How Many stars have Planets ?

[johnahmed]

what proportion of stars have planets ?
we are told astronomers have discovered the 10th planet orbiting a star thousands of light years away..but what about our nearest star which is only 7 light years away, and other stars closer ? if only 10 or so have been discovered that would mean planetery systems are a rarety ?

[James R]

Probably, many stars have planets.

Most of the planets found outside our solar system so far have been very large planets - Jupiter-sized or similar. Good techniques for finding small, rocky, Earth-like planets are only just now starting to be developed.

[Facial]

Astronomers have found so many of them - I don't know how many hundreds or thousands up to date - but the proportion still seems to be small. I'm sure that proportion will become larger as they find smaller rocky planets like JamesR said.

[Novacane]

Probably, many stars have planets.

Most of the planets found outside our solar system so far have been very large planets - Jupiter-sized or similar. Good techniques for finding small, rocky, Earth-like planets are only just now starting to be developed.


I imagine that the term; small, rocky/water Earth-like planets is more accurate to what I believe the actual planet Earth is like, instead of just calling it a small, rocky, Earth-like planet. Or should we just ignore the presence of the oceans?:D

[James R]

Or should we just ignore the presence of the oceans?

Well, the Earth has a radius of 6370 km. The deepest ocean is, I think, less that 10 km deep. So, out of the 6370 km, 6360 km is rock, essentially - much of it molten.

[Laika]

Forgive my pedantry, but the Earth is rock down to a depth of about 2900 km. Below that it's probably a mixture of iron and nickel with traces of lighter elements. Furthermore, of all the rock comprising the mantle and crust only a small volume of it is molten.

[James R]

Forgive my pedantry, but the Earth is rock down to a depth of about 2900 km. Below that it's probably a mixture of iron and nickel with traces of lighter elements.

Yeah, ok, if you want to be technical about it. The point was: it's not water.

Furthermore, of all the rock comprising the mantle and crust only a small volume of it is molten.

Really? I thought most of the mantle was liquid, and also the outer core.

[Facial]

The lower parts of the mantle are plastic. The upper parts are mostly solid, but also heavily laced with hotspots and convenction plumes from the lower mantle / outer core.

Hope I'm not wrong on this one. Laika?

[madanthonywayne]

Based on my limited knowledge of how stars form, it would seem likely that the vast majority of stars have planets. Now as to how many have truly earth like planets capable of supporting life, a much smaller fraction.

[Facial]

...which reminds me, astonomers haven't even settled on the def'n of a planet.

[Laika]

You're not wrong Facial. The mantle is a plastic solid and it can flow over geological timescales. Even the softest part of the mantle, the asthenosphere, only contains about 5% melt.

[phlogistician]

Based on my limited knowledge of how stars form, it would seem likely that the vast majority of stars have planets. Now as to how many have truly earth like planets capable of supporting life, a much smaller fraction.

Indeed. I was watching 'The Sky at Night' yesterday evening, and it was about the lengths astronomers go to to detect planets, and what they have discovered so far.

Now, discovering planets is tricky, but they have found lots of oddities. Gas giants in close proximity to their star, and terrestrial planets in highly elliptical orbits. Good stuff for science, just not great for life.

But it's early days, and the given the number of stars, we only need a small fraction, and there will be life, somewhere. It's just shame we'll probably never communicate.

[draqon]

what proportion of stars have planets ?
we are told astronomers have discovered the 10th planet orbiting a star thousands of light years away..but what about our nearest star which is only 7 light years away, and other stars closer ? if only 10 or so have been discovered that would mean planetery systems are a rarety ?

Are u talking Proxima Centauri?...anyways regarding your question on how many stars have planets...too many to mention...noone will ever know what is the ratio of stars with planets and no planets...is the question directed for the purpose of locating terra-like planets? that is Earth-like? theyve got some databases on the net that have possible extra-solar terra-planet candidates.

[c7ityi_]

Are there stars which don't have planets?

[draqon]

obviously

[Xylene]

As for how many stars have planets, probably the majority of the stars in the Universe. As for how many are habitable by Humans, that depends on how many are in the Goldilocks Zone.

[Clockwood]

More than just that. Our solar system has three planets the right distance from the sun to support life.
It just didn't quite work out in two of the three cases.

