If you thought HD 189733 b was already unimaginable with its glass rains and turbulent weather patterns, COROT-7b certainly won't disappoint you. This exoplanet is perhaps one of the most bizarre worlds we have yet discovered. Located just 480 light years away from us, in the constellation Unicorn, COROT-7b is considered the first ‘lava world’ ever discovered. Its surface resembles nothing we know on Earth - think a constantly boiling planet where the rock literally melts and even evaporates into the atmosphere. Here's everything you need to know about this extreme planet that defies all expectations.
Enormously close to its star
COROT-7b orbits its star so closely that it takes only 20 hours for a complete rotation. To make a comparison, Earth orbits the sun in 365 days, but on COROT-7b a year takes less than a day on Earth. This proximity causes the planet to be constantly exposed to intense radiation and heat. On the day side, temperatures soon reach around 2600°C, hot enough to liquefy and even vaporize rock.
A world of fire and glowing air
The extreme heat on the day side turns rock into a glowing sea of lava, and even the atmosphere is filled with vaporized minerals. This creates a landscape that seems to be constantly boiling and bubbling. This ‘atmosphere’ on COROT-7b is not as we know it on Earth - it consists of vapors of rock, such as silica and iron, that the heat turns into a kind of rocky fog that hangs over the surface. Here it is not water that evaporates and rains, but rock that rises and disappears into the thin air.
Rock rain - yes, it exists
Perhaps the most fascinating aspect of COROT-7b is the phenomenon of ‘rock rain. On the day side, rocks are first melted and then vaporized by the intense heat, then rise into the air and blow to the colder night side of the planet. On the night side, where the temperature drops dramatically to about -200°C, the rock vapor condenses and falls back to the surface in the form of rock grains. This means that rocks literally fall from the sky on COROT-7b. The idea of a shower of tiny rocks instead of water is almost unimaginable and illustrates how extreme the climate on this planet really is.
A planet that keeps changing
COROT-7b is still a mysterious object to scientists. Due to its constant exposure to the intense heat of its star and the evaporation of its surface rock, the planet may be losing small amounts of mass each year. This means that it is slowly ‘dissolving,’ while the stellar winds from its parent star are constantly blowing off pieces of the planet. Some even speculate that COROT-7b was once a gas giant that got close to its star and lost its gas layer due to the heat, what remained was a barren, fiery rocky world.
What COROT-7b can teach us about the universe
COROT-7b gives us a glimpse of how dynamic and surprising planets outside our solar system can be. Whereas we are used to planets with atmospheres of gas, clouds, and oceans, a planet like COROT-7b is about something completely different. This particular world shows that not all planets in the universe are like Earth or even like gas giants like Jupiter. Some exist in conditions so extreme that it is hard to imagine that they actually exist.
COROT-7b also shows us that galaxies and solar systems can produce a huge variety of types of planets, each with unique properties and environments that seem incredible even in our wildest dreams. For astronomers, COROT-7b is a valuable source of information about how planets can form and change under extreme conditions.
Conclusion: The unimaginable reality of COROT-7b
COROT-7b is not just another planet - it is a fiery, boiling world of rock rain and extreme heat, a landscape far beyond any representation of our own Earth. Its incredible proximity to its star, boiling surface, unique rock rain and potentially tragic ‘evaporation’ make COROT-7b a world of mystery. By observing planets like COROT-7b, we discover more about the versatility of planets in our universe and get a unique look at how incredibly diverse the cosmos really is.
Stay tuned for more exciting discoveries in the series Planets You Don't Believe Exist. The wonders of the universe await us - and there are many more unimaginable worlds to explore.
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