paragraph_text: Earth was initially molten due to extreme volcanism and frequent collisions with other bodies. Eventually, the outer layer of the planet cooled to form a solid crust when water began accumulating in the atmosphere. The Moon formed soon afterwards, possibly as the result of a Mars-sized object with about 10% of the Earth's mass impacting the planet in a glancing blow. Some of this object's mass merged with the Earth, significantly altering its internal composition, and a portion was ejected into space. Some of the material survived to form an orbiting moon. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered from comets, produced the oceans.

paragraph_text: Mercury is the smallest and innermost planet in the Solar System. Its orbital period around the Sun of 88 days is the shortest of all the planets in the Solar System. It is named after the Roman deity Mercury, the messenger to the gods.

paragraph_text: In 1543, the geocentric system met its first serious challenge with the publication of Copernicus' De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres), which posited that the Earth and the other planets instead revolved around the Sun. The geocentric system was still held for many years afterwards, as at the time the Copernican system did not offer better predictions than the geocentric system, and it posed problems for both natural philosophy and scripture. The Copernican system was no more accurate than Ptolemy's system, because it still used circular orbits. This was not altered until Johannes Kepler postulated that they were elliptical (Kepler's first law of planetary motion).

paragraph_text: When 2002 AA29 is approaching the Earth from in front (i.e. it is moving slightly slower, and the Earth is catching it up), the gravitational attraction of the Earth shifts it onto a slightly faster orbit, a little nearer the Sun. It now hurries ahead of the Earth along its new orbit, until after 95 years it has almost lapped the Earth and is coming up from behind. Again it comes under the Earth's gravitational influence; this time it is lifted onto a slower orbit, further from the Sun. On this orbit it can no longer keep pace with the Earth, and it falls behind until in 95 years it is once again approaching the Earth from in front. The Earth and 2002 AA29 chase each other in turn around the Sun, but do not get close enough to break the pattern.

paragraph_text: Astronomy: The first textual mention of astronomical concepts comes from the Vedas, religious literature of India. According to Sarma (2008): "One finds in the Rigveda intelligent speculations about the genesis of the universe from nonexistence, the configuration of the universe, the spherical self-supporting earth, and the year of 360 days divided into 12 equal parts of 30 days each with a periodical intercalary month.". The first 12 chapters of the Siddhanta Shiromani, written by Bhāskara in the 12th century, cover topics such as: mean longitudes of the planets; true longitudes of the planets; the three problems of diurnal rotation; syzygies; lunar eclipses; solar eclipses; latitudes of the planets; risings and settings; the moon's crescent; conjunctions of the planets with each other; conjunctions of the planets with the fixed stars; and the patas of the sun and moon. The 13 chapters of the second part cover the nature of the sphere, as well as significant astronomical and trigonometric calculations based on it.

paragraph_text: There were serious scientific objections to the process of natural selection as the key mechanism of evolution, including Karl von Nägeli's insistence that a trivial characteristic with no adaptive advantage could not be developed by selection. Darwin conceded that these could be linked to adaptive characteristics. His estimate that the age of the Earth allowed gradual evolution was disputed by William Thomson (later awarded the title Lord Kelvin), who calculated that it had cooled in less than 100 million years. Darwin accepted blending inheritance, but Fleeming Jenkin calculated that as it mixed traits, natural selection could not accumulate useful traits. Darwin tried to meet these objections in the 5th edition. Mivart supported directed evolution, and compiled scientific and religious objections to natural selection. In response, Darwin made considerable changes to the sixth edition. The problems of the age of the Earth and heredity were only resolved in the 20th century.

