Planet Mercury

A Planet Mercury is a planet (solar planet) that is first from The Sun.

• Counter-Example(s):
  • Venus (Planet).
• See: Mercury, False Color#True Color, Synodic Day, Ecliptic, Sun, Invariable Plane.

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References

2023

• (Wikipedia, 2023) ⇒ https://en.wikipedia.org/wiki/mercury_(planet) Retrieved:2023-9-20.
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    Mercury is the first planet from the Sun and the smallest in the Solar System. It is a terrestrial planet with a heavily cratered surface due to the planet having no geological activity and an extremely tenuous atmosphere (called an exosphere). Despite being the smallest planet in the Solar System with a mean diameter of , 38% of that of Earth, Mercury is dense enough to have roughly the same surface gravity as Mars. Mercury has a dynamic magnetic field with a strength about 1% of that of Earth's and has no natural satellites.

    According to current theories, Mercury may have a solid silicate crust and mantle overlying a solid outer core, a deeper liquid core layer, and a solid inner core. Having almost no atmosphere to retain heat, Mercury has surface temperatures that change wildly during the day, ranging from at night to during sunlight across the equator regions. At Mercury's poles though, there are large reservoirs of water ices that are never exposed to direct sunlight, which has an estimated mass of about 0.025–0.25% the Antarctic ice sheet. There are many competing hypotheses about Mercury's origins and development, some of which incorporate collision with planetesimal and rock vaporization.

    Because Mercury is very close to the Sun, the intensity of sunlight on its surface is between 4.59 and 10.61 times the solar constant (amount of the Sun's energy received at 1 astronomical unit, which is roughly the distance between Earth and the Sun). Mercury orbits the Sun in a 3:2 spin–orbit resonance, meaning that relative to the background stars, it rotates on its axis exactly three times for every two revolutions it makes around the Sun. Counterintuitively, due to Mercury's slow rotation, an observer on the planet would see only one Mercurian solar day (176 Earth days) every two Mercurian solar years (88 Earth days each). Mercury's axis has the smallest tilt of any of the Solar System's planets (about of a degree), and its orbital eccentricity is the largest of all known planets in the Solar System.Like Venus, Mercury orbits the Sun within Earth's orbit, making it appear in Earth's sky only as a "morning star" or "evening star" that's relatively close to the Sun. In English, it is named after the Roman god (Mercury), god of commerce, communication and the messenger of gods. Mercury is the most difficult planet to reach from Earth because it requires the greatest change in spacecraft's velocity. Only two spacecraft have visited Mercury as of 2023: ' flew by in 1974 and 1975, and MESSENGER launched in 2004 and orbited Mercury over 4,000 times in four years. The BepiColombo spacecraft is scheduled to make its final arrival at Mercury in 2025, and will then insert two orbiters.

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