Billions of years ago, when our solar system was just in its infant stage, three planets used to provide a habitable environment to sustain life. These three planets include Earth, Venus, and Mars. However, today, only Earth is known to have lifeforms. But why did Venus and Mars lose their thriving life-supporting environments? Both planets have unique reasons why their surface is completely hostile to life.
How Venus once possessed life in our solar system
Venus is about 30 percent closer to the Sun than Earth. After the formation of the planet, its environment cooled off and its thick atmosphere allowed water to exist on its surface. Since life often exists where there is water, scientists revealed that some forms of microbial lifeforms began to thrive on Venus’ oceans.
However, due to the planet’s closeness to the sun, its surface water began to boil away after just 200 million years. This led to a runaway greenhouse effect. As Venus continued to lose its surface water, the planet also began to lose some of its microbial life forms. The average surface temperature of Venus is 737 K (867 °F, 464 °C).
No form of life known to us could survive such a scorching temperature. However, scientists are now suggesting that Venus clouds could be habitable enough to sustain life. In fact, some researchers are even considering building floating cities on the Venusian clouds in the future for humans to thrive on. Let’s hope that our civilization will be able to thrive on Venus clouds soon.
Ancient Life on Mars
Scientists suggest that Mars once had river systems, seas, lakes, oceans, thick atmosphere, and other environmentally friendly features to support life. However, the red planet is completely dead today because of some reason. As for Mars, it had its core cooled so much that it no longer possesses a protective magnetic field around it.
As a result of the lack of a protective magnetic field, a powerful solar wind completely destroyed the Martian atmosphere billions of years ago, making the surface of the red planet completely hostile to any form of life known to humankind. After the solar wind stole away the Martian atmosphere, the Mars Ocean boiled away and froze below the surface.
Scientists estimate that Mars remained habitable for about 1.5 billion years before losing its atmosphere and oceans. This period is even much longer than it took life to evolve on Earth. This implies that there may be great evidence of possible Martian life which we are yet to discover.
Hence, fossil records of plants, animals, and other stuff similar to Earth may have once existed on the Martian terrain. As we continue to explore the red planet, we hope to discover some of these records on Mars.