What are the closest comet encounters with Earth?

This table provides a list of known comet close encounters with Earth, for objects whose orbits are known well enough to be confident of the approach distances. Encounters occurring after 1950 are highlighted as the modern era, which signifies the time that scientific studies began to focus on the physics and chemistry of comets, rather than just qualitative descriptions of their behavior.

Note that the distance from Earth is not necessarily an indicator of brightness. Of the comets on the modern-era list, only #4 IRAS-Araki-Alcock and #5 252P/LINEAR (and hopefully #10 46P/Wirtanen) reached naked eye brightness, while many of the others were not detected because they were too faint (#8 323P/SOHO)



Rank  Rank   Distance  Distance  Date (TT)       Permanent designation
all  Modern    (LD)     (AU)
---- ------- -------  ------   -----------    ----------------------------------
  1     1      4.70   0.0120   1999 Jun 12        P/SOHO 5 (1999 J6)  
  2            5.88   0.0151   1770 Jul  1        D/Lexell (1770 L1)
  3            8.91   0.0229   1366 Oct 26      55P/Tempel-Tuttle
  4     2      9.22   0.0237   2016 Mar 22	  P/PANSTARRS 51 (2016 BA14) 
  5     3      9.68   0.0248   2003 Dec 11     289P/Blanpain  
  6     4     12.14   0.0312   1983 May 11        C/IRAS-Araki-Alcock (1983 H1) 
  7           13.00   0.0334    837 Apr 10       1P/Halley
  8     5     13.93   0.0358   2016 Mar 21     252P/LINEAR 
  9           14.24   0.0366   1805 Dec  9       3D/Biela
 10           15.18   0.0390   1743 Feb  8        C/1743 C1
 11           15.33   0.0394   1927 Jun 26       7P/Pons-Winnecke
 12           15.88   0.0408   1930 Jun  3      73P/Schwassmann-Wachmann 3
 13           17.01   0.0437   1702 Apr 20        C/1702 H1
 14           18.46   0.0474   1947 Apr 11     322P/SOHO 1 
 15     6     21.60   0.0555   2014 May 29     209P/LINEAR 41
 16     7     22.60   0.0581   2000 Jan 13     323P/SOHO 2 
 17     8     23.50   0.0604   1966 Jan 16     323P/SOHO 2 
 18     9     24.44   0.0628   1983 Jun 12        C/Sugano-Saigusa-Fujikawa (1983 J1) 
 19           26.54   0.0682   1760 Jan  8        C/1760 A1 (Great comet)
 20    10     30.23   0.0775   2018 Dec 16      46P/Wirtanen 
 21    11     30.63   0.0787   2006 May 12      73P/Schwassmann-Wachmann 3 
 22    12     32.37   0.0831   2017 Feb 11      45P/Honda-Mrkos-Pajdusakova  
 23           32.65   0.0839   1853 Apr 29        C/Schweizer (1853 G1)
 24           34.21   0.0879   1797 Aug 16        C/Bouvard-Herschel (1797 P1)
 25           34.40   0.0884    374 Apr  1       1P/Halley
 26    13     34.58   0.0888   2011 Aug 11      45P/Honda-Mrkos-Pajdusakova         
 27           34.69   0.0891   1904 Jun  6     300P/Catalina 3     
 28           34.95   0.0898    607 Apr 19       1P/Halley
 39           36.23   0.0931   1926 Jun 16     300P/Catalina 3       
 30           36.35   0.0934   1763 Sep 23        C/Messier (1763 S1)
 31           37.52   0.0964   1864 Aug  8        C/Tempel (1864 N1)
 32    14     38.09   0.0979   1997 Apr 22     249P/LINEAR 53 
 33           38.22   0.0982   1862 Jul  4        C/Schmidt (1862 N1)


This list was updated on Feb 9, 2017 using information from the list provided at the Minor Planet Center and the list generated from the JPL NEO website. Where discrepancies exist, the JPL information was adopted, as it is more complete due to the criteria used for an objects' inclusion on the two lists.)