Venus Resurfacing - Tymofyeyeva

topex.ucsd.edu

Venus Resurfacing - Tymofyeyeva

The Neglected Planet

Venus


All 7 Venus proposals

were rejected in last

NASA Discovery AO.

Too hot for life and surface

landers.

The Venus science

community has dwindled

since Magellan.


• “The planet

resembled a small

skin melanoma.”

• “large and hos6le”

• “looked puny and

lacked drama6c

presence”

• “got nega6ve

reviews”

• “a plodding world”


• “I liked your ar6cle today

but see again that Venus

is never given the respect

of other planets such as

Mars or Jupiter.”

• “You should write a story

about the tectonic

wonders of Venus

-­‐David Sandwell, IGPP

-­‐Gary Robbins UT San

Diego


The Neglected Planet

About Venus

Missions and Data

Global Resurfacing

Future work

Venus

Authors:

David Sandwell

Franz Meyer

KaJa Mehnert


A liKle about Venus

• “Earth’s Twin”-­‐ similar in terms of size and density.

Venus is spherical

• A sidereal day on Venus is about 243 Earth days long. A year is

about 224 Earth days long.

• The sun rises in the West and sets in the East.

• No plate tectonics (OR ARE THERE).

• Very weak magneJc field.

• Very dense carbon dioxide atmosphere with clouds of sulfuric acid.

Surface temperature of about 450C. No water, and therefore very

slow to nonexistent erosion processes.

• Surface underwent relaJvely recent resurfacing

• Surface remarkably smooth-­‐ 64% are plains with variaJons < 2km.

Highlands are up to 10km above plains (5%) and lowlands 2-­‐3km

below plains (31%)


Venus

Earth

Mass (10 24 kg) 4.87 5.97

Radius (km) 5050 6371

Rotation Period (days) -243 1

Density (kg m -3 ) 5250 5515

Surface Gravity (m s -2 ) 8.6 9.8

Magnetic Field no yes

Active Volcanoes yes

Plate Tectonics yes

Surface Tectonic

Deformation

yes

Subduction Zones yes

Asthenosphere no yes

Basaltic Crust yes 10’s km thick yes 5-6 km thick

Heat Transport

vertical heat conduction

hotspot volcanism

plate recycling and

vertical conduction

hotspot volcanism

!


The Neglected Planet

About Venus

Missions and Data

Global resurfacing

Future work

Venus

Authors:

David Sandwell

Franz Meyer

KaJa Mehnert


Venus Missions


Venera-­‐15 and Venera-­‐16

• Arrived on Venus

in October 1983

• SAR mapping of 25%

of the planet


Magellan Science Team, 1991


hKp://www2.jpl.nasa.gov/magellan/


SAR data collected in 20-­‐km wide strips


Global SAR

Mosaic


Coronae -­‐ Flexure


Volcanoes -­‐ ComposiJon


Lava Flows -­‐ Resurfacing

Grindrod et al.


Impact Craters -­‐ Resurfacing


The Neglected Planet

About Venus

Missions and Data

Global resurfacing

Future work

Venus

Authors:

David Sandwell

Franz Meyer

KaJa Mehnert


Strom et al., 1994

The Crater Record


The Crater Record

• The crust is about 300-­‐600 million years old.

Venus has almost one thousand craters, the majority

of them in prisJne condiJon. Only 12% are cracked,

and only about 2% have been damaged by lava flows,

which make up about 80% of the planet.

• The ones that are damaged, are oien fractured by rii

zones rather than lava flows

• Craters are randomly distributed.

• Global resurfacing hypothesis, based on age of the

crust, the distribuJon of impact craters, and heat flow.


Catastrophic resurfacing

Schaber et al.


Equilibrium resurfacing

Phillips et al.

• A more peaceful alternaJve.

• Also supported by Monte Carlo simulaJons.

• Volcanoes on Venus are acJve, craters are made at the

same rate that they are destroyed.

• Some versions of this model also fit the crater record,

but it is difficult not to violate constraints.

• Volcanic events must be randomly distributed around

the planet in order for craters to also maintain a

random distribuJon. This is not the case.


The Neglected Planet

About Venus

Missions and Data

Global resurfacing

Future work

Venus

Authors:

David Sandwell

Franz Meyer

KaJa Mehnert


Venus

Earth

Mass (10 24 kg) 4.87 5.97

Radius (km) 5050 6371

Rotation Period (days) -243 1

Density (kg m -3 ) 5250 5515

Surface Gravity (m s -2 ) 8.6 9.8

Magnetic Field no yes

Active Volcanoes yes

Plate Tectonics yes

Surface Tectonic

Deformation

yes

Subduction Zones yes

Asthenosphere no yes

Basaltic Crust yes 10’s km thick yes 5-6 km thick

Heat Transport

vertical heat conduction

hotspot volcanism

plate recycling and

vertical conduction

hotspot volcanism

!


SubducJon zones


AcJve volcanoes


We need InSAR!

Topography and change detecJon

Lava flow detec7on from InSAR

decorrela7on -­‐ Kilauea


QuesJons!


Venus

About Venus

Venus Missions

Global resurfacing

Future work

Google Venus

Venus

Authors:

David Sandwell

Franz Meyer

KaJa Mehnert


Google Venus


Google Venus


Google Venus


Google Venus


Google Venus


Google Venus


Google Venus


Google Venus


Google Venus


Google Venus


Google Venus

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