<h1>Table of Planets</h1>

<table>
  <caption>Data about the planets of our solar system (Planetary facts taken from <a href="http://nssdc.gsfc.nasa.gov/planetary/factsheet/">Nasa's Planetary Fact Sheet - Metric</a>).
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      <td colspan="2">&nbsp;</td>
      <th id="name">Name</th>
      <th id="mass">Mass (10<sup>24</sup>kg)</th>
      <th id="diameter">Diameter (km)</th>
      <th id="density">Density (kg/m<sup>3</sup>)</th>
      <th id="gravity">Gravity (m/s<sup>2</sup>)</th>
      <th id="length">Length of day (hours)</th>
      <th id="distance">Distance from Sun (10<sup>6</sup>km)</th>
      <th id="temperature">Mean temperature (°C)</th>
      <th id="moons">Number of moons</th>
      <th id="notes">Notes</th>
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    <tr>
      <th id="terrestrial" rowspan="5" colspan="2">Terrestrial planets</th>

    <tr>
      <th id="mercury" headers="name terrestrial">Mercury</th>
      <td headers="mass terrestrial mercury">0.330</td>
      <td headers="diameter terrestrial mercury">4,879</td>
      <td headers="density terrestrial mercury">5427</td>
      <td headers="gravity terrestrial mercury">3.7</td>
      <td headers="length terrestrial mercury">4222.6</td>
      <td headers="distance terrestrial mercury">57.9</td>
      <td headers="temperature terrestrial mercury">167</td>
      <td headers="moons terrestrial mercury">0</td>
      <td headers="notes terrestrial mercury">Closest to the Sun</td>
    </tr>

    <tr>
      <th id="venus" headers="name terrestrial">Venus</th>
      <td headers="mass terrestrial venus">4.87</td>
      <td headers="diameter terrestrial venus">12,104</td>
      <td headers="density terrestrial venus">5243</td>
      <td headers="gravity terrestrial venus">8.9</td>
      <td headers="length terrestrial venus">2802.0</td>
      <td headers="distance terrestrial venus">108.2</td>
      <td headers="temperature terrestrial venus">464</td>
      <td headers="moons terrestrial venus">0</td>
      <td headers="notes terrestrial venus">&nbsp;</td>
    </tr>

    <tr>
      <th id="earth" headers="name terrestrial">Earth</th>
      <td headers="mass terrestrial earth">5.97</td>
      <td headers="diameter terrestrial earth">12,756</td>
      <td headers="density terrestrial earth">5514</td>
      <td headers="gravity terrestrial earth">9.8</td>
      <td headers="length terrestrial earth">24.0</td>
      <td headers="distance terrestrial earth">149.6</td>
      <td headers="temperature terrestrial earth">15</td>
      <td headers="moons terrestrial earth">1</td>
      <td headers="notes terrestrial earth">Our world</td>
    </tr>

    <tr>
      <th id="mars" headers="name terrestrial">Mars</th>
      <td headers="mass terrestrial mars">0.642</td>
      <td headers="diameter terrestrial mars">6,792</td>
      <td headers="density terrestrial mars">3933</td>
      <td headers="gravity terrestrial mars">3.7</td>
      <td headers="length terrestrial mars">24.7</td>
      <td headers="distance terrestrial mars">227.9</td>
      <td headers="temperature terrestrial mars">-65</td>
      <td headers="moons terrestrial mars">2</td>
      <td headers="notes terrestrial mars">The red planet</td>
    </tr>

    <tr>
      <th id="jovian" rowspan="7">Jovian planets</th>

    <tr>
      <th id="gas" rowspan="3" headers="jovian">Gas giants</th>
    <tr>
      <th id="jupiter" headers="name jovian gas">Jupiter</th>
      <td headers="mass jovian gas jupiter">1898</td>
      <td headers="diameter jovian gas jupiter">142,984</td>
      <td headers="density jovian gas jupiter">1326</td>
      <td headers="gravity jovian gas jupiter">23.1</td>
      <td headers="length jovian gas jupiter">9.9</td>
      <td headers="distance jovian gas jupiter">778.6</td>
      <td headers="temperature jovian gas jupiter">-110</td>
      <td headers="moons jovian gas jupiter">67</td>
      <td headers="notes jovian gas jupiter">The largest planet</td>
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      <th id="saturn" headers="name jovian gas">Saturn</th>
      <td headers="mass jovian gas saturn">568</td>
      <td headers="diameter jovian gas saturn">120,536</td>
      <td headers="density jovian gas saturn">687</td>
      <td headers="gravity jovian gas saturn">9.0</td>
      <td headers="length jovian gas saturn">10.7</td>
      <td headers="distance jovian gas saturn">1433.5</td>
      <td headers="temperature jovian gas saturn">-140</td>
      <td headers="moons jovian gas saturn">62</td>
      <td headers="notes jovian gas saturn">&nbsp;</td>
    </tr>

    <tr>
      <th id="ice" rowspan="3" headers="jovian">Ice giants</th>
    <tr>
      <th id="uranus" headers=" name jovian ice">Uranus</th>
      <td headers="mass jovian ice uranus">86.8</td>
      <td headers="diameter jovian ice uranus">51,118</td>
      <td headers="density jovian ice uranus">1271</td>
      <td headers="gravity jovian ice uranus">8.7</td>
      <td headers="length jovian ice uranus">17.2</td>
      <td headers="distance jovian ice uranus">2872.5</td>
      <td headers="temperature jovian ice uranus">-195</td>
      <td headers="moons jovian ice uranus">27</td>
      <td headers="notes jovian ice uranus">&nbsp;</td>
    </tr>
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      <th id="neptune" headers="name jovian ice">Neptune</th>
      <td headers="mass jovian ice neptune">102</td>
      <td headers="diameter jovian ice neptune">49,528</td>
      <td headers="density jovian ice neptune">1638</td>
      <td headers="gravity jovian ice neptune">11.0</td>
      <td headers="length jovian ice neptune">16.1</td>
      <td headers="distance jovian ice neptune">4495.1</td>
      <td headers="temperature jovian ice neptune">-200</td>
      <td headers="moons jovian ice neptune">14</td>
      <td headers="notes jovian ice neptune">&nbsp;</td>
    </tr>

    <tr>
      <th id="dwarf" colspan="2" rowspan="2">Dwarf planets*</th>
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      <th id="pluto" headers="name dwarf">Pluto</th>
      <td headers="mass dwarf pluto">0.0146</td>
      <td headers="diameter dwarf pluto">2,370</td>
      <td headers="density dwarf pluto">2095</td>
      <td headers="gravity dwarf pluto">0.7</td>
      <td headers="length dwarf pluto">153.3</td>
      <td headers="distance dwarf pluto">5906.4</td>
      <td headers="temperature dwarf pluto">-225</td>
      <td headers="moons dwarf pluto">5</td>
      <td headers="notes dwarf pluto">Declassified as a planet in 2006, but this <a href="http://www.usatoday.com/story/tech/2014/10/02/pluto-planet-solar-system/16578959/">remains controversial</a>.</td>
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