Several sites claim NASA has confirmed a second moon orbiting earth. This is the Asteroid 2016 HO3. One source states The newfound quasi-satellite/moon-2016 HO3, is likely larger than 120 feet (40 m) and smaller than 300 feet (100 m).


Question Is this claim true circling the internet and can anyone post a link from NASAs offical web site to conclude this is true?


It's not true; this object is not a moon of Earth's.

Here's a NASA/JPL announcement of it. 2016 HO3 is the "name" being used for it at the moment.

They're calling it a "quasi-moon". It's in an orbit that is in resonance with Earth's but is not permanently bound. (It's not the first object to be found with such properties too.)

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    $\begingroup$ Its current orbit is charted on the Wikipedia page I linked. These orbits are quite interesting really. But I stress it is not a moon of Earth's. People tend to write "quasi moon" etc. on their press releases to generate public interest. $\endgroup$ – Andy Jul 5 '16 at 7:52
  • $\begingroup$ @Andy-what makes this object different than 2016 H03? The orbit right? <en.wikipedia.org/wiki/3753_Cruithne> $\endgroup$ – user5434678 Jul 5 '16 at 7:57
  • $\begingroup$ Right, Cruithne is also in an orbit that overlaps to Earth's though it's more eccentric than 2016 HO3. There are quite a lot of asteroids in these "horseshoe" orbits. (As far as I know those ones never get really close to Earth.) $\endgroup$ – Andy Jul 5 '16 at 8:07
  • $\begingroup$ This statement by space.com <space.com/33185-earth-quasi-moon-asteroid-2016-ho3.html> says the object is orbiting the sun right next to earth traveling at a speed similar to earths. This seems to make no sense due to its size 100ft or so.... and if the object is that close to earth it would of been captured in earth's gravity field along time ago, if not when will earth capture this asteroid forever and pronounce it a moon, or is this exactly what has happened and now they are announcing it? $\endgroup$ – user5434678 Jul 5 '16 at 8:10
  • $\begingroup$ It's a long way outside Earth's Hill sphere so I'd have trouble defining it as a true moon of Earth's. And that's all I think I can really say on this matter. $\endgroup$ – Andy Jul 5 '16 at 8:19

2016 HO3 does not really orbit Earth. It orbits the Sun in such a way that it happens to loop around Earth at distances of 0.1 to 0.25 AU. Earth's gravitational sphere of influence is much smaller, about 0.01 AU at most; outside that radius, the Sun is the dominant attractor.

The Minor Planet Center has an orbital diagram which you can examine in 3D. Earth's orbit is light blue. 2016 HO3's orbit is orange to the north of Earth's orbital plane and medium blue to the south. A dark gray line passes through the Sun and the asteroid's perihelion and aphelion. It's a moderately eccentric, moderately inclined orbit around the Sun with a 1.00 year period.

In the course of its solar orbit, the asteroid alternately moves slower, outside, and to the north of Earth's orbit; and faster, inside, and to the south. In a rotating frame of reference fixed on Earth, as in the video you've seen, this looks like an oddly shaped, highly inclined, retrograde loop around Earth, but it is not due to Earth's gravity. Earth's slight influence helps to maintain this coincidental pattern but is not nearly enough to capture the asteroid.


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