Pivoting planets that lean one way and then change orientation within a short geological time period might be surprisingly habitable, according to new modeling by NASA and university scientists affiliated with the NASA Astrobiology Institute.
The climate effects generated on these wobbling worlds could prevent them from turning into glacier-covered ice lockers, even if those planets are somewhat far from their stars. And with some water remaining liquid on the surface long-term, such planets could maintain favorable conditions for life.
"Planets like these are far enough from their stars that it would be easy to write them off as frozen, and poor targets for exploration, but in fact, they might be well-suited to supporting life," said Shawn Domagal-Goldman, an astrobiologist at NASA's Goddard Space Flight Center in Greenbelt, Md. "This could expand our idea of what a habitable planet looks like and where habitable planets might be found."
The new modeling considers planets that have the same mass as Earth, orbit a sun-like star and have one or two gas giants orbiting nearby. In some cases, gravitational pulls from those massive planets could change the orientation of the terrestrial world's axis of rotation within tens to hundreds of thousands of years – a blink of an eye in geologic terms.
Though it might seem far-fetched for a world to experience such see-sawing action, scientists have already spotted an arrangement of planets where this could happen, in orbit around the star Upsilon Andromedae. There, the orbits of two enormous planets were found to be inclined at an angle of 30 degrees relative to each other. (One planet was, as usual, farther from the star than the other planet.)
Compared to our solar system, that arrangement looks extreme. The orbits of Earth and its seven neighboring planets differ by 7 degrees at most. Even the tilted orbit of the dwarf planet Pluto, which really stands out, is offset by a relatively modest 17 degrees.
"Knowing that this kind of planetary system existed raised the question of whether a world could be habitable under such conditions," said Rory Barnes, a scientist at the University of Washington in Seattle who was part of the team that studied the orbits of the two Andromedae planets.
The habitability concept is explored in a paper published in the April 2014 issue of Astrobiology and available online now. John Armstrong of Weber State University in Ogden, Utah, led the team, which includes Barnes, Domagal-Goldman, and other colleagues.
The team ran thousands of simulations for planets in 17 varieties of simplified planetary systems. The models the researchers built allowed them to adjust the tilt of the planetary orbits, the lean in the axes of rotation, and the ability of the terrestrial planet's atmosphere to let in light.
In some cases, tilted orbits can cause a planet to wobble like a top that's almost done spinning – and that wobbling should have a big impact on the planet's glaciers and climate. Earth's history indicates that the amount of sunlight glaciers receive strongly affects how much they grow and melt. Extreme wobbling, like that seen in some models in this study, would cause the poles to point directly at the sun from time to time, melting the glaciers. As a result, some planets would be able to maintain liquid water on the surface despite being located nearly twice as far from their stars as Earth is from the sun.
"In those cases, the habitable zone could be extended much farther from the star than we normally expect," said Armstrong, the lead author of the paper. "Rather than working against habitability, the rapid changes in the orientation of the planet could turn out be a real boon sometimes."
Liz Zubritsky | Eurek Alert!
Astronomers discover dizzying spin of the Milky Way galaxy's 'halo'
26.07.2016 | NASA/Goddard Space Flight Center
Lonely Atoms, Happily Reunited
26.07.2016 | Technische Universität Wien
Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.
To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...
A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology
On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...
Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.
While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
27.07.2016 | Earth Sciences
27.07.2016 | Materials Sciences
27.07.2016 | Earth Sciences