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 ")
Lava Tubes On Moon And Mars
'...it never was built, or anything like that; it's just a big volcanic bubble.' - Robert Heinlein, 1957.
SpaceX EVA Spacesuit Tested By Polaris Dawn Crew
'Now, except for weight and heat, the same conditions prevail in this chamber as in space.' - Otto Willi Gail, 1929.
ESA To Build Moon Bases Brick By Printed LEGO Brick
'We made a crude , small cell and were delighted - and, I admit, somewhat surprised - to find it worked.' - John W. Campbell, 1950.
FLOAT Levitating Train On The Moon ala Clarke
'The low-slung monorail car, straddling its single track, bored through the shadows on a slowly rising course.' - Arthur C. Clarke, 1955.
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
Biohybrid Robots Made Of Living And Synthetic Materials
'If the biological robots were not living creatures, they were certainly very good imitations.'
Drug Induces Hibernation-Like State In Humans
'... drugged and chilled and stowed in sleep tanks.'
Poul Anderson's 'Brain Wave'
"Everybody and his dog, it seemed, wanted to live out in the country; transportation and communication were no longer isolating factors."
AI Note-Taking From Google Meet
'... the new typewriter that could be talked to, and which transposed the spoken sound into typed words.'
Qore IcePlates Are Personal Cooling Suits
'... underneath they consisted of networks of cooling tubes against the skin.'
P1 Just The Latest Robot To Take A Beating From Humans
'...we mere people come second.'
Waymo Cars Shout At Each Other, Autonomously
'My cars talk to one another. I have no doubt about it...'
Your Solar Electric Paint Is Ready, Larry Niven
'...you spray it on.'
How Long Till We Have These Tattoos?
Truth or fiction?
Seeing Faces On Grains Of Sand (AI Pareidolia)
'... the imprint of her image on the telephoto cell.'
Lunar Biorepository Proposed For Cryo-Preservation Of Earth Species
'...there was no one alive who had ever seen them. But they existed in the Life Bank.'
Tele-Driving Offers Jobs For Tele-Drivers, Not AIs
''...some bored drone pusher in a remote driving centre...'
Autonomous Robotic Dentist - Would You Say 'Ahhh'?
You might be surprised at how much more efficient this could be.
GM Scraps Cruise Origin Robotaxi With No Steering Wheel
'Ames tinkered around with something on the instrument board when he got in; and in a few moments we were off.'
Taza Aya Air-Curtain Tech Protects Turkey Workers
'I'm going to have to buy a filter-mask.'
Torobo Humanoid Robot Hammers A Nail
7-axis dual arms, 3-axis waist (pitch, pitch, yaw), 3-axis neck (yaw, pitch, roll), and 4-axis undercarriage!
