Planets and stars

[calcmandan]

For years I've read current theories on solar system formation. While observations have confirmed the existing models as I've hoped they would, there are some questions. Mind you, I have almost no training in astronomy other than a college course. I studied math.

Is it conceivable that planetary bodies orphaned from their systems by gravitational ejection (by a gas giant for instance) can be swept up by another system after millions of years and be given a new lease on life? (I have a personal suspicion we obtained Pluto this way)

On the same note, assume an ejected planet supports life. The planet ejects from the system, the surface life dies out, the oceans freeze, atmosphere rains down, and after millions of years approaches another star and enters orbit in the green zone. Is it conceivable that life could be jumpstarted again once the atmosphere is re-established? Or would the length of time roaming solo in intergalactic space cool the planet core and halt geologic activity? If possible, would the gravittional pull from the star eventually warm the planet core again (similar to Io)?

Our sun is doomed to die out as a white dwarf. It'll shed mass. Does this mean that the planets will shift to farther orbits during this phase? Is it possible some planets may ultimately leave the system? If so, is it conceivable that neptune, or any other jovian planet, can eject and find itself in a nebula in the distant future? So a gas giant begins sweeping up gas from the nebula and grows to a large enough scale where fusion begins. In the meantime, it forms a planetary nebula around it where planets form.

In this sense, is it conceivable that planets can have more than one life? Is it possible that our sun or others may have formed with an existing planet as a basis? Is it possible our sun was once a jupiter in an ancient system?

I was thinking about clusters. Imagine a globular cluster, any globular cluster. Is it conceivable that stars may 'trade' planets as they approach other systems? Star1 approaches Star0 and jostles an outward planet just enough to eject it. That planet will either get adopted by star1 or find itself adrift until it finds another nearby star in the cluster.

I don't know if these ideas were already explored and please be kind if my questions are ignorant.

[Careyp74]

Well, I haven't ever read about that here, but the idea does sound a lot like what takes place in the Lensman series, I think it was in Galactic Patrol. So it isn't a novel idea. Ha, no pun intended.

As far as feasibility, sorry, I cannot help you there.

[Hans]

You might try asking that at BAUT, at the answers forum

http://www.bautforum.com/forumdispla...ns-and-Answers

...its probably been asked before

[Pulvinar]

Queue the theme for Space 1999...

Here's an article on a study of this, but I have my doubts.

[godless dave]

Why Pluto and not one of the other dwarf planets way out there?

It seems like in principle there should be no reason any of these couldn't happen, but I imagine it would take a hell of a lot of force to pull a planet out of a star's gravity well.

[calcmandan]

Originally Posted by godless dave

Why Pluto and not one of the other dwarf planets way out there?

No reason, it's just an example. Pluto has the strange and elliptical orbit and that's why I mentioned it.

Originally Posted by godless dave

It seems like in principle there should be no reason any of these couldn't happen, but I imagine it would take a hell of a lot of force to pull a planet out of a star's gravity well.

I read somewhere a while ago how Jupiter theorically changed its orbit a few times in the past before the system stabilized. If I recall correctly, it was a high time for cleanup of the solar system with jupiter consuming remnant gas from the disc as well as ejecting planetoids, asteroids, comets...

[MG1962]

Originally Posted by calcmandan

Is it conceivable that planetary bodies orphaned from their systems by gravitational ejection (by a gas giant for instance) can be swept up by another system after millions of years and be given a new lease on life?

Sure, the chances of it happening are very low, but there are lots of opportunity

Quote:

(I have a personal suspicion we obtained Pluto this way)

You are more than likely wrong, Pluto appears to be part of a large aray of similar objects in the outer system. When the Pluto probe arrives there we may be able to test your theory

Quote:

On the same note, assume an ejected planet supports life. The planet ejects from the system, the surface life dies out, the oceans freeze, atmosphere rains down, and after millions of years approaches another star and enters orbit in the green zone. Is it conceivable that life could be jumpstarted again once the atmosphere is re-established? Or would the length of time roaming solo in intergalactic space cool the planet core and halt geologic activity? If possible, would the gravittional pull from the star eventually warm the planet core again (similar to Io)?

