Venus: Atmosphere and surface

First thought to be water clouds, then studies from Earth showed lots of carbon dioxide.
Then space missions (Venera, Pioneer) gave a more detailed view of the atmosphere, through atmospheric probes.

Chemical Composition:

96% Carbon Dioxide (CO₂)
3.5% Nitrogen (N₂)
Trace amounts of neon, argon, and sulfur
Clouds of sulphuric acid (H₂SO₄ - Battery acid!)

Surface Pressure: 90 atmospheres!
Surface Temperature: 740 K! (above melting point of lead - yikes!)

What's it like on the ground? The view from Venera 13:

So how can we see the surface when it's covered in clouds?

Radar Mapping of Venus (Magellan early 1990s)

A Magellan Mosaic of Venus
Note: color shows elevation, not real color! red = high, blue = low

Details of Venusian Surface Features

Signs of volcanic activity, crustal fracturing, and impact events....
Surface age estimated at ~ 10 million years.
Active volcanos?

Atmospheric changes between space missions, similar to what would be expected from volcanic eruptions

Evidence of lava flows and volcanic activity

Lightning?