[c7ityi_]

It's not just about distance though.

[Xylene]

You're right, ct--it's about whether the parent star stays on the main sequence long enough to allow life to evolve

[Mr Anonymous]

More than just that. Our solar system has three planets the right distance from the sun to support life.
It just didn't quite work out in two of the three cases.

You'd also need to add an active geothermal core producing a magnetosphere for planetary bodies falling within the Goldilocks Zone as well if you're talking planets with a chance of developing life that close to a star - there's not going to be much else other than Crispy Critters without one or else your looking at a completely sub-terrestrial ecosystem.

[draqon]

More than just that. Our solar system has three planets the right distance from the sun to support life.
It just didn't quite work out in two of the three cases.

Thats debatable...I am talking of the 3rd planet...We just didnt find any there yet, but might, find psychrophiles methanogens, cold loving bacteria that breath or make methane. The bacteria might live in the Martian soil, close to Olympus Mon say.

[draqon]

You'd also need to add an active geothermal core producing a magnetosphere for planetary bodies falling within the Goldilocks Zone as well if you're talking planets with a chance of developing life that close to a star - there's not going to be much else other than Crispy Critters without one or else your looking at a completely sub-terrestrial ecosystem.

Sounds to me like all of you guys think of planets as the having the only potential to develop life, well what about moon Europa and moon Titan? The recent satellite-probe mission named Cassini-Huygens showed moon Titan to have an ocean of ethane, and a very possible scenario were bacteria can exist in the Titan's methane clouds. Think I am foolish to say so? Did you know there are bacteria living in Earth atmosphere just now?

[c7ityi_]

Xylene,

i mean that rotation, orbit and moons play a part too (for example). Venus has a very slow rotation and no moon, mars has two small moons. On earth, the sun and moon look like they are the same size, it means that their energy is wonderfully balanced. The Night and Day have the same power.

Water was created when the other 3 elements combined. The heat of the sun allowed liquification of matter and complexity through dilation of atoms. Particles became able to form and revolve around another nucleus in their "atomic galaxies". Alchemy.

[Nova1021]

Xylene,

i mean that rotation, orbit and moons play a part too (for example). Venus has a very slow rotation and no moon, mars has two small moons. On earth, the sun and moon look like they are the same size, it means that their energy is wonderfully balanced. The Night and Day have the same power.

Water was created when the other 3 elements combined. The heat of the sun allowed liquification of matter and complexity through dilation of atoms. Particles became able to form and revolve around another nucleus in their "atomic galaxies". Alchemy.

Sounds very lovely and mystical. Too bad this is a science board.

I've always been interested in the use of "energy" in new age mysticism. You said that the energy of the sun and moon are balanced; what energy is that referring to exactly?

Also, last I checked, there are 116 elements, and water is made of two of them.

[Mr Anonymous]

Sounds to me like all of you guys think of planets as the having the only potential to develop life, well what about moon Europa and moon Titan? The recent satellite-probe mission named Cassini-Huygens showed moon Titan to have an ocean of ethane, and a very possible scenario were bacteria can exist in the Titan's methane clouds. Think I am foolish to say so? Did you know there are bacteria living in Earth atmosphere just now?

:) ... Oh no, not at all old man. I believe most around here would consider more than tenable the possibility of life existing outside the so called Goldilocks Zone - I mean, you could also add to the list of possibilities planets or planetoids orbiting binary star systems if you wanted, the notion wouldn't get poo-pooed in the slightest - it's just the conversation as it stood at the time was touching upon smaller planetary sized bodies such as those within the inner solar system. In practice, when it comes to detecting extra solar system bodies, I'm not all that certain we've managed to yet pick up anything under a Jupiter class Planet...

Not that there probably aren't many types of smaller ones to be found, it's just our means of detecting such things remains in development.

But in the main, indeed, orbiting bodies such as Europa, Titan, etcetera continue to remain intriguing with regards to the possibilities of life generating process.

[draqon]

[FONT=Arial Narrow] :) ... Oh no, not at all old man. .....

Who u calling old? :bugeye: Mr. russian-no-making-sense-user-title ... The translation of your user title is: "during this time = vagina" wha????