Yes to all those questions

Quote:

Our sun is doomed to die out as a white dwarf. It'll shed mass. Does this mean that the planets will shift to farther orbits during this phase?

Yes

Quote:

Is it possible some planets may ultimately leave the system?

Doubtful in all probability they will be destroyed if not at the red giant stage then at the planetary nebular stage

[quote] So a gas giant begins sweeping up gas from the nebula and grows to a large enough scale where fusion begins. In the meantime, it forms a planetary nebula around it where planets form.

Planets don't form in a planetary nebular, that is the end game for most stars like the sun. The planets would need to form from the original cloud

Quote:

In this sense, is it conceivable that planets can have more than one life? Is it possible that our sun or others may have formed with an existing planet as a basis? Is it possible our sun was once a jupiter in an ancient system?

If that were the case we are unlikely to ever know. There are efforts being made to try and piece together the birth cluster the Sun came from, I suspect that is going to take a lot time before it produces results.

Quote:

I was thinking about clusters. Imagine a globular cluster, any globular cluster. Is it conceivable that stars may 'trade' planets as they approach other systems? Star1 approaches Star0 and jostles an outward planet just enough to eject it. That planet will either get adopted by star1 or find itself adrift until it finds another nearby star in the cluster.

No and the reason is, globular clusters never had the building blocks to form planets. The are ancient structures and made up of what is called population II stars. This means they have low metal content. Interesting however following further on your idea, there is distinct evidence that stars have merged with each other within a globular cluster

Quote:

I don't know if these ideas were already explored and please be kind if my questions are ignorant.

No problem, if we don't ask, we never know

[BowlOfRed]

There's evidence that there are lots of "rogue" planets out there, but capturing one would be a very rare event. I'd imagine that anything entering the system is going to have a lot of relative velocity, so you'd the entering object would have to encounter something of mass (like a planet of similar or larger size) to dump momentum for capture.

So you have the rare encounter of the rogue planet with a star, and then you have the rare event of a capture during the encounter. I'll bet it happens, but I would bet it is in the realm of "almost never".

[xtifr]

Originally Posted by BowlOfRed

There's evidence that there are lots of "rogue" planets out there, but capturing one would be a very rare event.

Depends. They could be a lot more common than we think. Pluto most likely hails from the Kuiper Belt, a region of the outer solar system filled with comet-like objects. We've found a couple of other Pluto-sized or larger bodies out there, and there may be more. (Note that Pluto itself is a comet-like object, except that it's unusually large.) Beyond the Kuiper belt, we believe there's a region called the Oort cloud, which is likely filled with a truly astounding number of comet-like objects, many of which may also be planet-sized or nearly so. The Oort cloud is estimated to be maybe two light-years across--meaning it stretches nearly a quarter of the way to Proxima Centauri. The number of planet-sized objects there might be many, many, many times larger than the number in the inner system.

Object in the Oort cloud are likely only loosely bound to the Sun, and can probably be stripped away fairly readily by a passing star. If other stars have Oort clouds, there could be a truly mind-boggling number of rogue bodies out there. Stars might even regularly exchange outer-system objects when they pass near each other. And they might regularly capture some of the knocked-off bodies that other stars have lost.

The problem is that we'll probably never know. All of this, if it's happening, is almost certainly far beyond what we're capable of detecting. We haven't even been able to confirm the existence of our own Oort cloud. We simply lack the data to say whether this sort of thing is extremely rare or quite common. I tend to lean towards thinking it's rare myself, but that's little more than gut instinct.

[trebor]

Originally Posted by calcmandan

No reason, it's just an example. Pluto has the strange and elliptical orbit and that's why I mentioned it.

Pluto's orbit is typical of the cloud of objects in its area of the solar system.

[Zeuzzz]

Originally Posted by calcmandan

Our sun is doomed to die out as a white dwarf.

Would not be so sure. The exact nature of the solar wind acceleration, coronal heating, solar inflow events, the exact cause of sunspots, the role of the heliospheric current circuit and heliospheric current sheet, the suns CNO cycle and the birkeland current esque filaments that are sometimes transiently observed imply that when the sun in particular states of magnetic configuration (it has complex pole structure unlike planets, tens of millions of magnetic poles) particles can just as easily enter the sun as leave it.

