Here they are and it is roughly a continuous conversation.
"Trying to get a handle on the protoplanetary disc.
http://www.daviddarling.info/encyclopedia/...toplandisk.html
"The Protoplanetary Disk
Conventional theory suggests that about 10 million years are required for a planetary system to form completely from a protoplanetary disk, so that, on this basis, the disks mentioned above might not yet be old enough to contain planets. They should, however, be at the stage where dust grains are accreting to give larger particles. This was confirmed in 1998 by observations carried out with the HST by Larry Esposito and colleagues at the University of Colorado which showed that the disks around three stars in the Orion Nebula contain dust at least 10 microns across, or nearly 100 times larger than dust grains in interstellar space.
Some young protoplanetary disks are thought to have a mass of 0.01 to 0.1 solar masses, or more than 10 times that needed to make a planetary system like our own. Much of this material will eventually be blown away by the strong stellar wind from the central star. Dust accounts for about 1 percent of the disk's initial mass, the rest being made up of gas, mainly hydrogen and helium. Young disks imaged by the HST, in Orion and Taurus, are seen at many different angles, from edge-on to nearly face-one, and are typically a few hundred astronomical units in diameter. Two of the most spectacular edge-on disks surround HH 30 and the "Butterfly Star," both of which are narrow in their central parts but gently flare at distances of about 100 astronomical units. Such flaring was predicted as a result of heating by the host star by Harvard-Smithsonian astronomers Lee Hartman and Scott Kenyon in the late 1980s.
As accretion continues within a protoplanetary disk, sizable objects known as planetesimals form which, after several million years, give rise to small, rocky planets close to the host star. Further out, where it is cold enough for ice to form in the disk, more solid material is available for world-building. Gas giants, like Jupiter and Saturn, may start with cores of rock and ice of about 10 Earth-masses and then sweep up large quantities of light gases to form thick atmospheres. This should result in the creation of a central cavity within the circumstellar disk, similar in size to the solar system, and a drastic depletion of the disk's gas content. Recent observations, for example of the 10-million-year-old star HR 4796A, provide evidence for this view. ...."
http://hubblesite.org/newscenter/archive/r...y-disk/2006/05/
"January 19, 2006: These two bright debris disks of ice and dust appear to be the equivalent of our own solar system's Kuiper Belt, a ring of icy rocks outside the orbit of Neptune and the source of short-period comets. The disks encircle the types of stars around which there could be habitable zones and planets for life to develop. The disks seem to have a central area cleared of debris, perhaps by planets."
The clearing of the central region in my opinion is from the contraction of the Protostar, and the action of the radiant pressure from the heating protostar.
There could be planets with this central part which would mean like in my hypothesis for our Solar System the inner planets formed before the Gas Giant and Ice Giant ones did.
There would be so many variations possible so really when I find an example that fits that is all we need.
A lot of good pics in that Hubble section.
This one shows the proplanetary disk divided into the protoplantary tori. But since the Star is shining the chances of planets developing from them will be minimal ( some big planet far out only.
The size of the Star (mass and composition) and the timing of the planets forming is so crucial.
Main Index:
http://hubblesite.org/newscenter/archive/r...-disk/index/10/
I see the NASA people said the protoplanetary disks seem to have 10 times the amount of mater in them than what remains as planets as in our Solar System. It was a bit undecided so I wouldn't make too many claims about that.
Shall we:
Reverse engineer the Solar system - spread out the planet masses (times that by ten), and spread it like the shape of the visible protoplanetary disks and find a value of the density and the amount of matter in each potential planetary belt. (Based on the current planetary spacings.)
Basically I would go with a triangular cross section with a hemispherical leading edge (carrot shaped disk). Does anyone know the formula for the volume of a ring but on with tapered sides?
Thanks that stimulated me to get looking for the formula myself. Luckily I remembered that the shape is called an annulus.
V=pi(d^2outer - d^2inner) l/4 where l is the thickness
So you have the inner and outer diameters and the thickness.
Well that will do as a rough guess to start with, and if we get results that look sensible we can refine it then.
So the next thing is to find the mass of material tied up in the Solar system (excluding the Sun) and then multiply that by 10.
Read more:
http://wiki.answers.com/Q/What_is_the_form...s#ixzz1hPWIhfev
http://en.wikipedia.org/wiki/Solar_System
QUOTE
The principal component of the Solar System is the Sun, a main-sequence G2 star that contains 99.86 percent of the system's known mass and dominates it gravitationally.[3] The Sun's four largest orbiting bodies, the gas giants, account for 99 percent of the remaining mass, with Jupiter and Saturn together comprising more than 90 percent.
