Discovery of Spherules of Likely Extrasolar Composition in the Pacific Ocean Site of the CNEOS 2014-01-08 Bolide

Brief

The Galileo Project expedition (June 14–28, 2023) towed a 200-kg neodymium-magnet sled across ~0.26 km² of Pacific seafloor ~85 km north of Manus Island, Papua New Guinea, recovering ~700 spherules (0.05–1.3 mm diameter) at depths of 1.5–2.2 km. Of 57 spherules analyzed, 47 by iCAP TQ quadrupole ICP-MS at Harvard, five classify as a previously undescribed 'D-type BeLaU' subclass with refractory lithophile element enrichments 80–1,000× CI chondrite levels and very low refractory siderophile elements (Re), suggesting derivation from a differentiated planetary crust with an iron core. These BeLaU spherules appear exclusively in runs 4, 13, and 14, which overlap the heatmap high-yield corridor aligned with IM1's seismometer-constrained path; they are absent from control runs 17 and 22. Iron isotope ratios (δ⁵⁶/⁵⁴Fe, δ⁵⁷/⁵⁴Fe) are consistent with mass-dependent evaporative loss during atmospheric entry.

Metadata

Category

Phenomenon

Venue

preprint (arXiv astro-ph.EP)

Type

Preprint

Year

2023

Authors

Abraham Loeb, Toby Adamson, Sophie Bergstrom, Richard Cloete, Shai Cohen, Kevin Conrad, Laura Domine, Hairuo Fu, Charles Hoskinson, Eugenia Hyung, Stein Jacobsen, Mike Kelly, Jason Kohn, Edwin Lard, Sebastian Lam, Frank Laukien, Jim Lem, Rob McCallum, Rob Millsap, Christopher Parendo, Michail Pataev, Chaitanya Peddeti, Jeff Pugh, Shmuel Samuha, Dimitar Sasselov, Max Schlereth, JJ Siler, Amir Siraj, Peter Mark Smith, Roald Tagle, Jonathan Taylor, Ryan Weed, Art Wright, Jeff Wynn

arXiv

2308.15623

Access

Open access

Length

5.2 M

Programs

Galileo Project

Instruments

towed neodymium magnetic sled (200 kg, 300 magnets), JEOL JXA 8230 Electron Probe Microanalyzer (EPMA), iCAP TQ quadrupole ICP-MS (ThermoFisher Scientific), Nu Sapphire MC-ICPMS, Bruker CTX XRF

Data sources

CNEOS fireball catalog, US Space Command trajectory certification, Manus Island seismometer data, USGS reference materials BCR-2, BHVO-2, AGV-2

Tags

interstellar objects, cosmic spherules, meteoritics, geochemistry, SETI-adjacent, astrobiology

Key points

• ~700 spherules recovered across ~0.26 km² of seafloor; 57 analyzed in detail, 47 by mass spectrometry; 5 classified as BeLaU-type with elemental abundances up to 1,000× CI chondrite levels.p.1
• US Space Command issued a formal letter certifying a 99.999% likelihood that IM1 was interstellar in origin, based on trajectory analysis.p.2
• IM1 broke apart at ~17 km altitude with a ram pressure of ~200 MPa, making it stronger than all 272 objects in the CNEOS catalog, including the ~5% iron-meteorite fraction.p.2
• BeLaU spherules found only in runs 4, 13, and 14 (IM1 path); absent from control runs 17 and 22, the pattern is not reproduced by known manufactured alloys or natural meteorites.p.15
• Of 57 spherules analyzed: 18 S-type chondritic, 18 I-type, and 21 D-type (a previously undescribed differentiated class); D-type divides into Low-La and BeLaU subtypes.p.15
• Fe isotope ratios (δ⁵⁶/⁵⁴Fe, δ⁵⁷/⁵⁴Fe) measured by Nu Sapphire MC-ICPMS are consistent with evaporative loss of light isotopes during atmospheric transit.p.12
• The ~0.26 km² survey covers an estimated ~1% of IM1's strewn field, implying ~100 g total spherule mass and ~10⁵ total spherules deposited on the seafloor.p.13
• IM1's speed relative to the Local Standard of Rest of the Milky Way was ~60 km/s, exceeding that of 95% of stars in the Sun's vicinity.p.2

Verbatim

• “The unique spherules show an excess of Be, La and U, by up to three orders of magnitude relative to the solar system standard of CI chondrites.”

  p.1

• “The bolide broke apart at an unusually low altitude of ∼ 17 km, corresponding to a ram pressure of ∼ 200 MPa. This implied that the object was substantially stronger than any of the other 272 objects in the CNEOS catalog, including the ∼ 5%-fraction of iron meteorites from the solar system”

  p.2

• “The "BeLaU" spherules have refractory lithophile element abundances that are 80 to 1,000 higher than in CI chondrites.”

  p.15

• “We suggest that the "BeLaU" abundance pattern could have originated from a highly differentiated magma ocean of a planet with an iron core outside the solar system or from more exotic sources.”

  p.1

Most interesting

• The 200-kg sled with 300 neodymium magnets had to have 50 kg of lead ballast added mid-expedition because ocean currents caused it to 'kite' above the seafloor rather than dragging along it.
• A triple-merger spherule (S21) was recovered, three liquid droplets that fused and solidified before becoming spherical; the authors calculate a ~10% collision probability for such triple mergers given IM1's ablation geometry.
• The BeLaU spherule type had never previously appeared in the cosmic spherule literature across decades of recovery from Antarctic ice, deep-sea sediments, and other meteor sites.
• The survey's 26 sled runs used a 5-km synthetic cable to the seafloor at ~2 km depth, meaning only the ship's GPS was recorded, not the sled's, introducing a 2.29 km cross-track error disc for each data point.
• Roughly 500 kg of IM1's mass is estimated to have ablated during the fireball; the surveyed spherules represent only ~1 g of that total, with most material converted to sub-micron particles or gas.
• IM1's three atmospheric detonations were separated by one-tenth of a second from each other, as recorded by US government satellite sensors on January 8, 2014.