Such inflows have been observed where the outward pressure of the solar wind is greatest, so it's not too unreasonable to infer inflows also occur further out in the solar system, maybe even from an extra-solar origin. A unipolar inductor based idea was even proposed before.

But for the particles entering the sun to be able to be used as fuel, you would have to propose that additional plasma fusion methods play a role as well as gravitational confinement fusion, which is currently not a very well supported idea. Just some food for thought.

[Reality Check]

Originally Posted by Zeuzzz

Just some food for thought.

And of course technologically advanced aliens may come and rejuvenate the Sun. Just as valid food for thought .

Scientifically the normal course of evolution for a star with the mass of the Sun is to a red giant and then a white dwarf star.

[calcmandan]

When I said the sun is doomed to die as a white dwarf star, i wasn't implying that it would skip the red giant stage.

I'd like to imagine what Andromeda would look like just prior to our sun entering the red giant phase.

I bet it would be ONE sight to see.

Originally Posted by Reality Check

And of course technologically advanced aliens may come and rejuvenate the Sun. Just as valid food for thought .

Scientifically the normal course of evolution for a star with the mass of the Sun is to a red giant and then a white dwarf star.

[catsmate1]

Originally Posted by Careyp74

Well, I haven't ever read about that here, but the idea does sound a lot like what takes place in the Lensman series, I think it was in Galactic Patrol. So it isn't a novel idea. Ha, no pun intended.

Not exactly. In the Lensman books and a lot of sci-fi of that period the nebular hypothesis for planetary formation wasn't used as it had fallen out of favour amongst astronomers (temporarily, until better calculations were done) in favour of the catastrophic model. In the latter planetary systems are only formed by the close passage of stars to one another, or inter-penetration of galaxies on a larger scale. Thus only two galaxies in the Lensman universe had many planets.
Later in the series engineering on a planetary scale is used to render planets mobile, as super-fortresses or kinetic missiles.

[MG1962]

Originally Posted by Zeuzzz

Would not be so sure. The exact nature of the solar wind acceleration, coronal heating, solar inflow events, the exact cause of sunspots, the role of the heliospheric current circuit and heliospheric current sheet, the suns CNO cycle and the birkeland current esque filaments that are sometimes transiently observed imply that when the sun in particular states of magnetic configuration (it has complex pole structure unlike planets, tens of millions of magnetic poles) particles can just as easily enter the sun as leave it.

Such inflows have been observed where the outward pressure of the solar wind is greatest, so it's not too unreasonable to infer inflows also occur further out in the solar system, maybe even from an extra-solar origin. A unipolar inductor based idea was even proposed before.

But for the particles entering the sun to be able to be used as fuel, you would have to propose that additional plasma fusion methods play a role as well as gravitational confinement fusion, which is currently not a very well supported idea. Just some food for thought.

No - just no

[Loss Leader]

Originally Posted by calcmandan

(I have a personal suspicion we obtained Pluto this way)

Pluto is part of an entire belt of objects of all size (up to the size of Pluto). I doubt we captured a belt of crud. It looks like they're part of the original disc or the result of collisions between objects on the edge of the disc and other ejected/captured/eliptical matter.

[sphenisc]

Originally Posted by Loss Leader

Pluto is part of an entire belt of objects of all size (up to the size of ErisPluto). I doubt we captured a belt of crud. It looks like they're part of the original disc or the result of collisions between objects on the edge of the disc and other ejected/captured/eliptical matter.

ftfy

[shadron]

Chances are so low that within o9ur galaxy the possibility is that it has never occurred. There are at least two reasons:

1. Any two free bodies in our galaxy are so spread apart as to have miniscule chance of ever encountering significant part of the gravitational field of the other. If you reduce the scale of everything by a factor of 10^10, then the sun is a 2.5" radius ball in Los Angeles; Alpha Centauri is a similar ball in New York. Neptune's orbit has a radius of .3 miles. Even in the densest clusters that we know of, the star are still at scaled distances of tens of miles. Collisions are very, very rare.

