Life, the Universe, and everything — the 42 most fundamental questions
Roland E. Allen Department of Physics and Astronomy, Texas A&M
Suzy Lidström Physica Scripta, Royal Swedish Academy of Sciences
Wrong!
Young(andolder)scien3stshaveatleastasmuchopportunitytomakemajorcontribu3onstohumanunderstandingasinanypreviouscentury. 2
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Butittakeshardwork!
Credit:h4p://e-sushi.fr/science/pierre-curie
MarieCurie:
“Some3mesIhadtospendawholedays3rringaboilingmasswithaheavyironrodnearlyasbigasmyself.Iwouldbebrokenwithfa3gueatday'send.”
JocelynBellBurnell:
“BytheendofmyPhDIcouldswingasledgehammer.”
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Credit:h4ps://www.howitworksdaily.com/heroes-of-science-marie-curie/
Credit:JocelynBellBurnell
Life
LynnMargulis:Cellorganellessuchasmitochondriaandchloroplastswereonceindependentbacteria.Credit:BostonUniversityPhotography.
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There are various theories of how life arose on Earth, and currently none are fully convincing. Experiments and genetic analyses strongly suggest that the last universal common ancestor (LUCA) lived near hot deep sea vents, where seawater interacts with magma escaping through the ocean floor. A separate and equally important question is how complex (multicellular) life arose from its one-celled precursors.
According to one interpretation, life would always have been limited to one-celled bacteria and archaea (prokaryotes) had not an archaeon undergone a symbiotic merger with a bacterium which ultimately led to the last of the three domains of life on earth -- the eukaryotes. A low probability bottleneck to intelligent life?
38.HowdidlifeonEarthbegin--andhowdidcomplexlifeoriginate?______________________________________________________________________________________________
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Kip Thorne and Stephen Hawking with actors David Gyasi, Anne Hathaway, Jessica Chastain, and Michael Caine at the world premiere of Interstellar. Kip Thorne was Executive Producer and Science Consultant. Earlier he had introduced wormholes into science fiction, via a novel of Carl Sagan – Contact – which was also made into a movie.Credit:KipThorne.
the Universe
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RainerWeissinventedthesophis3catedlaserinterferometrictechniqueswhicharethebasisforLIGO(theLaserInterferometerGravita3onal-WaveObservatory).HewasalsoanoriginatorofCOBEwithJohnMather.HereheisshownwithastronomerSarahHigdon.KipThornehasalsobeenaprincipaldrivingforceonLIGO,followinga1975all-nightdiscussionwithRaiWeiss,whentheysharedaroom.(Weiss,anexperimentalist,hadreservedaroom,andThorne,atheorist,hadnot.)
TheLIGOcollabora3onhasaspectaculardoublesuccess:thefirstdirectobserva3onofgravita3onalwavesandtheunexpectedobserva3onofthemergeroftwoverymassiveblackholes.ThewavesweresimultaneouslydetectedatthetwoseparateLIGOobservatoriesinHanford,WashingtonandLivingston,Louisiana.Thisobserva3onmarksthebeginningofgravita3onalwaveastronomy.
Credit:LIGO,NSF,AuroreSimonnet(SonomaStateU.) 7
Everything?
LynnMargulisandCarlSaganontheirweddingday,1957.Hegaveus“Cosmos”.(HersistermarriedSheldonGlashow.)Credit:C.E.Martyn,pinterest.com.
ButnowthemulWverse?
Credit:MaxTegmark,h4p://space.mit.edu/home/tegmark/crazy.html
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BrianHall:Whicheverwayyougo,you'resuretomisssomethinggoodontheotherpath.
Enoughsilliness!Now42deepquesWonsin<42minutes.
1.Whydoesconven3onalphysicspredictacosmologicalconstantthatisvastlytoolarge?2.Whatisthedarkenergy?3.HowcanEinsteingravitybereconciledwithquantummechanics?4.Whatistheoriginoftheentropyandtemperatureofblackholes?5.Isinforma3onlostinablackhole?6.Didtheuniversepassthroughaperiodofinfla3on,andifsohowandwhy?7.Whydoesmaeers3llexist?8.Whatisthedarkmaeer?9.Whyarethepar3clesofordinarymaeercopiedtwiceathigherenergy?10.Whatistheoriginofpar3clemasses,andwhatkindofmassesdoneutrinoshave?11.Doessupersymmetryexist,andwhyaretheenergiesofobservedpar3clessosmallcomparedtothemostfundamental(Planck)energyscale?12.Whatisthefundamentalgrandunifiedtheoryofforces,andwhy?13.AreEinsteinrela3vityandstandardfieldtheoryalwaysvalid?14.Isouruniversestable?
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15.Arequarksalwaysconfinedinsidethepar3clesthattheycompose?16.Whatarethecompletephasediagramsforsystemswithnontrivialforces,suchasthestrongnuclearforce?17.Whatnewpar3clesremaintobediscovered?18.Whatnewastrophysicalobjectsareawai3ngdiscovery?19.Whatnewformsofsuperconduc3vityandsuperfluidityremaintobediscovered?20.Whatfurtherproper3esremaintobediscoveredinhighlycorrelatedelectronicmaterials?21.Whatnewtopologicalphasesremaintobediscovered?22.Whatothernewphasesandformsofmaeerremaintobediscovered?23.Whatisthefutureofquantumcompu3ng,quantuminforma3on,andotherapplica3onsofentanglement?24.Whatisthefutureofquantumop3csandphotonics?25.Aretherehigherdimensions,andifthereisaninternalspace,whatisitsgeometry?26.Isthereamul3verse?27.Arethereexo3cfeaturesinthegeometryofspace3me,perhapsincludingthosewhichcouldpermit3metravel?28.Howdidtheuniverseoriginate,andwhatisitsfate?
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29.Whatistheoriginofspace3me,whyisspace3mefour-dimensional,andwhyis3medifferentfromspace?30.Whatexplainsrela3vityandEinsteingravity?31.Whydoallforceshavetheformofgaugetheories?32.WhyisNaturedescribedbyquantumfields?33.Isphysicsmathema3callyconsistent?34.Whatistheconnec3onbetweentheformalismofphysicsandtherealityofhumanexperience?35.Whataretheul3matelimitstotheore3cal,computa3onal,experimental,andobserva3onaltechniques?36.Whataretheul3matelimitsofchemistry,appliedphysics,andtechnology?37.Whatislife?38.HowdidlifeonEarthbegin--andhowdidcomplexlifeoriginate?39.Howabundantislifeintheuniverse,andwhatisthedes3nyoflife?40.Howdoeslifesolveproblemsofseeminglyimpossiblecomplexity?41.Canweunderstandandcurethediseasesthatafflictlife?42.Whatisconsciousness?
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1. Why does conventional physics predict a cosmological constant that is vastly too large?
Steven Weinberg is a principal architect of the Standard Model of particle physics. He and others have adopted the point of view that, of all proposed solutions to this problem, the only acceptable one is the anthropic bound that he obtained in 1987.
Credit:AIPEmilioSegreVisualArchives.
Accordingtostandardphysics,thevacuumhasanenormousenergy.AtypicalposiWvecontribuWonisthezero-pointenergyoftheelectromagneWcfield,andatypicalnegaWvecontribuWonarisesfromHiggscondensaWon.AllthevariouscontribuWonsaredeterminedindependentlyandthereisnoreasonwhytheyshouldcancel.Againaccordingtostandardphysics,thevacuumenergyshouldactasagravita3onalsource--effec3velyanenormouscosmologicalconstant.Itshouldthenhaveanenormouseffectonthecurvatureofspace3me,roughly120ordersofmagnitudelargerthaniscompa3blewithobserva3on(withthePlanckscaleanaturalcutoff).
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2. What is the dark energy?
Theaccelera3onintheexpansionoftheuniversewasdiscoveredbytwogroups.Thefirstwasini3allyorganizedbyNicholasSuntzeff,ontheright,togetherwithBrianSchmidt.MarkPhillips,onthelel,alsoplayedaleadingroleinthisdiscovery.AllmembersoftheHigh-zSupernovaSearchTeamandtheSupernovaCosmologyProjectsharedthe2007GruberCosmologyPrize.HereNickSuntzeffandMarkPhillipsareshownduringthe2011NobelWeekinStockholm.
Thedarkenergystronglyresemblesacosmologicalconstantorvacuumenergy,butonly0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001aslargeasinstandardtheory.Credit:NicholasSuntzeff.
