the ultimate hacker seti signals may need to be decontaminated dick carrigan fermi national...

THE ULTIMATE HACKER SETI Signals May Need to Be Decontaminated

Dick CarriganFermi National Accelerator Laboratory

Box 500, Batavia, IL 60510, USA ([email protected])

Cocconi and Morrison close their famous 1959 SETI article in Nature with the comment “The reader may seek to consign these speculations wholly to the domain of science-fiction. We submit rather, that the foregoing line of argument demonstrates that the presence of interstellar signals are entirely consistent with all we

now know…We therefore feel that a discriminating search for signals deserves a considerable effort. The probability of success

is difficult to estimate; but if we never search the chance of success is zero.”

D. Carrigan-Fermilab IAC-03-IAA.8.3.06 Bremen 9/30/03 2

Introduction

Topics• Current SETI picture• SETI messages• The possibility of SETI viruses • Interstellar signal transfer• Denaturing signals• Actions


Current SETI picture

•SETI searches are pregnant


SETI

ETI searches (radio and optical) are now approaching a level where a substantial fraction of sun-like stars out to several hundred light years have been monitored at least once.

Credits: Allen Telescope, Harvard SETI



•SETI searches are pregnant•more planets than expected•planets within range of our radio signals


Extra solar planets• A thousand or so sun-like

stars within 100 light years have been searched

• At least 8% have Jupiter-sized planets (lower limit since measurements limit detection to Jupiter-scale)

• The fraction of stars with planets may be higher so that a sizeable fraction of sun-like stars could have planets



•SETI searches are pregnant•more planets than expected•planets within range of our radio signals•Origin of life seems fairly easy•computer "life"•Earth may not be so “rare”

The chance of detecting ETI has increased many-fold!


MessagesElectromagnetic or matter (DNA, silicon, spacecraft, ..?)

Plants

talk?

Smells? Pictures? Compression

Want to get signal rate up!

Newtechnology

Message content?


Do analogies help?

Sender of a SETI message will look to the stars but its core perspectives may be more like the ant’s than our human one.

Moral arguments hard. Darwinian “Survival of the Fittest” rules.


Artifacts and beacons versus messages

Beacon (acquisition signal)-little information, locates source

Message (information signal)-lots of information

Material and electromagnetic ET artifacts like Dyson sphere signature


Nature of a signal

Altruistic: encyclopedia, philosopher, galactic bible

Self serving: like a fishing lure….Potentially dangerous

Radio’s advantage-speed of lightBUT-need a receiver!


Biological contamination from space samples is a remote but accepted possibility. SETI signals could also contain harmful information similar to a computer virus.

SETI viruses?


Biocontamination• Possible biological contamination led to the

establishment of a protocol for decontaminating material returning from space

• International Committee on Space Research (COSPAR) developed protocol through international space bodies and the United Nations


Is a SETI virus just fiction?

Received from Leslie Sage, Senior Editor of Nature, “While the subject does cross interdisciplinary lines this is not the main criterion we use for selection. Rather, papers should report deep new physical insights, … We have been unable to identify such aspects in the paper. The general premise of the manuscript even lacks some conceptual novelty, as it has already been explored in the book 3001, the Final Odyssey by Arthur C. Clarke.”


One way versus two way signals

• One way-message in an attractive bottle

• someone must find the bottle and read the message

Credit: http://www.sonic.net/bristlecone/

Two way conversations hard-bristlecone pine trees get only 20 exchanges at 100 light years


TV30 ly

Radio50 ly

Sun

Dangerous ETI signals

An intelligent system on a star fifty light years away detecting earth’s first radio signals could have broadcast a return signal that would now be reaching earth. There are on the ordr of 400 stars within this fifty light year sphere. Tarter notes TV transmitters on earth can be detected one light year away with contemporary technology.


• human genome-3 Gbytes of DNA base pairs, actual information content is on the order of 0.05 Gbytes

• typical education through graduate school subsumed in 1-10 Gbytes

• “memory” of an acquaintance might require 1-10 Mbytes so 1000 people could be summarized in 10 Gbytes

• lifetime of images stored on DVD might be 1000 Gbytes

• knowledge base in a human brain-30 Gbyte range*. 6*109 people gives 1011 Gbytes to profile everyone on earth

• 106 Gbytes of material printed every year

Size of SETI signals

*credit: D. Crevier. “The tumultuous history of the search for AI”. Basic Books-NY (93).

Based on this anticipate long signals possibly interspersed with short lures


Electromagnetic energy needs

2lnN

rm kT

PC

Channel capacity for low signal to noise ratio case. Max channel capacity depends on power received but not bandwidth*.

*D. Leigh-Harvard thesis

22R

AAPP rt

tr

Power received where Pt is transmitter power,

Ar-area of receiving antenna, R-separation

distance.

Channel capacity in bits/s -B bandwidth, TN noise temperature, k Boltzmann’s constant, Pr the power received by earth antenna.

BkT

PBC

N

r1ln2ln

Electromagnetic gain: λ is wavelength, At is transmitter area. The antenna broadcast to a smaller region as gain increases.

te AG2

4


Electromagnetic energy/bit

δEt = the transmitter energy/received bit.

Increases as R2, decreases as Ge, Ar increased. For the example: 3.6 Joules.

r

N

em

tt A

kT

G

R

C

PE

)2ln(4

2

δEr = the receiver energy/received bit. For

the example: 10-22 Joules or .0006 eV, corresponding to 14 photons at receiver.

)2ln(Nm

rr kT

C

PE

)2ln(Nr

s

e

mt kT

A

A

G

CP

Transmitted power-As is area of sky. First

parenthetical term is sky area divided by receiver area, second is energy per bit at receiver.