2. Any object falling into the gravitational well of another has to have the assistance of a third body in order to be captured. Possible orbits without such an assist range from parabolic to essentially flat hyperbolic; no capture is possible. That third body might be another planet (like Jupiter) or a sufficiently dense gas/dust cloud, but it has to be placed in just the right position to have enough influence on the orbit to not simply act like a piece of the primary's gravity well. Again, this drastically lowers the probability of a capture.

Originally Posted by calcmandan

When I said the sun is doomed to die as a white dwarf star, i wasn't implying that it would skip the red giant stage.

I'd like to imagine what Andromeda would look like just prior to our sun entering the red giant phase.

You might also want to note that quite apart from the red giant phase, the sun (and all main sequence stars) slowly increase luminosity; for the sun the rate is about 10% every 1.1 billion years. In about 1.5 by from now the Earth will be hot enough to start boiling off oceans.

[calcmandan]

Quote:

Pluto is part of an entire belt of objects of all size (up to the size of Pluto). I doubt we captured a belt of crud. It looks like they're part of the original disc or the result of collisions between objects on the edge of the disc and other ejected/captured/eliptical matter.

that makes sense.


-- Sent from my Palm TouchPad using Communities

[Zeuzzz]

Originally Posted by MG1962

No - just no

Hello MG1962.

An accompany reason would be nice. I supplied you with a scientific theory with quite a few references in support for you to comment on, and you reply with three words?

[MG1962]

Originally Posted by Zeuzzz

Hello MG1962.

An accompany reason would be nice. I supplied you with a scientific theory with quite a few references in support for you to comment on, and you reply with three words?

You supplied scientific theories that had nothing to do with the topic being discussed. That does not entitle you to a rebutting. If you supply arguments relevant to the topic I will be more than happy to engage you in discussions on the points at hand

[calcmandan]

Quote:

Hello MG1962.

An accompany reason would be nice. I supplied you with a scientific theory with quite a few references in support for you to comment on, and you reply with three words?

here we go...


-- Sent from my Palm TouchPad using Communities

[Zeuzzz]

Originally Posted by MG1962

You supplied scientific theories that had nothing to do with the topic being discussed. That does not entitle you to a rebutting.

If you re-read the OP the implications of what I said are totally relevant to the OP's description as it stands.

We really sticking to just textbook theories explanations here?

The dogmatic eduction of science without being honest that a lot of things in such complex extra terrestrial systems we really just don't know yet with enough certainty, definitely not enough to replace many scientifically valid theories with the curriculum as a form of gospel; scientific skepticism and open mindedness needs to be at the forefront of such institutionalized ideas.

[wollery]

Just a few points for Zeuzzz;

Do you have any idea how much mass would need to be flowing into the Sun to maintain core fusion for a significant time?

Considering that the Sun is not fully convective, how would this material get to the core?

If the Sun's mass were increased it would speed up the rate of core fusion, thus speeding up the Sun's evolution.

[MG1962]

Originally Posted by Zeuzzz

If you re-read the OP the implications of what I said are totally relevant to the OP's description as it stands.

We really sticking to just textbook theories explanations here?

The dogmatic eduction of science without being honest that a lot of things in such complex extra terrestrial systems we really just don't know yet with enough certainty, definitely not enough to replace many scientifically valid theories with the curriculum as a form of gospel; scientific skepticism and open mindedness needs to be at the forefront of such institutionalized ideas.

It is your job to show how current theories about main sequence transitions from red giant phase to white dwarf phase, typically producing a planetary nebular, are wrong.

No one is disputing white dwarfs can add mass. However you have to now demonstrate how you get around the Chandra limit.

http://en.wikipedia.org/wiki/Chandra_Limit

Or how the theory promoted by Subrahmanyan Chandrasekhar is wrong

[Skeptic Ginger]

Originally Posted by calcmandan

... (I have a personal suspicion we obtained Pluto this way)...

The evidence is overwhelming that Pluto is a Kuiper Belt Object along with thousands (don't know the latest count) of additional objects in the Belt that have now been discovered. Pluto is not even the largets of them.