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3. How can Einstein gravity be reconciled with quantum mechanics?
The theorists shown above are among the major leaders in the long quest for a quantum theory of gravity (and fundamental understanding of other forces and particles). From left to right: Bryce DeWitt, who obtained the Wheeler-DeWitt equation for the ”wavefunction of the universe”; it is based on the ADM classical description of gravity developed by Arnowitt, Deser, and Misner, two of whom are also shown in this photo. Stanley Deser, co-discoverer of supergravity. Mary K. Gaillard, a leader in supersymmetry, superstrings, and related areas of theoretical physics. Bruno Zumino, co-discoverer of supersymmetry and supergravity. Michael Duff, a leading string theorist. Richard Arnowitt, co-inventor of the minimal supergravity model used in many analyses of experiment and observation.
Abdus Salam hosts Mary K. Gaillard at 1976 neutrino conference in Aachen. Credit: Mary K. Gaillard.
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4. What is the origin of the entropy and temperature of black holes?
John Wheeler invented the terms “black hole”, “wormhole”, “quantum foam”, and “neutron moderator”, and made many important contributions to gravitational and nuclear physics. He is shown here at age 4.
Credit:AIPEmilioSegreVisualArchives,WheelerCollecWon.
Stephen Hawking plays tag with an emu on a Texas ranch.
Credit:HansSchuessler.
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But so far there is no such general or convincing derivation of the extremely simple results of Bekenstein and Hawking: Results have been obtained for special cases in string theory (and loop quantum gravity etc.), but not for actual static or rotating black holes in real 4-dimensional spacetime. Once again, it appears that some major principle has been missed.
One would like a derivation of the black hole entropy from the counting of microstates, as inscribed on Ludwig Boltzmann’s gravestone.
16AlluncreditedphotosweretakenbyRolandAllen.
5. Is information lost in a black hole?
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There are two possibilities for black hole thermodynamics: If it is only a statistical description at the macroscopic level, essentially reflecting the ignorance of an observer, then there is only an apparent loss of information when objects are incorporated into the black hole and later emerge as Hawking radiation. In this case there is presumably a deeper microscopic description (yet to be convincingly found) in which the time evolution is fully deterministic (and unitary) and no information is truly lost. On the other hand, if the entropy and temperature are fundamental features of a black hole, determined directly by gravity and quantum mechanics alone, then the original matter (which collapsed to form the black hole) would have its detailed nature obliterated within the event horizon. In this case the original information would be lost, perhaps through quantum gravity processes to be understood in the future. The various attempts to resolve this issue -- described by phrases like holographic principle and firewall -- have been well covered in even the popular media, but none has so far proved convincing.
6. Did the universe pass through a period of inflation, and if so how and why?Cosmic microwave background Seen by ESA Planck space-based observatory
7. Why does matter still exist?
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Among Andrei Sakharov’s many contributions to applied and fundamental physics are the Sakharov criteria for baryogenesis, which are key to understanding how matter survived after the extreme conditions of the Big Bang. But the origin of the required CP violation is still not understood, and requires new physics.
Credit:WikimediaCommons.
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8. What is the dark matter?
Fritz Zwicky Credit: http://www.astro.caltech.edu/palomar/about/timeline.html
VeraRubin
Credit:ArchivesandSpecialCollecWons,VassarCollegeLibrary
Despite increasingly powerful attempts to detect dark matter, via terrestrial collisions with atomic nuclei, emission of particles from extraterrestrial dark matter annihilations, and production of dark matter particles in accelerator laboratories, the composition of dark matter is still unknown.
9. Why are the particles of ordinary matter copied twice at higher energy? 10. What is the origin of particle masses, and what kind of masses do neutrinos have? 11. Does supersymmetry exist, and why are the energies of observed particles so small compared to the most fundamental (Planck) energy scale? 12. What is the fundamental grand unified theory of forces, and why?
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MakotoKobayashiandToshihideMaskawawiththeir2008NobelPrizeMedals.Theyshowedthatathirdgenera3onofmaeerpar3clesimpliestheCPviola3ondiscoveredin1964.Athirdgenera3onwasthuspredicted,anditsmemberssubsequentlyfound.Credit:\copyrightTheNobelFoundaWon,Photo:HansMehlin
13. Are Einstein relativity and standard field theory always valid? 14. Is our universe stable? 15. Are quarks always confined inside the particles that they compose? 16. What are the complete phase diagrams for systems with nontrivial forces, such as the strong nuclear force?
