Mercury (planet)

MercuryMercurioplanet MercuryDe GraftMercurianMercury's orbitplanet(Mercury)3:2 spin–orbit resonancea planet
Mercury is the smallest and innermost planet in the Solar System.wikipedia
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Iron

FeFe 2+ Fe(III)
The other terrestrial planets (Mercury, Venus, and Mars) as well as the Moon are believed to have a metallic core consisting mostly of iron.

Qutb al-Din al-Shirazi

Qotb al-Din ShiraziQutb al-Din ShiraziQotb-ed-Din Shirazi
In the 12th century, Ibn Bajjah observed "two planets as black spots on the face of the Sun", which was later suggested as the transit of Mercury and/or Venus by the Maragha astronomer Qotb al-Din Shirazi in the 13th century.
Shirazi identified observations by the scholar Avicenna in the 11th century and Ibn Bajjah in the 12th century as transits of Venus and Mercury.

Nilakantha Somayaji

Neelakanta SomayajiNilakanthaKelallur Neelakandhan Somayaji
In India, the Kerala school astronomer Nilakantha Somayaji in the 15th century developed a partially heliocentric planetary model in which Mercury orbits the Sun, which in turn orbits Earth, similar to the Tychonic system later proposed by Tycho Brahe in the late 16th century.
In his Tantrasangraha, Nilakantha revised Aryabhata's model for the planets Mercury and Venus.

Giovanni Schiaparelli

Giovanni Virginio SchiaparelliSchiaparelliG. Schiaparelli
In the 1880s, Giovanni Schiaparelli mapped the planet more accurately, and suggested that Mercury's rotational period was 88 days, the same as its orbital period due to tidal locking.
He was also a keen observer of the inner planets Mercury and Venus.

Vladimir Kotelnikov

Vladimir A. KotelnikovVladimir Aleksandrovich KotelnikovV. A. Kotelnikov
In June 1962, Soviet scientists at the Institute of Radio-engineering and Electronics of the USSR Academy of Sciences, led by Vladimir Kotelnikov, became the first to bounce a radar signal off Mercury and receive it, starting radar observations of the planet.
In June 1962 he led the first probe of the planet Mercury with radar.

Planets in astrology

JupiterMoonMars
Mercury is the ruling planet of both Virgo and Gemini and is exalted in Virgo and Aquarius.

Argon

Arargon gas 40 Ar
The atmospheres of Mars, Mercury and Titan (the largest moon of Saturn) contain argon, predominantly as, and its content may be as high as 1.93% (Mars).

Gordon Pettengill

Gordon H. Pettengill
Three years later, radar observations by Americans Gordon Pettengill and R. Dyce, using the 300-meter Arecibo Observatory radio telescope in Puerto Rico, showed conclusively that the planet's rotational period was about 59 days.
At Arecibo, Pettengill with Rolf Dyce, used radar pulses to measure the spin rate of Mercury and found that Mercury's 'day' was 59 Earth days, not 88 as had been previously thought.

Abū Ishāq Ibrāhīm al-Zarqālī

Al-ZarqaliArzachelal-Zarqālī
In medieval Islamic astronomy, the Andalusian astronomer Abū Ishāq Ibrāhīm al-Zarqālī in the 11th century described the deferent of Mercury's geocentric orbit as being oval, like an egg or a pignon, although this insight did not influence his astronomical theory or his astronomical calculations.
In designing an instrument to deal with Ptolemy's complex model for the planet Mercury, in which the center of the deferent moves on a secondary epicycle, al-Zarqālī noted that the path of the center of the primary epicycle is not a circle, as it is for the other planets.

Maya civilization

MayaMayanMayans
The Maya may have represented Mercury as an owl (or possibly four owls; two for the morning aspect and two for the evening) that served as a messenger to the underworld.
The Maya also followed the movements of Jupiter, Mars and Mercury.

NASA

National Aeronautics and Space AdministrationNASA Advisory CouncilU.S. space program
The first spacecraft to visit Mercury was NASA's Mariner 10 (1974–1975).
The first was Mariner in the 1960s and 1970s, which made multiple visits to Venus and Mars and one to Mercury.

Hohmann transfer orbit

Hohmann transfertransfer orbitsHohmann orbit
Therefore, the spacecraft must make a large change in velocity (delta-v) to enter a Hohmann transfer orbit that passes near Mercury, as compared to the delta-v required for other planetary missions.

European Space Agency

ESAEuropeanEuropean Space Agency (ESA)
The European Space Agency and the Japanese Space Agency developed and launched a joint mission called BepiColombo, which will orbit Mercury with two probes: one to map the planet and the other to study its magnetosphere.
ESA is also co-operating with Japan, the most notable current project in collaboration with JAXA is the BepiColombo mission to Mercury.

Earth's orbit

orbitEarth orbitsEarth-Sun distance
Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°.

Angular distance

angular separationapparent distanceangular separations
Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°.

Dusk

nightfallafter sunsetAstronomical dusk
This proximity to the Sun means the planet can only be seen near the western horizon after sunset or eastern horizon before sunrise, usually in twilight.

Dawn

daybreakastronomical dawnbefore sunrise
This proximity to the Sun means the planet can only be seen near the western horizon after sunset or eastern horizon before sunrise, usually in twilight.

Twilight

civil twilightastronomical twilightnautical twilight
This proximity to the Sun means the planet can only be seen near the western horizon after sunset or eastern horizon before sunrise, usually in twilight.

Fixed stars

fixed starfixedstars
It is tidally locked with the Sun in a 3:2 spin-orbit resonance, meaning that relative to the fixed stars, it rotates on its axis exactly three times for every two revolutions it makes around the Sun.

Frame of reference

reference frameframes of referencereference frames
As seen from the Sun, in a frame of reference that rotates with the orbital motion, it appears to rotate only once every two Mercurian years.

Equator

equatorial planeThe Equator
It is the smallest planet in the Solar System, with an equatorial radius of 2439.7 km.