A recently discovered planet, known as LP 791-18d, has caught the attention of scientists due to its unique characteristics. Despite being similar in size to Earth, this planet is vastly different from our own. Its surface is divided into two halves, with one half permanently bathed in sunlight and the other half plunged into eternal darkness. The planet’s terrain is covered in active volcanoes, making it a prime candidate for studying the interaction between a planet’s interior and exterior. This interaction plays a vital role in the development of a planetary atmosphere that could potentially support life.
LP 791-18d orbits a red dwarf star located roughly 90 light years away and is part of a star system that comprises two other planets. The outermost planet, LP 791-18c, is 2.5 times the size of Earth and nearly nine times as heavy. LP 791-18d is tidally locked to its star, meaning that one side always faces the star while the other side remains in perpetual darkness. As a result, the planet’s surface is too hot for liquid water to exist.
However, the constant volcanic activity on LP 791-18d could potentially sustain an atmosphere that may allow water to condense on the night side. This discovery is of great significance, as it offers new insights into the evolution and origins of life on Earth and beyond. Volcanic emissions, such as carbon dioxide and water vapor, are greenhouse gases that can help maintain a planet’s warmth. A prime example of this is Venus, where volcanic carbon dioxide remained in the atmosphere and led the planet into a runaway greenhouse state with surface temperatures exceeding 850 degrees Fahrenheit.
The recent discovery of active volcanoes on Venus has shown that planets similar in size to Earth can continue to add to their atmospheres, with or without plate tectonics. LP 791-18d presents an excellent opportunity for scientists to better understand how volcanic activity can shape planetary environments over time, including those of Venus and our own planet Earth.
