Tuesday, November 4, 2025

A01989 - George Smoot, Nobel Prize Recipient for Big Bang Measurement

 88888888888888888888888888888888888888888888888888888888888888888888888888888888888

George Smoot
Smoot at Ithaka Science Center in 2009
Born
George Fitzgerald Smoot III

February 20, 1945
Yukon, Florida, US
DiedSeptember 18, 2025 (aged 80)
Paris, France
Alma mater
Known forCosmic microwave background
Awards
See list
Scientific career
FieldsPhysics
Institutions
ThesisCharge exchange of positive Kaon on platinum at three GeV/C (1971)
Doctoral advisorDavid H. Frisch[2]

88888888888888888888888888888888888888888888888888888888888888888888888888888888888

George Smoot (born February 20, 1945, Yukon, Florida, U.S.—died September 18, 2025, Paris, France) was an American physicist who was corecipient, with John C. Mather, of the Nobel Prize for Physics in 2006 for discoveries supporting the big-bang model.

Smoot received a Ph.D. in physics from the Massachusetts Institute of Technology in 1970. The following year he joined the faculty at the University of California at Berkeley.

In the 1980s Smoot and Mather helped develop the Cosmic Background Explorer (COBE) for the National Aeronautics and Space Administration (NASA). Launched in 1989, the satellite measured the cosmic microwave background radiation formed during the early phases of creation of the universe. The resulting data support the theory that the universe was created in a primordial explosion known as the big bang.


88888888888888888888888888888888888888888888888888888888888888888888888888888888888

George Fitzgerald Smoot III (February 20, 1945 – September 18, 2025) was an American astrophysicist, cosmologist, and Nobel laureate. He won the Nobel Prize in Physics in 2006 for his work on the Cosmic Background Explorer (COBE) with John C. Mather that led to the "discovery of the black body form and anisotropy of the cosmic microwave background radiation".[3]

This work helped further the Big Bang theory of the universe using the COBE satellite.[4] According to the Nobel Prize committee, "the COBE project can also be regarded as the starting point for cosmology as a precision science."[5] In 2007, Smoot donated $500,000 to fund the Berkeley Center for Cosmological Physics,[6] and an additional amount from his Nobel Prize money, less travel costs, to the East Bay Community Foundation, a charity.[7]

Smoot had been at the University of California, Berkeley, and the Lawrence Berkeley National Laboratory since 1970. He was Chair of the Endowment Fund "Physics of the Universe" of Paris Center for Cosmological Physics. Apart from being elected a member of the US National Academy of Sciences and a Fellow of the American Physical Society, Smoot had been honored by several universities worldwide with doctorates or professorships. He was also the recipient of the Gruber Prize in Cosmology (2006), the Daniel Chalonge Medal from the International School of Astrophysics (2006), the Einstein Medal from the Albert Einstein Society (2003), the Ernest Orlando Lawrence Award from the U.S. Department of Energy (1995), and the Exceptional Scientific Achievement Medal from NASA (1991). He was a member of the advisory board of the journal Universe.[8]

Smoot was one of the 20 American recipients of the Nobel Prize in Physics to sign a letter addressed to President George W. Bush in May 2008, urging him to "reverse the damage done to basic science research in the Fiscal Year 2008 Omnibus Appropriations Bill" by requesting additional emergency funding for the Department of Energy's Office of Science, the National Science Foundation, and the National Institute of Standards and Technology.[9]

Early life, family and education

Smoot was born in Yukon, Florida, on February 20, 1945.[10][11] His father was a hydrologist for the US Geological Survey, and his mother was a teacher and school principal.[6][10] He had a sister, Sharon.[6] Their maternal grandfather was Johnson Tal Crawford. The family lived in Alaska before relocating to Ohio.[10][6] He graduated from Upper Arlington High School in Upper Arlington, Ohio, in 1962.[12]

At the Massachusetts Institute of Technology, he obtained dual bachelor's degrees in mathematics and physics in 1966, then a Ph.D. in particle physics in 1970.[11][13][14] A distant relative, Oliver R. Smoot, was the MIT student who was used as the unit of measure known as the smoot.[15][16]

Initial research

Smoot switched to cosmology and began work at Berkeley, collaborating with Luis Walter Alvarez on the High Altitude Particle Physics Experiment, a stratospheric weather balloon designed to detect antimatter in Earth's upper atmosphere,[17] the presence of which was predicted by the now discredited steady state theory of cosmology.

