Featured Research

from universities, journals, and other organizations

Astronomers: 'Tilt-a-worlds' could harbor life

Date:
April 15, 2014
Source:
University of Washington
Summary:
A fluctuating tilt in a planet's orbit does not preclude the possibility of life, according to new research. In fact, sometimes it may help. That's because such "tilt-a-worlds," as astronomers sometimes call them -- turned from their orbital plane by the influence of companion planets -- are less likely than fixed-spin planets to freeze over, as heat from their host star is more evenly distributed.

Tilted orbits such as those shown might make some planets wobble like a top that’s almost done spinning, an effect that could maintain liquid water on the surface, thus giving life a chance.
Credit: NASA/GSFC

A fluctuating tilt in a planet's orbit does not preclude the possibility of life, according to new research by astronomers at the University of Washington, Utah's Weber State University and NASA. In fact, sometimes it may help.

That's because such "tilt-a-worlds," as astronomers sometimes call them -- turned from their orbital plane by the influence of companion planets -- are less likely than fixed-spin planets to freeze over, as heat from their host star is more evenly distributed.

This happens only at the outer edge of a star's habitable zone, the swath of space around it where rocky worlds could maintain liquid water at their surface, a necessary condition for life. Further out, a "snowball state" of global ice becomes inevitable, and life impossible.

The findings, which are published online and will appear in the April issue of Astrobiology, have the effect of expanding that perceived habitable zone by 10 to 20 percent.

And that in turn dramatically increases the number of worlds considered potentially right for life.

Such a tilt-a-world becomes potentially habitable because its spin would cause poles to occasionally point toward the host star, causing ice caps to quickly melt.

"Without this sort of 'home base' for ice, global glaciation is more difficult," said UW astronomer Rory Barnes. "So the rapid tilting of an exoplanet actually increases the likelihood that there might be liquid water on a planet's surface."

Barnes is second author on the paper. First author is John Armstrong of Weber State, who earned his doctorate at the UW.

Earth and its neighbor planets occupy roughly the same plane in space. But there is evidence, Barnes said, of systems whose planets ride along at angles to each other. As such, "they can tug on each other from above or below, changing their poles' direction compared to the host star."

The team used computer simulations to reproduce such off-kilter planetary alignments, wondering, he said, "what an Earthlike planet might do if it had similar neighbors." Their findings also argue against the long-held view among astronomers and astrobiologists that a planet needs the stabilizing influence of a large moon -- as Earth has -- to have a chance at hosting life.

"We're finding that planets don't have to have a stable tilt to be habitable," Barnes said. Minus the moon, he said, Earth's tilt, now at a fairly stable 23.5 degrees, might increase by 10 degrees or so. Climates might fluctuate, but life would still be possible. "This study suggests the presence of a large moon might inhibit life, at least at the edge of the habitable zone."

The work was done through the UW's Virtual Planetary Laboratory, an interdisciplinary research group that studies how to determine if exoplanets -- those outside the solar system -- might have the potential for life.

"The research involved orbital dynamics, planetary dynamics and climate studies. It's bigger than any of those disciplines on their own," Barnes said.

Armstrong said that expanding the habitable zone might almost double the number of potentially habitable planets in the galaxy.

Applying the research and its expanded habitable zone to our own celestial neighborhood for context, he said, "It would give the ability to put Earth, say, past the orbit of Mars and still be habitable at least some of the time -- and that's a lot of real estate."

Barnes' UW co-authors are Victoria Meadows, Thomas Quinn and Jonathan Breiner. Shawn Domagal-Goldman of NASA's Goddard Space Flight Center is also a co-author. The research was funded by a grant from the NASA Astrobiology Institute.


Story Source:

The above story is based on materials provided by University of Washington. The original article was written by Peter Kelley. Note: Materials may be edited for content and length.


Journal Reference:

  1. J.C. Armstrong, R. Barnes, S. Domagal-Goldman, J. Breiner, T.R. Quinn, V.S. Meadows. Effects of Extreme Obliquity Variations on the Habitability of Exoplanets. Astrobiology, 2014; 140310073849007 DOI: 10.1089/ast.2013.1129

Cite This Page:

University of Washington. "Astronomers: 'Tilt-a-worlds' could harbor life." ScienceDaily. ScienceDaily, 15 April 2014. <www.sciencedaily.com/releases/2014/04/140415153739.htm>.
University of Washington. (2014, April 15). Astronomers: 'Tilt-a-worlds' could harbor life. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2014/04/140415153739.htm
University of Washington. "Astronomers: 'Tilt-a-worlds' could harbor life." ScienceDaily. www.sciencedaily.com/releases/2014/04/140415153739.htm (accessed October 22, 2014).

Share This



More Space & Time News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Comet Siding Spring Grazes Mars' Atmosphere

Comet Siding Spring Grazes Mars' Atmosphere

Newsy (Oct. 19, 2014) — A comet from the farthest reaches of the solar system passed extremely close to Mars this weekend, giving astronomers a rare opportunity to study it. Video provided by Newsy
Powered by NewsLook.com
Latin America Launches Communications Satellite

Latin America Launches Communications Satellite

AFP (Oct. 17, 2014) — Argentina launches a home-built satellite, a first for Latin America. It will ride a French-made Ariane 5 rocket into orbit, and will provide cell phone, digital TV, Internet and data services to the lower half of South America. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
This Week @ NASA, October 17, 2014

This Week @ NASA, October 17, 2014

NASA (Oct. 17, 2014) — Power spacewalk, MAVEN’s “First Light”, Hubble finds extremely distant galaxy and more... Video provided by NASA
Powered by NewsLook.com
Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Newsy (Oct. 17, 2014) — The smallest of Saturn's main moons, Mimas, wobbles as it orbits. Research reveals it might be due to a global ocean underneath its icy surface. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

More Coverage


Odd Tilts Could Make More Worlds Habitable

Apr. 15, 2014 — Pivoting planets that lean one way and then change orientation within a short geological time period might be surprisingly habitable, according to new ... read more

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins