A Collision With a Dwarf Planet Likely Caused Our Moon to Become Lopsided

Our Moon features a nearside and far side with dramatically different geological features . This anomaly has puzzled scientists for years , but new computer simulations indicate the Moon ’s asymmetric inclination can be follow back to an ancient collision with another physical object — possibly a dwarf planet .

For thousands and thousands of eld , manhood had no musical theme what the Moon ’s far side looked like . Our natural planet is tidally mesh to Earth , forcing us to stare perpetually upon one of its two hemispheres . begin with the Apollo missions , however , we finally acquired the capacity to investigate the Moon ’s unseen face . To the surprise of uranologist , the Moon ’s two lobe were found to exhibit spectacular differences in topography , crustal heaviness , and chemical composition . Scientists figured this marked asymmetry was the issue of ancient , but unknown , strong-arm processes .

Newresearchpublished in the Journal of Geophysical Research : planet suggests this unexpected asymmetry was because of an ancient hit with a rather large aim , likely a midget satellite .

Artist’s depiction of a massive collision involving two large objects.

Artist’s depiction of a massive collision involving two large objects.Image: (NASA/JPL-Caltech)

“ This is a paper that will be very provocative , ” Steve Hauck , a professor of planetary geodynamics at Case Western Reserve University who was n’t involved with the cogitation , said in a printing press freeing . “ understand the ancestry of the differences between the nearside and the far side of the Moon is a fundamental consequence in lunar science,”Hauck , who is the editor - in - chief of JGR : Planets , supply .

The lead source of the new study , Zhu Meng - Hua of the Space Science Institute at Macau University of Science and Technology , had a hunch the dear side - far side asymmetries were the effect of heavenly collision after look at data gathered in 2012 by the Gravity Recovery and Interior Laboratory ( GRAIL ) mission . This data showed that the far side crust was about 10 kilometers ( 6 miles ) thicker than the crust on the near side . What ’s more , the far side also exhibited an surplus layer of crust consisting of materials rich in magnesium and iron .

Using the GRAIL data point , Zhu ran a series of computer simulations to try out the hypothesis that a elephantine collision give the Moon wonky . In all , 360 dissimilar electronic computer models were conducted to ascertain if an impact could produce the same form of physical features note on the Moon today .

Image:

Maps showing differences in lunar topography (A), crustal thickness (B), and thorium distribution (C). The star at the top right shows the possible point of impact on the nearside.Image: (JGR: Planets/Zhu et al. 2019/AGU.)

Of the simulations conducted , two were in tune with the GRAIL datum . Specifically , the skinny side - far side asymmetry was evidence to be cause by a large object valuate 780 kilometers ( 480 Admiralty mile ) in diam reach the Moon ’s nearside at 22,550 km / h ( 14,000 miles per hour ) or a slightly smaller target at 720 kilometer across ( 450 miles ) at a higher speed of 24,500 km / hydrogen ( 15,000 mph ) . By comparability , the dwarf major planet Ceres is 945 kilometers ( 590 miles ) across .

Both of these scenarios kick up voluminous amounts of rubble that rained back down onto the lunar Earth’s surface , particularly on the side opposite to the collision . The falling fabric bury the primordial cheekiness on the far side with a layer quantify 5 to 10 kilometers ( 3 to 6 nautical mile ) thick , which is consistent with the observations made by GRAIL . The authors of the new study say the offending target was potential a midget planet in eye socket around the Sun and not a 2nd Earth moon .

Importantly , the new discipline has the potential difference to lick a linger mystery about differences maintain in isotopes of potassium , daystar , and various rarified - earthly concern element between the Earth and Moon . This new possibility happily explains this discrepancy by indicate the element arrived later to the Moon via the impact .

Image:

The modeled impact of an object 780 kilometers wide containing a 200-kilometer wide iron core hitting the Moon at 22,500 km/h (14,000 mph). The right halves represent the temperature variations during the impact process, and the black arrows in (C) and (D) show the movement of debris around the Moon.Image: (JGR: Planets/Zhu et al. 2019/AGU.)

Excitingly , the new result could also explain similar asymmetric features seen on other planets in the solar system of rules , including Mars .

“ Indeed , several planets have hemispherical dichotomies , yet for the Moon we have a lot of datum to be able to examine models and guess with , so the implications of the work could likely be broader than just the Moon , ” state Hauck .

It ’s an intriguing conclusion , but one intemperately reliant upon computer poser . Other researchers should take to the woods their own pretense , preferably with data point gathered from GRAIL and other sources . It would be interesting to see , for example , if the radioactive dust patterns find out in the raw study can be match by others . Future enquiry should also focus on the presence of “ foreign ” material on the Moon ( i.e. the end of the aim gnome major planet ) that could further corroborate the findings of the young paper . Until then , the fresh possibility will have to remain just that — a theory .

Argentina’s President Javier Milei (left) and Robert F. Kennedy Jr., holding a chainsaw in a photo posted to Kennedy’s X account on May 27. 2025.