Mercury
<p><img src="/9ea265bf-8104-59da-915a-2f6a81e4afef.png"/>mercury
<b>Mercury</b></p>
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<li >(<a href="http://en.wiktionary.org/wiki/Roman" title="Roman" >Roman</a> <a href="http://en.wiktionary.org/wiki/mythology" title="mythology" >mythology</a>) The <a href="http://en.wiktionary.org/wiki/Roman" title="Roman" >Roman</a> god associated with speed, sometimes used as a messenger. He wore winged sandals. Mercury corresponded to the Greek god <a href="http://en.wiktionary.org/wiki/Hermes" title="Hermes" >Hermes</a>.</li>
<li >(<a href="http://en.wiktionary.org/wiki/astronomy" title="astronomy" >astronomy</a>) The planet in the solar system with the closest orbit to the <a href="http://en.wiktionary.org/wiki/Sun" title="Sun" >Sun</a>, named after the god; represented by <a href="http://en.wiktionary.org/wiki/%E2%98%BF" title="☿" >☿</a>.</li>
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<p>
<b>Mercury</b> is the innermost of the eight <a href="http://en.wikipedia.org/wiki/Planet" title="Planet" >planets</a> in the <a href="http://en.wikipedia.org/wiki/Solar_System" title="Solar System" >Solar System</a>. It is also the smallest, and its orbit has the highest <a href="http://en.wikipedia.org/wiki/Orbital_eccentricity" title="Orbital eccentricity" >eccentricity</a> of the eight.<sup id="cite_ref-dwarf_planet_11-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Mercury(planet)#cite_note-dwarf_planet-11" >[a]</a></sup> It <a href="http://en.wikipedia.org/wiki/Orbit" title="Orbit" >orbits</a> the <a href="http://en.wikipedia.org/wiki/Sun" title="Sun" >Sun</a> once in about 88 Earth days, completing three rotations about its axis for every two orbits. Mercury has the smallest <a href="http://en.wikipedia.org/wiki/Axial_tilt" title="Axial tilt" >axial tilt</a>of the Solar System planets. The <a href="http://en.wikipedia.org/wiki/Apsis" title="Apsis" >perihelion</a> of Mercury's orbit <a href="http://en.wikipedia.org/wiki/Apsidal_precession" title="Apsidal precession" >precesses</a> around the Sun at an excess of 43 <a href="http://en.wikipedia.org/wiki/Minute_of_arc" title="Minute of arc" >arcseconds</a> per century beyond what is predicted by <a href="http://en.wikipedia.org/wiki/Newtonian_mechanics" title="Newtonian mechanics" class="mw-redirect" >Newtonian mechanics</a>, <a href="http://en.wikipedia.org/wiki/Tests_of_general_relativity#Perihelion_precession_of_Mercury" title="Tests of general relativity" >a phenomenon</a> that was explained in the 20th century by <a href="http://en.wikipedia.org/wiki/Albert_Einstein" title="Albert Einstein" >Albert Einstein</a>'s <a href="http://en.wikipedia.org/wiki/General_Theory_of_Relativity" title="General Theory of Relativity" class="mw-redirect" >General Theory of Relativity</a>.<sup id="cite_ref-wudka1998_12-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Mercury(planet)#cite_note-wudka1998-12" >[12]</a></sup>
Mercury, being an <a href="http://en.wikipedia.org/wiki/Inferior_planet" title="Inferior planet" class="mw-redirect" >inferior planet</a>, appears as a morning star and an evening star, but is much more difficult to see than the other inferior planet, <a href="http://en.wikipedia.org/wiki/Venus" title="Venus" >Venus</a>. At its brightest, Mercury is technically a very bright object when viewed from Earth, but it is not easily seen in practice because of its proximity in the sky to the Sun.</p>