He then took up an interest in cosmic microwave background radiation (CMB), previously discovered by Arno Allan Penzias and Robert Woodrow Wilson in 1964. There were, at that time, several open questions about this topic, relating directly to fundamental questions about the structure of the universe. Certain models predicted the universe as a whole was rotating, which would have an effect on the CMB: its temperature would depend on the direction of observation. With the help of Alvarez and Richard A. Muller, Smoot developed a differential radiometer which measured the difference in temperature of the CMB between two directions 60 degrees apart. The instrument, which was mounted on a Lockheed U-2 plane, made it possible to determine that the overall rotation of the universe was zero, which was within the limits of accuracy of the instrument. It did, however, detect a variation in the temperature of the CMB of a different sort. That the CMB appears to be at a higher temperature on one side of the sky than on the opposite side, referred to as a dipole pattern, has been explained as a Doppler effect of the Earth's motion relative to the area of CMB emission, which is called the last scattering surface. Such a Doppler effect arises because the Sun, and in fact the Milky Way as a whole, is not stationary, but rather is moving at nearly 600 km/s with respect to the last scattering surface. This is probably due to the gravitational attraction between our galaxy and a concentration of mass like the Great Attractor.[17]

Cosmic Background Explorer (COBE)

Map of the CMB fluctuations found by COBE.

At that time, the CMB appeared to be perfectly uniform excluding the distortion caused by the Doppler effect as mentioned above. This result contradicted observations of the universe, with various structures such as galaxies and galaxy clusters indicating that the universe was relatively heterogeneous on a small scale. However, these structures formed slowly. Thus, if the universe is heterogeneous today, it would have been heterogeneous at the time of the emission of the CMB as well, and observable today through weak variations in the temperature of the CMB. It was the detection of these anisotropies that Smoot was working on in the late 1970s. He then proposed to NASA a project involving a satellite equipped with a detector that was similar to the one mounted on the U-2 but was more sensitive and not influenced by air pollution. The proposal was accepted and incorporated as one of the instruments of the satellite Cosmic Background Explorer (COBE), which cost $160 million. COBE was launched on November 18, 1989, after a delay owing to the destruction of the Space Shuttle Challenger. After more than two years of observation and analysis, the COBE research team announced on April 23, 1992, that the satellite had detected tiny fluctuations in the CMB, a breakthrough in the study of the early universe.[18] The observations were "evidence for the birth of the universe" and led Smoot to say regarding the importance of his discovery that "if you're religious, it's like looking at God."[19][20]

Smoot celebrating his Nobel Prize at Lawrence Berkeley National Laboratory, October 3, 2006

The success of COBE was the outcome of extensive teamwork involving more than 1,000 researchers, engineers and other participants. John Mather coordinated the entire process and also had primary responsibility for the experiment that revealed the blackbody form of the CMB measured by COBE. Smoot had the main responsibility of measuring the small variations in the temperature of the radiation.[21]

Smoot collaborated with San Francisco Chronicle journalist Keay Davidson to write the general-audience book Wrinkles in Time, that chronicled his team's efforts.[22] In the book The Very First Light, John Mather and John Boslough complemented and broadened the COBE story,[23] but also suggested that Smoot violated team policy by leaking news of COBE's discoveries to the press before NASA's formal announcement, a leak that, to Mather, smacked of self-promotion and betrayal. Smoot eventually apologized for not following the agreed publicity plan and Mather said tensions eventually eased. Mather acknowledged that Smoot had "brought COBE worldwide publicity" the project might not normally have received.[24]

Other projects

After COBE, Smoot took part in another experiment involving a stratospheric balloon, Millimeter Anisotropy eXperiment IMaging Array, which had improved angular resolution compared to COBE, and refined the measurements of the anisotropies of the CMB. Smoot has continued CMB observations and analysis and was a collaborator on the third generation CMB anisotropy observatory Planck satellite. He was also a collaborator of the design of the Supernova/Acceleration Probe, a satellite which is proposed to measure the properties of dark energy.[25] He has also assisted in analyzing data from the Spitzer Space Telescope in connection with measuring far infrared background radiation.[26]

