ETMightWriteNotRadiate

ChristopherRose1andGregoryWright2

1WINLAB

RutgersUniversity

Piscataway,NewJersey08854USA

2AntiopeAssociates

18ClayStreet

FairHaven,NewJersey07704USA

March24,2004

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10YearsofWINLABResearch(Infostationsredux)

Infostations:

–Delaytolerant?transmitwhennearbase!

ChannelQuality

–HowgoodcanthatRFchannelbe?reallygood!

InterferenceAvoidance,Pricing&SpectrumManagement

–Interferencehurtsdealwithit!

C.RoseWINLABDIMACSStorage3/24/04

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AnEpiphany!

RFInterferenceisbad

Storagedensityisincreasing

Channelgoodwhennearby

Cantoleratedelay

IMPLICATION:

–ForgetRF!Writemessagedown!Tossittorecipient!

Completelyridiculous.........right?

C.RoseWINLABDIMACSStorage3/24/04

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ALittleEmpiricalRigor

OpticalLithographywithSiO2:3851018bits/kg

E-beamLithographywithSiO2:1541021bits/kg

STMwithXeonNi:1741022bits/kg

RNA:361024bits/kg

AndmaybeaLOTmoreroomatthebottom

C.RoseWINLABDIMACSStorage3/24/04

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ALittleAnalyticRigor

R2

π aperture

0D

0Dr

τ=D/c+T

T

radiated message

D/c 0

Mass Transport

Radiation

mass delivered

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CommunicationsTheoryISRocketScience

Maxbiggerthanmean:

maxv

hvEhV

IfVdeterministic:

maxv

hvEhV

Ifhconvex(Jensen):

EhVhv

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RocketScienceAveragevelocity

1τ

τ

0vtdtD

τ

vEvt

Minimumimpartedenergy

Eminv

maxt

hvt

subjecttovDτ.

Jensensays

Eminv

maxt

hvtminv

Ehvthv

withequalityiffvtisconstant

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MinimumTransportEnergyGIVEN:handv

Ehv

hvmc21

1v2

c21:

Emc21

1

vc

2

1

hv12mv2:

E

12

mv2

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PotentialFieldsSetupqxpotentialenergy:

Et hvtqxt

Energyminimization:

Eminx

maxtEtmin

x

1τ

τ

0Etdt

Calculusofvariations:

ddt

∂E∂v

∂E∂x

0

xh

xq

x0

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PotentialFieldResultsNon-relativistic:

mxq

x

q

xisforceatpositionx:“freefall”

Freefall?Et constant

Etconstantminimizationsatisfiedwithequality,so...

.

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PotentialFieldResultsLowspeed:

mxq

x

q

xisforceatpositionx:“freefall”

Freefall?Et constant

Etconstantminimizationsatisfiedwithequality,so...

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ArtilleryProblemMinimumenergy:

E12

mgD

LetδcτD

–δ1nearlightspeed

–δ1lowspeed

Delayatminimumenergy

δc2gD

Payafactorof2overfreespace

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EscapeProblem

Needsnumericalcalculation

Boilsdownto:needinitialvelocitylargerthanescape.

Someenergypenalty(butnotalot)

Escapeexamples(rough):

–Earth:δ27104

–Solar:δ71103

–MilkyWay:δ6102

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InscribedMatterEnergyRequirementsMessagesizeB,massinformationdensityρ

General

EwBρ

c2δ

δ21

1

δ1:

Ew12

Bρ

cδ

2

Offbyonly10%at04cand50%at075c

Lowspeedain’tsolow!

We’llignorerelativity

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RadiationEnergyRequirementsEnergycapture

νDAG4πD2

BitsalaShannon:

BTCTWlog2PGA

4πD2N0W

1

ErPT,

ErBN04πD2

AGTWB

2B

TW1

LargeTW:

ErBN04πD2

AGln2

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RadiationtoTransportEnergyRatio

Definition:

Ω

Er

Ew

LargeTW,δ1

ΩρN0

c2

4πD2

AG

2ln2δ2

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102

104

106

108

1010

1012

1014

1016

1018

1020

1022

D

100

104

108

1012

1016

1020

A

Energy Capture BoundArecibo@10GHz10m Optical (500nm)1m Xray (0.1 nm)Earth@10GHz

Ω

1

10-6

106

1012

1018

1024

1030

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IsRadiationBetterforBroadcast?

Radiationilluminatesmanymatterpenalty

MilkyWaystellardensity64103stars(LY)3

Sphericalgalaxy,isotropicradiation,Arecibo-Arecibo

R104LY:271010stars(butΩ1028)

R106LY:271016stars(butΩ1032)

No,inscribedmatterstillwins!

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DoesInscriptionEnergy/SpeedEatBudget?

MatterInscription/ReadoutEnergyandTime

–Landauersaiditcanbereversibleandabitrarilyfast

Empiricalenergycalc:

–60000ATP/secondfor20minutes:4639KbaseofE-coli

–81020JperATPmolecule

–621019Jbit1.

–Eatearthescape:1681017Jbit1.

Constructionenergynotaproblem

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RadiationNeedsRepetition

CivilizationBirthRate:α1109peryear

CivilizationExtinctionRate:β1108peryear

Successcriterion0Φ1

NowmanyrepetitionsN(optimallyplaced)?

Φ099N2000

Φ09999N200000,

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DeliveryMethods

Bigrock?

Dust?

Embeddeddust&rock(comet)?

Probe(Bracewell)

Onwardtowardlunaticfringe

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DeliveryMethods(moredetail)

Needexhaustbraking

Energypenalty(excessmass):ec

δgIsp

IspSpecificImpulse

–Chemical:102

–NuclearElectric:104

–Fusion:106

Isp20000,δ1000penalty46

δ100orIsp2000penalty44106

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CosmicInsultsInsults:

–Highenergyparticlebombardment

–Heating(diffusion)

–Iontracks,dislocations,subatomiccascades

Shielding:

–10millionyearsat10%bacteriaviability:3mradiusrock

(3gcm3density)

–34106penalty

CleverComposition,CodingandCorrection:

–???????

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PUNCHLINES

InscribedmattermessagingisNOTridiculous

InscribedmattermessagingmightoftenbePREFERRED

Questionsforstoragetypes:

–Generaltheoryofinscribedmatterstorage?

–CompositionandCodingforsurvivability?

–Easeofdecoding(obviousness)?

Learnmore:

http://www.winlab.rutgers.edu/crose/cgi-bin/cosmic4.html

C.RoseWINLABDIMACSStorage3/24/04