Abraham "Avi" Loeb (Hebrew: אברהם (אבי) לייב; born February 26, 1962) is an Israeli and American theoretical physicist who works on astrophysics and cosmology. Loeb is the Frank B. Baird Jr. Professor of Science at Harvard University.[1][2][3][4][5][6] He chaired the Department of Astronomy from 2011 to 2020, and founded the Black Hole Initiative in 2016.
Avi Loeb | |
|---|---|
אבי לייב | |
Loeb in 2023 | |
| Born | Abraham Loeb February 26, 1962 Beit Hanan, Israel |
| Alma mater | Hebrew University of Jerusalem (BSc, MSc, PhD) |
| Scientific career | |
| Fields | Cosmology, astrophysics |
| Institutions | Institute for Advanced Study Harvard University |
| Thesis | Particle acceleration to high energies and amplification of coherent radiation by electromagnetic interactions in plasmas (1986) |
| Doctoral advisor | Shalom Eliezer Lazar Friedland |
| Other academic advisors | John N. Bahcall |
| Doctoral students | Daniel Eisenstein |
Loeb is a fellow of the American Academy of Arts and Sciences, the American Physical Society, and the International Academy of Astronautics. In 2015, he was appointed as the science theory director for the Breakthrough Initiatives of the Breakthrough Prize Foundation.
Loeb has published popular science books including Extraterrestrial: The First Sign of Intelligent Life Beyond Earth (2021) and Interstellar: The Search for Extraterrestrial Life and Our Future in the Stars (2023).
Since 2017, Loeb has made a series of claims that alien space craft may be in the Solar System. He has argued that ʻOumuamua and other interstellar objects, including the reputedly interstellar meteor CNEOS 2014-01-08, are potential examples of such craft.[7] These claims have been widely rejected by the scientific community.[8][9][10] In 2023, he claimed to have recovered spherules formed by the impact of CNEOS 2014-01-08 that he alleged could be evidence of an alien starship,[11] but the location in the ocean where he recovered the spherules was based on mistaking a seismic signal from a truck for the impact of the meteor.[12][9] Loeb tends to publicize his results before undergoing peer review, contributing to a climate of sensationalism around his claims.[13]
Life and career
editLoeb was born in Beit Hanan,[14] Israel, in 1962. He took part in the national Talpiot program research program of the Israeli Defense Forces at age 18.[15] While in Talpiot, he obtained a BSc degree in physics and mathematics in 1983, an MSc degree in physics in 1985, and a PhD in plasma physics in 1986, all from the Hebrew University of Jerusalem (HUJI).[5] During his doctoral studies, Loeb conducted research at the Soreq Nuclear Research Center in Yavne.[16] His PhD thesis focused on the modeling of plasma acceleration of charged particles.[17] From 1983 to 1988, he led the first international project supported by the U.S. Strategic Defense Initiative on a new propulsion method for high-speed projectiles.[18] Between 1988 and 1993, Loeb was a long-term member at the Institute for Advanced Study at Princeton, where he started to work in theoretical astrophysics under the supervision of John Bahcall.
In 1993, he moved to Harvard University as an assistant professor in the department of astronomy, and was tenured three years later.[4][6][2] Since 2007, he has been Director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics.[1] Since 2012, Loeb became the Frank B. Baird Jr. Professor of Science at Harvard.[19]
Loeb has written eight books, including the textbooks How Did the First Stars and Galaxies Form?[20][21] and The First Galaxies in the Universe.[22] He has co-authored many papers on topics in astrophysics and cosmology,[2][5] including the first stars, the epoch of reionization, the formation and evolution of massive black holes, the search for extraterrestrial life, gravitational lensing by planets, gamma-ray bursts at high redshifts, the use of the Lyman-alpha forest to measure the acceleration/deceleration of the universe in real time,[23] the future collision between the Milky Way and Andromeda galaxies,[24] the future state of extragalactic astronomy,[25] astrophysical implications of black hole recoil in galaxy mergers,[26] tidal disruption of stars,[27] and imaging black hole silhouettes.[28][3]
Together with his postdoc James Guillochon, Loeb predicted the existence of a new population of stars moving near the speed of light throughout the universe.[29] Together with his postdoc John Forbes and Howard Chen of Northwestern University, Loeb made another prediction that sub-Neptune-sized exoplanets have been transformed into rocky super-Earths by the activity of Sagittarius A*.[30]
Together with Paolo Pani, Loeb showed in 2013 that primordial black holes in the range between the masses of the Moon and the Sun cannot make up dark matter.[31] In 2025, Loeb, in collaboration with Oem Trivedi, proposed that dark matter could consist of remnants of Planck Stars formed after the evaporation of primordial black holes.[32] Loeb led a team that reported tentative evidence for the birth of a black hole in the young nearby supernova SN 1979C.[33] In collaboration with Dan Maoz, Loeb demonstrated in 2013 that biomarkers, such as molecular oxygen (O
2), can be detected by the James Webb Space Telescope (JWST) in the atmosphere of Earth-mass planets in the habitable zone of white dwarfs.[34]
In 2018, he served a term as chair of the Board on Physics and Astronomy (BPA)[35] of the National Academies of Sciences, Engineering, and Medicine (NASEM).
