ET Might Write Not Radiate Christopher Rose 1 and Gregory Wright 2 1 - - PowerPoint PPT Presentation

SLIDE 1

ET Might Write Not Radiate

Christopher Rose1 and Gregory Wright2

1WINLAB

Rutgers University Piscataway, New Jersey 08854 USA

2Antiope Associates

18 Clay Street Fair Haven, New Jersey 07704 USA

March 24, 2004

SLIDE 2

Write Not Radiate 1

10 Years of WINLAB Research (Infostations redux)

• Infostations:

– Delay tolerant?

✁

transmit when near base!

• Channel Quality

– How good can that RF channel be?

✁

really good!

• Interference Avoidance, Pricing & Spectrum Management

– Interference hurts

✁

deal with it!

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 3

Write Not Radiate 2

An Epiphany!

• RF Interference is bad
• Storage density is increasing
• Channel good when nearby
• Can tolerate delay
• IMPLICATION:

– Forget RF! Write message down! Toss it to recipient!

Completely ridiculous ......... right?

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 4

Write Not Radiate 3

A Little Empirical Rigor

• Optical Lithography with SiO2: 3
• 85

✁

1018 bits/kg

• E-beam Lithography with SiO2: 1
• 54

✁

1021 bits/kg

• STM with Xe on Ni: 1
• 74

✁

1022 bits/kg

• RNA: 3
• 6

✁

1024 bits/kg

• And maybe a LOT more room at the bottom
• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 5

Write Not Radiate 4

A Little Analytic Rigor

R2 π aperture D

D r

τ =D/c+T T

radiated message

D/c

Mass Transport Radiation

mass delivered

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 6

Write Not Radiate 5

Communications Theory IS Rocket Science

• Max bigger than mean:

max

v

h

• v

✁ ✂

E

✄

h

• V

✁ ☎

• If V deterministic:

max

v

h

• v

✁✝✆

E

✄

h

• V

✁ ☎

• If h
• ✁

convex (Jensen): E

✄

h

• V

✁ ☎ ✂

h

• ¯

v

✁

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 7

Write Not Radiate 6

Rocket Science

• Average velocity

1 τ

τ 0 v

• t

✁

dt

✆

D τ

✆

¯ v

✆

E

✄

v

• t

✁ ☎

• Minimum imparted energy

E

• ✆

min

v

✁✂

max

t

h

• v
• t

✁ ✁

subject to ¯ v

✆

D τ .

• Jensen says

E

• ✆

min

v

✁✂

max

t

h

• v
• t

✁ ✁ ✂

min

v

✁✂

E

✄

h

• v
• t

✁ ✁ ☎ ✂

h

• ¯

v

✁

with equality iff v

• t

✁

is constant

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 8

Write Not Radiate 7

Minimum Transport Energy

• GIVEN: h
• ✁

and ¯ v E

• ✆

h

• ¯

v

✁

• h
• v

✁✝✆

mc2

1 1

• v2

c2

✁

1 : E

• ✆

mc2 1 1

✁ ✂

¯v c

✄

2

✁

1

• h
• v

✁✆☎

1 2mv2:

E

• ☎

1 2m¯ v2

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 9

Write Not Radiate 8

Potential Fields Setup

• q
• x

✁

potential energy:

E

• t

✁ ✆

h

• v
• t

✁ ✁✁

q

• x
• t

✁ ✁

• Energy minimization:

E

• ✆

min

x

✁✂

max

t

E

• t

✁ ✂

min

x

✁✂

1 τ

τ 0 E

• t

✁

dt

• Calculus of variations:

d dt ∂E ∂v

✁

∂E ∂x

✆

¨ xh

✂ ✂

• ˙

x

✁ ✁

q

✂

• x

✁✝✆

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 10

Write Not Radiate 9

Potential Field Results

• Non-relativistic:

m¨ x

✆

q

✂

• x

✁

• q

✂

• x

✁

is force at position x:

• “free fall”
• Freefall?
• E
• t

✁ ✆

constant

• E
• t

✁

constant

• minimization satisfied with equality, so ...

.

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 11

Write Not Radiate 10

Potential Field Results

• Low speed:

m¨ x

✆

q

✂

• x

✁

• q

✂

• x

✁

is force at position x:

• “free fall”
• Freefall?
• E
• t

✁ ✆

constant

• E
• t

✁

constant

• minimization satisfied with equality, so ...
• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 12

Write Not Radiate 11

Artillery Problem

• Minimum energy:

E

• ✆

1 2mgD

• Let δ

✆

cτ

• D

– δ

☎

1

✁

near light speed – δ

✂

1

✁

low speed

• Delay at minimum energy

δ

• ✆

c 2

• gD
• Pay a factor of 2 over free space
• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 13

Write Not Radiate 12

Escape Problem

• Needs numerical calculation
• Boils down to: need initial velocity larger than escape.
• Some energy penalty (but not a lot)
• Escape examples (rough):

