FUTURES

NATURE|Vol 437|29 September 2005

788

FUTURES

World beater.

Report on the paper “Analysis of the grav-

itational signals from a newly discovered

Kardashev II civilization in the Sombrero

Galaxy: Part 1 by Whimbrel et al.”, sub-

mitted to the Journal of Xenoastronomical

Studies.

The authors present an analysis of gravita-

tional signals of intelligent origin arising

in the Sombrero Galaxy, detected in

publicly available archival data from the

System-Wide Imaging Network for Exo-

astronomy (SWINE). The transmitting

culture, which has not been the subject of

an earlier paper, is shown to be a

type II civilization on the Karda-

shev scheme, by which it is under-

stood that they have the means to

tap the entire energy output of

their star. This classification is

made partly on the basis of the

strength of the SWINE signal

(which in itself implies a basic

competence in stellar husbandry)

and partly on the basis of the cul-

tural information embedded in the

datathemselves. This assessmentis

probably correct, but given the

likelihoodthatbothtypeI and type

III civilizations may occasionally

emulate type II civilizations for their own

purposes (see, for instance, Chukar, Fran-

colin and Dickcissel, 2051), a word of cau-

tionmight well havebeen in order.

The species is shown to have originated

on a rocky terrestrial planet about the size

of Mars, and to have followed an evolu-

tionary pathway that is well approximated

by the uppermost track on the three-

parameter model of Bataleur and Becard

(2049). In their unmodified form, adult

members of this species are 3-metre tall

hexapodal oxygen-breathers with a DNA-

based reproductive system. The species

has a well-developed central nervous sys-

tem withmarked hemispheric asymmetry.

The authors apply standard analysis

tools and methods to extract cultural

information from the intercepted signal.

Given the absence of anything startlingly

new in their approach, the amount of

space that the authors spend discussing

this process is puzzling. Itmight havebeen

better simply to reference one of the many

review papers on the matter, such as the

recent and comprehensive overview of

analysis methods given in [omitted].

The authors then move on to the main

part of their paper: a lengthy discussion of

the information content of the decoded

message. They summarize the nature of

the transmitting civilization, the physiol-

ogy and evolutionary background of the

inhabitants, their technology and culture.

Although broadly satisfactory in its

details, this section would benefit from

shortening. As an example, the authors

dwell on the construction methods used

in the Dyson sphere that the aliens have

erected around their star, despite the fact

that broadly similar planet-dismantling,

reforging and gravity-control methods

have been used by at least 138 other Kar-

dashev II cultures (see, for instance,

Takahe and Smew, 2045). In the very first

sentence of subsection 3.2, the authors

state that there is “nothing particularly

novel about the construction methods”,

before nevertheless embarking on a blow-

by-blow account of those selfsame meth-

ods. I agree with the first sentence.

They conclude this section by present-

ing, in excerpted form, several images and

texts deemed to be of high significance

within the culture. These include 18 ‘stan-

zas’ of a much longer epic ‘poem’ written

in commemoration of the collapse of part

of the polar region of their Dyson sphere

about 1.2 million years ago, an accident

that resulted in the deaths of

5.6 10

12

sentient beings. Although undoubtedly

touching, it is not clear that a great deal is

gained from the inclusion of this some-

what taxing material.

The authors conclude their paper by

movingontoa wider discussionofthe sig-

nificance of their newly found civilization

against the known sample of other intelli-

gent alien species. Here the authors place

(in my view) undue emphasis on the posi-

tion of their civilization in the ‘cultural

H–R diagram’ (Wonga and Grebe, 2044),

in which the total information capacity of

a transmitting culture, measured in bits, is

plotted against the light-crossing time in

light-seconds oftheir total colonized space.

On the basis of Figure 8, the authors claim

that their culture lies significantly to the

right ofthe ‘asymptotic singularity branch’,

which on the face of it would suggest that

the culture had avoided a singularity

despite occupying a total volume only

72,000 light-seconds in diameter. If true,

this would extend the total number of

known collapse-resistant cultures to eight.

The evidence, however,is verymuch less

compelling than the authors claim. Close

examination of their statistical sample

shows it to be derived from the

Third Gonolek catalogue,which is

now known to be afflicted by seri-

ous sampling errors. Visual inspec-

tion would suggest that a more

reliable sample — such as that of

[omitted] — would either bring

their civilization into line with the

singularity branch, or reveal it as

nomorethanamildoutlier.

In short, although the new civi-

lization undoubtedly provides a

useful new datum point, I remain

unconvinced that it merits an

entire paper, and certainly not the

multi-paper saga that the authors

clearly havein mind. Thanks tothe torrent

of data supplied by SWINE, and the

planned Obscenely Large Gravity Array

(OLGA), weare fast movingintothe era of

statistical xenoastronomy — one in which

thestudy ofindividualextraterrestrial civ-

ilizations has much less to offer than a

global, survey-based approach. The

authors might therefore beadvised towait

until their archival enquiries have turned

up several dozen such cultures, and then

gather these results into a single paper.

Otherwise, I fear, they may be open to

accusations of [omitted] the [omitted].

Other matters:

Fig. 6 was incorrectly labelled (see Fig. 5).

This text has been swept by Semantic

Anonymity Preserver Version 5.1 — cer-

tain stylistic or cultural markers may have

been altered or removed. Complete legi-

bility is not guaranteed.

■

Alastair Reynolds lives in the Netherlands.

He worked at the European Space Agency for

12 years on a variety of astronomical projects

before turning to full-time writing. His latest

book is Century Rain (Orion, 2004).

J

A

CEY

©2005