Life in the universe
editIn 2013, Loeb wrote about the "Habitable Epoch of the Early Universe", noting that the Cosmic Microwave Background would temporarily have been at temperatures compatible with liquid water around 15 million years after the Big Bang.[36][37] In April 2021, he presented an updated summary of his ideas of life in the early universe.[38]
In 2020, Loeb published a paper about the possibility that life can propagate from one planet to another,[39] followed by the opinion piece "Noah's Spaceship" about directed panspermia.[40]
Claims about alien life
editLoeb's claims about alien life have attracted sustained criticism from other scientists. Steve Desch, an astrophysicist at Arizona State University referred to Loeb's claims as "ridiculous sensationalism" which represent "a real breakdown of the peer review process and the scientific method".[12] Some of Loeb's claims have been described as conspiracy theories, with USA Today referring to Loeb's speculation about 3I/ATLAS as an "outlandish conspiracy theor[y]."[41] Other scientists have described Loeb's theories as "nonsense", comparable to the idea that "the moon is made of cheese."[42]
In 2024, Loeb delivered a speech in which he declared his view that the Messiah will be an alien who arrives from outer space.[43]
ʻOumuamua
editʻOumuamua was the first confirmed interstellar object detected in the Solar System. In December 2017, Loeb cited ʻOumuamua's unusually elongated shape as one of the reasons the Green Bank Telescope in West Virginia should listen for radio emissions from it to see if there were any unexpected signs that it might be of artificial origin,[44] although earlier limited observations by other radio telescopes such as the SETI Institute's Allen Telescope Array had produced no such results.[45] The Green Bank Telescope observed the asteroid for six hours, detecting no radio signals.[46][47]
On October 26, 2018, Loeb and his postdoctoral student Shmuel Bialy submitted a paper exploring the possibility that ʻOumuamua is an artificial thin solar sail accelerated by solar radiation pressure in an effort to help explain the object's non-gravitational acceleration.[48][49][50] The consensus among other astrophysicists was that the available evidence is insufficient to consider such a premise,[51][52][53] and that a tumbling solar sail would not be able to accelerate.[54][55] In response, Loeb wrote an article detailing six anomalous properties of ʻOumuamua that make it unusual, unlike any comets or asteroids seen before.[56][57] By 2021, there was widespread consensus in the scientific community that 1I/ʻOumuamua had properties entirely consistent with a naturally occurring object, perhaps made of nitrogen ice,[10] or a comet-like body that was altered by warming as it travelled through the solar system.[58]
On November 27, 2018, Loeb and Amir Siraj, a Harvard undergraduate, proposed a search for ʻOumuamua-like objects that might be trapped in the Solar System as a result of losing orbital energy through a close encounter with Jupiter.[59] They identified four candidates (2011 SP25, 2017 RR2, 2017 SV13, and 2018 TL6) for trapped interstellar objects that dedicated missions could visit. The authors pointed out that future sky surveys, such as with Large Synoptic Survey Telescope, could find many more.[60]
In public interviews and private communications with reporters and academic colleagues, Loeb has become more vocal about the prospects of proving the existence of alien life.[61] On April 16, 2019, Loeb and Siraj reported the discovery of a meteor of interstellar origin.[62] Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, a popular science account of ʻOumuamua by Loeb,[63] was published in 2021.[64][65][66] A followup book, Interstellar: The Search for Extraterrestrial Life and Our Future in the Stars, was published on August 29, 2023.[67][68]
The Galileo Project
editIn July 2021, Loeb founded the Galileo Project for the Systematic Scientific Search for Evidence of Extraterrestrial Technological Artifacts.[70][71] The project was inspired by the detection of ʻOumuamua and by release of the Office of the Director of National Intelligence report on Unidentified Aerial Phenomena (UAP). As stated on the project's website, the aim is:
Given the recently discovered abundance of Earth-Sun systems, the Galileo Project is dedicated to the proposition that humans can no longer ignore the possible existence of Extraterrestrial Technological Civilizations (ETCs), and that science should not dogmatically reject potential extraterrestrial explanations because of social stigma or cultural preferences, factors which are not conducive to the scientific method of unbiased, empirical inquiry. We now must 'dare to look through new telescopes', both literally and figuratively.[70]
The three main avenues of research are:[72]
- Obtaining high-resolution images of UAPs and discovering their nature
- Searching for and research of ʻOumuamua-like interstellar objects
- Searching for potential ETC satellites
Unlike other similar projects, the goal of the Galileo Project is to search for physical objects, and not electromagnetic signals, associated with extraterrestrial technological equipment.[73] The project was covered by many independent publishers, among them Nature, Science, New York Post, Scientific American, The Guardian, etc.[74] To allegations that studies of UFOs is pseudoscience, Loeb answers that the project aims not to study UFOs based on previous data, but to study Unidentified Aerial Phenomena "using the standard scientific method based on a transparent analysis of open scientific data to be collected using optimized instruments".[75]
CNEOS 2014-01-08
editIn 2014, the US Department of Defense observed a fireball entering the atmosphere.[76] Loeb made a series of claims about this event, from the meteor being from outside the Solar System to its likely area of impact based on, among other things, a seismic signal that occurred around the same time,[77] all culminating in 2023, when Loeb announced that he had found interstellar material on the ocean floor[78] that he asserted came from the meteor and could be remnants of an extraterrestrial starship.[76] These claims were criticized by other scientists as hasty, sensational, and part of a pattern of improper behavior. Peter Brown, a meteor physicist at the University of Western Ontario, argued the material can be explained as non-interstellar, noting that measurements from Defense Department data are opaque and error-prone. Brown further said he was disturbed by Loeb's lack of engagement with relevant experts.[12] In March 2022, the U.S. Space Force affirmed that their 2014 data indicated an interstellar origin, while the following month NASA stated the evidence for this was inconclusive.[8]