Smoot was credited by Mickey Hart with inspiring the album Mysterium Tremendum, which is based, in part on "sounds" that can be extracted from the background signature of the Big Bang.[27]

Smoot was an artificial intelligence scientist for the GTA Foundation, whose business is storing genomic sequencing data and using it in scientific applications.[28]

Smoot joined Kazakhstan's National Council for Science and Technology in January 2023.[29]

Media appearances

Smoot had a cameo appearance as himself in "The Terminator Decoupling" episode of The Big Bang Theory.[30] He contacted the show as a fan of their often physics-based plots and was incorporated into an episode featuring him lecturing at a fictional physics symposium.[31] He is also credited by the producer of the show with providing a joke told by Penny in the episode "The Dead Hooker Juxtaposition".[32] He appeared in a later episode, "The Laureate Accumulation", initially broadcast in April 2019.

On September 18, 2009, Smoot appeared on an episode of the Fox television show Are You Smarter Than a 5th Grader? During filming, he reached the final question, "What US state is home to Acadia National Park?", to which he gave the correct answer "Maine", becoming the second person to win a million-dollar prize.[6][33]

On December 10, 2009, he appeared in a BBC interview of Nobel laureates, discussing the value science has to offer society.

Smoot gave a 2014 TEDx lecture in which he suggested that certain aspects of physics support the simulation hypothesis, the idea that our reality is a computer-generated virtual reality.[34][35]

In 2016, Smoot appeared in a television commercial for Intuit TurboTax, advising a user of the software on what to do.[36]

Personal life and death

Smoot died from a heart attack in Paris, on September 18, 2025, at age 80.[10] The Astroparticle and Cosmology Laboratory announced his death on September 25.[37][38]