Interstellar information transfer

• Larger separation between the sender and receiver requires more energy

• Bigger transmitting and receiving antennas lower the energy• Better or more sensitive detectors help. For fundamental

reasons this implies cold detectors.• For electromagnetic signals the attenuation of the interstellar

medium is important• Antenna gain-the ability of an antenna to focus the beam.

Bigger dishes with higher gain focus better• For the example-the transmitter cost of a received

electromagnetic bit is 4 Joules

Energy to launch electromagnetic bit, transmit it through space, detect


From 50 light years away a 1000 kW transmitter using a 10 GHz carrier (λ = 3 cm) could send more than 10 Kbytes/s. A 1 Gbyte program or computer encyclopedia would take a day to transmit and cost $2400. (This is only an order of magnitude more expensive than buying software on a CD.)

Radio signals


• Laser beam spread may be too small. Have to point with great care and lead star for stellar motion

• Beyond 1000 light years signals in the visible suffer significantly from extinction

• Background effects less important• Nanosecond megajoule laser pulse outshines sun

Optical and near optical signalsDifferent than radio SETI:

Cost per laser bit ranges from 104 to 10-3 of a radio bit based on different estimates


Matter transfer• Receiver is not needed,

but landing, …?• Launch cost for DNA bit

can be precisely determined. A DNA word with three base pairs is 1.44 bits

• Stellar escape velocity about 3*104 m/s or .0001 of the speed of light

• Then DNA bit is 10-16 Joules

• Panspermia with stellar perturbations: Gain = 4*108. Launch energy/bit is 0.03 Joules

Surprising fact: sphere of DNA roughly 1 cm in diameter could contain an amazing 1020 bytes of information


Panspermia, the flow of seeds of life across space

mrm

r

s

m

mmt E

A

A

G

CP

Matter power to send a panspermia “message.”

Arm might be area of receiving planet.

Transmitter energy per received bit is 10-2 Joules or 10-4 of electromagnetic for example.

2

2

1vME

b

mt Transmitted energy per bit, Mb-mass of bit,

v-velocity, ves 4*104 m/s (about 0.0001c) for sun at earth. If no landing or processing “costs” maybe Et

m=Erm. Et

m = 6*10-16 Joules for example.22

GM

bvG

bm

Matter “gain” due to random stellar interactions. b-stellar impact parameter, G-universal gravitation constant.

bpbpb nMM / DNA case. bp is base pair. Typically Mbp is

600 Daltons, nbp is 1.44,


Spacecraft case• Mission profiles: ~ 107 kg Saturn rocket, payload ~ 105 kg . Ion thrusters in infancy but better. Antimatter fuel-five nanograms is basket of batteries.• Payload: guidance rockets, crew (small robots?), shielding, decelerating gear, information payload. • 10 kg can be boosted outside the sun’s gravitational field.• Panspermia energy costs might not be so different..

Kinetic energy/rest mass

1.E-09

1.E-07

1.E-05

1.E-03

1.E-01

1.E+01

0.0001 0.001 0.01 0.1 1v/c

KE

/m

Note that the spacecraft approach has a very high bandwidth


Matter transfer continued• Receiver is not needed,

but landing, …?• Launch cost for DNA bit

can be precisely determined. A DNA word with three base pairs is 1.44 bits

• Stellar escape velocity about 3*104 m/s or .0001 of the speed of light

• Then DNA bit is 10-16 Joules

• Panspermia with stellar perturbations: Gain = 4*108. Launch energy/bit is 0.03 Joules

• Spaceship and DNA about same

Electromagnetic and matter costs per bit are comparable

Surprising fact: sphere of DNA roughly 1 cm in diameter could contain an amazing 1020 bytes of information


Virus Threat List W32.Fishlet.A@mm June 10, 2002 W32.Chier@mm June 8, 2002 W32.Frethem.D@mm June 7, 2002 VBS.Chick.F@m June 7, 2002 Backdoor.AntiLam June 7, 2002 W32.HLLW.Nople June 6, 2002 VBS.VBSWG.AQ@mm June 6, 2002 W32.Shermnar.Worm June 5, 2002 Backdoor.Tron June 4, 2002 W32.Pet_Ticky.B@mm June 3,

An ETI computer virus

Expert criticisms:• Viruses use known features of system to find a portal• Idiosyncratic language is an unbreakable firewall• Download process seriously scrambles the signal content• ETI code too complicated and not earth-adapted

• Raw signal in memory must bootstrap to status of operating program (can test this as a possibility)

• Program must then untangle the inner workings of the host. (Is it possible to now build a diagnosis program to determine the operating set of an unfamiliar computer?)

• Then learn how to translate unpacking program into local computer language


Prophylactic measures• Keep downloaded SETI signals on machines

isolated from analysis• Fragment SETI signals into small packets and

keep apart• Quarantine on isolated computers and watch for

aberrant behavior• Check sums and program integrity checks• Could SETI translation use one-time ciphers for

operating codes?• Beacons can be handled without as much care as

messages


Actions• Revise item 6 of the present SETI signal detection

protocol so data is more tightly controlled• Rethink widely dispersed data of SETI@home• Prepare to act promptly if a signal is found• Convene a COSPAR type workshop of experts in

SETI, computer security, cryptography, biological contamination, and archaeology

To paraphrase Cocconi and Morrison for the possibility of a malevolent SETI signal …the probability of a contaminated SETI signal is difficult to estimate; but if we never consider it the chance of infection is not zero.

the ultimate hacker seti signals may need to be decontaminated dick carrigan fermi national...

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