- The Moon is closer, better shielded, and chemically friendlier than Mars for terraforming.
- Messages reach the Moon in 1.25 seconds; Mars takes up to 22 minutes.
- Lunar soil is literally Earth's ejected crust, making agriculture simpler than on Mars.
Mars captures our imagination as the obvious first world to terraform. But physicist Ethan Siegel, writing in Big Think's Starts With a Bang column, makes a compelling case for a closer target: the Moon.
The argument isn't romantic. It's practical.
What is terraforming?
Terraforming means modifying a planet or moon to make it habitable for humans – adjusting its atmosphere, temperature, and soil so that life can survive and eventually thrive without artificial support. The word comes from "terra," Latin for Earth.
Distance Changes Everything
A message to the Moon takes 1.25 seconds. A message to Mars takes 7 to 22 minutes depending on where Earth and Mars are in their respective orbits around the Sun.
Deliveries to the Moon take days; deliveries to Mars take months to over a year. When you're building the first extraterrestrial civilization, that difference isn't trivial - it's the gap between constant support and dangerous isolation.
The Moon offers something else Mars can't match: Earth's magnetosphere actually shields it from much of the solar wind. Despite having no magnetic field of its own, lunar surface dwellers would face less radiation than Martians. During lunar daytime, the surface picks up a positive charge that deflects harmful protons.
It’s really a matter of conveniences that make the Moon our top candidate for our first terraforming location.
Ethan Siegel, astrophysicist
Identical Chemistry, Simpler Agriculture
Lunar regolith isn't just similar to Earth's crust. It literally is Earth's crust, ejected during the ancient collision that formed the Moon.
In 2008, researchers crushed Moon-like rocks, added bacteria, and grew healthy marigolds. In 2019, China's Chang'e-4 lander sprouted a cotton plant on the far side of the Moon. Two leaves emerged before the brutal lunar night killed it. The experiment proved the concept works.
Mars soil, by contrast, resembles fresh Hawaiian basalt: workable but alien. The chemical differences add complexity to every agricultural attempt.
Solar Power Without Compromise
No atmosphere means no absorption. Solar panels on the Moon receive the same radiation as orbital satellites, with efficiency more than twice what Mars offers per square meter. The lack of sandstorms means panels stay clean for decades, not months.
Key figure
2×
more solar energy per square meter on the Moon than on Mars
The need for infrastructure is an important factor. Siegel points out that lunar settlements could share Earth's internet and communication networks. Mars would need standalone systems for everything.
More on the Moon
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→Permanently shadowed craters contain frozen water - dirty, slushy, but abundant. Combined with airtight domes, breathable air, and bacterial enrichment of the regolith, we have everything needed to start growing food within weeks of arrival.
The terraforming vision is incremental: one dome at a time. Learn the lessons close to home before attempting to transform an entire distant planet.
NASA has already suggested a 'Mars First' vision for space exploration. For humanity's first expansion beyond Earth, the Moon offers the luxury of proximity and the advantage of familiar chemistry.
Terraforming Mars can wait until we know what we're doing.
Fact Check: Claim-by-Claim Verification Verified
All claims verified against the Big Think source article, NASA references, and independent sources. Communication delays, radiation shielding, lunar chemistry, plant experiments, and solar energy claims all confirmed.
Commentary
- Earth's magnetospheric protection of the Moon is partial and intermittent (mainly when Moon passes through Earth's magnetotail), not constant.
- The 2008 marigold experiment used lunar analog rock (anorthosite), not actual lunar samples.
- The "2x solar energy" comparison is based on inverse square law at average Mars distance; actual values vary with Mars orbital position.
- The article presents Siegel's argument faithfully; terraforming feasibility remains highly speculative for both bodies.
Sources used for verification
Academic/Peer-reviewed:
- Lunar regolith agriculture experiment - LPI 2008
- Earth-Moon magnetic shield - NASA
Other reliable sources:
- Terraforming the Moon vs Mars - Big Think
- Chang'e-4 cotton experiment - World Economic Forum
- Lunar surface charge deflection - RAL Space
Fact-checked by Perplexity Sonar Pro on 2026-03-15