Selected publications

References

  1.  "Golden Plate Awardees of the American Academy of Achievement". achievement.org. American Academy of Achievement.
  2.  Bourzac, Katherine (January 12, 2007). "Nobel Causes". Technology Review. Archived from the original on January 29, 2012. Retrieved September 5, 2007. And Smoot himself can still vividly recall playing a practical joke on his graduate thesis advisor, MIT physics professor David Frisch.
  3.  "All Nobel Prizes in Physics". The Nobel Prize. Retrieved October 21, 2025.
  4.  Horgan, J. (1992). "Profile: George F. Smoot – COBE's Cosmic Cartographer". Scientific American. 267 (1): 34–41. doi:10.1038/scientificamerican0792-34.
  5.  "The Nobel Prize in Physics 2006" (Press release). The Royal Swedish Academy of Sciences. October 3, 2006. Archived from the original (PDF) on August 15, 2010. Retrieved October 5, 2006.
  6.  Sanders, Robert. "Nobelist George Smoot, whose satellite experiments validated the Big Bang theory, dies at 80". berkeley.edu. University of California Berkeley. Retrieved September 30, 2025.
  7.  "Berkeley Nobel laureates donate prize money to charity" (PDF). Associated Press. March 22, 2007. Archived from the original (PDF) on July 26, 2011. Retrieved March 31, 2010.
  8.  "Editorial Board – Members", MDPI.com, retrieved September 25, 2025
  9.  "A Letter from America's Physics Nobel Laureates" (PDF). pppl.gov. Princeton Plasma Physics Laboratory. Retrieved September 30, 2025.
  10.  Barthélémy, Pierre (September 25, 2025). "George Smoot, explorateur de la soupe cosmique primordiale et Prix Nobel de physique, est mort" [George Smoot, explorer of the primordial cosmic soup and Nobel Prize winner in physics, has died]. Le Monde (in French). Archived from the original on September 25, 2025. Retrieved September 30, 2025.
  11.  "George F. Smoot III". lbl.gov. Lawrence Berkeley National Laboratory. Retrieved September 28, 2025.
  12.  Jones, Gregory L. (April 18, 2007). "Nobel Prize winner returns home" (PDF). Upper Arlington News. Archived from the original (PDF) on August 7, 2020. Retrieved September 30, 2025 – via lbl.gov.
  13.  Smoot, George Fitzgerald III (1971). Charge exchange of positive Kaon on platinum at three GeV/C (Ph.D. thesis). Massachusetts Institute of Technology. OCLC 25256702. ProQuest 302620738.
  14.  "Nobelists' work supports big-bang theory" (Press release). Massachusetts Institute of Technology. October 3, 2006. Retrieved October 3, 2006.
  15.  "At MIT, future Nobelist not above a prank or two". The Boston Globe. October 4, 2006. Retrieved March 24, 2022.
  16.  "The SMOOT as unit of Length". aether.lbl.gov. Lawrence Berkeley National Laboratory. Archived from the original on September 8, 2025. Retrieved March 24, 2022.
  17.  Corbyn, Zoë (April 19, 2014). "George Smoot: We mapped the embryonic universe". The Guardian. ISSN 0261-3077. Retrieved September 25, 2025.
  18.  Smoot, G.F.; et al. (September 1992). "Structure in the COBE differential microwave radiometer first-year maps". Astrophysical Journal. 396 (1): L1 – L5. Bibcode:1992ApJ...396L...1S. doi:10.1086/186504. S2CID 120701913.
  19.  "U.S. Scientists Find a 'Holy Grail': Ripples at Edge of the Universe". International Herald Tribune. Associated Press. April 24, 1992. p. 1.
  20.  Maugh, Thomas H. II (April 24, 1992). "Relics of Big Bang, Seen for First Time". Los Angeles Times. pp. A1, A30.
  21.  "Pictures of a Newborn Universe" (Press release). Royal Swedish Academy of Sciences. October 3, 2006. Retrieved September 5, 2007.
  22.  Smoot, George; Davidson, Keay (1993). Wrinkles in Time. New York: W. Morrow. ISBN 0-688-12330-9.
  23.  Mather, John; Boslough, John (1997). The Very First Light: The True Inside Story of the Scientific Journey Back to the Dawn of the Universe. New York: Basic Books. ISBN 0-465-01575-1.
  24.  Yarris, Lynn (October 26, 2006). "After the Phone Call". Science@Berkeley Lab. Lawrence Berkeley National Laboratory. Archived from the original on May 6, 2008. Retrieved September 5, 2007.
  25.  "Supernova/Acceleration Probe (SNAP)". snap.lbl.gov. Lawrence Berkeley National Laboratory. Retrieved September 5, 2007.
  26.  "Spitzer Cosmic Far-IR Background Project". lbl.gov. Lawrence Berkeley National Laboratory. Retrieved September 5, 2007.
  27.  "Into the Heart of Music: Recording the Mickey Hart Band's 'Mysterium Tremendum'". dead.net. Grateful Dead. April 16, 2012. Retrieved January 2, 2016.
  28.  "The Grand Opening of GTA Gene Data Storage and Application Summit Forum Heralds A Promising Future of Gene Technology". Benzinga.com. September 27, 2019. Retrieved January 10, 2022.
  29.  "Касым-Жомарт Токаев подписал указ о создании Нацсовета по науке и технологиям при Президенте РК" [Kassym-Jomart Tokayev signed a decree establishing the National Council for Science and Technology under the President of the Republic of Kazakhstan]. inform.kz (in Russian). January 26, 2023.
  30.  "The Terminator Decoupling". The Big Bang Theory. Season 2. Episode 17. March 9, 2009. 20 minutes in. CBS.
  31.  "The Big Bang Theory Videos". CBS. Retrieved August 4, 2012.
  32.  Lorre, Chuck. "Big Bang Theory Season 2 Episode 19 Vanity Card". Retrieved January 17, 2014.
  33.  "Are You Smarter Than 5th Grader? Season 3 Ep. 27". FOX, Mark Burnett Productions. Archived from the original on September 22, 2009. Retrieved September 26, 2009.
  34.  "You are a Simulation & Physics Can Prove It: George Smoot at TEDxSalford". Tedx Talks. February 11, 2014.
  35.  Sean Martin (February 24, 2016). "Humans already living in a Computer Simulation, leading Nobel Prize astrophysicist warns". Express.co.uk.
  36.  Staff. (January 4, 2016) "Physics Geniuses Illustrate the Mind-Bending Simplicity of TurboTax in W+K's New Ads; Campaign will include a Super Bowl spot By David Gianatasio" Adweek
  37.  "In Memory – George Fitzgerald Smoot, III". AstroParticule & Cosmologie. Retrieved September 25, 2025.
  38.  https://apnews.com/article/physicist-george-smooth-big-bang-nobel-berkeley-3e4f1ac718c627806bcfd7c4653c5b54

8888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888

George F. Smoot, Who Showed How the Cosmos Began, Is Dead at 80

He led a team of scientists who helped confirm that a Big Bang was the source of the universe. The discovery earned him a Nobel Prize.