[Mr Anonymous]

Who u calling old? :bugeye: Mr. russian-no-making-sense-user-title ... The translation of your user title is: "during this time = vagina" wha????

:) ... Well, with regards to that first, "old man" is just an expression, a manner of speaking pertinent to the way the British supposedly speak.

As to that latter matter of my user title - oh, trust me. It makes perfect sense. Stick around, you'll probably end up coming to the same conclusion... ;)

[c7ityi_]

Sounds very lovely and mystical. Too bad this is a science board.

There's nothing mystical about anything if you understand it. Today's science (physics) is not the right science for reality.

I've always been interested in the use of "energy" in new age mysticism. You said that the energy of the sun and moon are balanced; what energy is that referring to exactly?

There is only one kind of energy: the magnetic energy. Depending upon the circumstances, this one energy produces such and such a behavior, to which physicists give special names. But the source is the same.

Also, last I checked, there are 116 elements, and water is made of two of them.

Depends on how many parts you want to divide infinity into.

[eburacum45]

A magnetosphere is a useful accessory in the habitable (Goldilocks) zone of a Sun-like star; but it may not be necessary if we consider a slightly smaller K-class stars.
The radiation from a K class star has less UV and other energetic types of radiation so a planet could be habitable with a minimal magnetic field.

Other advantages of considering K class stars;
There are more K class stars in the galaxy than G class, and they have a longer period on the main sequence. So there is more time and more opportunity for life to develop around these orange dwarfs.

On the other hand the goldilocks zone around a K class star is smaller in extent, so it is unlikely that there is more than one planet in the zone around any particular star.

[Mr Anonymous]

What about Flare activity emanating from a K-Class star, is surface particulate ejection equally reduced or is that something astronomers are still trying to ascertain?

[Nova1021]

There's nothing mystical about anything if you understand it. Today's science (physics) is not the right science for reality.


Ok, just for fun: what is the correct science for understanding reality? And why is physics so good at it, if it's incorrect?


There is only one kind of energy: the magnetic energy. Depending upon the circumstances, this one energy produces such and such a behavior, to which physicists give special names. But the source is the same.


So the sun and moon are magnetically bound to the earth, and that magnetic energy has to do with their apparent size in the sky? Could you explain that in more detail? And all other physical interactions are magnetic as well? That's very interesting.


Depends on how many parts you want to divide infinity into.


I believe in your previous post you said that there are three elements which came together to form water. Now they are infinite? Odd.

[Nova1021]

What about Flare activity emanating from a K-Class star, is surface particulate ejection equally reduced or is that something astronomers are still trying to ascertain?

It's difficult to tell what sort of particle ejection occurs in stellar flares, since all we have to go on are spectra. We can estimate temperature, electron density, and other properties of the star's surface, but not much about the ejections. Chances are, for a flare of equal strength, the amount of "stuff" thrown off the star is the same. It may even be more, since a K star will be less massive.

[c7ityi_]

Ok, just for fun: what is the correct science for understanding reality? And why is physics so good at it, if it's incorrect?

The correct science for reality would be a science of consciousness. Is physics good at explaning the world? I wouldn't say so. The "less scientific" like philosophy and religion explain it much better.

So the sun and moon are magnetically bound to the earth, and that magnetic energy has to do with their apparent size in the sky? Could you explain that in more detail?

I don't know what more to tell, it's just so simple. No complexification is necessary. People only complicate in order to not understand because they are afraid of the truth and themselves because they don't want to lose what they love.

And all other physical interactions are magnetic as well? That's very interesting.

Yeah...

I believe in your previous post you said that there are three elements which came together to form water. Now they are infinite? Odd.

It's like with colors, they are infinite, still they can be divided into 7 main colors for example. It's often unnecessary to speak of so many as 116. The ancients spoke of only 4, and sometimes 2, and sometimes 12.

Those people knew everything thousands of years ago. They knew all the laws of nature, so they could also manipulate them. They knew why the universe existed and they knew also their own mystery, the mystery of the sphinx.

[Nova1021]

The correct science for reality would be a science of consciousness. Is physics good at explaning the world? I wouldn't say so. The "less scientific" like philosophy and religion explain it much better.