Could an ejected planet from one system be captured by another? Sure. It might be more likely in a binary star system. There's an awful lot of empty space out there and an ejected planet would take a very long time to bump into another solar system.

[Skeptic Ginger]

TAOS project:

Quote:

The Taiwan American Occultation Survey (TAOS) aims to detect small (~1 km diameter) objects in the Kuiper Belt and beyond. More than 1,000 small bodies with diameters larger than 100 km have been detected beyond Neptune over the past decade using large telescopes. Pluto and its satellite Charon are two of the largest members of this family. The goal of the TAOS project is to measure directly the number of Kuiper Belt Objects (KBOs) with diameters in the range of 500 m to 30 km.

[Skeptic Ginger]

Originally Posted by xtifr

Depends. They could be a lot more common than we think. Pluto most likely hails from the Kuiper Belt, a region of the outer solar system filled with comet-like objects. We've found a couple of other Pluto-sized or larger bodies out there, and there may be more. (Note that Pluto itself is a comet-like object, except that it's unusually large.) Beyond the Kuiper belt, we believe there's a region called the Oort cloud, which is likely filled with a truly astounding number of comet-like objects, many of which may also be planet-sized or nearly so. The Oort cloud is estimated to be maybe two light-years across--meaning it stretches nearly a quarter of the way to Proxima Centauri. The number of planet-sized objects there might be many, many, many times larger than the number in the inner system....

...The problem is that we'll probably never know. All of this, if it's happening, is almost certainly far beyond what we're capable of detecting. We haven't even been able to confirm the existence of our own Oort cloud. We simply lack the data to say whether this sort of thing is extremely rare or quite common. I tend to lean towards thinking it's rare myself, but that's little more than gut instinct.

Of course we will eventually detect objects in the Oort cloud. I'm not sure why you would say, "probably never know".

Can Kepler Detect Oort Cloud Objects?

Quote:

Although we have no direct observations of objects in the Oort Cloud, we may be able to change that with space missions like Kepler and CoRoT. So argue Eran Ofek (Caltech) and Ehud Nakar (Tel-Aviv University) in a recent paper. If they’re right, we’ll improve our understanding of the Solar System’s planetary accretion disk and get a better feel for the dynamics of planet formation. Right now even the largest telescopes can’t find Oort Cloud objects. Where do Kepler and CoRoT fit in?

The answer is that they may be able to observe occultations of background stars, a method that has been put to use for Kuiper Belt Objects already, although to date there is only one reported occultation by a KBO. Ofek and Nakar look at the rate of occultation events, creating an estimate that shows the possibility of Kepler detections of Oort objects and presenting statistical methods that can be used to verify that any occultations are real events and not simply noise in the data. Moreover, they think we should be able to differentiate between Oort objects and KBOs using these methods.

And of course we also have Voyager 1 that just reached the edge of the solar system and Voyager 2 is following behind.

[xtifr]

Originally Posted by Skeptic Ginger

Of course we will eventually detect objects in the Oort cloud. I'm not sure why you would say, "probably never know".

I'm definitely not saying we can't detect the Oort cloud; I'm saying that we're unlikely to detect significant loss or exchange of Oort cloud bodies between different stars! Our own star isn't really close enough to another star for this to occur, so to see it happening, we'd have to study the Oort clouds of other stars. In particular, the Oort clouds of stars that are passing sufficiently close to each other, which is moderately rare--unless the phenomenon can occur in double-star systems.

[MG1962]

Originally Posted by xtifr

I'm definitely not saying we can't detect the Oort cloud; I'm saying that we're unlikely to detect significant loss or exchange of Oort cloud bodies between different stars! Our own star isn't really close enough to another star for this to occur, so to see it happening, we'd have to study the Oort clouds of other stars. In particular, the Oort clouds of stars that are passing sufficiently close to each other, which is moderately rare--unless the phenomenon can occur in double-star systems.

