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This looks like the original press release: http://news.unm.edu/news/new-evidence-for-oceans-of-water-deep-in-the-earth

Here's an explanation of what's going on.

The paper is already used as a reference on the Wikipedia page for Ringwoodite.

Here are the research pages of the various authors:

Brandon Schmandt, Department of Earth and Planetary Science, University of New Mexico

Steven D. "Steve" Jacobsen, Department of Earth and Planetary Sciences, Northwestern University

Thorsten W. Becker, Department of Earth Sciences, University of Southern California

Zhenxian Liu, Geophysical Laboratory, Carnegie Institution of Washington

Kenneth G. "Ken" Dueker, Department of Geology and Geophysics, University of Wyoming

"The origin of the heat generated inside the Earth is one of the great mysteries of geophysics. Researchers know..."

Researchers don't "know" squat. They have lots of theories, none of which have supporting data. That's what makes the heat of the Earth's core a mystery. By all rights it should not be this hot. It should be dead cold like the moon.

In the 1800s, famed physicist Lord Kelvin (for whom the absolute Kelvin temperature scale is named) was the first to calculate that even if the earth was born in an incandescent molten state (and there is no evidence for this), it would have cooled to its current temperature billions of years sooner than the 4.6 billion years accepted today. Even using generous assumptions about the thermal energy produced by radioactive decay (which also have no direct evidence), the earth would still cool to its current temperature much sooner than 4.6 billion years.

A related mystery is how planets form at all. The conventional theory is that they "clump up" from smaller particles, eventually achieving enough critical mass form an accretion disk that gains heat from compression, gradually acquiring a gravitationally-optimal spheroid shape. But that model has been shown to be inadequate: "Growth beyond meter size via pairwise sticking is problematic, especially in a turbulent disk. Turbulence also prevents the direct formation of planetesimals in a gravitationally unstable dust layer."

So when someone says "scientists know", they are often flat out wrong, as is this story's author.

The three little words so many scientists are deathly afraid to say: "We don't know."

The cutoff seems to be somewhat higher, at around 13 times the mass of Jupiter.

An object can be "cleared" from another object's orbit without actually leaving the physical proximity of the other object. It suffices that the dynamics of the situation are such that there's no chance that the two objects will ever collide. This means that both moons and objects in resonant orbits (eg Jupiter's Trojan asteroids, which are in a 1:1 resonant orbit, and Pluto, which is in a 3:2 resonance with Neptune) are considered "cleared" from a planet's orbit.

There actually are more rigorous ways of defining and measuring the degree to which a planet has cleared its orbit, or the degree to which a planet is capable of clearing its orbit. You can see a good summary of them here: http://en.wikipedia.org/wiki/Clearing_the_neighbourhood. I expect the Stern-Levison method is the main one the IAU had in mind since the paper describing it was presented to the IAU back in 2000. It's a mathematical formula that's applicable to any planet that you know the mass and orbital period of and gives an objective value for how capable it is of clearing its orbital neighborhood. Plotting the Stern-Levison parameters for the major bodies of the Solar System shows an orders-of-magnitude gap between the planets and the dwarf planets.

The IAU already has a separate working definition for what constitutes an "extrasolar planet", BTW: http://www.dtm.ciw.edu/boss/definition.html. It says that "The minimum mass/size required for an extrasolar object to be considered a planet should be the same as that used in our Solar System." So probably the 2006 IAU definition of Sun-orbiting planets already applies to extrasolar ones even though the 2006 definition explicitly required planets to orbit the Sun. It just doesn't matter much yet because we generally can't detect anything small enough around other stars to be considered borderline.

CMU doesn't receive any grant money for this research because it wasn't done at CMU. This is a Carnegie Institution for Science project, not a CMU one.

The Carnegie Institution for Science published something like this exactly one year ago today.

Granted, it doesn't mention Europium, but the same principle applies.

No, that's a definition of planet for the Solar System. For extrasolar planets, the criteria is much simpler, namely that fusion doesn't occur and that the object is in orbit around a star. Since that link dates from 2001, I assume the definition has evolved in the meantime. But it is an example of the IAU defining planets outside of the Solar System. My point here is that the IAU made a seperate definition for planets in the Solar System from planets outside. This makes no sense in the long run.

Thanks.

The TVF page was written in 1997, with an update to a table in 2004.

According to this IAU "Working Group on Extrasolar Planets" webpage (http://www.dtm.ciw.edu/boss/planets.html), only a pulsar had a detected planetary system in 1997, with the first 'regular' system detected in 1999 (Ups And).

According to this tracking website (http://exoplanet.eu/catalog.php), ~25 multiple planet systems have now been discovered, of which eight have three or more planets.

While this - likely - isn't enough to do a statistically rigorous test of the TVF's idea, the rate of discovery, and the number and quality of soon-to-be-onstream new projects, suggests that such a test may be possible in less than a decade.

