Olympus Mons, the largest known volcano in the solar system sits atop a tectonically dead Mars.

Mars is tectonically dead as it’s not as large as Earth, has a much smaller molten core and did not get hit by a Theia-like planet early in its formation. Eventually its electro-magneto engine slowed to a near stop, its core cooled, its volcanoes froze up.

Theia was the Mars sized planet that is theorized to have hit Earth early in the history of the solar system.

When Theia hit, much of its own iron & nickel core was transferred to Earth. The remainder of that planet was strewn around Earth in a massive debris disk that eventually formed the Moon.

This rare incident is most likely the prime reason life exists on Earth.

What did this impact contribute toward our humanly existence?

Firstly, an extra large iron/nickel core which provides the massive molten dynamo which drives the Magnetosphere. The Magnetosphere protects Earth from both solar and galactic winds (radiation). Winds that would blow our atmosphere away just as they did on Mars. This extra iron/nickel core also continues to contribute to the amount of magma on which the tectonic plates float.

And this impact gave us the Moon — the largest (in comparison to its host planet) moon in the solar system. And most likely a very rare sized moon for most of the galaxy/universe—especially for Goldilocks distance, rocky planets like Earth.

The existence of the Moon may actually be more important to our health and well being than we think.

The moon is like a shield that has obviously absorbed thousands of asteroid impacts in its history, many which would have struck Earth.

The Moon’s size means that it adds to tectonic flexing of Earth’s inner molten core thereby stress-heating the mantel (which is important, more on this later).

The Moon’s size also induces the tidal movement of Earth’s vast water system, a thing that probably aided the formation and rapid evolution of coastal life.

But back to the extra heavy iron/nickel core donated by Theia…

Earth’s tectonic plates and their constant movement–pulling and crushing together–contributes in multiple dimensions to the recycling of critical life sustaining elements. Vulcanism allows buried carbon, sequestered by hundreds of millions of years of plant growth and death, to be blasted back into the atmosphere as CO2. Which is a good thing. Without Carbon recycling the Earth would have froze and never emerged from its deep freeze.

Plate tectonics create mountain ranges—mineral-rich rock lifted into the sky where weathering erodes the rock and all the elements of life, allowing these minerals to drain into streams, rivers and the oceans where algae and zooplankton can consume them and thrive.

Continental plates and volcanoes keep the planet alive by recycling nutrients and green house gasses. There is the water cycle, the carbon cycle and the nutrients cycle—two of which would not happen without active tectonic plates and volcanoes.

However, this activity comes at a cost. Volcanoes and massive lava flows have destroyed millions of square kilometers of plant and animal life most likely contributing to if not causing most of the past extinction events. Even relatively small eruptions: Toba, Yellowstone, Krakatoa, Taupo, and hundreds of others cooled the planet, sometimes five to ten degrees Centigrade. A decades long volcanic winter would be no fun for a young technologically burgeoning species.

Theia and her contribution helped provide the environment where humanity could exist. But it also doomed us to live on a dangerous planet that has proven it regards life not at all.

We’re here because of Theia. A rare incident in the Cosmos. Fermi’s Paradox is not a paradox at all. We are unique in the Universe. But if Earth’s volcanoes have anything say in the matter, being unique may mean being dead.