An Ocean Expedition by the Galileo Project to Retrieve Fragments of the First Large Interstellar Meteor CNEOS 2014-01-08

Brief

Using the CNEOS bolide catalog and a DoD-confirmed velocity measurement, the authors establish that CNEOS 2014-01-08 entered Earth's atmosphere on 2014-01-08 at 44.8 km/s on an unbound hyperbolic orbit (e = 2.4 ± 0.3), deviating 58 ± 6 km/s from the Local Standard of Rest, a speed shared by fewer than 5% of stars. Ram-pressure analysis of the fireball's three-flash light curve constrains the object's yield strength to 113–194 MPa, exceeding that of iron meteorites (~50 MPa) and surpassing all 272 other bolides in the CNEOS database. The planned Galileo Project recovery expedition would deploy a ~55 kg magnetic sled at ~3.3 km/hr over a 10 km × 10 km seafloor search box approximately 300 km north of Manus Island across ten survey days.

Metadata

Category

Phenomenon

Venue

preprint (arXiv astro-ph.EP)

Type

Preprint

Year

2022

Authors

Amir Siraj, Abraham Loeb, Tim Gallaudet

arXiv

2208.00092

Access

Open access

Length

417.6 K

Programs

Galileo Project

Instruments

magnetic sled (towed ferromagnetic collector), CNEOS bolide sensor network, Pan-STARRS

Data sources

CNEOS fireball catalog, DoD classified velocity data (declassified letter), CNEOS 2014-01-08 light curve

Tags

interstellar objects, meteoritics, SETI-adjacent, astrobiology, ocean expedition, bolide analysis

Key points

• DoD formally confirmed interstellar origin on April 6, 2022, stating the velocity estimate is 'sufficiently accurate to indicate an interstellar trajectory' at 99.999% confidence.p.1
• Orbital elements at impact: semi-major axis a = −0.47 ± 0.15 AU, eccentricity e = 2.4 ± 0.3, inclination i = 10 ± 2°; heliocentric incoming speed 58 ± 6 km/s from LSR.p.2
• Meteor mass was approximately 4.6 × 10^5 g based on impact speed of 44.8 km/s and total impact energy of 4.6 × 10^18 ergs.p.2
• Three fireball flares occurred at altitudes 23.0, 21.0, and 18.7 km, producing ram pressures of 113, 145, and 194 MPa, the 194 MPa peak exceeds every other bolide in the 273-entry CNEOS database; second place is 81 MPa.p.4
• Inferred local number density of similarly sized interstellar objects: n ~ 10^6 AU^-3, implying 0.2–20 Earth masses of such material ejected per local star, in tension with minimum-mass solar nebula estimates.p.2
• The seafloor search targets ~0.1 mm ferromagnetic fragments within a 10 km × 10 km box; sedimentation rate of 1 mm–1 cm per thousand years limits burial depth to ≤5 cm.p.5
• Expedition logistics: seven sled operators, ~126 effective towing hours over seven survey days, covering ~40 10-km lines and disturbing roughly 0.4 km² of seafloor.p.5
• The fireball energy (4.6 × 10^18 ergs total; 3.1 × 10^17 ergs optical at ~6.9% optical efficiency) is described as a few percent of the Hiroshima bomb yield.p.2

Verbatim

• “Dr. Mozer confirmed that the velocity estimate reported to NASA is sufficiently accurate to indicate an interstellar trajectory”

  p.2

• “CNEOS 2014-01-08 is an outlier both in terms of its LSR speed (shared by less than 5% of all stars) and its composition (tougher than all 272 other bolides in the CNEOS database).”

  p.5

• “The required material strength for CNEOS-2014-01-08 suggests a composition tougher than that of typical iron meteorites or else it would have not survived the ram pressure down to an altitude of 18.7 kilometers where its brightest flare was observed.”

  p.5

• “Of course, this result does not imply that the first interstellar meteor was artificially made by a technological civilization and not natural in origin”

  p.5

• “which created a fireball carrying a few percent of the energy of the Hiroshima bomb”

  p.2

• “This was followed by the discovery of Borisov, which allowed for a similar calibration of its size ∼ 0 . 4 − 1 km.”

  p.1

Most interesting

• CNEOS 2014-01-08's yield strength (113–194 MPa) is more than twice that of iron meteorites (~50 MPa), ruling out every common meteorite class and all compositional analogs proposed for 'Oumuamua, including nitrogen icebergs, H2 icebergs, and fluffy dust clouds.
• At ~0.5 m diameter, this object is two orders of magnitude smaller than 'Oumuamua, yet was detectable purely because it entered Earth's atmosphere, demonstrating that Earth itself acts as a 'fishing net' for interstellar material at a scale no telescope survey can access.
• Recovering interstellar fragments via ocean sled is estimated to cost roughly 10,000 times less than a dedicated sample-return space mission to an interstellar object like 'Oumuamua.
• The slowdown calculation implies the object entered the top of the atmosphere at least 66.5 km/s, 48% faster than the 44.8 km/s speed measured at peak brightness, making its interstellar origin even more statistically secure than the original classification.
• A control sampling zone is built into the expedition design to distinguish interstellar particles from the ambient micrometeorite background on the seafloor.
• The inferred number density of ~10^6 interstellar objects per AU^3 of this size class requires an amount of ejected planetesimal material per star that strains standard minimum-mass solar nebula models, which predict roughly one Earth mass of total material.