Venus Analogues Used to Gain Insights into Earth’s Future
Scientists are the closest they have ever been to finding Earth’s twin through the compilation of all known information on Venus analogues. If Earth’s twin is located, it could reveal valuable insights into Earth’s future, and our risk of developing a runaway greenhouse climate as Venus did, the Astronomical Journal reported.
The team began with more than 300 known terrestrial planets orbiting other stars, called exoplanets. This list was narrowed down to the five most likely to resemble Venus in terms of their radii, masses, densities, the shapes of their orbits, and most significantly, distances from their stars.
The paper also ranked the most Venus-like planets in terms of the brightness of the stars they orbit. This would increase the likelihood that the James Webb Space Telescope would get more informative signals regarding the composition of their atmospheres.
Venus floats in a nest of sulfuric acid clouds, has no water, and features surface temperatures of up to 900°F. The team are using the Webb telescope to observe the possible Venus analogues to try and gain insight into ever different to today’s Venus.
“One thing we wonder is if Venus could once have been habitable,” said Colby Ostberg, lead study author and UC Riverside PhD student. “To confirm this, we want to look at the coolest of the planets in the outer edge of the Venus zone, where they get less energy from their stars.”
Proposed by UCR astrophysicist Stephen Kane, the Venus Zone is similar to the concept of a habitable zone. This is a region around a star where liquid surface water could exist.
“The Venus Zone is where it would be too hot to have water, but not hot enough that the planet’s atmosphere gets stripped away,” Ostberg explained. “We want to find planets that still have significant atmospheres.”
It is crucial to find a Venus analogue with a similar planet mass to our Venus because mass affects how long a planet is able to maintain an active interior, with the movement of rocky plates across its outer shell known as plate tectonics.
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