TVF's assessment ("it is difficult to separate out periods for bodies of similar mass that are either close to the same value or are in resonance with one another") is unduly pessimistic ... at the time, 'radial velocity' was the only game in (detection) town; today, microlensing and transits are both proven, and neither is affected by the difficulty TVF mentions.

And a correction: I wrote 'weak lensing'; I should have written 'microlensing'.

Hopkins and Carnegie are doing something people care about? The government better take back that grant money ASAP!

More precisely, the new definition does not attempt to classify extra-solar bodies as either planets or not-planets. It starts out like this (emphasis mine):

The IAU therefore resolves that "planets" and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:

The IAU's working group on extra-solar planets does offer a working definition, subject to change. See Wikipedia for more details. See also rogue planets.

More precisely, the new definition does not attempt to classify extra-solar bodies as either planets or not-planets. It starts out like this (emphasis mine):

The IAU therefore resolves that "planets" and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:

The IAU's working group on extra-solar planets does offer a working definition, subject to change. See Wikipedia for more details. See also rogue planets.

High-Pressure Diamond-Anvil Cell Center at the NSLS

High-Pressure Diamond-Anvil Cell Center at the NSLS

I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition [ciw.edu] to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS [arizona.edu].

bh

I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition [ciw.edu] to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS [arizona.edu].

lzx

I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition [ciw.edu] to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS [arizona.edu].

fu

I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition [ciw.edu] to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS [arizona.edu].

ebi

I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition [ciw.edu] to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS [arizona.edu].

wrg

I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS.

The IAU's current concern is to distinguish between extrasolar planets and dark stars. It takes about 13x the mass of Jupiter before an object generates the gravitational pressure needed to ignite the D-D reaction. So the IAU says that if it's smaller than 13x Jupiter, it's a planet. Bigger than that, it's a "brown dwarf" if not shining.

I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS.

After 1 year I'll say this:

I really like the long life, I get a total of ~8 hours of use between rechargings, with my spare double strength battery. (Ideal for 14 hour flights to Oz & other plane or outdoors trips I take). I think other laptops find this hard to beat.

I also like the size. I put in in the outer pouch of my backpack, don't even notice its there. Weight is 1 kilogram, 2.2 lb.

I like the pictures, but I have to admit it doesn't compete with a modern digital camera. Another downside is: If you see something cool, it takes a few minutes to boot up & you might have missed it already. :-(

Some of my photos can be found here: montage1 montage2 full list

Mine is 667 Mhz (down to ~300 Mhz when "crusoe" is invoked), but that's fine for Netscape, LaTeX, emacs, xboard, civ, etc. No CD. Ethernet is all I need. I've experimented with video (.avi file format, haven't used sound but it can be done) It looks good as long as the smaller size frames are used. With the larger frames it looks slow. All in all, I'm very happy with it & glad I bought it.

After 1 year I'll say this:

I really like the long life, I get a total of ~8 hours of use between rechargings, with my spare double strength battery. (Ideal for 14 hour flights to Oz & other plane or outdoors trips I take). I think other laptops find this hard to beat.

I also like the size. I put in in the outer pouch of my backpack, don't even notice its there. Weight is 1 kilogram, 2.2 lb.

I like the pictures, but I have to admit it doesn't compete with a modern digital camera. Another downside is: If you see something cool, it takes a few minutes to boot up & you might have missed it already. :-(

Some of my photos can be found here: montage1 montage2 full list

Mine is 667 Mhz (down to ~300 Mhz when "crusoe" is invoked), but that's fine for Netscape, LaTeX, emacs, xboard, civ, etc. No CD. Ethernet is all I need. I've experimented with video (.avi file format, haven't used sound but it can be done) It looks good as long as the smaller size frames are used. With the larger frames it looks slow. All in all, I'm very happy with it & glad I bought it.

After 1 year I'll say this:

I really like the long life, I get a total of ~8 hours of use between rechargings, with my spare double strength battery. (Ideal for 14 hour flights to Oz & other plane or outdoors trips I take). I think other laptops find this hard to beat.

I also like the size. I put in in the outer pouch of my backpack, don't even notice its there. Weight is 1 kilogram, 2.2 lb.

I like the pictures, but I have to admit it doesn't compete with a modern digital camera. Another downside is: If you see something cool, it takes a few minutes to boot up & you might have missed it already. :-(

Some of my photos can be found here: montage1 montage2 full list

Mine is 667 Mhz (down to ~300 Mhz when "crusoe" is invoked), but that's fine for Netscape, LaTeX, emacs, xboard, civ, etc. No CD. Ethernet is all I need. I've experimented with video (.avi file format, haven't used sound but it can be done) It looks good as long as the smaller size frames are used. With the larger frames it looks slow. All in all, I'm very happy with it & glad I bought it.