<a href="https://en.wikipedia.org/wiki/Halley's_Comet" id="mwGg" rel="mw:WikiLink" title="Halley's Comet">Halley's Comet</a> makes its closest approach to Earth at a distance equal to 0.0342 <a href="https://en.wikipedia.org/wiki/Astronomical_unit" id="mwGw" rel="mw:WikiLink" title="Astronomical unit">AU</a> (5.1<span id="mwHA" typeof="mw:Entity"> </span>million kilometres/3.2<span id="mwHQ" typeof="mw:Entity"> </span>million miles).<sup about="#mwt23" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-2"}}' id="cite_ref-2" rel="dc:references" typeof="mw:Extension/ref"><a href="./April_10#cite_note-2" id="mwHg" style="counter-reset: mw-Ref 2;"><span class="mw-reflink-text" id="mwHw">[2]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-2"><cite about="#mwt20" class="citation book cs1" id="CITEREFSeargent2008">Seargent, David (2008). <a class="external text" href="https://books.google.com/books?id=DFgMAaU3vA8C" id="mwB1U" rel="mw:ExtLink nofollow"><i id="mwB1Y">The Greatest Comets in History: Broom Stars and Celestial Scimitars</i></a>. New York: Springer Verlag. pp.<span id="mwB1c" typeof="mw:Entity"> </span>44–45. <a class="mw-redirect" href="./ISBN_(identifier)" id="mwB1g" rel="mw:WikiLink" title="ISBN (identifier)">ISBN</a><span id="mwB1k" typeof="mw:Entity"> </span><a href="./Special:BookSources/9780387095127" id="mwB1o" rel="mw:WikiLink" title="Special:BookSources/9780387095127"><bdi id="mwB1s">9780387095127</bdi></a>.</cite><span about="#mwt20" class="Z3988" id="mwB1w" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=The+Greatest+Comets+in+History%3A+Broom+Stars+and+Celestial+Scimitars&amp;rft.place=New+York&amp;rft.pages=44-45&amp;rft.pub=Springer+Verlag&amp;rft.date=2008&amp;rft.isbn=9780387095127&amp;rft.aulast=Seargent&amp;rft.aufirst=David&amp;rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DDFgMAaU3vA8C&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AApril+10"></span></span>