Astronomy - September 2015

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6 ASTRONOMY • SEPTEMBER 2015

BY DAVID J. EICHER

FROM THE EDITOR

Editor David J. Eicher

Art Director LuAnn Williams Belter

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B

efore last year, a little

piece of our knowledge

of the cosmos was

completely different.

In the collective his-

tory of humans studying the

universe around us, we had

looked up close at a comet

only a few times — with rela-

tively fleeting glances and not

with the kind of resolution

we now have.

And then came Rosetta’s

rendezvous with Comet 67P/

Churyumov-Gerasimenko.

In August 2014, the space-

craft arrived at this periodic

comet, commencing a series

of maneuvers that swung it

along triangular paths, stay-

ing around 30 to 60 miles

(50 to 100 kilometers) from

the comet’s 3-mile-wide

(5k m) nucleus. L ast

November, the spacecraft

detached its Philae lander,

which touched down and

transmitted the first detailed

pictures from the surface of

a comet’s nucleus. After

some 60 hours of operations,

the lander shut down, only

waking up again in June as

sunlight generated power.

Meanwhile, the Rosetta

spacecraft is busily stream-

ing data and fresh images all

the time. Let’s set aside the

incredible science we will

reap from this mission — for

more on that, you can read

Senior Editor Richard

Talcott’s story, “Rendezvous

with an evolving comet,”

beginning on p. 44.

Taken simply at a level of

new imagery, the mission is

completely mind-blowing.

We now see the surface of a

comet in unprecedented

detail, in new images every

week, with blocks of ice the

size of football fields, boul-

ders the size of houses, shad-

ows splaying over cliffs

rising up “skyward,” and

dune-like ripples, surface

irregularities caused by

“winds” of gas outf lows. We

see jets of icy water outbursts

regularly in such detail that

it is mind-numbing. And

more and more and more.

Human beings knew

about none of these features

just a year ago. This comet,

an icy body preserving

secrets from the solar sys-

tem’s early days, presents a

new adventure to planetary

scientists all the time. Every

day, the spacecraft produces

new imagery and data to be

analyzed that uncovers

things never seen before.

I remember back several

months to the fantastic

excitement felt by the whole

astronomy community. Now,

just a few months later,

many of the community

seem to take these images

for granted.

Do we really lose the

sense of brand new adven-

ture that quickly?

Thank goodness I can

remember back to Martin

Harwit’s book Cosmic

Discovery, which in 1981

documented that astrono-

mers have likely uncovered

only some 20 percent or so

of the kinds of phenomena

in the universe.

That’s not to say that new

discoveries will completely

rewrite science. That’s

another disease of thinking

many people seem to have.

“We don’t know everything;

therefore, what we do know

might be completely over-

turned in the future.” That’s

not clear thinking, however.

The law of gravitation, for

example, has held up pretty

well for a very long time.

Thankfully, we certainly

have countless more exciting

moments of discovery and

exploration left ahead of us

to enjoy in many ways and

excite us again and again, if

only for a few months at a

time!

Yo u r s t r u l y,

David J. Eicher

Editor

The

breathtaking

pace of science

Follow the Dave’s Universe blog:

http://www.Astronomy.com/davesuniverse

Follow Dave Eicher on Twitter: @deicherstar