paragraph_text: Saturn and its rings are best seen when the planet is at, or near, opposition, the configuration of a planet when it is at an elongation of 180°, and thus appears opposite the Sun in the sky. A Saturnian opposition occurs every year—approximately every 378 days—and results in the planet appearing at its brightest. Both the Earth and Saturn orbit the Sun on eccentric orbits, which means their distances from the Sun vary over time, and therefore so do their distances from each other, hence varying the brightness of Saturn from one opposition to the next.  Saturn also appears brighter when the rings are angled such that they are more visible.  For example, during the opposition of 17 December 2002, Saturn appeared at its brightest due to a favorable orientation of its rings relative to the Earth, even though Saturn was closer to the Earth and Sun in late 2003.From time to time Saturn is occulted by the Moon (that is, the Moon covers up Saturn in the sky). As with all the planets in the Solar System, occultations of Saturn occur in "seasons". Saturnian occultations will take place 12 or more times over a 12-month period, followed by about a five-year period in which no such activity is registered. Australian astronomy experts Hill and Horner explain the seasonal nature of Saturnian occultations:

paragraph_text: The Galilean moons are the four largest moons of Jupiter -- Io, Europa, Ganymede, and Callisto. They were first seen by Galileo Galilei in January 1610, and recognized by him as satellites of Jupiter in March 1610. They are the first objects found to orbit another planet. Their names derive from the lovers of Zeus. They are among the largest objects in the Solar System with the exception of the Sun and the eight planets, with a radius larger than any of the dwarf planets. Ganymede is the largest moon in the Solar System, and is even bigger than the planet Mercury. The three inner moons -- Io, Europa, and Ganymede -- are in a 4: 2: 1 orbital resonance with each other. Because of their much smaller size, and therefore weaker self - gravitation, all of Jupiter's remaining moons have irregular forms rather than a spherical shape.

paragraph_text: Earth, Moon, and Planets is a peer-reviewed scientific journal, published approximately ten times per year by Springer Science+Business Media. It was established in 1969 under the title "The Moon", was known as "The Moon and the Planets" from 1978 to 1983, and was first published under the current title in February 1984. The editor-in-chief is Murthy S. Gudipati (Caltech and JPL). The journal's main focus is on research about the Solar System. Besides original research articles, "Earth, Moon, and Planets" publishes conference proceedings, review articles, book reviews, and special issues.

paragraph_text: David Attenborough was later granted sabbatical leave from his job as Controller to work with the BBC Natural History Unit which had existed since the 1950s. This unit is now famed throughout the world for producing high quality programmes with Attenborough such as Life on Earth, The Private Life of Plants, The Blue Planet, The Life of Mammals, Planet Earth and Frozen Planet.

paragraph_text: Newton's First Law of Motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force or resultant force. This law is an extension of Galileo's insight that constant velocity was associated with a lack of net force (see a more detailed description of this below). Newton proposed that every object with mass has an innate inertia that functions as the fundamental equilibrium "natural state" in place of the Aristotelian idea of the "natural state of rest". That is, the first law contradicts the intuitive Aristotelian belief that a net force is required to keep an object moving with constant velocity. By making rest physically indistinguishable from non-zero constant velocity, Newton's First Law directly connects inertia with the concept of relative velocities. Specifically, in systems where objects are moving with different velocities, it is impossible to determine which object is "in motion" and which object is "at rest". In other words, to phrase matters more technically, the laws of physics are the same in every inertial frame of reference, that is, in all frames related by a Galilean transformation.

paragraph_text: The acceleration due to gravity on the surface of the Moon is about 1.625 m / s, about 16.6% that on Earth's surface or 0.16 ɡ. Over the entire surface, the variation in gravitational acceleration is about 0.0253 m / s (1.6% of the acceleration due to gravity). Because weight is directly dependent upon gravitational acceleration, things on the Moon will weigh only 16.6% of what they weigh on the Earth.

