Astronomy

16 ASTRONOMY • JULY 2018

T

he starling seems an

unexceptional bird,

but gather thousands

together into a mur-

muration (named

for the sound of a multitude

of rapidly beating wings) and

they become the grandest show

in the sky. A murmuration in

f light looks a bit like an amoeba

on steroids as it morphs through

a never-ending sequence of

complex shapes. (Type “murmu-

ration” into a web browser and

play a video. Now. Really!)

Why do starlings do what

they do? Ancient Romans

believed that starlings foretold

the will of the gods. The word

auspicious comes from the Latin

auspicium, or “divination by

observing the f light of birds.” In

the 1930s, ornithologist

Edmund Selous asserted that

starlings are telepathic. Even

today, biologist Rupert

Sheldrake attributes starling

behavior to his hypothetical

“morphic resonances.”

The real answer is a lot cooler!

Some of computing’s most

revolutionary and frankly fun

contributions to science have

come from an ability to answer

seemingly straightforward ques-

tions like, “When you combine

lots of simple things into a

larger system, what happens?”

The f locking behavior of star-

lings is a gorgeous example.

Individual starlings all obey

the same few f light rules: Watch

your seven nearest neighbors.

Fly toward each other, but don’t

crowd. If any of your neighbors

turn, turn with them.

Simplicity itself, right? But

now put a bunch of virtual star-

lings into a computer, each pro-

grammed to obey those same

rules, turn the crank, and see

what happens. There are no

FORYOURCONSIDERATION

BY JEFF HESTER

A murmuration of starlings

Emergence and the unity of science.

gods, telepathy, or morphic reso-

nances at work in the computer

simulation. Even so, the com-

puter-simulated f lock behaves

exactly like the real thing!

In December 2017, the story

came full circle when those

mesmerizing f locks of virtual

birds took wing — or rather

propeller — back into the real

sky. Artists Lonneke Gordijn

and Ralph Nauta programmed

300 drones to obey starling

flight rules, then turned them

loose above Miami Beach, much

to the wonderment of onlook-

ers. Welcome to the burgeoning

science of emergence.

By definition, an emergent

property is one that is possessed

by a system as a whole but not

by the components from which

the system is made. While com-

puter simulations of emergence

may be a fairly new thing, the

idea of emergence has been cru-

cial to science for a long time.

At one extreme, physics is a

remarkably successful quest for

a few fundamental rules

describing how matter and

energy behave. At the other

extreme, physics encompasses a

complex universe filled with

stars, planets, galaxies, and

much more. That’s quite a

chasm, but we don’t have to

jump. Near the first end,

nuclear physics emerges from

interactions among particles.

Atomic physics emerges when

nuclei and electrons interact.

Chemistry emerges from com-

plex electromagnetic interac-

tions among atoms. On things

go as step by step, emergence

bridges the divide, unifying

science into a coherent whole.

Full disclosure: Like most

scientists, when I talk about

emergence, I mean physics-is-

fundamental-but-as-things-get-

complex-it-can-really-surprise-

you emergence. Philosophers

often mean a very different woo-

woo-like-morphic-field-pops-

up-and-snarfs-the-controls-away

emergence. Mischief managed!

You might guess that emer-

gence would be uncommon, but

actually it’s hard to avoid. From

chemical reactions, to weather

patterns, to the beating of your

heart, emergence is ubiquitous

in the world around us. (As you

read this, somewhere an unan-

ticipated emergent behavior is

costing an engineer her sanity.)

And when life emerges from

the chemistry of molecules

that encode and replicate

information, things get really

interesting. Inventing emer-

gent properties is sort of evolu-

tion’s gig.

Starlings have one more

f light rule: If you spot a preda-

tor, f ly away! As a falcon dives,

the first starlings to notice

hightail it. Their neighbors

quickly respond, then their

neighbors’ neighbors respond,

and so on. Before the falcon

even arrives, birds throughout

the murmuration are f lying

about in chaotic, unpredictable

ways in response to a predator

that only a few have even seen.

Surrounded by prey but unable

to single out an individual tar-

get, the fastest raptor on the

planet usually goes home

hungry.

It turns out that watching

seven neighbors is a sweet spot

where the strategy works best.

So when the falcon comes to

visit, any starlings tracking

something other than seven

neighbors make easier targets.

The falcon is more than happy

to remove the nonconformists

from the gene pool. Thus did

evolution happen upon and

fine-tune the starlings’ success-

ful emergent strategy.

It is hard to count the num-

ber of times throughout history

when authorities have pointed

to a gap in then-current knowl-

edge about the natural world

and proclaimed, “This is obvi-

ously beyond the reach of sci-

ence!” Science seldom fails to

answer such a challenge, and

quite often it is emergence that

fills the gap. To be honest,

there aren’t an awful lot of gaps

left in which to look.

BROWSE THE “FOR YOUR CONSIDERATION” ARCHIVE AT http://www.Astronomy.com/Hester.

A huge flock of starlings creates a wonderfully complex shape as it lifts into the sky

in this image taken in 2013. Such shapes tell us a lot about how science works.

Jeff Hester is a keynote speaker,

coach, and astrophysicist.

Follow his thoughts at

jeff-hester.com.

© THOMAS LANGLANDS | DREAMSTIME.COM