Astrophysicist Steve Desch, at Arizona State University, commented "[Loeb's claims are] polluting good science—conflating the good science we do with this ridiculous sensationalism and sucking all the oxygen out of the room", and said several of his colleagues are consequently refusing to engage with Loeb in the peer review process.[12] Monica Grady from the Open University argued that the evidence for Loeb's claims is "rather shaky" and pointed more plausibly to terrestrial pollution.[76] Patricio A. Gallardo in an American Astronomical Society paper similarly concluded the samples were consistent with coal ash contamination.[79] Loeb subsequently authored a preprint saying chemical analysis ruled out coal ash contamination and indicated extrasolar origins.[80][81] Loeb and Morgan MacLeod proposed a tidal disruption mechanism that could cause meteors to be ejected into trajectories leading to the described observations.[82] In 2024 planetary seismologist Benjamin Fernando led a team that analyzed the seismic signals that led Loeb to search that specific region of the ocean, and they concluded that the seismic signals from one of the sensors used was in fact caused not by a meteor, but by a truck driving near the sensor, so that, "Not only did they use the wrong signal, they were looking in the wrong place."[83]
3I/ATLAS
editIn 2025, ATLAS (Asteroid Terrestrial-impact Last Alert System) the NASA-funded survey telescope in Rio Hurtado, Chile, observed a comet approaching from the constellation of Sagittarius at an interstellar velocity. Loeb hypothesized in the press that it, the third known interstellar object, could be an alien device with potentially malevolent intent. He based these speculations on his calculations of the likelihood of a comet of natural origins having these characteristics. "The retrograde orbital plane of 3I/ATLAS around the Sun lies within 5 degrees of that of Earth... The likelihood for that coincidence out of all random orientations is 0.2 percent," Loeb told Newsweek. He further claimed that the brightness of 3I/ATLAS implies an object that is around 20 kilometers in diameter which is "too large for an interstellar asteroid." 3I/ATLAS' trajectory will bring it close to Venus, Mars and Jupiter, a path Loeb calculated as having a probability of just 0.005 percent. "It might have targeted the inner Solar System as expected from alien technology," he added. Richard Moissl, Head of Planetary Defence at the European Space Agency told Newsweek: "There have been no signs pointing to non-natural origins of 3I/ATLAS in the available observations."[84] Since then, observations have reported evidence of 3I/ATLAS containing water, which is a substance commonly found in comets.[85][86]
Independent assessments have resoundingly rejected the idea that 3I/ATLAS is anything except a comet. Nicola Fox, associate administrator of NASA's Science Mission Directorate said that "We certainly haven't seen any technosignatures or anything from it that would lead us to believe it was anything other than a comet". Similarly, NASA Associate Administrator Amit Kshatriya stated that "all evidence points to it being a comet."[87] In the face of this growing body of evidence, Loeb conceded that 3I/ATLAS is "most likely" a comet, though he continued to speculate about its supposed technological nature regardless.[88][89]
Media appearances
editIn 2006, Loeb was featured in a Time magazine cover story on the first stars, and in a Scientific American article on the Dark Ages of the universe. In 2008, he was featured in a Smithsonian magazine cover story on black holes, and in two Astronomy magazine cover stories, one on the collision between the Milky Way and the Andromeda Galaxy and the second on the future state of our universe. In 2009, Loeb reviewed in a Scientific American article a new technique for imaging black hole silhouettes. Loeb received considerable media attention[90] after proposing in 2011 (with E.L. Turner) a new technique for detecting artificially-illuminated objects in the Solar System and beyond,[91] and showing in 2012 (with I. Ginsburg) that planets may transit hypervelocity stars or get kicked to a fraction of the speed of light near the black hole at the center of the Milky Way.[92]
He has been profiled a number of times, including in Science magazine,[93] Discover,[94] and The New York Times.[95] He has been interviewed by Astronomy magazine,[96] by Lex Fridman,[97] Let's Get Haunted,[98] Joe Rogan,[99] Mick West,[100] and by the H3 Podcast.[101] On August 24, 2023, The New York Times published an article about Loeb and his search for signs of extraterrestrial life.[67]
Loeb also regularly writes opinion essays on science and policy.[102][103]
Honors and awards
editLoeb has received many honors, including:[5]
- 1987 – The Kennedy Prize of the Hebrew University of Jerusalem
- 2002 – Guggenheim Fellowship[104]
- 2004 – Distinguished Visiting Professorship at the Faculty of Physics & Einstein Center for Theoretical Physics of the Weizmann Institute of Science
- 2006/7 – John Bahcall Lecturer at the Tel Aviv University
- 2006 – Salpeter Lectureship at Cornell University
- 2012 – Time magazine's 25 most influential people in space.[105]
- 2012 – Elected member of the American Academy of Arts and Sciences
- 2012 – Galileo Galilei Chair (Cattedra Galileiana) Award of the Scuola Normale Superiore, Pisa, Italy
- 2013 – Chambliss Astronomical Writing Award from the American Astronomical Society, for How Did the First Stars and Galaxies Form? (2010)
- 2014 – Member of the Board on Physics and Astronomy (BPA) of the National Academies of Sciences, Engineering, and Medicine
- 2015 – Elected Fellow of the International Academy of Astronautics (IAA) SETI Permanent Committee
- 2015 – Elected Member of the American Physical Society (APS)
- 2020 – Appointed to the President's Council of Advisors on Science and Technology[106]
See also
editSelected publications
edit- Abraham Loeb, Adam Hibberd, and Adam Crowl (2025). "Intercepting 3I/ATLAS at Closest Approach to Jupiter with the Juno spacecraft". arXiv.
