris Strugatsky. Cited sources * *Galilean moons (the four biggest moons of Jupiter) Amalthea Profile by NASA's Solar System Exploration.

List of spaceflight records

Spaceflight recordsrecordlongest single space flight by a woman
Mattingly orbited solo around the Moon for more than 3 days and 9 hours. Eugene Cernan and Harrison Schmitt of the Apollo 17 mission stayed for 74 hours 59 minutes and 40 seconds (over 3 days) on the lunar surface after they landed on 11 December 1972. They performed three EVAs (extra-vehicular activity) totaling 22 hours 3 minutes, 57 seconds (as commanders were always the first one out of the LM and the last to get back in, Cernan's EVA time was slightly longer). Ronald Evans of Apollo 17 mission stayed in lunar orbit for 6 days and 4 hours (148 hours); however, for the solo portion of that flight around the Moon, T. K.


gravitationgravitationalgravitational force
A discrepancy in Mercury's orbit pointed out flaws in Newton's theory. By the end of the 19th century, it was known that its orbit showed slight perturbations that could not be accounted for entirely under Newton's theory, but all searches for another perturbing body (such as a planet orbiting the Sun even closer than Mercury) had been fruitless. The issue was resolved in 1915 by Albert Einstein's new theory of general relativity, which accounted for the small discrepancy in Mercury's orbit. This discrepancy was the advance in the perihelion of Mercury of 42.98 arcseconds per century.

New Horizons

New Horizons KBO SearchNew HorizonNew Horizons mission
New Horizons Mission Archive at the NASA Planetary Data System, Small Bodies Node. New Horizons: Kuiper Belt Extended Mission (KEM) Mission Archive at the NASA Planetary Data System, Small Bodies Node.

Adrastea (moon)

Amalthea's density implies that the moon is composed of water ice with a porosity of 10–15%, and Adrastea may be similar. No surface details of Adrastea are known, due to the low resolution of available images. Adrastea is the smallest and second-closest member of the inner Jovian satellite family. It orbits Jupiter at a radius of about 129,000 km (1.806 Jupiter radii) at the exterior edge of the planet's Main Ring. Adrastea is one of only three moons in the Solar System known to orbit its planet in less than the length of that planet's day—the other two being Jupiter's innermost moon Metis, and Mars' moon Phobos.


Mercury, the Moon and the Galilean satellites of Jupiter have surface boundary exospheres, which are exospheres without a denser atmosphere underneath. The gases that can be found in the exosphere are mostly hydrogen, and carbon dioxide. Mercury and several large moons, such as the Moon and the Galilean satellites of Jupiter, have exospheres without a denser atmosphere underneath, referred to as a surface boundary exosphere. Here, molecules are ejected on elliptic trajectories until they collide with the surface. Smaller bodies such as asteroids, in which the molecules emitted from the surface escape to space, are not considered to have exospheres.

List of possible dwarf planets

dwarf planet candidatepossible dwarf planetdwarf-planet candidate
Which are the Dwarfs in the Solar System? Tancredi, G.; Favre, S. Icarus, Volume 195, Issue 2, p. 851–862. NASA JPL Small-Body Database Search Engine.

Gravity assist

gravitational slingshotgravitational assistslingshot
With its substituted solid rocket upper stage, the IUS, which could not provide as much delta-v, Galileo did not ascend directly to Jupiter, but flew by Venus once and Earth twice in order to reach Jupiter in December 1995. The Galileo engineering review speculated (but was never able to prove conclusively) that this longer flight time coupled with the stronger sunlight near Venus caused lubricant in Galileo main antenna to fail, forcing the use of a much smaller backup antenna with a consequent lowering of data rate from the spacecraft. Its subsequent tour of the Jovian moons also used numerous slingshot maneuvers with those moons to conserve fuel and maximize the number of encounters.


Sirius BSirius superclusterDog Star
Sirius appears bright because of its intrinsic luminosity and its proximity to the Solar System. At a distance of 2.64 pc, the Sirius system is one of Earth's nearest neighbours. Sirius is gradually moving closer to the Solar System, so it will slightly increase in brightness over the next 60,000 years. After that time, its distance will begin to increase, and it will become fainter, but it will continue to be the brightest star in the Earth's night sky for the next 210,000 years. Sirius A is about twice as massive as the Sun and has an absolute visual magnitude of +1.42.

Perturbation (astronomy)

In the Solar System, this is usually the case; Jupiter, the second largest body, has a mass of about 1/1000 that of the Sun. General perturbation methods are preferred for some types of problems, as the source of certain observed motions are readily found. This is not necessarily so for special perturbations; the motions would be predicted with similar accuracy, but no information on the configurations of the perturbing bodies (for instance, an orbital resonance) which caused them would be available.

Inferior and superior planets

superior planetinferior planetinferior planets
In the Solar System, a planet is said to be inferior or interior with respect to another planet if its orbit lies inside the other planet's orbit around the Sun. In this situation, the latter planet is said to be superior to the former. In the reference frame of the Earth, in which the terms were originally used, the inferior planets are Mercury and Venus, while the superior planets are Mars, Jupiter, Saturn, Uranus and Neptune. Dwarf planets like Ceres or Pluto and most asteroids are 'superior' in the sense that they almost all orbit outside the orbit of Earth.

