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| Artist's impression of the view from a hypothetical moon around an exoplanet orbiting a triple star system. |
In a recent article posted by Space.com , scientists have discovered that alien moons may actually be easier to photograph than their planetary counterparts!
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As a moon travels around its planet, the larger body tries to circularize the orbit of the smaller. But if the planet hosts more than one moon, a power struggle may ensue as the smaller bodies tug at one another. The resulting heat radiates from the moon, making it bright enough to show up in a visual image.
Planets emit heat for only a short time after their formation, limiting how long they can be directly imaged. But tidally heated moons would continue to give off heat throughout their lifetimes.
How much heating a moon undergoes would depend on its location. A tighter orbit results in stronger gravitational tugs and a brighter image. But too close would be fatal."
Though we apparently don't need to look much further than our own solar system to see this effect -
" Io, Europa, and Ganymede orbit Jupiter. Their tugs on one another counteract the attempts of the gas giant to circularize their orbit. All three experience some form of tidal heating, with the closest, Io, feeling the strongest effects."
So , in the deformation of Io by way of Jupiter's tidal tug, heat is generated !
"Warmed by their planet rather than their star, tidally heated moons could also shift the definition of the habitable zone, the region where liquid water could exist on a body, making it ideal for the generation of life. For water to exist, the planet — or moon — must be not too hot and not too cold. Traditionally, the region is defined by the distance from the star, but a tidally heated planet doesn’t rely on its sun."
Of course, this is promising because of more than just the prospect of finding water, but also the creation of an "early atmosphere" for life to thrive!:
"Like Io and Enceladus, tidally heated exomoons would be more likely to be volcanically active, Peters said. Such volcanism could aid in the creation of an atmosphere on the moon, another helpful ingredient when it comes to the evolution of life."
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| If a distant moon were larger than Jupiter's tidally heated volcanic
moon Io (seen here), it could be large enough to image from Earth,
scientists say. CREDIT: NASA/JPL/University of Arizona |
I must say the prospect of extrasolar worlds and life has really been a source of great intrigue for me - perhaps my next few posts will be about expoplanets!
Read the full article here: http://www.space.com/19610-exomoons-alien-planets-photography.html