Listen to this article · 8:29 min Learn more
A middle-aged George Smoot with short, dark hair and a salt-and-pepper beard and mustache, wearing glasses, a red polo shirt and dark pants, standing in front of a white board filled with scientific equations.
George Smoot in 2006, the year he shared the Nobel Prize in Physics with John C. Mather, a cosmologist at NASA Goddard Space Flight Center.Credit...Upi Photo/Roy Kaltschmidt, via LBNL

By Katrina Miller

George F. Smoot, an American physicist and Nobel laureate who helped elucidate the story of cosmic creation, providing evidence of what he called the primordial seeds that grew into galaxies and galaxy clusters, died on Sept. 18 at his home in Paris. He was 80.

His death, from cardiac arrest, was confirmed by his sister, Sharon Bowie.

Dr. Smoot was a research scientist at Lawrence Berkeley National Laboratory and the Space Sciences Laboratory at the University of California, Berkeley, when he led a team that constructed a picture of the infant universe using an instrument he developed in the 1970s.

The instrument was launched into space in 1989 aboard a NASA satellite, the Cosmic Background Explorer, or COBE, from which it detected tiny variations in the temperature of the light that was left over from what most scientists presumed was a Big Bang. The pattern of those temperature variations was a record of how unevenly cosmic matter was distributed billions of years ago — the seeds from which the current design of the universe, dense in some parts and empty in others, sprouted.

“If you’re religious, it’s like seeing God,” Dr. Smoot said when he announced the COBE findings in 1992 at an American Physical Society conference, making front-page news around the world. (The account in The New York Times — its lead story in the paper of April 24 — appeared under the headline “Scientists Report Profound Insight on How Time Began.”)

Advertisement

SKIP ADVERTISEMENT

The theoretical physicist Stephen Hawking called it “the greatest discovery of the century, if not of all time.”

Dr. Smoot’s research built on that of the physicists Arno A. Penzias and Robert W. Wilson, who in 1964 discovered that the universe was bathed in a sea of ancient light, known as the cosmic microwave background. It was evidence that the universe had a beginning and had exploded into existence with a Big Bang.

Before that discovery, cosmology had been a theoretical playground, full of imaginative ideas virtually untethered to data. Measurements taken with the COBE satellite provided data by which scientists could test those various theories about how the universe began, what it was made of and how it had evolved. It helped transform cosmology from a field largely based in speculation to a science grounded in precise measurement.

Dr. Smoot shared the 2006 Nobel Prize in Physics with John C. Mather, a cosmologist at the NASA Goddard Space Flight Center in Maryland, for groundbreaking discoveries made by the COBE team. Each was a team leader in the project.

Image
A black-and-white photo of a youngish George Smoot, wearing glasses, a button-down shirt and tie and dark trousers, standing in front of a transparent globe.
Dr. Smoot in 1992, the year he announced findings that helped transform cosmology from a field largely based in speculation to a science grounded in precise measurement.Credit...Susan Spann

As a scientist, Dr. Smoot was revered for his brilliance but also resented by some colleagues, who felt he took undue credit for scientific results that others had achieved. Days before the physics conference announcement in 1992, Berkeley Lab published a news release that many viewed as unfairly attributing the discovery of light temperature variations solely to Dr. Smoot and the lab, overlooking other team leaders and NASA.

Advertisement

SKIP ADVERTISEMENT

In his 1993 book, “Wrinkles in Time: Witness to the Birth of the Universe,” written with Keay Davidson, Dr. Smoot documented the process leading up to the discovery. Some of his collaborators disagreed with his version of events and encouraged Dr. Mather to write his own account. He did, publishing it three years later as “The Very First Light: The True Inside Story of the Scientific Journey Back to the Dawn of the Universe,” which differed from Dr. Smoot’s version in some details.

Dr. Smoot “was a lot of trouble,” Dr. Mather allowed in an interview, but also “ingenious and thoughtful and enthusiastic, as everybody knows.”