References
edit- ^ a b "Avi Loeb". Institute for Theory and Computation @ Harvard University. Harvard University.
- ^ a b c "Professor Avi Loeb". Harvard & Smithsonian Center For Astronomy. Harvard University.
- ^ a b "Abraham (Avi) Loeb". Black Hole Initiative @ Harvard University. Harvard University.
- ^ a b Loeb, Avi. "Autobiographical sketch" (PDF). Harvard University.
- ^ a b c d Loeb, Abraham. "Curriculum Vitae of Abraham Loeb" (PDF). Harvard–Smithsonian Center for Astrophysics.
- ^ a b "Avi Loeb". Department of Astronomy @ Harvard University. Harvard University.
- ^ Groll, Johan (January 7, 2019). "Thinking About Distant Civilizations Isn't Speculative". Der Spiegel. Retrieved January 7, 2019.
- ^ a b "Harvard astronomer believes an interstellar meteor (or craft) smashed into Earth in 2014 — others aren't so sure". Inverse. April 15, 2022. Retrieved November 17, 2023.
- ^ a b "The humiliating truth behind Harvard astronomer's "alien" spherules". Big Think. March 13, 2024. Retrieved July 29, 2025.
- ^ a b "'Oumuamua wasn't an alien spacecraft, and ignoring the science can't make it so". Big Think. November 18, 2021. Retrieved July 29, 2025.
- ^ "Why a Harvard professor thinks he may have found fragments of an alien spacecraft". The Independent. July 5, 2023. Retrieved July 25, 2023.
- ^ a b c d Miller, Katrina (July 24, 2023). "Scientist's Deep Dive for Alien Life Leaves His Peers Dubious - Avi Loeb, a Harvard astrophysicist, says that material recovered from the seafloor could be from an extraterrestrial spacecraft. His peers are skeptical. + comment". The New York Times. Archived from the original on July 25, 2023. Retrieved July 24, 2023.
{{cite news}}: CS1 maint: bot: original URL status unknown (link) - ^ Miller, Katrina (July 24, 2023). "Scientist's Deep Dive for Alien Life Leaves His Peers Dubious (Published 2023)". The New York Times. Retrieved November 21, 2025.
Many astronomers, though, see the announcement as the latest example of Dr. Loeb making an outlandish declaration that is too strong and too hasty. His pronouncements (and a promotional video in Times Square about the search for extraterrestrial life) skew public perception of how science actually works, they say.
"People are sick of hearing about Avi Loeb's wild claims," said Steve Desch, an astrophysicist at Arizona State University. "It's polluting good science — conflating the good science we do with this ridiculous sensationalism and sucking all the oxygen out of the room."
Dr. Desch added that several of his colleagues were now refusing to engage with Dr. Loeb's work in peer review, the process by which scholars evaluate one another's research to ensure that only high-quality studies are published. "It's a real breakdown of the peer review process and the scientific method," he said. "And it's so demoralizing and tiring." - ^ Carmeli, Oded (2019). "If true, this could be one of the greatest discoveries in human history". Haaretz.com.
- ^ Avi Loeb - website American Friends of the Hebrew University
- ^ Miryam (October 24, 2018). "Avi Loeb". American Friends of the Hebrew University.
- ^ Loeb, Abraham (1986). "Particle acceleration to high energies and amplification of coherent radiation by electromagnetic interactions in plasmas".
- ^ Gritz, Jennie Rothenberg. "The Wonder of Avi Loeb". Smithsonian Magazine. Retrieved October 23, 2025.
- ^ "Avi Loeb appointed the Frank B. Baird Jr. Professor of Science | Department of Astronomy". astronomy.fas.harvard.edu. September 10, 2012.
- ^ "How Did the First Stars and Galaxies Form?" book jacket (pdf)
- ^ Loeb, Abraham (February 8, 2016). Loeb, A.: How Did the First Stars and Galaxies Form? (eBook and Paperback). Princeton University Press. ISBN 978-0-691-14516-7. Retrieved February 19, 2016.
- ^ ""The First Galaxies in the Universe" by Loeb and Furlanetto". Cfa.harvard.edu. Retrieved February 19, 2016.
