Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
Our Galaxy's Habitable Zone
Where are the habitable planets in our galaxy and how numerous are they during the course of the galaxy's life? A new paper by researchers Michael G. Gowanlock, David R. Patton and Sabine M. McConnell seeks to provide answers to these questions.
We present a model of the Galactic Habitable Zone (GHZ), described in terms of
the spatial and temporal dimensions of the Galaxy that may favour the development
of complex life. The Milky Way galaxy is modelled using a computational approach
by populating stars and their planetary systems on an individual basis using MonteCarlo methods. We begin with well-established properties of the disk of the Milky
Way, such as the stellar number density distribution, the initial mass function, the
star formation history, and the metallicity gradient as a function of radial position and
time. We vary some of these properties, creating four models to test the sensitivity
of our assumptions. To assess habitability on the Galactic scale, we model supernova
rates, planet formation, and the time required for complex life to evolve. Our study
improves on other literature on the GHZ by populating stars on an individual basis and
by modelling SNII and SNIa sterilizations by selecting their progenitors from within
this preexisting stellar population. Furthermore, we consider habitability on tidally
locked and non-tidally locked planets separately, and study habitability as a function
of height above and below the Galactic midplane. In the model that most accurately
reproduces the properties of the Galaxy, the results indicate that an individual SNIa
is ∼5.6× more lethal than an individual SNII on average. In addition, we predict that
∼1.2% of all stars host a planet that may have been capable of supporting complex
life at some point in the history of the Galaxy. Of those stars with a habitable planet,
∼75% of planets are predicted to be in a tidally locked configuration with their host
star. The majority of these planets that may support complex life are found towards
the inner Galaxy, distributed within, and significantly above and below, the Galactic
midplane.
(Habitable planets [pdf])
In this Figure, Model 1 is plotted. Top Left panel: The number of planets that are habitable (tidally-locked and non-locked) as a function of radial distance and time. We trace the history of each habitable planet to determine in which periods they remain habitable. It is clear, given the assumptions made in our model, that the number of habitable planets is greatest in the inner Galaxy, at all epochs. Top right panel: The fraction of stars with a habitable planet as a function of time and radial distance. We trace the history of each habitable planet to determine in which periods they remain habitable. Given the assumptions made in the model, the inner region of the Galaxy exhibits the highest probability of having habitable planets at the present day. At R∼5-11 kpc, at the present day, the entire range has roughly the same probability of having habitable planets. Lower Left panel: The number of habitable planets integrated over all epochs as a function of radial distance and height above the midplane. We predict that the position in the Galaxy with the greatest number of habitable planets is located in and around the midplane in the inner Galaxy. Lower Right panel: The fraction of habitable planets integrated over all epochs as a function of radial distance and height above the midplane. The region with the greatest fraction of habitable planets exists above the midplane in the inner Galaxy. The high metallicity that produces a high planet formation rate and the lower stellar density that exists well above the midplane at this radial position permits a greater fraction of habitable planets to form.
When I read about this kind of research, I think about the science fiction authors who expanded our ideas about life in the galaxy, like E.E. 'Doc' Smith and Isaac Asimov. Your favorites?
From A Model of Habitability Within the Milky Way Galaxy by Michael G. Gowanlock, David R. Patton and Sabine M. McConnell.
Scroll down for more stories in the same category. (Story submitted 7/15/2011)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 1 )
Related News Stories - (" Space Tech ")
JAXA Int Ball 2 Coming Right Along As Star Wars Remote
'Hocus-pocus religions and archaic weapons are no substitute for a good blaster at your side.' George Lucas, 1976.
Space Traffic Management (STM) Needed Now
'...the spot was a lonely one in an uncharted region, far from the normal lanes of space traffic.' - Arthur William Bernal (1935)
Denmark Joins The 'Zero Debris Charter' To Clean Up Space
'Then their lasers vaporized the smaller satellites...' Arthur C. Clarke, 1978.
Starship Special Edition For Lunar Shuttle
Love those special edition spaceships.
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
Huawei Pura X Folding Phattie Phone
Why can't we get more innovative phone configurations?
Sleep Pods At Daxing International Airport
'Do not waste your priceless company on the unappreciative folds of a sleep pod...'
Robot Baristas Learn Their Trade Without Paying Royalties
'...so we've promised him a generous pension from the royalties.'
JAXA Int Ball 2 Coming Right Along As Star Wars Remote
'Hocus-pocus religions and archaic weapons are no substitute for a good blaster at your side.'
Robot Bricklayer Or Passer-By Bricklayer?
'Oscar picked up a trowel. 'I'm the tool for the mortar,' the little trowel squeaked cheerfully.'
Robot Gas Station Attendant Pumps Gas For You
'... he waited for the robotrix attendant to finish fueling up his ship.'
Engineer Creates Crazy Motorized Track Hospital Bed
The Roujin Z system provides care to fully bedridden patients - and then some!
Tiny Flying Robot Weighs Just One Gram
'Aerostat meant anything that hung in the air. This was an easy trick to pull off nowadays.'
Some Ringworld Configurations Are Stable
'The Ringworld had no horizon. There was no line where the land curved away from the sky.'
TRANSFORM Dynamic Furniture Concept Becomes What You Need
'An adjustment panel outside the door would cause it to extrude various appurtenances in memory plastic...'
Harvard Metamaterials Change Structure Instantly
'Annealed in any shape for a time, and codified, the structure of that shape is retained down to the molecules.'
SnapBot Robots - You Choose Their Legs And They Choose Their Gaits
It's not really polite to tear the limbs off robots.
Dino From Magical Toys An AI Companion To Children
'...the imaginary companions discovered by needful children.'
Humanoid Robots Building Humanoid Robots
''Pardon me, Struthers,' he broke in suddenly... 'haven't you a section of the factory where only robot labor is employed?''
Darpa 'Defiant' Unmanned Autonomous Ship
'There was no wheel, and no steersman!'
What's The Best Way To Ship And Unpack Humanoid Robots?
'I opened the oblong box, where lay the automatons side by side...'
