Earth: no longer the lonely planet

SpaceRef ^ | 9/26/03

[KevinDavis]

The question of whether we're alone in the universe just got a lot bigger.

Two astronomers from the University of New South Wales, Australia - Dr Charles Lineweaver and Daniel Grether - have found that at least 25 per cent of Sun-like stars have planets.

"This means there are at least 100 billion stars with planets in our Galaxy," says Dr Lineweaver, a Senior Research Fellow at the University's School of Physics.

Until now, astronomers believed that only five to 15 per cent of Sun-like stars had orbiting planets, but Lineweaver and Grether's work shows that previous estimates under-reported the proportion of so-called extrasolar planets.

The Astrophysical Journal, the world's leading journal of astrophysics, has accepted their research for publication.

Astronomers have been carefully monitoring 2,000 nearby stars for the presence of orbiting extrasolar planets.

"To date, they've detected a hundred or so, meaning the fraction of stars with extrasolar planets was around five per cent," says Dr Lineweaver.

"But most planets are too small or take too long to orbit their host stars to be detected. For example, if the Sun were one of the stars being monitored, we still wouldn't have detected any planets around it.

"Using a new method to correct for this incompleteness, we found that at least 25 per cent of Sun-like stars have planets."

Dr Lineweaver believes that the figure of at least 100 billion stars with orbiting planets could be on the low side when it comes to cosmic counting. It could be that close to 100 per cent of stars have planets.

"Given that there are about 400 billion stars in our Galaxy alone, it means there could be up to 400 billion stars with planets," he says.

"With about 100 billion galaxies in the observable universe, our result suggests that there are at least 10 trillion planetary systems in the Universe."

'What Fraction of Sun-like Stars have Planets?' by Charles H Lineweaver and Daniel Grether will be published later this year. It is available online.

Dr Lineweaver is an ARC Senior Research Fellow and Senior Lecturer, School of Physics, UNSW. Daniel Grether is working on a PhD.

[f.Christian]

Evo logic - science !



The fact that freezing water makes ice crystals - snowflakes ... proves evolution too --- hailstones will be people some day !



Anti - entropy (( physics )) too !



Evolution is an open system

(( not subject ... exempted --- to natural physical laws - thermodynamics )) ---


solar - sun generated ...


turn on the lights and the house will clean itself ...

eventually a family will appear !



Wash and dry dishes on a rock ...

rain washed ---

sun dried !



Road kill cabin fever science !

[bert]

Define earth-like.

There's sceptics lurking here ya know.

[Old Professer]

Do these guys get paid to sit around and come up with this stuff?

[bert]

...Kepler, a NASA Discovery mission, is a spaceborne telescope.....

Wow! Thanks for this excellent bit of info.

Eat your heart out Disney trashed Discovery magazine.

[PatrickHenry]

I donno. My very limited understanding of dark energy is that it only manifests its effect on a cosmological scale. In that case, it wouldn't affect the formation of planets. I think that plain old gravitational attraction would be sufficient for planetary formation. I'm pinging RA for his input (which will be much more informed than mine).

[bert]

Get your self a colony of bees. They know you are there and learn to appreciate you.

[Orion78]

Your posts never make any sense. What is up with that?

[Alamo-Girl]

Thank you so much for your reply and for sharing your view of it! I also am hopeful that RadioAstronomer will have some answers or perhaps, leads to follow.

[Old Professer]

Well, considering that you could get about 1.8 billion such silver dollars on a 10 square mile grid, if you had a vantage point that allowed you to scan from high enough I believe you could spot the red one rather quickly; scanning the universe from the inside through and about would be as difficult as Archimedes searching for a "place to stand."

[bert]

There is a reference to Darwin. His computer always alerts him to Darwin posts so he can give fair and balanced treatment to creationist thoughts.

[f.Christian]

You think evolution makes sense ?

[RadioAstronomer]

I donno. My very limited understanding of dark energy is that it only manifests its effect on a cosmological scale. In that case, it wouldn't affect the formation of planets. I think that plain old gravitational attraction would be sufficient for planetary formation. I'm pinging RA for his input (which will be much more informed than mine).

I am not so sure about that in this case. Miked or Physicist may be closer to this question. However, here is a really cool link to an ongoing compilation of knowlege that includes discussions on dark energy.

http://nedwww.ipac.caltech.edu/level5/

I will look into this a bit further myself as well. :-)

[Old Professer]

Isn't the mathematical problem the fact that the necessary mass can't be found so, to keep the equations balanced, we must posit some mysterious, unseen mass (or energy) to balance the equation?

If what we see now demands that a process is in progress then we must explain our rationalizations or admit to a cyclical phenomenon which we are only allowed to witness; it is this nasty beginning bit that we can't get past.

[Alamo-Girl]

Thank you so much for the lead and for pinging others to find an answer or perhaps, more leads!

[Orion78]

So you post nonsense to show that evolution doesn't make sense?

[f.Christian]

Spontaneous - morphing matter - life makes sense ?

You believe that on face value with out understanding - explaining it ... and you think --- I have a problem ?

[RadioAstronomer]

Good luck in your attempt here. :-)

[Orion78]

ROFL, you put words in my mouth. I never said anything about what I believe. All I did was say your posts never make sense. They are too cryptic to understand.

[Orion78]

Thanks =)

[f.Christian]

The wonders - blessings - joys of evolution ...

I hear it on the FR all the time ---

I SEE THE OPPOSITE - THE BRAIN SOUL DEAD !

The zombification of earth - America ... FR too !

Ego mad man maniacs !