- ^ Abraham Loeb (1998). "Direct Measurement of Cosmological Parameters from the Cosmic Deceleration of Extragalactic Objects". The Astrophysical Journal. 499 (2): L111 – L114. arXiv:astro-ph/9802122. Bibcode:1998ApJ...499L.111L. doi:10.1086/311375. S2CID 6479300.
- ^ Cox, T. J.; Loeb, Abraham (2008). "The collision between the Milky Way and Andromeda". Monthly Notices of the Royal Astronomical Society. 386 (1): 461–474. arXiv:0705.1170. Bibcode:2008MNRAS.386..461C. doi:10.1111/j.1365-2966.2008.13048.x. S2CID 14964036.
- ^ Loeb, Abraham (2002). "Long-term future of extragalactic astronomy". Physical Review D. 65 (4) 47301. arXiv:astro-ph/0107568. Bibcode:2002PhRvD..65d7301L. doi:10.1103/PhysRevD.65.047301. S2CID 1791226.
- ^ o'Leary, Ryan M.; Loeb, Abraham (2012). "Recoiled star clusters in the Milky Way halo: N-body simulations and a candidate search through the SDSS". Monthly Notices of the Royal Astronomical Society. 421 (4): 2737–2750. arXiv:1102.3695. Bibcode:2012MNRAS.421.2737O. doi:10.1111/j.1365-2966.2011.20078.x. S2CID 118524459.
- ^ Stone, N; Loeb, A (2012). "Observing Lense-Thirring Precession in Tidal Disruption Flares". Physical Review Letters. 108 (6) 61302. arXiv:1109.6660. Bibcode:2012PhRvL.108f1302S. doi:10.1103/PhysRevLett.108.061302. PMID 22401052. S2CID 33103563.
- ^ Broderick, Avery E.; Loeb, Abraham (2006). "Testing General Relativity with High-Resolution Imaging of Sgr A*". Journal of Physics: Conference Series. 54: 448–455. arXiv:astro-ph/0607279. Bibcode:2006JPhCS..54..448B. doi:10.1088/1742-6596/54/1/070. S2CID 16053017.
- ^ Lemonick, Michael D. (November 26, 2014). "You've Heard of Shooting Stars, But This is Ridiculous". Time.
- ^ Howard Chen; John C. Forbes; Abraham Loeb (2018). "Habitable Evaporated Cores and the Occurrence of Panspermia Near the Galactic Center". The Astrophysical Journal Letters. 855 (1): L1. arXiv:1711.06692. Bibcode:2018ApJ...855L...1C. doi:10.3847/2041-8213/aaab46. S2CID 119398803.
- ^ "The Mystery of Dark Matter Clarified—a Little". Time. September 5, 2013.
- ^ Trivedi, Oem; Loeb, Avi (2025). "Could Planck Star Remnants Be Dark Matter?". Physics of the Dark Universe. 44 102003. arXiv:2506.03334. Bibcode:2025PDU....4902003T. doi:10.1016/j.dark.2025.102003.
- ^ "Supernova Shines Light On Black Hole Formation". NPR.org. Retrieved February 19, 2016.
- ^ "Could Tiny Stars Be Home to Mirror Earths?". Time. March 6, 2013.
- ^ "BPA". nationalacademies.org. Retrieved September 7, 2016.
- ^ Loeb, Abraham (September 9, 2014). "The habitable epoch of the early Universe". International Journal of Astrobiology. 13 (4): 337–339. arXiv:1312.0613. Bibcode:2014IJAsB..13..337L. doi:10.1017/S1473550414000196. S2CID 2777386.
- ^ Adam Frank (February 4, 2014). "First Life In The Universe: 13.7: Cosmos And Culture". NPR.org. Retrieved February 19, 2016.
- ^ Loeb, Avi (April 4, 2021). "When Did Life First Emerge in the Universe? - We don't know, but we could try to find out by searching for it on planets orbiting the very oldest stars". Scientific American. Retrieved April 4, 2021.
- ^ Siraj, Amir; Loeb, Abraham (April 17, 2020). "Possible Transfer of Life by Earth-Grazing Objects to Exoplanetary Systems". Life. 10 (4): 44. arXiv:2001.02235. Bibcode:2020Life...10...44S. doi:10.3390/life10040044. ISSN 2075-1729. PMC 7235815. PMID 32316564.
- ^ Loeb, Avi (November 29, 2020). "Noah's Spaceship". Scientific American. Archived from the original on November 29, 2020. Retrieved February 18, 2021.
- ^ Lagatta, Eric. "NASA drops never-before-seen photos of interstellar 3I/ATLAS. Here's a look". USA TODAY. Retrieved November 21, 2025.
The strange outsider's jaunt through Earth's cosmic neighborhood has sparked plenty of outlandish conspiracy theories regarding its nature.
One particularly infamous idea – put forth by a Harvard astrophysicist named Avi Loeb – is that 3I/ATLAS could be an alien spaceship. - ^ Dunham, Will. "NASA releases images of comet 3I/ATLAS, rejects alien spacecraft 'rumors'". Reuters.
