Solar neutrino and hot jupitar

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i have heard that there exists an anomaly in amount of neutrinos coming from sun. are there any explanations around? how is the presence of jupiter sized planets near stars have been explained?
 

marcus

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Originally posted by sage
how is the presence of jupiter sized planets near stars have been explained?
warning, this is highly speculative

I believe there are some unexplained questions regarding this. For example, why has Jupiter not spiraled into the sun? Why is our system apparently stable?
It seems that in other systems there may possibly be a lot of crud and debris which by collision and turbulence gradually drain energy out of planet orbits so that the giant planets, more often than not, creep in closer and closer to the star. Almost as if
a kind of "friction" were at work.

Perhaps these systems did not start off with as much angular momentum as ours. Anyway it does seem that we were rather lucky.

If Jupiter were to start squandering its own angular momentum and energy in gradually cleaning out the asteroid belt, and catapulting one asteroid after another out of the system, by the gravity-slingshot type of encounter, then it would lose energy and gradually creep in somewhat closer to the sun. this would be a major screwup. Bad things can happen in a complex orbital system----but we (thanks be to Allah the all-merciful) have apparently not suffered the worst that nature can deal out.



Originally posted by sage
i have heard that there exists an anomaly in amount of neutrinos coming from sun. are there any explanations around?
Yes the anomaly has been resolved. An acquaintance of mine was on the team that ran the big tank of Heavy Water in Canada that detected the missing neutrinos. These devious neutrinos had, with devlish elusiveness, been evading detection by changing into other types of neutrinos which the earlier detectors couldn't see. The whole point seems to be that there are three types (and three corresponding antineutrino types for a total of 6) and that the normal type-----electron-neutrino or electon-antineutrino----that the sun makes can change during flight into other types that are harder to detect because they do not undergo the same reactions. This is admittedly confusing but doubtless it is all for the best :wink:
 

mathman

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have heard that there exists an anomaly in amount of neutrinos coming from sun. are there any explanations around?
There are three kinds of neutrinos. The reactions in the sun generate electron neutrinos. The older experiments looked for electron neutrinos and didn't find enough. More recently they have found, by looking for all three kinds, that there are enough, assuming that neutrinos can change from one kind to another. Under this assumption, it is necessary to assume that neutrinos have mass. That is the current state of neutrino theory.
 

LURCH

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Originally posted by sage
how is the presence of jupiter sized planets near stars have been explained?
Many astronomers think that giant planets in close to a star is the norm, and it is our star system that needs explaining. One theory called, http://www.space.com/scienceastronomy/solarsystem/jupiter_elements_991117.html [Broken] has gained considerable popularity. It claims that jupiter formed very close to the Sun, "as most giants do", and then moved outward later.

(Note: I don't happen to agree with this theory, just thought it worth mention.)
 
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Originally posted by mathman
There are three kinds of neutrinos. The reactions in the sun generate electron neutrinos. The older experiments looked for electron neutrinos and didn't find enough. More recently they have found, by looking for all three kinds, that there are enough, assuming that neutrinos can change from one kind to another. Under this assumption, it is necessary to assume that neutrinos have mass. That is the current state of neutrino theory.
DOES THIS MEAN IT HAS BEEN PROVED NEUTRINOS HAVE MASS. DOES this solve the dark matter problem?thanks for reply marcus and mathman:smile:looking for more.
 

damgo

Yes, neutrinos are now known to have mass; the SNO and Super-K experiments confirmed this a few years ago. We do not yet know their actual masses, we just have data on the mass differences. But it appears highly probably that neutrino masses will only make up a tiny portion of the missing dark matter.
 
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thanks for the attachment about planetary formation lurch.
but you don't seem to agree with it.what's yours theory.of course i don't
know anything about the dynamics of planetary formation.but to a layman
like myself the idea of large planets like jupiter(and also saturn,uranus,neptune
and like)actually wandering about without a care in the world is a little too difficult to swallow.
moreover will it not make a fledging planetary system too unstable to last?
if time differnce between the beggining of planetary formations in different
star systems could explain the inconvenience of hot jupiters it might be worth a try.
what do you all think?
 

LURCH

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Originally posted by sage
thanks for the attachment about planetary formation lurch.
but you don't seem to agree with it.what's yours theory.
It seems to mean that the distribution of elements within our solar system matches the distribution one would expect to find without planetary migration. If the solar system did indeed form from an amorphous cloud of dust particles and gas molecules pulled together by gravity, one would expect to find the heavier elements near the gravitational "bottom" (the center). And that is exactly what we do find; rocky planets made of carbon and various metals occupy the center of our system, while the outside is the domain of the "gas giants". There is even a belt made of rocky asteroids marking the borderland between the two zones.

For the planetary migration model to work, we would need some excuse as to why the innermost part of the solar system was originally composed of lighter elements. To me, this seems to oppose Occum's Razor.
 
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Regarding planetary formation of gas-giants around other stars...

Could it be that the protoplanet's initial velocity was the major factor in it's present location? We know that (for circular satellite orbits) it's mass has nothing to do with it's orbital radius. It's orbital radius is totally dependant on the tangential velocity and mass of the object it is orbiting (assuming it is orbiting a much more massive object than itself.) I wouldn't expect many of these planets to have circular orbits, but probably close enough to presume that the planet's mass has little correlation to it's position.
I wonder if Kepler's Laws hold for these extrasolar planets? Probably don't have accurate enough metrics on them yet.
 

Alexander

Tidal friction could be the "sling" to propel heavy planets (usually up to higher orbit, but in some cases interplay of angular momentum of star vs planet can propel it inward too).
 

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