week 9 venus

Venus visibility

Venus is easily observable and was discovered in ancient times due to high brightness.

Venus brightness cause

Venus is bright because it is close to the Sun and covered in reflective clouds.

Venus rotation type

Venus rotates retrograde, opposite to most terrestrial planets.

Venus size comparison

Venus is similar in size and mass to Earth.

Venus distance from Sun

Venus orbits at 2/3 of Earth’s solar distance.

Venus surface visibility

Venus has no visible surface features in optical wavelengths.

1761 transit significance

The 1761 transit revealed Venus has an atmosphere.

Transit event purpose

Transits helped early astronomers calculate planetary distances.

Country best exploring Venus

The Soviet Union conducted the most successful Venus missions.

Mariner 2 date

Mariner 2 flew by Venus in 1962.

Mariner 2 findings

Found CO₂-rich atmosphere, cool upper atmosphere, and >400°C surface.

Venus magnetic field

Venus has no magnetic field.

Mariner 5 date

Mariner 5 flew by Venus in 1967.

Mariner 5 purpose

Measured atmosphere remotely.

Venera 4 date

1967.

Venera 4 result

Crashed under 15–22× Earth’s atmospheric pressure.

Mariner 10 date

1973.

Mariner 10 discovery

Observed active cloud systems but could not see surface.

Method to see Venus surface

Landing probes or using radar wavelengths.

Venera 7 date

1970.

Venera 7 surface data

Measured 430–480°C temperature and 93× Earth’s pressure.

Venera 8 purpose

Confirmed temperature, pressure, and carried a light detector.

Venera 9 year

1975.

Venera 9 achievement

First surface image of Venus.

Venera 9 rock size

Rocks were angular and 30–40 cm.

Venera 10

Provided additional rock surface images.

Venera rock composition

Basalt.

Venera 13 atmospheric tint

Atmosphere tints surface images; corrected images show darker terrain.

Venera 13–14 X-ray analysis

Detected low silica, high MgO, and high potassium.

Mantle melting evidence

Chemistry suggests partial mantle melting.

Vega 1

Failed.

Vega 2

Landed, survived 1 hour, found evolved rocks.

Pioneer Venus date

1978.

Pioneer Venus components

Orbiter plus four probes.

Pioneer Venus radar use

Mapped elevation through clouds.

Venus terrain type

Unimodal highlands/lowlands, no continents.

Naming protocol

Features named after goddesses.

Maxwell Mons

Highest mountain on Venus.

Venera 15–16 date

1983.

Venera 15–16 mapping

1.2–2.4 km-resolution radar mapping.

Magellan mission date

1990.

Magellan mapping resolution

250–600 m radar resolution.

Radar bright surface

Indicates rough terrain.

Radar dark surface

Indicates smooth terrain.

Venus crater density

Few craters indicate a 300–500 Ma-old surface.

Venus Express

Mapped atmosphere, temperature, and seasonal weather.

Venus water amount

Very dry atmosphere.

Akatsuki mission

Mapped clouds, lightning, and atmospheric vertical structure.

Venus atmospheric composition

Rich in CO₂, N₂, and sulphuric acid.

Hydrogen loss

Venus lost hydrogen through hydrodynamic escape.

Venus/Earth radius/density

Nearly identical.

Venus atmospheric pressure

~100× Earth's pressure.

Greenhouse temperature

Venus should be ~56°C but is 422–442°C due to greenhouse effect.

Upper cloud deck temperature

30–60°C.

Venus upper winds

100 m/s super-rotation, 60× planet rotation.

Geological exploration difficulty

Thick atmosphere blocks imaging.

Venus interior knowledge

No seismic data; interior poorly constrained.

Magnetic field absence cause

Slow rotation prevents dynamo generation.

Solar wind effect

Solar wind strips atmosphere, but Venus replenishes it over time.

Venus surface age

300–500 Ma, indicating a young surface.

Surface formed by

Volcanism and partial mantle melting.

Crater size bias

Small impacts burn up before reaching surface.

Maxwell Mons significance

Largest mountain on Venus.

Impact crater rays

Dense atmosphere suppresses crater rays.

Flood basalts

Present across Venusian plains.

Crust thickness typical

20–30 km.

Crust thickness maximum

Possibly up to 300 km.

Pre-Fortunian era

Before 1 Ga; no preserved record.

Guineverian period

Distributed deformation, mountains, and grooves.

Tessera terrain

Highly deformed, bright, possibly granitic crust.

Tessera percentage

~7% of Venus’s surface.

Tessera reflectivity

Possibly due to metal-rich minerals.

Tessera significance

Might preserve ancient sedimentary or altered rocks.

Planet-scale resurfacing

Venus may have undergone global volcanic resurfacing.

Heat retention

Venus retains primordial heat more effectively than Earth.

Tectonics style

Stagnant-lid tectonics, no plate movement.

Mantle convection

Active convection produces hotspots.

Venus volcano size

Wide but short due to atmospheric pressure constraints.

Venera 13/14 basalt evidence

X-ray spectrometers detected basaltic rock.

Pancake domes

25 km wide, 1 km tall, silica-rich viscous lava.

Canali

Long sinuous lava channels.

Coronae formation

Uplift plus magma chamber collapse and refilling.

Novae

Radial fracture systems caused by mantle upwelling.

Need for seismometer

Needed to confirm subsurface volcanic activity.

Active volcanism evidence

Radar change detected between 1991 Magellan images.

VIRTIS thermal detections

Detected warm, rough surfaces suggesting recent lava.

Current surface habitability

Surface too hot and pressurized for life.

Past ocean hypothesis

Models suggest early Venus may have had oceans.

Runaway greenhouse timing

Uncertain when productive conditions ended.

Tessera exploration importance

May show signs of past water or biosignatures.

Alternative habitability models

Some propose Venus never had liquid water.

Cloud-deck habitability

Cloud tops have Earth-like pressure and temperature.

Phosphine detection

Phosphine detected; origin debated (biotic or abiotic).

EnVision mission

ESA mission (launch ~2031) to study Venus geology and hotspots.

EnVision duration

4-year orbital science mission.

VERITAS mission

NASA mission studying emissivity, radar, INSAR, and topography.

DAVINCI mission

NASA probe studying deep atmosphere and noble gases.

Water loss mechanism

UV photolysis and hydrogen escape.

Venus cloud composition

Sulphuric acid aerosol clouds.

Super-rotation cause

Caused by slow rotation and atmospheric momentum transfer.