Exploration and Features of Mercury, Venus, and Mars

Mercury

The innermost planet of the Solar System, known for its extreme temperature variations and lack of moons.

Mariner 10

A space mission in the 1970s that took pictures of 45% of Mercury's surface and discovered a magnetic field.

Messenger

A space mission from 2004 to 2012 that orbited Mercury, taking high-resolution images and revealing volcanoes and signs of water.

BepiColombo

A space mission launched in 2018 that is en route to Mercury to study its magnetic field and surface.

Size of Mercury

Smallest planet, approximately ⅓ the size of Earth.

Gravity of Mercury

Very low, about ⅓ of Earth's gravity.

Temperature of Mercury

Extreme temperature range from -173°C (freezing) to 427°C (scorching).

Orbit of Mercury

Closest planet to the Sun with a very fast orbit of 88 Earth days.

Caloris Basin

A giant impact crater on Mercury over 1500 km wide, filled with lava and surrounded by mountains.

Lobate scarps

Cracks and cliffs on Mercury created as the planet shrank while cooling.

Magnetic field of Mercury

Weak magnetic field, about 1% of Earth's.

Core of Mercury

Huge core that takes up 85% of the planet's radius.

Iron content of Mercury

High iron content makes Mercury very dense.

Atmosphere of Mercury

No real atmosphere, just a thin layer of gases.

Ice on Mercury

Ice exists at the poles, likely in permanently shadowed craters.

Formation of Mercury

Formed with a huge iron core approximately 4.6 billion years ago.

Venera missions

Soviet missions from the 1960s to 1980s that achieved the first landings on Venus and provided atmospheric data.

Crushing pressure on Venus

Pressure on Venus is 90 times that of Earth's.

Extreme heat on Venus

Surface temperature around 465°C due to a runaway greenhouse effect.

Surface features of Venus

Includes lowlands, uplands, highlands, and numerous volcanoes.

Runaway greenhouse effect

A phenomenon where thick atmosphere traps heat very efficiently, leading to extreme temperatures.

Mars

The Red Planet, linked to war in ancient cultures and known for its ice caps and thin atmosphere.

Mars' moons

Mars has two small moons: Phobos and Deimos.

Curiosity

A modern Mars mission that studies geology and searches for past water.

Perseverance

A modern Mars mission focused on astrobiology and the search for signs of ancient life.

InSight

A modern Mars mission that studies the planet's interior and seismic activity.

North Hemisphere of Mars

Flat, young, few craters.

South Hemisphere of Mars

Old, high, heavily cratered.

Tharsis region

Massive volcanic plateau.

Olympus Mons

Tallest volcano in the Solar System (25 km high).

Valles Marineris

Giant canyon system (4000 km long!).

Shield volcanoes

Type of volcano characterized by broad, gentle slopes.

Lava plains

Flat areas formed by the flow of lava.

Plate tectonics

Mars has no plate tectonics, but the surface has been stretched, cracked, and uplifted by internal forces.

Wrinkle ridges

Features that show where the crust was compressed.

Water on Mars

Once had rivers, lakes, and even a possible ocean.

Polar ice caps

Today, water is locked in polar ice caps, soil, and subsurface reservoirs.

Seasonal flow features

Suggest liquid water might appear occasionally.

Atmosphere of Mars

Very thin—can't support liquid water for long.

Composition of Mars' atmosphere

Mainly CO₂, with some nitrogen and argon.

Brown sky

Due to dust in the atmosphere.

Interior of Mars

Thin crust, rocky mantle, and an iron-rich core (possibly liquid).

Magnetic field of Mars

No strong magnetic field.

Geologic history of Mars

Formed 4.6 billion years ago.

Heavy impacts

Shaped much of the surface of Mars.

Tharsis uplift

Caused massive geological activity.

Cooling of Mars

Eventually cooled down, with erosion and dust storms becoming dominant.

Mercury's core

Largest core relative to its size in the Solar System.

First spacecraft to orbit Mercury

Messenger.

Venus' surface temperature

Mainly caused by runaway greenhouse effect.

Unique feature of Venus

Coronae linked to mantle upwelling.

Tallest volcano in the Solar System

Olympus Mons.

Retrograde rotation

Venus rotates in the opposite direction compared to most others.

Transition feature on Mars

Global escarpment marks the transition between the northern lowlands and southern highlands.

Mercury's temperature variation

Varies more than any other planet because it rotates very slowly and has no atmosphere.

Evidence of ancient water on Mars

Mars has evidence of ancient water flows and possibly an early ocean.

Mercury's moons

Mercury has no moons.

Venus' orbit

Venus has the most circular orbit of all planets.

Highlands on Venus

Mainly located in the southern hemisphere.

Mars' natural satellites

Phobos and Deimos are Mars' natural satellites.

Mercury's atmosphere

Mercury has a dense atmosphere composed mostly of CO₂.

Plate tectonics on Venus

Venus lacks plate tectonics due to the absence of water.

Mars' geological processes

The surface of Mars shows signs of both volcanic and sedimentary processes.

Surface winds on Venus

Venus has strong surface winds that create yardangs and wind streaks.

Mercury's magnetic field

Mercury's magnetic field is not stronger than Earth's.