paragraph_text: John Locke in particular exemplified this new age of political theory with his work Two Treatises of Government. In it Locke proposes a state of nature theory that directly complements his conception of how political development occurs and how it can be founded through contractual obligation. Locke stood to refute Sir Robert Filmer's paternally founded political theory in favor of a natural system based on nature in a particular given system. The theory of the divine right of kings became a passing fancy, exposed to the type of ridicule with which John Locke treated it. Unlike Machiavelli and Hobbes but like Aquinas, Locke would accept Aristotle's dictum that man seeks to be happy in a state of social harmony as a social animal. Unlike Aquinas's preponderant view on the salvation of the soul from original sin, Locke believes man's mind comes into this world as tabula rasa. For Locke, knowledge is neither innate, revealed nor based on authority but subject to uncertainty tempered by reason, tolerance and moderation. According to Locke, an absolute ruler as proposed by Hobbes is unnecessary, for natural law is based on reason and seeking peace and survival for man.

paragraph_text: Philosophers in antiquity used the concept of force in the study of stationary and moving objects and simple machines, but thinkers such as Aristotle and Archimedes retained fundamental errors in understanding force. In part this was due to an incomplete understanding of the sometimes non-obvious force of friction, and a consequently inadequate view of the nature of natural motion. A fundamental error was the belief that a force is required to maintain motion, even at a constant velocity. Most of the previous misunderstandings about motion and force were eventually corrected by Galileo Galilei and Sir Isaac Newton. With his mathematical insight, Sir Isaac Newton formulated laws of motion that were not improved-on for nearly three hundred years. By the early 20th century, Einstein developed a theory of relativity that correctly predicted the action of forces on objects with increasing momenta near the speed of light, and also provided insight into the forces produced by gravitation and inertia.

paragraph_text: Planet Earth is a 2006 British television series produced by the BBC Natural History Unit. Five years in the making, it was the most expensive nature documentary series ever commissioned by the BBC and also the first to be filmed in high definition. The series received multiple awards, including four Emmy Awards, a Peabody Award, and an award from the Royal Television Society.

paragraph_text: In the context of spaceflight, a satellite is an artificial object which has been intentionally placed into orbit. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as Earth's Moon.

paragraph_text: A Small Solar System Body (SSSB) is an object in the Solar System that is neither a planet, nor a dwarf planet, nor a natural satellite. The term was first defined in 2006 by the International Astronomical Union.

paragraph_text: In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing - by is the use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense. Gravity assistance can be used to accelerate a spacecraft, that is, to increase or decrease its speed or redirect its path. The ``assist ''is provided by the motion of the gravitating body as it pulls on the spacecraft. The gravity assist maneuver was first used in 1959 when the Soviet probe Luna 3 photographed the far side of Earth's Moon and it was used by interplanetary probes from Mariner 10 onwards, including the two Voyager probes' notable flybys of Jupiter and Saturn.

paragraph_text: It was only the orbit of the planet Mercury that Newton's Law of Gravitation seemed not to fully explain. Some astrophysicists predicted the existence of another planet (Vulcan) that would explain the discrepancies; however, despite some early indications, no such planet could be found. When Albert Einstein formulated his theory of general relativity (GR) he turned his attention to the problem of Mercury's orbit and found that his theory added a correction, which could account for the discrepancy. This was the first time that Newton's Theory of Gravity had been shown to be less correct than an alternative.

paragraph_text: The concept of inertia can be further generalized to explain the tendency of objects to continue in many different forms of constant motion, even those that are not strictly constant velocity. The rotational inertia of planet Earth is what fixes the constancy of the length of a day and the length of a year. Albert Einstein extended the principle of inertia further when he explained that reference frames subject to constant acceleration, such as those free-falling toward a gravitating object, were physically equivalent to inertial reference frames. This is why, for example, astronauts experience weightlessness when in free-fall orbit around the Earth, and why Newton's Laws of Motion are more easily discernible in such environments. If an astronaut places an object with mass in mid-air next to himself, it will remain stationary with respect to the astronaut due to its inertia. This is the same thing that would occur if the astronaut and the object were in intergalactic space with no net force of gravity acting on their shared reference frame. This principle of equivalence was one of the foundational underpinnings for the development of the general theory of relativity.

Question: What is the period of revolution of the planet that seemed to buck the gravitational laws of the man who proposed that innate inertial is the natural state of objects?
Answer: 88 days