Until philosophy and religion can satisfactorily (that is, with verifiable, reproducable results and predictions) explain gravity, electricity, magnetism, the strong and weak interactions, I'll stick with physics.



I don't know what more to tell, it's just so simple. No complexification is necessary. People only complicate in order to not understand because they are afraid of the truth and themselves because they don't want to lose what they love.

If it's so simple, explain it to me. I'm not asking for "complexification," I'm asking for the opposite: clarity. All I'm asking is for an explanation. Tell me how the moon and sun interact with earth through magnetic energy that depends on their perceived size in the sky, as you mentioned before, and I'll be satisfied. If you cannot explain it, I have no reason to think your beliefs have any value.


It's like with colors, they are infinite, still they can be divided into 7 main colors for example. It's often unnecessary to speak of so many as 116. The ancients spoke of only 4, and sometimes 2, and sometimes 12.


There are shades of color, granted. There are not shades of water. It is water or it isn't. If it is, it is made of two hydrogen atoms and an oxygen. If it isn't, it isn't.


Those people knew everything thousands of years ago. They knew all the laws of nature, so they could also manipulate them. They knew why the universe existed and they knew also their own mystery, the mystery of the sphinx.

Which people? If they could manipulate the laws of nature, why did they have gods? Why did they get sick and die, or have wars or famine? And what does the sphinx have to do with this?


To everyone else reading this, thanks for bearing with this side discussion in the midst of the serious one going on about planets around other stars. :)

[Nova1021]

Thats debatable...I am talking of the 3rd planet...We just didnt find any there yet, but might, find psychrophiles methanogens, cold loving bacteria that breath or make methane. The bacteria might live in the Martian soil, close to Olympus Mon say.

It is important to consider that, although life on earth can be found in extreme environments, it probably did not originate there (deep sea vents aside). More likely, most extremophiles on earth have ancestors who lived in more hospitable areas, and only found their unpleasant niches later on.

So, if the planet or moon you're considering has *only* extreme environments, it's possible that if life was already going strong, it could adapt to that environment. Its chances of originating there, however, are slim.

[Mr Anonymous]

It's difficult to tell what sort of particle ejection occurs in stellar flares, since all we have to go on are spectra. We can estimate temperature, electron density, and other properties of the star's surface, but not much about the ejections. Chances are, for a flare of equal strength, the amount of "stuff" thrown off the star is the same. It may even be more, since a K star will be less massive.

:) ... My word, y'have been busy tonight. Many thanks for the info, much obliged. I was thinking as much but always does to check.

Thank you once again. A ;)

[c7ityi_]

Tell me how the moon and sun interact with earth through magnetic energy that depends on their perceived size in the sky, as you mentioned before, and I'll be satisfied.

I'm not trying to satisfy you. Everything I do, I do for myself. There is no one else. Everything is me. All planets are just big magnets, and magnetism causes movement and rotation which generates gravity. The sun is a big Rock like the earth, just under different circumstances. All things are magnets because they consist of bipolar particles.

There are only one kind of particles. Bipolar ones. Protons, neutrons, electrons are the same particles under different circumstances.

There are shades of color, granted. There are not shades of water. It is water or it isn't. If it is, it is made of two hydrogen atoms and an oxygen. If it isn't, it isn't.

There are shades of elements. You've lost yourself in definitions.

Which people? If they could manipulate the laws of nature, why did they have gods?

Ancient people. You don't remember them. They had no "gods". But among them, there were primitive people who had.

Why did they get sick and die, or have wars or famine?

They didn't get sick, they healed themselves using the staff of life/death. But often they chose to be sick because it was their destiny. They didn't have wars or famine (because they could manipulate weather. pyramid. thunder), but they did die, because they chose to. They went back to the primal state of paradisical oneness.

This is fun. Are you happy too?

And what does the sphinx have to do with this?

not that stone statue, the meaning, what the sphinx represents.

[Nova1021]

All planets are just big magnets, and magnetism causes movement and rotation which generates gravity. The sun is a big Rock like the earth, just under different circumstances. All things are magnets because they consist of bipolar particles.


