Graham Hancock & Randall Carlson on the Joe Rogan Experience #872, fact-checked

What the evidence shows: The guest describes the February 15, 2013 Chelyabinsk object as about 50 feet in diameter entering at a low angle, in the context of an event that injured roughly 1,500 people. NASA's Jet Propulsion Laboratory estimated the object's effective diameter at about 18 meters (roughly 59 feet), with peak brightness and disruption occurring at an altitude of about 23.3 kilometers (14.5 miles); a Scientific American analysis of later research puts the diameter at about 19 meters and the main fragmentation between roughly 30 and 40 kilometers up. NASA also reports the event injured more than 1,600 people, mostly from broken glass, with no fatalities. The claimed 50-foot diameter is somewhat below the roughly 59-62 foot (18-19 meter) figure in the scientific literature, and the low-angle entry description is consistent with published trajectory analyses, while the injury toll cited is close to but slightly under NASA's figure. Overall the claim is directionally accurate but understates the object's size and is imprecise on entry/explosion altitude.

What the evidence shows: The claim combines an uncontroversial physical description with a highly contested scientific hypothesis. The Taurid meteor stream is a real, large debris complex whose extent has been measured at roughly 20-40 million km from Earth (e.g., via 1960s Mars 1 probe micrometeorite detections), so the "30 million km wide" figure is within the documented range. However, the assertion that this stream originated from the breakup of a single ~100-km-diameter "progenitor comet," and that a fragment of it caused a catastrophic impact on the North American ice sheet 12,800 years ago ending the last ice age, reflects the Younger Dryas Impact Hypothesis (YDIH), a minority position first proposed in 2007 that remains actively disputed rather than scientifically accepted. Early attempts by independent groups to replicate the hypothesis's key physical evidence (impact spherules, nanodiamonds) failed, leading much of the geoscience community to reject it by around 2011, and no impact crater from this era has ever been identified. A subset of researchers (including the Comet Research Group) continue to publish supporting studies and argue the hypothesis was rejected prematurely, so the scientific debate continues, but it has not resolved into mainstream acceptance of a 100-km comet or a Younger Dryas cataclysm. The guest's related books (e.g., "Magicians of the Gods") are built around this same comet-impact thesis.

What the evidence shows: The guest, speaking on this episode which aired November 16, 2016, stated that NASA was spending about $50 million a year on near-Earth object (NEO) detection and planetary defense. NASA's own record of the program corroborates this: the enacted fiscal year 2016 federal budget allocated $50 million to NEO observations and planetary defense, more than a ten-fold increase since the start of the prior administration, and NASA formalized the effort as the Planetary Defense Coordination Office (PDCO) in January 2016. A June 2025 NASA Office of Inspector General review of PDCO funding (Figure 3, budget by fiscal year) shows the total planetary defense budget was about $50 million in FY2015, roughly $60 million in FY2016, and about $65 million in FY2017, the period surrounding this episode's broadcast, before rising to roughly $155 million by FY2019 and peaking near $350-380 million in FY2024 and FY2026 (with FY2026-2030 figures still proposed as of the report). The $50 million figure the guest cited was therefore an accurate contemporaneous figure at the time it was stated, though it would become a significant understatement of NASA's planetary defense spending within a few years of the episode airing. Status: well-supported for the period the claim was made.

What the evidence shows: The reference is to the Pantelleria Vecchia Bank Megalith, a roughly 12-meter, 15-ton limestone block found on the seabed of the Sicilian Channel at about 40 meters (approximately 131 feet) depth, consistent with the "more than 120 feet" figure cited. Its discoverers, geophysicists Emanuele Lodolo and Zvi Ben-Avraham, proposed in a 2015 study that the block's regular shape and three hole-like features indicated it was shaped by Mesolithic humans before the site was submerged by rising sea levels around 9,350 years ago. That anthropogenic (man-made) interpretation has not been independently confirmed: no stone tools, cultural artifacts, or other unambiguous archaeological finds have been recovered from the site, and no professional underwater archaeologist verified the claim at the time. A 2023 peer-reviewed follow-up study by the same research group, examining separate but nearby stone ridges in the same bank, concluded that the available data "do not conclusively reveal either a natural or anthropogenic origin" for those features, underscoring that claims of human construction in this specific location remain scientifically unresolved rather than established. Describing the structure outright as a proven man-made megalith therefore overstates the current evidence; its origin is best characterized as disputed, with a natural (erosional/depositional) origin not ruled out.

What the evidence shows: Geologist Robert Schoch proposed in 1991 that the deep, undulating weathering on the Great Sphinx's body and enclosure walls resulted from centuries of heavy rainfall in a wetter climate period, implying the monument was carved well before the conventional Fourth Dynasty date of roughly 2500 BC under Pharaoh Khafre. This water-erosion hypothesis, later popularized in Graham Hancock and Robert Bauval's book The Message of the Sphinx, has not been accepted by mainstream Egyptology or geology, which continues to date the Sphinx to about 4,500 years ago. Critics tie the rainfall-redating to the broader Younger Dryas 'lost advanced civilization' hypothesis, for which mainstream science finds no supporting physical evidence, such as impact craters or artifacts of an advanced culture, and characterize the argument as reasoning from a lack of evidence rather than from positive evidence. Researchers have also proposed alternative natural explanations for the Sphinx's form: a 2023 fluid-dynamics study found that wind and sand erosion alone can carve yardang rock formations resembling a lying lion, suggesting ancient Egyptians may have refined an already-weathered natural outcrop rather than that the monument's shape requires millennia of rainfall to explain. The rainfall/Younger Dryas redating of the Sphinx remains a minority position rejected by the broader archaeological and geological community.

What the evidence shows: Smithsonian Magazine reported that in the summer of 2014, archaeologists from the German Archaeological Institute excavating the Baalbek quarry in Lebanon uncovered a limestone block measuring roughly 64 by 19.6 by 18 feet and weighing an estimated 1,650 tons, which the Institute described as 'the biggest boulder known from antiquity,' i.e. the largest ancient quarried stone block yet documented. This supports the core of the guest's claim that the block is the largest ever cut and quarried in the ancient world. The guest's cited weight of 1,460 tons runs somewhat below the approximately 1,650-ton figure most commonly reported for this block, so the claim is directionally accurate but imprecise on tonnage.