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Is there any known celestial body of at least 500 ft (150 m) diameter whose Minimum Orbit Intersection Distance (MOID) is within the Earth, meaning it's sure that it can impact the Earth? I know Comet 109P/(Kegler-)Swift-Tuttle has a very close MOID at 130,000 km (81,000 mi) and the Earth probably would be struck by particles from its tail if it came that close. And Apophis can come as close as 47,200 km (29,300 mi) but that's an asteroid (no tail). Are there any large bodies whose MOID is closer?

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    $\begingroup$ If there was, I'm sure that the World and his dog would know about it. $\endgroup$ – Mick Oct 28 at 21:44
  • $\begingroup$ This is an interesting question! Can you clarify the following: "...whose MOID is closer?" is not the same as "...whose Minimum Orbit Intersection Distance (MOID) is within the Earth." Are you asking for "closer" or "within the Earth?" $\endgroup$ – uhoh Oct 28 at 22:52
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    $\begingroup$ @uhoh I'm primarily asking for an MOID within the Earth so that would be a maximum of 6378 km + additional 60 km of atmosphere that would slow down enough or burst even the faster asteroids, so primarily I asked for an MOID up to 6438 km. As for asteroids and especially comets within Apophis' MOID that was a secondary question. $\endgroup$ – John Oct 29 at 7:43
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JPL and ESA provide tools to search for small bodies meeting user-defined criteria. I tried:

  • H <= 24
  • MOID <= 1e-4 au

with each and got these results in common:

  • (89959) 2002 NT7, an H=16.5 (~1.4 km) asteroid with a 2.29 year period. MOID≈4000 km but closest approach between 1900 and 2200 is 0.37 au; orbit rather highly inclined (i=42.3°).

  • (292220) 2006 SU49, an H=19.4 (390-780 m) asteroid with a 1.68 year period. MOID≈10,000 km; 3.2 lunar distance (LD) approach expected in 2029.

  • 2014 DA, an H=22.7 (85-170 m) asteroid with a 1.85 year period and MOID≈4000 km. Discovered after a 9.3 LD approach; other approaches uncertain (JPL condition code 7) due to limited observational data.

  • 2008 BO16, H=22.9 (80-160 m), 3.78 year period, MOID≈15,000 km, condition code 7.

  • 2010 VB1, H=23.2 (70-140 m), 1.21 year period, MOID≈8000 km, 1.5 LD approach expected in 2068.

Each tool also listed a few bodies which the other didn't. MOID computation methods vary, and I wouldn't assume that it's known very precisely even for numbered asteroids. The ESA database appears to store MOID at a resolution of 1e-5 AU (1500 km).

JPL Sentry uses different criteria and shows different results including Apophis and Bennu.

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