Supersized rocky planets are out there.

[Anomalocaris]

Kepler 10 is a type G star like our sun, with 70% of the sun's metallicity. Given it's mass, age, and metallicity, it would be within the population II group (our sun is population I). Iron, et al, were obviously present in quantity when Kepler 10 formed (a star with Kepler 10's mass would not produce iron, it would have to be present at time of formation).

Good thing Kepler 10 is only 90% as massive as the sun. If it were as massive as the sun it would have become a white dwarf by now and the two planets in company would have been vaporized during the star's red giant stage a billion years ago.

These two planets are already older than the earth will ever be.

I wonder if this super earth is really the rocky core of an partially disintegrated jovian gas giant, the outter gaseous envelop having been stripped away either by solar radiation or by some giant impact.

[vorlon13]

Regarding Fermi paradox, picture our galaxy as growth media for the first civilization to achieve the technology (and the motivation) to exploit it.

That we haven't encounted 'them' yet (by their arrival here to colonize) is a somewhat vigorous argument that the first civilization to achieve that level has not arisen, yet. The time to exploit the galaxy is on the order of 1 to a few million years, even with crappy nuclear impulse propulsion, the galaxy has been chugging along far, far longer.

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For the majority of the last 2 or 3 million years, humans have been knocking rocks together and poking animals with sticks. Seems like a more advanced culture might have been more productively occupied . . . .

[Losty]

I just discovered this guy today an this post seemed somewhat relevant

[Jackalope]

Kepler 10 is a type G star like our sun, with 70% of the sun's metallicity. Given it's mass, age, and metallicity, it would be within the population II group (our sun is population I). Iron, et al, were obviously present in quantity when Kepler 10 formed (a star with Kepler 10's mass would not produce iron, it would have to be present at time of formation).

Good thing Kepler 10 is only 90% as massive as the sun. If it were as massive as the sun it would have become a white dwarf by now and the two planets in company would have been vaporized during the star's red giant stage a billion years ago.

These two planets are already older than the earth will ever be.

I wonder if this super earth is really the core of an partially disintegrated jovian gas giant, the outter gaseous envelop having been stripped away either by solar radiation or by some giant impact.

Very true - Kepler 10 is 6-7 billion years older than our sun and likely has billions of years to go.

Interesting bit of speculation - younger gas giants may have molten cores of heavy elements - it seems on the surface to be at least plausible.

[Jackalope]

I just discovered this guy today an this post seemed somewhat relevant

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"Ken M" apparently has a room-temperature IQ.

[Anomalocaris]

I believe the current consensus is all the gas giants in our solar sytem have solid cores of heavy elements. The core of Jupiter, if stripped bare of the overlying hydrogen and helium mantle, would be similar, perhaps somewhat larger and denser, compared to this newly discovered "mega"earth.

Hence my speculation about this megaearth being the stripped core of a former gas giant.

The problem is current model have a hard time accummulating enough rocky material in the inner portion of a protoplanetary disk to form a bare rocky planet as large as Kepler 10c around a roughly solar massed star. If so large a rocky planet were to form further out in the protoplanetary disk then it would also capture a very large inventory of gaseous or icey material, so it would end up as either a gas giant or a ice giant with a rocky core buried in the middle. So it is not easy to postulate a trajectory that would lead to so large a bare terresterial planet without postulaing either a gas giant forerunner to this giant terresterial planet, or some very unusual evolutionary history for the original protoplanetary nebula.

If the central star was much more massive, say 20 times the mass of the sun, then it becomes easy to form huge bare terresterial planets in the protoplanetary nebula. In fact, around very large protostars, it is possible to form rocky planets with the masses as large as the largest possible gas giants.

[LastPoet]

"Ken M" apparently has a room-temperature IQ.

In Farenheit or Celsius?

[Jackalope]

I believe the current consensus is all the gas giants in our solar sytem have solid cores of heavy elements. The core of Jupiter, if stripped bare of the overlying hydrogen and helium mantle, would be very similar in mass, but somewhat smaller in size and higher in density, compare to this newly discovered "mega"earth.

IIRC, the exact composition of Jupiter's core is subject to debate. It's core mass is suggestive of heavy elements - though I would not expect it to be "solid" due to pressure and heat. However, there appears to be some controversy about the presence of significant portions of heavy elements

[Anomalocaris]

I believe the current consensus is all the gas giants in our solar sytem have solid cores of heavy elements. The core of Jupiter, if stripped bare of the overlying hydrogen and helium mantle, would be very similar in mass, but somewhat smaller in size and higher in density, compare to this newly discovered "mega"earth.

IIRC, the exact composition of Jupiter's core is subject to debate. It's core mass is suggestive of heavy elements - though I would not expect it to be "solid" due to pressure and heat. However, there appears to be some controversy about the presence of significant portions of heavy elements

The pressure would enhance the chance of it being solid if it is a distinct entity. The existence of singificant portion of heavy elements is deduced from the condition required for it to have attract its inventory of light elements during its formation. I think there is little doubt these heavy element formed a distinct core sometime during Jupiter's formation and early history. The gravity profile of the planet also suggests a matching dense entity continue to exist in the middle of jupiter. The question is whether the core later mixed with the lower mantle to form a rather blurry instinct central zone, or whether it remained a separate and distinct core with a sharp compositional transition.

But I think either way, it would be possible to strip Jupiter of most of its gaseous envelope and metalic hydrogen mantle and leave behind something like the mega-earth.

[max-greece]

The reason it was thought that rocky planets couldn't exist so early in the universe isn't merely the availability of metals (heavier elements) but profundity. A lot of massive stars have to collapse for there to be a chance of sufficient amounts to be caught under gravitation to form a planet. Remember that when a star explodes it does so in all directions and at high speed. What you need is overlays of exploded metals from multiple stars to gather in a sufficiently small area to be caught up and combined into a planet.

That, was considered unlikely until now. Obviously somewhere along the line we got something wrong. That's why it is a surprise.