University of Oxford astrophysicist Chris Lintott told Reuters: "So far, it seems to be made of the same sort of stuff we see for comets in our solar system - plenty of carbon dioxide and some water, carbon monoxide and other such molecules. We've also seen cyanide - normal for a comet - and lots of nickel, which is a bit surprising but not too unprecedented. We saw similar things in a previous interstellar comet, 2I/Borisov, and in some solar system comets."
"The idea that 3I/ATLAS could be an alien spacecraft is simply nonsense. There's nothing about it that suggests such a thing, and you might as well argue that the moon is made of cheese," Lintott said. - ^ Wiedeman, Reeves (February 12, 2024). "Bill Ackman Strikes Back". Intelligencer. Retrieved February 23, 2024.
Loeb took the idea and suggested looking for hope from above. "My personal belief is that the Messiah will arrive, not necessarily from Brooklyn, as some Orthodox Jews believe, but rather from outer space," Loeb told the group.
- ^ Ian Sample (December 11, 2017). "Astronomers to check interstellar body for signs of alien technology". The Guardian. Retrieved December 12, 2017.
Green Bank telescope in West Virginia will listen for radio signals from ʻOumuamua, an object from another solar system ... "Most likely it is of natural origin, but because it is so peculiar, we would like to check if it has any sign of artificial origin, such as radio emissions," said Avi Loeb, professor of astronomy at Harvard University and an adviser to the Breakthrough Listen project. "If we do detect a signal that appears artificial in origin, we'll know immediately." ... While many astronomers believe the object is an interstellar asteroid, its elongated shape is unlike anything seen in the asteroid belt in our own solar system. Early observations of ʻOumuamua show that it is about 400m long but only one tenth as wide. "It's curious that the first object we see from outside the solar system looks like that," said Loeb.
- ^ Billings, Lee (December 11, 2017). "Alien Probe or Galactic Driftwood? SETI Tunes In to ʻOumuamua". Scientific American. Retrieved December 12, 2017.
So far limited observations of 'Oumuamua, using facilities such as the SETI Institute's Allen Telescope Array, have turned up nothing.
- ^ "Breakthrough Listen Releases Initial Results and Data from Observations of 'Oumuamua". Breakthrough Listen. December 13, 2017. Retrieved December 15, 2017.
No evidence of artificial signals emanating from the object so far detected by the Green Bank Telescope, but monitoring and analysis continue. Initial data are available for public inspection in the Breakthrough Listen archive
- ^ Ian Sample (December 15, 2017). "Is 'Oumuamua an alien spacecraft? Initial scans show no signs of technology". The Guardian. Retrieved December 15, 2017.
- ^ Williams, Matt (November 2, 2018). "Could Oumuamua Be an Extra-Terrestrial Solar Sail?". Universe Today. Retrieved November 2, 2018.
- ^ Bialy, Shmuel; Loeb, Abraham (October 26, 2018). "Could Solar Radiation Pressure Explain 'Oumuamua's Peculiar Acceleration?". The Astrophysical Journal. 868 (1): L1. arXiv:1810.11490. Bibcode:2018ApJ...868L...1B. doi:10.3847/2041-8213/aaeda8. S2CID 118956077.
- ^ Loeb, Abraham (September 26, 2018). "How to Search for Dead Cosmic Civilizations". Scientific American. Retrieved September 26, 2018.
- ^ Scientists push back against Harvard 'alien spacecraft' theory. Kerry Sheridan, PhysOrg. November 7, 2018.
- ^ Boyle, Alan (November 6, 2018). "'Oumuamua, oh my! Was interstellar object actually an alien solar sail? Not so fast". Yahoo!. Retrieved November 8, 2018.
- ^ Schadwinkel, Alina (November 8, 2018). "Glaubt dieser Harvard-Professor selbst, was er sagt?". Zeit Online. Retrieved November 8, 2018.
- ^ Cigar-shaped interstellar object may have been an alien probe, Harvard paper claims. CNN News. November 6, 2018.
- ^ Koren, Marina (January 23, 2019). "When a Harvard Professor Talks About Aliens – News about extraterrestrial life sounds better coming from an expert at a high-prestige institution". The Atlantic. Retrieved January 23, 2019.
- ^ Loeb, Abraham (November 20, 2018). "6 Strange Facts about the Interstellar Visitor 'Oumuamua". Scientific American. Retrieved November 20, 2018.
- ^ Chotiner, Isaac (January 16, 2019). "Have Aliens Found Us? A Harvard Astronomer on the Mysterious Interstellar Object 'Oumuamua". The New Yorker. Retrieved January 16, 2019.
- ^ Bergner, Jennifer B.; Seligman, Darryl Z. (March 23, 2023). "Acceleration of 1I/'Oumuamua from radiolytically produced H2 in H2O ice". Nature. 615 (7953): 610–613. arXiv:2303.13698. doi:10.1038/s41586-022-05687-w. ISSN 0028-0836. PMID 36949336.
- ^ Siraj, Amir; Loeb, Abraham (November 27, 2018). "Identifying Interstellar Objects Trapped in the Solar System through Their Orbital Parameters". arXiv:1811.09632v2 [astro-ph.EP].