Accretion (astrophysics)

The formation of terrestrial planets differs from that of giant gas planets, also called Jovian planets. The particles that make up the terrestrial planets are made from metal and rock that condense in the inner Solar System. However, Jovian planets begin as large, icy planetesimals, which then capture hydrogen and helium gas from the solar nebula. Differentiation between these two classes of planetesimals arise due to the frost line of the solar nebula. Meteorites contain a record of accretion and impacts during all stages of asteroid origin and evolution; however, the mechanism of asteroid accretion and growth is not well understood.

Angular diameter

apparent diameterangular sizeapparent size
The angular diameter of the Sun is about the same as that of the Moon. (The Sun's diameter is 400 times as large and its distance also; the Sun is 200,000 to 500,000 times as bright as the full Moon (figures vary), corresponding to an angular diameter ratio of 450 to 700, so a celestial body with a diameter of 2.5–4″ and the same brightness per unit solid angle would have the same brightness as the full Moon.) Even though Pluto is physically larger than Ceres, when viewed from Earth (e.g., through the Hubble Space Telescope) Ceres has a much larger apparent size. Angular sizes measured in degrees are useful for larger patches of sky.


heliocentricheliocentric modelheliocentric theory
Even if the discussion is limited to the Solar System, the Sun is not at the geometric center of any planet's orbit, but rather approximately at one focus of the elliptical orbit. Furthermore, to the extent that a planet's mass cannot be neglected in comparison to the Sun's mass, the center of gravity of the Solar System is displaced slightly away from the center of the Sun. (The masses of the planets, mostly Jupiter, amount to 0.14% of that of the Sun.) Therefore, a hypothetical astronomer on an extrasolar planet would observe a small "wobble" in the Sun's motion. In modern calculations, the terms "geocentric" and "heliocentric" are often used to refer to reference frames.


occultedlunar occultationoccults
List of Solar System objects by size. Transit of Mercury. Transit of Venus. Solar eclipse. Grazing lunar occultation. Grazing occultation. Syzygy (astronomy). Radio occultation. GPS occultation. TAOS: The Taiwanese-American Occultation Survey. Occultations, transits, and eclipses. Marco Peuschel – Astronomische Tabellen für den Mond von 2007 bis 2016, Mondphasen, Apsiden, Knotendurchgänge, Maximale und minimale Deklinationswerte und Sternbedeckungen sowie ausführliche Ephemeriden für jeden Tag des Jahres, inkl. Mondauf-und Untergänge und physische Daten. Occultation Studies at Williams College,

Apparent magnitude

apparent visual magnitudemagnitudevisual magnitude
For planets and other Solar System bodies the apparent magnitude is derived from its phase curve and the distances to the Sun and observer. Some of the above magnitudes are only approximate. Telescope sensitivity also depends on observing time, optical bandpass, and interfering light from scattering and airglow. * Luminosity in astronomy. List of nearest bright stars. List of nearest stars. Surface brightness. Distance modulus.

Multi-ringed basin

multi-ring basinsmulti-ringedMulti-ring impact basin
On the largest moon of Jupiter, Ganymede, Anubis Crater is a multi-ringed basin. On the moon of Saturn, Dione, Evander is a multi-ringed basin. On Mercury, Caloris Basin, surrounded by Caloris Montes is a multi-ringed basin. The Earth's Moon, Mare Orientale is a multi-ringed basin, created by an impactor perhaps 285 miles in diameter, near as wide as the state of New York, traveling at 9 miles per second, or about 32,400 miles per hour.

Timeline of the far future

far future40,000 years296,000 years
All projections of the future of Earth, the Solar System, and the universe must account for the second law of thermodynamics, which states that entropy, or a loss of the energy available to do work, must rise over time. Stars will eventually exhaust their supply of hydrogen fuel and burn out. Close encounters between astronomical objects gravitationally fling planets from their star systems, and star systems from galaxies. Physicists expect that matter itself will eventually come under the influence of radioactive decay, as even the most stable materials break apart into subatomic particles.

Apparent retrograde motion

retrograde motionretrograderetrogradation
From any point on the daytime surface of Mercury when the planet is near perihelion (closest approach to the Sun), the Sun undergoes apparent retrograde motion. This occurs because, from approximately four Earth days before perihelion until approximately four Earth days after it, Mercury's angular orbital speed exceeds its angular rotational velocity. Mercury's elliptical orbit is farther from circular than that of any other planet in the Solar System, resulting in a substantially higher orbital speed near perihelion.

Tidal force

tidal forcestidaltidal effects
The tidal accelerations at the surfaces of planets in the Solar System are generally very small. For example, the lunar tidal acceleration at the Earth's surface along the Moon-Earth axis is about 1.1 × 10 −7 g, while the solar tidal acceleration at the Earth's surface along the Sun-Earth axis is about 0.52 × 10 −7 g, where g is the gravitational acceleration at the Earth's surface. Hence the tide-raising force (acceleration) due to the Sun is about 45% of that due to the Moon. The solar tidal acceleration at the Earth's surface was first given by Newton in the Principia. Tidal tensor. Amphidromic point. Disrupted planet. Galactic tide. Tidal resonance. Spacetime curvature.