Cancer Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority The problem in the core is not forming them. It's having them survive. Star-star encounters are more or less guaranteed to destroy planetary systems. Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority That's what I was hunting for, to be sure. So scratch another nine-tenth of all possible star systems ... Two to four billions, then. And then, nine out of ten of those would be around measly M stars. Quote Link to comment Share on other sites More sharing options...
Nyrath Posted January 6, 2010 Author Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Given a typical distribution of stars' date=' what would the average distance between "Sol-type" systems be, with this result?[/quote'] Latest estimate I've seen is that the density of stars in our stellar neighborhood is about 2.45x10^-3 stars per cubic light year. If 1 in 10 has a sol-type system, that would be 2.45x10^-4 systems per cubic light year. Assuming that I have not made a silly mistake in arithmetic, that translates into an average distance between sol-type system to be about 19.8 light-years Quote Link to comment Share on other sites More sharing options...
Cancer Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority I am listening to/watching the presentation screens recorded from this week's American Astronomical Society meeting in DC ... the most tittilating comment so far is from Dave Latham, "What you can do with 20 part per million photometry is ... quite remarkable." This is in reference to the ongoing Kepler mission to find Earthlike planets orbiting other stars. EDIT: OTOH, it has to be that good. A transit of Earth across the disk of the Sun causes a fractional decrease in the apparent brightness of the Sun of only 0.0086 percent, that is, 86 parts per million. So if your threshold is at 20 parts per million, that's only a signal-to-noise ratio of 4. But it is awesome compared to the photometric precisions I'm used to thinking about. Quote Link to comment Share on other sites More sharing options...
RexMundi Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Considering I can't begin to do that math above without initiating a fire on my head from the excess heat of thinking in numbers, I'll take your word for it. I do know though that 19.8 Light-years isn't that much on an Inter stellar scale. Now, if you had to walk......different story. ~Rex Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority That's why we invented bikes! Quote Link to comment Share on other sites More sharing options...
Nyrath Posted January 6, 2010 Author Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority So how big of a volume around Sol should it take to find' date=' say, 1000 Sol-type systems?[/quote'] at a density of 2.45x10^-4 sol systems per cubic light year, you'd need about 4,100,000 cubic light years. Volume of a sphere is 4/3 pi radius^3, so you'd need a sphere with a radius of about 99 light years or a diameter of 198 light years Quote Link to comment Share on other sites More sharing options...
Nyrath Posted January 6, 2010 Author Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority ... Anyone want to guess at the likelihood of planetary systems forming in the galactic core? That holds' date=' what, ninety percent of all stars?[/quote'] Ah, but even the Star Hero manual mentions the Galactic Habitable Zones. http://atropos.as.arizona.edu/aiz/teaching/a204/etlife/SciAm01.pdf http://arxiv.org/pdf/astro-ph/0401024 Once you get to a region closer to the galactic core than about 23,000 light years, there is so much radiation and other hazards that most life would be destroyed. Quote Link to comment Share on other sites More sharing options...
Nyrath Posted January 6, 2010 Author Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority On my galactic map poster I do have marked the boundaries of the galactic habitable zones. Sadly you have to purchase the map to see this. http://www.projectrho.com/smap12.html#map04 Quote Link to comment Share on other sites More sharing options...
Kristopher Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority at a density of 2.45x10^-4 sol systems per cubic light year, you'd need about 4,100,000 cubic light years. Volume of a sphere is 4/3 pi radius^3, so you'd need a sphere with a radius of about 99 light years or a diameter of 198 light years So if the typical ship in a setting runs at about 1 ly/day in FTL, you'd be looking at a direct trip of 200 days, which still seems to work well for what I'm going for. Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Three weeks on average between solar systems, three months and change from Earth to the frontier. That's playable. Quote Link to comment Share on other sites More sharing options...
RexMundi Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority On my galactic map poster I do have marked the boundaries of the galactic habitable zones. Sadly you have to purchase the map to see this. http://www.projectrho.com/smap12.html#map04 Must....have.....maps....... ~Rex Quote Link to comment Share on other sites More sharing options...
McCoy Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Ah, but even the Star Hero manual mentions the Galactic Habitable Zones. http://atropos.as.arizona.edu/aiz/teaching/a204/etlife/SciAm01.pdf http://arxiv.org/pdf/astro-ph/0401024 Once you get to a region closer to the galactic core than about 23,000 light years, there is so much radiation and other hazards that most life would be destroyed. That's life as we know it, life that has evolved under a blanket of ozone inside a honking huge magnetic field. We've found some samples that can survive radiation several orders of magnitude stronger than the average lifeform sharing our ecosystem, who can say how they would evolve if the available niches for them were wider? Quote Link to comment Share on other sites More sharing options...
Old Man Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Yes. Latest estimates I've seen say 200 to 400 billion stars in our galaxy, which means 20 to 40 billion solar systems That means I get 3-5 systems all to myself after we divide them up! Quote Link to comment Share on other sites More sharing options...
McCoy Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority That means I get 3-5 systems all to myself after we divide them up! Um, yeah, that's right. We all get our own solar systems! Really! It's not like you're being exiled or anything like that! The fact that yours are on the edge of the galaxy is because, um, they had the best view! You got first pick! Quote Link to comment Share on other sites More sharing options...
RexMundi Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Your own Solar system, but the nearest good Pizza place is 19.8 Light-years that way. ------> ~Rex Quote Link to comment Share on other sites More sharing options...
Old Man Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Um' date=' yeah, that's right. We[i'] all[/i] get our own solar systems! Really! It's not like you're being exiled or anything like that! The fact that yours are on the edge of the galaxy is because, um, they had the best view! You got first pick! I did get first pick. I'm the oldest, remember? Now all you whippersnappers need to get out of my solar system! And take all this garbage with you! Quote Link to comment Share on other sites More sharing options...
RexMundi Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority You can have the OLDEST Solar system then.....not sure what the property value of it would be though with that impending solar collapse and boom upcoming. ~Rex Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Collapse and boom -- very appropriate for blue giant stars. ^^ Quote Link to comment Share on other sites More sharing options...
Cancer Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Your own Solar system' date=' but the nearest good Pizza place is 19.8 Light-years that way. ------>[/quote'] That seems different from reality only in the "Your own" part, actually. Quote Link to comment Share on other sites More sharing options...
Captain Obvious Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Yeah I work in construction though. My math, is strictly limited to Square Footage, Square Yardage, and Cubic Footage and Yardage. You get me out of that arena and I can barely do 2+2 anymore. ~Rex Well heck, just figure out how many cubic feet a star system takes up and go from there. Easy peasy. Quote Link to comment Share on other sites More sharing options...
Cancer Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Well heck' date=' just figure out how many cubic feet a star system takes up and go from there. Easy peasy. [/quote'] Hey, remember that 3.26 light-years is 1 parsec. And a cubic attoparsec is almost exactly 1 fluid ounce. So you can express the volume of the Galaxy in terms of cans (or cases) of beer. Quote Link to comment Share on other sites More sharing options...
RexMundi Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority Now Cans of Beer I can relate to, after all I am a Wisconsin born man of Dane heritage. Amount of Beer Consumption by volume is genetic memory for me. ~Rex Quote Link to comment Share on other sites More sharing options...
Cancer Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority ... Then I think the volume of the Galaxy is about 2.6 times 10^64 ...cans of beer. Quote Link to comment Share on other sites More sharing options...
Kristopher Posted January 6, 2010 Report Share Posted January 6, 2010 Re: Solar Systems Like Ours in the Minority ... Then I think the volume of the Galaxy is about 2.6 times 10^64 ...cans of beer. . Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.