George Fitzgerald Smoot III was born on Feb. 20, 1945, in Yukon, Fla., to George Smoot II, who served as a fighter pilot during World War II, and Talicia (Crawford) Smoot, a science teacher and school principal.

The family moved to Alabama after the war. George’s father was a hydrologist with the United States Geological Survey, a job that also took the family to Alaska, Ohio and Virginia. By Dr. Smoot’s account, his mother instilled in him a love of science and education; from his father, who traveled the world measuring river flows, he learned to appreciate the value of invention and instrumentation.

Advertisement

SKIP ADVERTISEMENT

Dr. Smoot attended the Massachusetts Institute of Technology, where he earned degrees in physics and mathematics in 1966 and his Ph.D. in particle physics in 1970, before moving to Berkeley to study under Luis Alvarez, a particle physicist who had won the Nobel Prize in 1968.

There, Dr. Smoot pivoted to cosmology. With the physicist Richard Muller, he developed an instrument that could measure temperature differences in the cosmic microwave background; he put it to use by mounting it on a U-2 spy plane operated by NASA. The experiment led to one of the first measurements indicating that our galaxy, the Milky Way, is hurtling through space at more than a million miles an hour, suggesting that it is being pulled by the gravitational force of an even more gigantic mass.

In 1974, Dr. Smoot approached NASA proposing a mission to send the instrument into space. NASA combined the proposal with two others, establishing the team behind COBE, which carried three instruments into orbit.

Weeks after the launch, data analyzed by the team overseen by Dr. Mather, the Goddard cosmologist, solidified the link between the cosmic microwave background and the Big Bang. It also measured the temperature of that background: a chilly 2.7 kelvin (about minus 455 degrees Fahrenheit), just a smidgen above absolute zero.

Dr. Smoot’s team measured minute variations in that temperature across the universe, at the level of about 10 millionths of a degree. He would describe this measurement in his book as similar to “listening for a whisper during a noisy beach party while radios blare, waves crash, people yell, dogs bark and dune buggies roar.”

Advertisement

SKIP ADVERTISEMENT
Image
A black-and-white photo of a youngish George Smoot, wearing glasses and a suit and tie, sitting in front of a large, boxy computer.
Dr. Smoot in 1992. “If you’re religious, it’s like seeing God,” he said of the discoveries about the origins of the universe. Credit...Susan Spann

The announcement of this discovery inspired countless creation analogies. “It really is like finding the driving mechanism for the universe,” Dr. Smoot told The Times in 1992. “And isn’t that what God is?”

In addition to confirming the Big Bang picture of the universe, the COBE discoveries strengthened evidence for the existence of dark matter and the theory of cosmic inflation, which posits that the universe went through a period of rapid expansion shortly after its birth.

Two more space missions refined COBE’s measurements of the cosmic microwave background; one, the Planck observatory, launched by the European Space Agency in 2009, had been proposed by a team that included Dr. Smoot.

Dr. Smoot, who became a professor at Berkeley in 1994, donated a large share of his Nobel Prize award money (he and Dr. Mather split a gift of about $1.37 million) to endow the Berkeley Center for Cosmological Physics, where he was the founding director. He helped establish cosmology institutes around the world, including in France and South Korea, and was elected to the National Academy of Sciences and the National Academy of Inventors. In 2009, he joined the faculty of Paris Cité University and became an affiliate of the Astroparticle and Cosmology Laboratory.

Advertisement

SKIP ADVERTISEMENT

He married Maxine Bixby in 1969; they divorced in 1979. In addition to his sister, Dr. Smoot is survived by his partner, Nóra Csiszár.

Toward the end of his career, Dr. Smoot grew more involved in public outreach and science education. He helped start programs to teach high school teachers and students about cosmology, and taught an online course about gravity that attracted an audience of more than 87,000.

He also made appearances on the CBS sitcom “The Big Bang Theory” and, in 2009, competed on the Fox network game show “Are You Smarter Than a Fifth Grader?” He went on the show, he said, to encourage his students to try new things; in doing so, he became the second person to win $1 million.

During his appearance, Dr. Smoot noted that he had donated his Nobel winnings to create scholarships and fellowships for young scientists. Pointing to the students on the stage as the crowd cheered, he said, “I’m hoping one of these guys gets one of them.”

at

No comments:

Post a Comment