The Future - University of...
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The Future
Transcript of The Future - University of...
The Future
Summary:DarkEnergyandCosmicFateΩtot=1;ΩΛ=0.7
Trending:exp[(Λ/3)1/2t]
GravityDarkEnergy
Λ≈10-122!
Long-termCosmicOutcomesWhatdoyouexpect?
BeforelongmasswillplayaninsignificantroleinrestrainingtheacceleraQonofspace.
Dark Energy Will Rule!
now3xnow
2xnow
AdaptedfromO&MFig7.2
exp[(Λ/3)½t]“runaway”
Thebiggeritgetsthefasteritgrows
Ωm=allmass
Gravitywon’tmaYermuchlonger
Gravitynowplaysaminorrole
ΛDM
“baryons”&radiaQon
^present
Long-termCosmicOutcomes
TheUniversedoublesinsizeevery12billionyrs
² Darker,colder,andlessdense² ExisQnggravitaQonallyboundsystemswillpersist
(andslowlybecomeevendenser)² High-massstarproducQonwilldropoff.Supernova
ratewillgodown,aswilltheproducQonofmostheavyelements.
² AllstarformaQonendsoncetheISMisdepleted² Whitedwarfsandneutronstarswilleventually
depletethereservoirofinterstellardustandgas.² FricQonresultsintheEarth’sorbitaldeathspiral
The Cosmic Future Short-Term Cosmic Forecast
(< 100× present time)
hYp://www.bbc.com/future/story/20140105-Qmeline-of-the-far-future
106 to 108 y
108 to 1010 y
1011 to 1020 y
1014 y
1020 y
• SupposethattheexponenQalexpansion(runawayinflaQon)ofspaceandQmeconQnues.
• Ourhorizongrowsatthespeedoflight.• Butspace-Qmeexpandsevenfaster!
Thespeedofdistantobjectsincreasesun=l,eventually,theirapparentspeedexceedsc.Theseobjectsdisappearoverthehorizonandareneverobservableagain.
More:hYps:/hYps://en.wikipedia.org/wiki/Future_of_an_expanding_universe
TheUniversedoublesinsizeevery12billionyrs
• TheCMBisnolongervisiblein50billionyears• Aher150billionyearsastronomy(andintergalacQc
transportaQonandcommunicaQon)beyondtheLocalGroupbecomescausallyimpossible.
² The“CosmicSprawl”:Accelera:onoftheCosmicExpansion(ifitcon:nues)makeseveryplacelonely
² 100trillion(1014)y:AllISMdepleted² Starforma:onends² Thelastredgiantbecomesawhitedwarf² Occasionalflaresasbrowndwarfscollide² Galaxiesfadeastheirwhitedwarfscool² Allchemicalandnuclearenergydepleted
The Cosmic Future Medium-Term Cosmic Forecast
( 104 × present time)
² 1039y:whitedwarfsdiefromprotondecayandneutronstarsdecayfromneutronbetadecay
² >10100y:frigidandorderless‘ULTRA-LOW-densitysea’ofphotons(subradioenergy)electrons,positrons.
The Cosmic Future Ultimate Cosmic Forecast
(>1010 × present time)
The 2nd Law and local quantum effects rule!
Frontiers of Cosmology Research
² 1039y:whitedwarfsdiefromprotondecayandneutronstarsdecayfromneutronbetadecay
² >10100y:frigidandorderless(butlumpy)‘sea’ofsparsephotons(subradioenergy)electrons,positrons.
The2ndLawandlocalquantumeffectsrule!
The Cosmic Future Ultimate Cosmic Forecast
(>1010 × present time)
Frontiers of Cosmology Research
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