The life puzzle: The location of land on a planet can affect its habitability

Climate models show that the amount of land on a planet can affect its habitability. There are significant differences in surface temperature, sea ice and water Vapor across a planet's surface. The work will be presented by a graduate student at the National Astronomy Meeting.

The dark side of the Moon faces away from the Earth due to the fact that many planets are locked to their stars. The star's energy is focused on the day side of the planet where it can be seen. The atmosphere and oceans need to redistribute some of the energy received from the star to the night side of the planet in order for a planet to support life.

A team of researchers at the University of Toronto have applied a 3-dimensional climate model to simulations of Earth-like planets. There is a circular continent in the middle of the day. There is a circular ocean in the middle of the day side with land everywhere else. The size of the circle was changed to show how the climate depends on land fraction.

A planet's habitability is dependent on its surface temperature and atmospheric humidity. The study shows the net precipitation, cloud fraction, and surface temperature on the day side of the planet.

The amount of land and its configuration can have a large effect on the surface of the planet. The average surface temperature can be changed by up to 20C for models with the same dayside land fractions. Planets with high land fractions have hot and dry days with little precipitation in the central areas.

It is a key challenge of astronomy and science to find out if life exists elsewhere in the universe. Our work shows that the distribution of land on an Earth-like planet has a big impact on its climate, and should help astronomy look at planets with instruments like the James Webb Space Telescope to better understand what they're seeing.

More information: Evelyn Macdonald et al, Climate uncertainties caused by unknown land distribution on habitable M-Earths, Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac1040

The Monthly Notices of the Royal Astronomical Society were written by Adiv Paradise and her team. 10.093/mnras/stac172

Journal information: Monthly Notices of the Royal Astronomical Society