– Earth: δ

• 2
• 7

✁

104 – Solar: δ

• 7
• 1

✁

103 – Milky Way: δ

• 6

✁

102

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 14

Write Not Radiate 13

Inscribed Matter Energy Requirements

• Message size B, mass information density ˜

ρ

• General

Ew

✆

B ˜ ρ c2 δ

• δ2

✁

1

✁

1

• δ

✂

1: Ew

☎

1 2 B ˜ ρ

✁

c δ

✂

2

• Off by only

☎

10% at 0

• 4c and

☎

50% at 0

• 75c
• Low speed ain’t so low!
• We’ll ignore relativity
• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 15

Write Not Radiate 14

Radiation Energy Requirements

• Energy capture

ν

• D

✁✝✆

AG 4πD2

• Bits a la Shannon:

B

✆

TC

✆

TW log2 PGA 4πD2N0W

• 1
• Er

✆

PT, Er

✆

BN0 4πD2 AG TW B

• 2

B TW

✁

1

✁

• Large TW:

Er

✂

BN0 4πD2 AG ln2

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 16

Write Not Radiate 15

Radiation to Transport Energy Ratio

• Definition:

Ω

• Er

Ew

• Large TW, δ

✂

1

Ω ˜ ρN0 c2 4πD2 AG

✁

2ln2

✂

δ2

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 17

Write Not Radiate 16

10

2

10

4

10

6

10

8 10 10 10 12 10 14 10 16 10 18 10 20 10 22

D

10 10

4

10

8

10

12

10

16

10

20

A

Energy Capture Bound Arecibo@10GHz 10m Optical (500nm) 1m Xray (0.1 nm) Earth@10GHz

Ω

1

10

• 6

10

6

10

1 2

10

1 8

10

2 4

10

3

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 18

Write Not Radiate 17

Is Radiation Better for Broadcast?

• Radiation illuminates many
• matter penalty
• Milky Way stellar density 6
• 4

✁

10

• 3 stars (LY)
• 3
• Spherical galaxy, isotropic radiation, Arecibo-Arecibo
• R

✆

104 LY: 2

• 7

✁

1010 stars (but Ω

✆

1028)

• R

✆

106 LY: 2

• 7

✁

1016 stars (but Ω

✆

1032)

No, inscribed matter still wins!

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 19

Write Not Radiate 18

Does Inscription Energy/Speed Eat Budget?

• Matter Inscription/Readout Energy and Time

– Landauer said it can be reversible and abitrarily fast

• Empirical energy calc:

– 60000 ATP/second for 20 minutes: 4639 Kbase of E-coli – 8

✁

10

• 20J per ATP molecule

– 6

• 2

✁

10

• 19J bit
• 1.

– E

• at earth escape: 1
• 68

✁

10

• 17 J bit
• 1.
• Construction energy not a problem
• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 20

Write Not Radiate 19

Radiation Needs Repetition

• Civilization Birth Rate: α

✆

1

• 109 per year
• Civilization Extinction Rate: β

✆

1

• 108 per year
• Success criterion 0
• Φ
• 1
• Now many repetitions N (optimally placed)?
• Φ

✆

• 99
• N

✆

2000 Φ

✆

• 9999
• N

✆

200

✁

000,

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 21

Write Not Radiate 20

Delivery Methods

• Big rock?
• Dust?
• Embedded dust & rock (comet)?
• Probe (Bracewell)
• Onward toward lunatic fringe
• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 22

Write Not Radiate 21

Delivery Methods (more detail)

• Need exhaust braking
• Energy penalty (excess mass): e

c δgIsp

• Isp

✁

Specific Impulse – Chemical: 102 – Nuclear Electric: 104 – Fusion: 106

• Isp

✆

20

✁

000, δ

✆

1000

• penalty 4
• 6
• δ

✆

100 or Isp

✆

2000

• penalty 4
• 4

✁

106

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 23

Write Not Radiate 22

Cosmic Insults

• Insults:

– High energy particle bombardment – Heating (diffusion) – Ion tracks, dislocations, subatomic cascades

• Shielding:

– 10 million years at 10% bacteria viability: 3 m radius rock (3g cm

• 3 density)

– 3

• 4

✁

106 penalty

• Clever Composition, Coding and Correction:

– ???????

• C. Rose

WINLAB

DIMACS Storage 3/24/04

SLIDE 24

Write Not Radiate 23

PUNCHLINES

• Inscribed matter messaging is NOT ridiculous
• Inscribed matter messaging might often be PREFERRED
• Questions for storage types:

– General theory of inscribed matter storage? – Composition and Coding for survivability? – Ease of decoding (obviousness)?

• Learn more:

http://www.winlab.rutgers.edu/

• crose/cgi-bin/cosmic4.html
• C. Rose

WINLAB

DIMACS Storage 3/24/04