- ^ Siraj, Amir; Loeb, Abraham (2019). "Identifying Interstellar Objects Trapped in the Solar System through Their Orbital Parameters". The Astrophysical Journal. 872 (1): L10. arXiv:1811.09632. Bibcode:2019ApJ...872L..10S. doi:10.3847/2041-8213/ab042a. S2CID 119198820.
- ^ Post, The Washington. "Harvard's top astronomer says an alien ship may be among us". nola.com. Archived from the original on February 5, 2019. Retrieved February 5, 2019.
- ^ Siraj, A.; Loeb, A. (April 16, 2019). "Discovery of a Meteor of Interstellar Origin". arXiv:1904.07224 [astro-ph.EP].
- ^ Loeb, Avi (June 22, 2021). "A Possible Link between 'Oumuamua and Unidentified Aerial Phenomena - If some UAP turn out to be extraterrestrial technology, they could be dropping sensors for a subsequent craft to tune into. What if 'Oumuamua is such a craft?". Scientific American. Retrieved June 22, 2021.
- ^ "Object that whizzed by Earth probably came from alien world, Harvard professor asserts". cbsnews.com. January 8, 2021. Retrieved January 13, 2021.
- ^ Tucker, Reed (January 2, 2021). "A Harvard professor says an alien visited in 2017 — and more are coming". New York Post. Retrieved January 13, 2021.
- ^ Anderson, Travis (January 4, 2021). "In new book, Harvard astronomer pushes theory about object that passed through solar system; alien world may have sent it – The Boston Globe". BostonGlobe.com. Retrieved January 13, 2021.
- ^ a b Fletcher, Seth (August 24, 2023). "How a Harvard Professor Became the World's Leading Alien Hunter – Avi Loeb's single-minded search for extraterrestrial life has made him the most famous practicing astronomer in the country — and possibly the most controversial. + comment". The New York Times. Archived from the original on August 24, 2023. Retrieved August 24, 2023.
- ^ Tingley, -Brett (July 20, 2023). "Interstellar meteor fragments found? Harvard astronomer's claim sparks debate, criticism - Avi Loeb is no stranger to controversy". Space.com. Archived from the original on August 25, 2023. Retrieved August 25, 2023.
- ^ Loeb, Abraham (2023). "Overview of the Galileo Project". Journal of Astronomical Instrumentation. 12 (1) 2340003. arXiv:2209.02479. Bibcode:2023JAI....1240003L. doi:10.1142/S2251171723400032. S2CID 252089170.
- ^ a b "The Galileo Project: "Daring to Look Through New Telescopes"". Harvard University. Retrieved August 12, 2021.
- ^ Loeb, Avi (September 19, 2021). "Astronomers Should be Willing to Look Closer at Weird Objects in the Sky - The Galileo Project seeks to train telescopes on unidentified aerial phenomena". Scientific American. Retrieved September 19, 2021.
- ^ "The Galileo Project: Activities". Harvard University.
- ^ "The Galileo Project". projects.iq.harvard.edu. Retrieved November 17, 2022.
- ^ "The Galileo Project: Press Coverage". Harvard University.
- ^ "The Galileo Project: Scope". Harvard University. Retrieved August 12, 2021.
- ^ a b c Grady, Monica (July 7, 2023). "Physicist who found spherical meteor fragments claims they may come from an alien spaceship – here's what to make of it". The Conversation. Retrieved July 25, 2023.
- ^ "The humiliating truth behind Harvard astronomer's "alien" spherules". Big Think. March 13, 2024. Retrieved July 15, 2024.
- ^ "I'm a Harvard astronomer. I think we found interstellar material". Newsweek. July 5, 2023. Retrieved July 25, 2023.
- ^ Gallardo, Patricio A. (October 19, 2023). "Anthropogenic Coal Ash as a Contaminant in a Micro-meteoritic Underwater Search". Research Notes of the AAS. 7 (10): 220. Bibcode:2023RNAAS...7..220G. doi:10.3847/2515-5172/ad03f9. ISSN 2515-5172.
- ^ Loeb, Abraham; et al. (February 15, 2024). "Chemical Classification of Spherules from the Pacific Ocean Site of the CNEOS 2014 January 8 (IM1) Bolide". arXiv:2401.09882 [astro-ph.EP].
- ^ Loeb, Abraham; et al. (January 19, 2024). "Recovery and Classification of Spherules from the Pacific Ocean Site of the CNEOS 2014 January 8 (IM1) Bolide". Research Notes of the AAS. 8 (10): 39. arXiv:2401.09882. Bibcode:2024RNAAS...8...39L. doi:10.3847/2515-5172/ad2370. ISSN 2515-5172.
- ^ Loeb, Abraham and MacLeod Morgan (February 20, 2024). "Interstellar meteors from the tidal disruption of rocky planets on eccentric orbits around M dwarfs". Astronomy and Astrophysics. 686: A123. arXiv:2310.09399. Bibcode:2024A&A...686A.123L. doi:10.1051/0004-6361/202449250.
- ^ Krajick, Kevin (April 9, 2024). "Was It an Alien Spacecraft—Or a Delivery Truck?". News from the Columbia Climate School. Columbia. Retrieved December 26, 2024.
- ^ "Harvard physicist claims new interstellar comet is alien probe". Newsweek. July 21, 2025. Retrieved August 12, 2025.