Actually rather than swap material I think an inner system bombardment might be more on the cards......for both systems

[xtifr]

Originally Posted by MG1962

Actually rather than swap material I think an inner system bombardment might be more on the cards......for both systems

Oh, absolutely. No question there. I was just speculating about the general idea of rogue-planet capture, and how common or rare it might be. Taking Oort-cloud planet-like objects into account would seem to make both loss and capture far more likely than if you only consider inner-system planets. But yes, bombardment is certainly going to be a far more common effect of stellar approaches.

[Skeptic Ginger]

Originally Posted by xtifr

I'm definitely not saying we can't detect the Oort cloud; I'm saying that we're unlikely to detect significant loss or exchange of Oort cloud bodies between different stars! Our own star isn't really close enough to another star for this to occur, so to see it happening, we'd have to study the Oort clouds of other stars. In particular, the Oort clouds of stars that are passing sufficiently close to each other, which is moderately rare--unless the phenomenon can occur in double-star systems.

Be patient young Yedi, all things in time.

[calcmandan]

Quote:

Of course we will eventually detect objects in the Oort cloud. I'm not sure why you would say, "probably never know".

Can Kepler Detect Oort Cloud Objects?

And of course we also have Voyager 1 that just reached the edge of the solar system and Voyager 2 is following behind.

Lets hope neither Voyager meet their doom as a fly into the oort soup. Sorry bad joke. What I mean is, I hope neither Voyager probe meet their doom colliding with objects in the theoretical oort cloud.

Okay already with Pluto being a juiper belt object, I get it.

-- Sent from my Palm TouchPad using Communities

[MG1962]

Originally Posted by calcmandan

Lets hope neither Voyager meet their doom as a fly into the oort soup. Sorry bad joke. What I mean is, I hope neither Voyager probe meet their doom colliding with objects in the theoretical oort cloud.

Okay already with Pluto being a juiper belt object, I get it.

-- Sent from my Palm TouchPad using Communities

Kuiper

[wollery]

Originally Posted by calcmandan

Lets hope neither Voyager meet their doom as a fly into the oort soup. Sorry bad joke. What I mean is, I hope neither Voyager probe meet their doom colliding with objects in the theoretical oort cloud.

To give you an idea of how likely that is try this thought experiment.

Take 10,000 marbles and spread them randomly around the Earth's tropical regions. You can assume that there's no oceans - like I said, it's a thought experiment. Now, pick a random spot in the tropics and walk about for half an hour. What do you think is the probability that you'll trip over one of the marbles?

[DrDave]

Originally Posted by wollery

To give you an idea of how likely that is try this thought experiment.

Take 10,000 marbles and spread them randomly around the Earth's tropical regions. You can assume that there's no oceans - like I said, it's a thought experiment. Now, pick a random spot in the tropics and walk about for half an hour. What do you think is the probability that you'll trip over one of the marbles?

1/10,000 of course

[/troll-science]

[wollery]

Originally Posted by DrDave

1/10,000 of course

[/troll-science]

[calcmandan]

you all have a real knack in making a fellow feel real stupid.

[xtifr]

Originally Posted by wollery

To give you an idea of how likely that is try this thought experiment.

Take 10,000 marbles and spread them randomly around the Earth's tropical regions. You can assume that there's no oceans - like I said, it's a thought experiment. Now, pick a random spot in the tropics and walk about for half an hour. What do you think is the probability that you'll trip over one of the marbles?

Insufficient data? What's the terrain like? That's going to affect my walking speed, as well as the potential visibility of the marbles. Define "trip over". Within visual range, or actually putting my foot on? In the desert, if there's any wind, the marble might not be visible even if I put my foot on it. Ditto for dense jungle. And desert and jungle are both common in the tropics. Both will have a major impact on my walking speed. As will things like hills and canyons, especially underwater canyons after we've removed all that ocean. Crossing a few horizontal feet across the edge of the Marianas Trench could easily use my whole half-hour. Are we flattening out the surface?

Anyway, averaging out all the possibilities to get a rough estimate, the answer I come up with is: within epsilon of zero. Am I close?

[Dr.Sid]

Originally Posted by DrDave

1/10,000 of course

[/troll-science]

I'd say 50% .. either you'll find one, or not.