After discovering more than 4,500 planets outside the Solar System, we now know that rocky planets slightly larger than our own, commonly referred to as super-Earths, are common in the Universe. Now, a new study suggests these worlds may also be even more inviting to life than our own.
The key is the magnetic field. Generated by the presence of liquid iron in the planet’s core, it acts like a giant magnet that shields the surface from much of the harmful radiation from the Sun and the interstellar medium. But we know that the planetary interior cools over time, and the ability to generate a magnetic field is not forever. Mars, for example, smaller than Earth, has already lost his.
Super-Earths, however, are a challenge: as there is no similar world in the Solar System, we can only estimate their magnetosphere by modeling the planet’s interior. And for that it is necessary to understand how iron behaves in the core of these worlds, under immense pressure. Using one of the most powerful laser systems ever built, researchers led by Richard Kraus of Lawrence Livermore National Laboratory in California compressed iron to pressures of up to 1,000 gigapascals — three times the pressure of Earth’s inner core and four times that of Earth’s inner core. the record of previous experiments.
By plotting the melting point curve of iron at increasing pressures, the team generated experimental data to correctly model the interior of super-Earths. The results were published in the latest issue of Science and indicate that beefier worlds than ours can maintain a protective magnetosphere for longer. The peak would be among planets with 4 to 6 times the mass of Earth.
By the way, the researchers used the experimental data to estimate the duration of our planet’s magnetosphere based on the experimental data, and the news is good: some 6.2 billion years. As the Earth has 4.5 billion, there is still a long period of protection ahead. But super-Earths are even longer-lived in their habitability.
The finding is a great confirming example of the classic Copernican principle, also known as the mediocrity principle. In the 16th century, Nicolaus Copernicus defended the idea that the Earth was not the center of the Universe, but just another planet, like others, revolving around the Sun. , ours is by far the friendliest to life. But that’s not to say this is the best it gets when we look at other planetary systems. It appears that super-Earths orbiting the habitable zone of Sun-like stars have more time and opportunity for life to develop and evolve than we have here.
It is worth remembering, however, that the presence of a robust magnetosphere is just one of several conditions that need to be satisfied for a planet to be truly habitable.
This column is published on Mondays, in Folha Corrida.
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