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Schema3cphasediagramformaeerinterac3ngviathestrongforce.AlerSaskiaMioduszewski,“ThequesttounderstandQCDmaeerusingheavynucleiincollisions”,PhysicaScripta90,108014(2015).FromU.S.NuclearScienceAdvisoryCommi4ee2007LongRangePlan.
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17. What new particles remain to be discovered? 18. What new astrophysical objects are awaiting discovery? 19. What new forms of superconductivity and superfluidity remain to be discovered? 20. What further properties remain to be discovered in highly correlated electronic materials? 21. What new topological phases remain to be discovered? 22. What other new phases or forms of matter remain to be discovered? 23. What is the future of quantum computing, quantum information, and other applications of entanglement? 24. What is the future of quantum optics and photonics?
Mildred Dresselhaus, “queen of carbon science”
Credit:CalvinCampbell,MIT
Credit:InsWtuteforQuantumScienceandEngineering
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Duncan Haldane, speaking on his behalf and on that of David Thouless on the work for which the 2016 Nobel Prize was awarded:
“These were all things that weren’t expected at all… but came as nice surprises.”
“…buttheworkcouldn’tbepublishedattheWmebecausetwojournalsrejectedit.”
Last December, Nobel Week in Stockholm:
Photocredit:SuzyLidström.
25. Are there higher dimensions, and if there is an internal space, what is its geometry?
26. Is there a multiverse?
27. Are there exotic features in the geometry of spacetime, perhaps including those which could permit time travel?
28. How did the universe originate, and what is its fate?
29. What is the origin of spacetime, why is spacetime four-dimensional, and why is time different from space?
30. What explains relativity and Einstein gravity?
31. Why do all forces have the form of gauge theories?
32. Why is Nature described by quantum fields?
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33. Is physics mathematically consistent? 34. What is the connection between the formalism of physics and the reality of human experience?
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Why is there something rather than nothing?
Simplest answer: “Why not?”
Sidney Morgenbesser: “If there were nothing you'd still be complaining!”
Frank Wilczek and others: “nothing” is unstable.
But the instability results from assumed laws of physics. And these laws are still something.
So either this question is beyond ordinary logic or a new principle is again needed.
Emily Dickinson:
Nature is what we know But have no art to say, So impotent our wisdom is To Her simplicity.
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DespitetheamazingsophisWcaWonofmodernscience,wesWlldonotreallyunderstandNature.
37. What is life? 38. How did life on Earth begin -- and how did complex life originate? 39. How abundant is life in the universe, and what is the destiny of life? 40. How does life solve problems of seemingly impossible complexity? 41. Can we understand and cure the diseases that afflict life? 42. What is consciousness?
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It is still not established what physical processes correlate with consciousness -- i.e., our global awareness of the input from our senses and our internal mental processes. A primary issue is whether consciousness is localized in one region or is instead distributed throughout the brain.
Finally,whowillsolvetheseproblems?
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Twelve prizewinning Swedish school girls on a visit to the Institut Laue-Langevin in Grenoble. Their guide, centre front, was from Gabon. The girls' parents were born in Finland, Iran, Iraq, Poland and Sweden. During their visit they met or were accompanied by English, French, Icelandic, Italian, Russian, and Swedish scientists. (One of the authors, Suzy Lidström, is at the upper right, as the organizer of the program at Uppsala University.) PhotographbyMaxAlexander.Copyright:UppsalaUniversity.
The paper related to this talk initiated “21st Century frontiers” — a series of articles on current challenges and future opportunities.
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The “ultimate hadron collider” proposed by Peter McIntyre, with 500 TeV collision energy and extremely high luminosity.
[From preface to series. Credit: Peter McIntyre.]
Article on Gordon Chen’s computational science and technology paper, just published and one of the first in the series.
Credit:ShanaHutchins,TexasA&MCollegeofScience
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Today’s intelligent man-made constructions would have been science fiction 50 years ago…
Christina Moberg, President, Royal Swedish Academy of Sciences
Photocredit:SuzyLidström.