Man, I need to tell the physics faculty about this. It'll make their lives so much easier to have to deal with only one force. And the astronomy folks will be fascinated to hear about the sun being a rock. I always suspected that those solar specta were fishy, saying it was made of hydrogen with other trace elements.


There are only one kind of particles. Bipolar ones. Protons, neutrons, electrons are the same particles under different circumstances.


Again, I know some people who would love to have to deal with only one particle. Too bad they didn't know this before; could've saved a lot of money on all those supercolliders.


There are shades of elements. You've lost yourself in definitions.


My definitions are clear and consistant. You haven't yet defined anything that I asked you about.


Ancient people. You don't remember them. They had no "gods". But among them, there were primitive people who had.


No, I only remember things that occurred during my lifetime, oddly enough. I mentioned gods because you seemed to be talking about the egyptians. They either had gods, or had friends with very strange looking heads.


They didn't get sick, they healed themselves using the staff of life/death. But often they chose to be sick because it was their destiny. They didn't have wars or famine (because they could manipulate weather. pyramid. thunder), but they did die, because they chose to. They went back to the primal state of paradisical oneness.

This is fun. Are you happy too?



I'm amused, but am not happy. It makes me sad that there are people like you.



not that stone statue, the meaning, what the sphinx represents.

Of course, how could I be so silly?


It's been fun c7ityi_, but it appears that we aren't going to change each others' beliefs. I'll stop asking pesky questions about your magnetic sphinx of infinite elemental shades if you'll stop making nonsensical claims in the science forums.

[c7ityi_]

And the astronomy folks will be fascinated to hear about the sun being a rock. I always suspected that those solar specta were fishy, saying it was made of hydrogen with other trace elements.

You see, because of the magnetic relations the sun has to planets, it has to turn at a specific speed (24h/day), but since the sun is such a big rock, its surface can't turn so fast, it requires 25h (27h at latitude 45°, and 30 or 35h at the poles). Between the nucleus and the surface, a rubbing together of the different layers of the sun occurs, which increases the heat, and makes the matter fluid and the sun bright.

Of course, the nucleus of the Sun spins in 24 hours (or an entire multiple or submultiple). If it did not, IT COULD NOT ATTRACT THE EARTH. Only synchronized spins produce gravitation between stars and planets.

The heat of the sun is never caused by nuclear explosions: They are the consequence of heat and not the cause.

Again, I know some people who would love to have to deal with only one particle. Too bad they didn't know this before; could've saved a lot of money on all those supercolliders.

Physicists never observed magnets to explain the universe. And now they don't want to hear about it. It's too simple. They spend too much money on discovering very few things. They generally refuse to imagine that they could answer the greatest questions in the world with only five dollars worth of magnets.

I mentioned gods because you seemed to be talking about the egyptians. They either had gods, or had friends with very strange looking heads.

Those gods are symbolic representations of various things. Speaking of strange heads, the ancients had elongated heads which gave them abilities which we don't even know we have.

I'm amused, but am not happy. It makes me sad that there are people like you.

Don't be sad, I'm a part of you which you couldn't accept, that's why we became two different persons. Don't you see that we are the same?

But that's the reason why the universe exists. Fear. Repulsion. The other half: Love. Attraction. Creation begins with the negative pole being expelled from unity and the two poles consequently drawing apart and becoming opposed to each other as force and resistance.

It's been fun c7ityi_, but it appears that we aren't going to change each others' beliefs.

But I never tried to change your beliefs.

I'll stop asking pesky questions about your magnetic sphinx of infinite elemental shades if you'll stop making nonsensical claims in the science forums.

But I like when you ask questions..

[MariEmerald]

Orbits and rotation

So what you're saying is that the rotation of a planet has something to do with the amount of satellites it has?

- Mari

[draqon]

well my guess the rotation does have something to do with the satellites the body has, mass certainly does...take jupiter for example, or saturn...

[MariEmerald]

well my guess the rotation does have something to do with the satellites the body has, mass certainly does...take jupiter for example, or saturn...

This is an interesting concept. I didn't think rotation could have much to do with satellites. Do you have any links, or books where I might learn more about this concept?

[draqon]

http://library.thinkquest.org/C0126626/evo/evolution%20of%20the%20universe.formation%20of%20t he%20solar%20system.rotation%20and%20satellites.ht m