Sky and Telescope - September 2018 - 16

The Case for Venus
90°

Fortuna Tessera
Maxwell
Montes

60°

ISHTAR TERRA

A t a la n t a P la n i ti a

Audra Planitia

Till

i

nu
-Ha

la
m P

Tellus
Tessera

30°

Nio

be

nit

ia

Pla

niti

a

Latitude

S ap as
Mo ns
Eistla Regio
0°

M aat
M o ns

Manatum
Tessera

O zza
M o ns

APHRODITE TERRA

Alpha Regio
-30°

Ai

Artemis
Corona

no
Pl

an

iti

a

Zh

k
ibe

I m a p in u a
P la n it ia

-60°

Pla

niti

a

Imdr Regio

Ns o meka
Pl ani ti a

LADA TERRA

-4

-90°

0°

45°

ELEVATION (kilometers)

-2

0

2

4

90°

6

8

Nu
10

135°

180°

225°

Or it might be that Venus never had plate tectonics in the
traditional sense. Instead, as the crust piles up with lava, it
thickens and grows more massive, pushing the crust beneath
it back down into Venus's interior. That process would also
create compressional crumpling that, together with the lava
flows, would wipe away craters, thus explaining why the surface looks so young.
Some scientists argue that a similar process could have
provided the initial force that kick-started plate tectonics on
Earth. That's important because plate tectonics just might be
a crucial ingredient for sustaining life (given that it keeps our
planet's temperature in check), and yet scientists can't yet pin
down just how and when it began here.
16

S E P TE M B E R 2 018 * SK Y & TELESCOPE

As such, Venus harbors secrets that might bear on our pale
blue dot. Take its stifling atmosphere as a second example. It's
a department store of climate puzzles, says David Grinspoon
(Planetary Science Institute), including the circulation of the
atmosphere, the balance of radiation, the function of clouds,
and the role of trace greenhouse gases. Although scientists
have a fairly good understanding of how those processes work
on Earth, seeing them in an altered way on a new world will
help them better understand the underlying physics and thus
improve their models for Earth overall.
Grinspoon even argues that Venus might reveal hidden
fine-tunings that could help climate scientists better forecast
our own future in a warming world and better understand

M A P: USGS ASTROG EOLOGY SCIENCE CEN TER, DATA: E.
R. STOFA N A ND S. E. SMREK A R / PL ATES, PLUMES, AND
PAR ADIGMS 20 0 5 A ND DA RBY DYA R

Longitude



Table of Contents for the Digital Edition of Sky and Telescope - September 2018

Contents
Sky and Telescope - September 2018 - Cover1
Sky and Telescope - September 2018 - Cover2
Sky and Telescope - September 2018 - 1
Sky and Telescope - September 2018 - Contents
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