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ANU: Thank Earth's Magnetic Field for Water That Gives You Life

Posted: Thu Mar 14, 2019 6:57 pm
by bystander
Thank Earth's Magnetic Field for Water That Gives You Life
Australian National University | 2019 Mar 13
A study by scientists at ANU on the magnetic fields of planets has found that most planets discovered in other solar systems are unlikely to be as hospitable to life as Earth.

Plants and animals would not survive without water on Earth. The sheer strength of Earth's magnetic field helps to maintain liquid water on our blue planet's surface, thereby making it possible for life to thrive.

Scientists from the ANU Research School of Astronomy and Astrophysics modelled the magnetic fields of exoplanets - planets beyond our solar system - and found very few have a magnetic field as strong as Earth.

They contend that techniques for finding exoplanets the size of Earth are more likely to find slowly rotating planets locked to their host star in the same way the Moon is locked to Earth, with the same side always facing their host star.

The lead author of the study, PhD scholar Sarah McIntyre, said strong magnetic fields may be necessary to keep wet rocky exoplanets habitable. ...

Planetary Magnetism as a Parameter in Exoplanet Habitability ~ Sarah R.N. McIntyre et al

Re: ANU: Thank Earth's Magnetic Field for Water That Gives You Life

Posted: Fri Mar 15, 2019 2:54 am
by Ann
Australian National University wrote:
Ms McIntyre said Earth's strong magnetic field had probably played an important role in protecting the atmosphere from the solar wind and keeping the planet wet and habitable.

"Venus and Mars have negligible magnetic fields and do not support life, while Earth's magnetic field is relatively strong and does," she said.

"We find most detected exoplanets have very weak magnetic fields, so this is an important factor when searching for potentially habitable planets."
I'm reminded of the book Rare Earth by Peter Ward and Donald Brownlee. The authors made the point that planets with abundant complex life are very rare, and that it takes a number of different factors to make a planet so habitable. Orbiting inside the habitable zone of a star is not nearly enough.

Ann

Re: ANU: Thank Earth's Magnetic Field for Water That Gives You Life

Posted: Fri Mar 15, 2019 5:21 am
by Chris Peterson
Ann wrote: Fri Mar 15, 2019 2:54 am
Australian National University wrote:
Ms McIntyre said Earth's strong magnetic field had probably played an important role in protecting the atmosphere from the solar wind and keeping the planet wet and habitable.

"Venus and Mars have negligible magnetic fields and do not support life, while Earth's magnetic field is relatively strong and does," she said.

"We find most detected exoplanets have very weak magnetic fields, so this is an important factor when searching for potentially habitable planets."
I'm reminded of the book Rare Earth by Peter Ward and Donald Brownlee. The authors made the point that planets with abundant complex life are very rare, and that it takes a number of different factors to make a planet so habitable. Orbiting inside the habitable zone of a star is not nearly enough.
Important to emphasize here complex life. Earth appears to have had life almost as soon as the surface was cool enough to have liquid water. The development of multicellular life took a great deal longer, and complex life longer yet. I wouldn't be at all surprised if we start finding evidence of life on many exoplanets in the near future... but I expect simple life will vastly outnumber the complex.