- ^ Yang, Bin; Meech, Karen J.; Connelley, Michael; Keane, Jacqueline V. (July 20, 2025). "Spectroscopic Characterization of Interstellar Object 3I/ATLAS: Water Ice in the Coma". The Astrophysical Journal. 992 (1): L9. arXiv:2507.14916. Bibcode:2025ApJ...992L...9Y. doi:10.3847/2041-8213/ae08a7.
- ^ Hopkins, Matthew J.; Dorsey, Rosemary C.; Forbes, John C.; Bannister, Michele T.; Lintott, Chris J.; Leicester, Brayden (July 9, 2025). "From a Different Star: 3I/ATLAS in the Context of the Ōtautahi–Oxford Interstellar Object Population Model". The Astrophysical Journal Letters. 990 (2): L30. arXiv:2507.05318. Bibcode:2025ApJ...990L..30H. doi:10.3847/2041-8213/adfbf4., Preprint, submitted to ApJ Letters
- ^ Dunham, Will. "NASA releases images of comet 3I/ATLAS, rejects alien spacecraft 'rumors'". Reuters.
- ^ Lagatta, Eric. "NASA drops never-before-seen photos of interstellar 3I/ATLAS. Here's a look". USA TODAY. Retrieved November 21, 2025.
One particularly infamous idea – put forth by a Harvard astrophysicist named Avi Loeb – is that 3I/ATLAS could be an alien spaceship. Though Loeb has conceded on publishing platform Medium that the object is "most likely a comet of natural origin," he has not ruled out the possibility that it could be extraterrestrial technology.
- ^ Loeb, Abraham (October 29, 2025). "A Q & A on 3I/ATLAS at Perihelion". Medium.
- ^ Lemonick, Michael D. (November 10, 2011). "Is There a City on Pluto? Before You Answer, Consider: We've Never Looked. Two Scientists Want to Change That". Time. Archived from the original on June 16, 2021.
- ^ Loeb, Abraham; Turner, Edwin L. (April 2012). "Detection Technique for Artificially Illuminated Objects in the Outer Solar System and Beyond". Astrobiology. 12 (4): 290–294. arXiv:1110.6181. Bibcode:2012AsBio..12..290L. doi:10.1089/ast.2011.0758. PMC 3330268. PMID 22490065.
- ^ Ginsburg, Idan; Loeb, Abraham; Wegner, Gary A. (June 11, 2012). "Hypervelocity planets and transits around hypervelocity stars". Monthly Notices of the Royal Astronomical Society. 423 (1): 948–954. arXiv:1201.1446. Bibcode:2012MNRAS.423..948G. doi:10.1111/j.1365-2966.2012.20930.x. S2CID 119193699.
- ^ Avi Loeb. "NewsFocus: From Cosmic Dawn to Milkomeda, and Beyond" (PDF). Cfa.harvard.edu. Retrieved February 19, 2016.
- ^ Steve Nadis. "First" (PDF). Cfa.harvard.edu. Retrieved February 19, 2016.
- ^ Dreifus, Claudia (December 2, 2014). "Much-Discussed Views That Go Way Back – Avi Loeb Ponders the Early Universe, Nature and Life". The New York Times. Retrieved December 3, 2014.
- ^ "Abraham Loeb: From cosmic origins to our galaxy's fate". Astronomy.com. May 6, 2015. Retrieved February 19, 2016.
- ^ "#154 – Avi Loeb: Aliens, Black Holes, and the Mystery of the Oumuamua". Lex Fridman. January 14, 2021. Archived from the original on January 24, 2021. Retrieved April 1, 2021.
- ^ Interstellar Object 3I/ATLAS Feat. Dr. Avi Loeb, September 24, 2025, retrieved October 2, 2025
- ^ "#1596 - Avi Loeb". Spotify. January 16, 2021. Archived from the original on January 19, 2021. Retrieved April 1, 2021.
- ^ TFTRH #55: Avi Loeb and The Galileo Project, August 10, 2021, retrieved November 8, 2021
- ^ Avi Loeb - Aliens, Black Holes & The End of the Universe - H3 Podcast #257, November 4, 2022, retrieved November 4, 2022
- ^ From the First Star to Milkomeda, Abraham Loeb, Dror Burstein, Todd Hasak-Lowy, Noa Moav. Abraham Loeb. August 24, 2015. ASIN B014GCTXF0.
- ^ "Opinion Essays by Abraham Loeb". cfa.harvard.edu~/loeb/Opinion.html. March 18, 2018. Retrieved March 18, 2018.
- ^ "Avi Loeb". John Simon Guggenheim Foundation.
- ^ David Bjerklie. "The 25 Most Influential People in Space" (PDF). cfa.harvard.edu. Retrieved February 19, 2016.
- ^ "PCAST_Members". osti.gov. Retrieved July 1, 2020.
External links
edit- Avi Loeb's home page
- Loeb's recent preprints
- Loeb's published papers
- Search for Interstellar Monuments (Avi Loeb; Scientific American; September 2021).
- Kloor, Keith (January 27, 2023). "Why is a Harvard astrophysicist working with UFO buffs?". www.science.org. Retrieved June 17, 2023.