30 Billion Star systems like Sol?

[Alpha_Geek]

Just read this:

Plenty of Solar Systems Like Ours Expected

With between 100 and 400 billion stars in the milky way, that 15% comes up to somewhere between 15 and 60 billion star systems that are similar to ours.

 

[Lindley]

The word "similar" is extremely imprecise, and probably doesn't mean what most laymen think it means in this context.

 

[RoJoHen]

The word "similar" is extremely imprecise, and probably doesn't mean what most laymen think it means in this context.

What a vague statement.

 

[Jetfire]

I hope the universe is full of life and one day they take me off this mudhole to their mudhole.

 

[Ensign_Redshirt]

The word "similar" is extremely imprecise, and probably doesn't mean what most laymen think it means in this context.

What a vague statement.

Well, then the media reports "New Earth discovered!" they often mean a planet which has an atmosphere, but is not a gas giant... so a planet like Mars or Venus.

 

[Alpha_Geek]

I'm taking it to mean "multiple planets, some of them smaller and rocky", not "Class-M here!"

Still, it's nice to see some numbers being crunched on the subject.

 

[Jadzia]

With between 100 and 400 billion stars in the milky way, that 15% comes up to somewhere between 15 and 60 billion star systems that are similar to ours.

That figure sounds awfully generous for Sol-like systems.

I think the 15% figure refers to the number of systems with habitable zone planets, without regard for what the parent star is.

Because G type stars like ours constitute only 7.6% of stars by current estimates. This is before we tick the box for habitable zone planets.

 

[Alpha_Geek]

*nod* To me as well, which is why I clarified my opinion in the post just above.

Goldilocks is out there somewhere, and maybe, just maybe, she has sisters.

 

[Luckyflux]

Because G type stars like ours constitute only 7.6% of stars by current estimates. This is before we tick the box for habitable zone planets.

Really? I though the Sun was a Main Sequence Star, which is very common throughout the Universe.

 

[Jadzia]

Because G type stars like ours constitute only 7.6% of stars by current estimates. This is before we tick the box for habitable zone planets.

Really? I though the Sun was a Main Sequence Star, which is very common throughout the Universe.

It is a Main Sequence Star too. It is also a Star. The main distinction is mass and colour temperature.

So if we're talking about likeness to our own system, these two characteristics should be taken into consideration

 

[Darth Picardous]

I wouldn't just consider G type stars as possible stars fir life, also consider the late F series and early K series stars as stable, therefore have probable goldilock zones surrounding them.

 

[Alpha_Geek]

Linky

 

[Jadzia]

I wouldn't just consider G type stars as possible stars fir life, also consider the late F series and early K series stars as stable, therefore have probable goldilock zones surrounding them.

I completely agree, but the thread is discussing "star systems like Sol", which does restrict the discussion to certain kinds of stars ~ those approximately 6000K and one solar mass.

I'd also speculate that some ultraviolet light is good for life bearing planets, as it helps some chemistry along. The K series stars, while able to provide liquid water temperatures on a nearby planet, would supply negligible UV.

 

[Darth Picardous]

Oh I would hate to limit myself to those parameters, we both know our own sun has changed spectral class over its lifetime as it has aged. Plus we also have to eliminate G class stars in multiple star systems like Alpha Centauri A. Would be interesting to know how much of a drop occurs from 7.6% of the total G class population if we eliminate those from multiple star systems.

 

[Darth Picardous]

Also a quick laugh for any astronomy nerds out there:

http://www.theage.com.au/world/astronomers-spot-superearth-80-light-years-away-20100109-lzbu.html

The paragraph that made me laugh was:

"The smallest exoplanet previously discovered by astronomers was Gliese 581 e, detected by a Swiss astronomer in April 2009 some 20.5 light years from Earth in the Balance constellation."

Balance constellation? Yes I have observed Alpha Balancis recently, have you? I know Libra sucks as a name but sheesh thats no excuse for slack nomenclature.