Scientists have found that the many planets outside our solar system get their outside magnetic protective covering from a flowing liquid metal. This liquid metal protects the planet from coming harmful radiations.
This research has been published online in the journal Science.
Researchers have found that magnesium oxide, which is a common mineral found in the rocks on Earth ranging from the surface to the deepest mantle, can change into liquid metal at the very high pressures and temperatures of super-Earths, which are larger than Earth outside the solar system. This liquid metal could help in developing the magnetic dynamos on those planets.
“Melting in planets is very important. In planets like the Earth, melting leads to many features of the world around us — volcanoes, and the Earth’s magnetic field, for example. In the early history of planets like Earth, it is possible the entire planet was liquefied, forming a deep ocean of magma on the surface. Even today, some super-Earth planets may have these magma oceans,” Lead study author R. Stewart McWilliams, a geophysicist at the Carnegie Institution of Washington, said in a statement.
In order to study the behavior of this mineral on the super-Earths, scientists expose small pieces of these rocky materials to potent lasers for a billionth of a second thereby heating and squeezing the mineral to similar conditions of those planets i.e. pressures up to 14 million times that of Earth atmospheric pressure and temperatures up to 90,000 degrees Fahrenheit (50,000 Celsius). They found that the substance first changed to a new type of crystal structure and then into a liquid metal.
“What was most surprising was how well-behaved magnesium oxide is in the laboratory,” McWilliams said in a statement. “The physical properties of magnesium oxide look very similar to what has been predicted for decades by theorists. As scientists, we can’t ask for much better.”
However, according to experts this research could decrease the differentiation between planetary cores and mantle. This research also proposed that magnetic covering could be present in a large number of planets than previously thought.
“It is often said that life on planets may require the presence of a strong magnetic field to protect organisms from dangerous radiation from space such as cosmic rays — at least this may be true for certain types of life, similar to humans, that live on a planet’s surface,” McWilliams said. “We find that magnetic fields may occur on a wider range of planets than previously thought, possibly creating unexpected environments for life in the universe.”
R. Stewart McWilliams, Dylan K. Spaulding, Jon H. Eggert, Peter M. Celliers, Damien G. Hicks, Raymond F. Smith, Gilbert W. Collins, Raymond Jeanloz, (2012). said Science, DOI: 10.1126/science.1229450