The Sun is the Solar System's star, and by far its chief component. Its large mass (332,900 Earth masses)[19] produces temperatures and densities in its core great enough to sustain nuclear fusion,[20] which releases enormous amounts of energy, mostly radiated into space as electromagnetic radiation, peaking in the 400–700 nm band we call visible light.[21]
So working in Earth Mass (Me) The whole Solar system is about 333366.7134 Me.
466.7133988 Me tied up in the planets etc.
Multiply this by 10 => 4667.133988 Me in the protoplanetary disk
You start to see that the planets if they were to share this protoplanetary disk mass in proportion to the area of their annulus are going to be much larger than their current sizes, but let's not jump the gun.
Planet Real distance (AU)
Start 0, , R1 , R2
Mercury 0.39, , 0.195 ,0.555
Venus 0.72, , 0.555 ,0.86
Earth 1, , 0.86 , 1.26
Mars 1.52 , 1.26 , 2.145
Ceres1 2.77 , 2.145 ,3.985
Jupiter 5.2 , 3.985 ,7.37
Saturn 9.54 , 7.37 , 14.37
Uranus 19.2 , 14.37 ,24.63
Neptune 30.0 , 24.63 ,34.75
Pluto1 39.44, 34.75 ,44.72
End 50 ,
These are the proposed bands for the planetary masses. All mass within the annulus is available to contribute to the proto-planet. How long it stays associated with that planet depends on the strength of the Solar Wind. If it moves it can contribute to the mass of the next planet further out, for the wind and radiant pressure drive the dust outward.
Now it is hard to draw the picture but the protoplanetary disk extends from the start to the end and the AU dimension assigned to that are (start half way between Mercury and the Sun = 0.195
The end 5 AU beyond Pluto = 44.72
So that means the bulk of the Protoplanetary disc matter was in the region 0.195 - 44.72 AU and in this belt was dust with the total mass 4667.133988 Me. or an average of 104.8205275 Me/AU over the entire 44.525 AU width.
So I will multiply the average mass/AU within the R1 and R2 values assigned for each planet as per the previous table.
Mercury , 0.36, 37.73538991
Venus, 0.305, 31.97026089
Earth, 0.4, 41.92821101
Mars, 0.885, 92.76616685
Ceres1 , 1.84, 192.8697706
Jupiter , 3.385, 354.8174856
Saturn , 7, 733.7436926
Uranus, 10.26, 1075.458612
Neptune, 10.12, 1060.783738
Pluto1, 9.97, 1045.060659
Now these estimates certainly far exceed the figures I had in 1998. I would say the NASA estimate of the solar system only retaining 10% of the protoplanetary disc mass is to severe.
My original calculations brought a value of the Earth to 28, which equates to 15%.
I also tapered the annulus so there was not the extreme amounts of matter at the Pluto end. But if it gets lost to the outer parts of the solar system so be it.
Earth, 0.4, 41.92821101
These are the figures for the Earth from the previous table. That is indicating using NASA figures that in the region of the Earth there was enough matter in the protoplanetary disk to form an Earth with nearly 42 times its current mass.
What this means is that the early Earth had an enormous amount of volatile gasses liquids associated with it. Enough to cause the compression as in my Compressed Earth Hypothesis. This fits with the findings which initiated the Expanding earth Theory, but they never had the mechanism for expanding the Earth. Clearly from these figures the expansion is the release from the extreme compression as the volatiles were ripped away from the Earth in the early stages.
So now we need to look at whether the Earth was a hot or a cold place to live right from the start till now.
When did the Goldilocks period start?
Where are we up to in our exploration of this topic.
We have this very gassy fluid covered Earth. What happens when a Moon is captured by this large Earth, and what sort of effects will it have on the large water world?
Another calculation would be to regress back into the past and see how close the moon might have been 4.5 Billions years ago.
Note I prefer a capture theory rather than a collision. This is possible when the mass is higher.
Will the Moon be flung further out in it's orbit with this type of history?
I was discussing the issue of the Moon being so much closer in to the Earth at the beginning, and it creates some interesting ideas to explore.
Firstly the Moon was much closer and the elliptical orbit would have been extremely erratic.
The orbital velocity would extremely rapid. Were there 20 high tides per day? with the tides 1000 times greater displacement? (The Moon was so much closer and hence greater gravitational activity.)
Would the Continental plates have survived the extreme erosion a situation like this?
I have a feeling if there isn't a compressed Earth with a pile of water, there is no way the current geological conditions would be found. Bare land only became exposed late the in life of Earth.
Right to see if we can understand how close the moon was at the beginning.
Looking to see what clues we can get from Wikipedia to begin with.
http://en.wikipedia.org/wiki/Geology_of_th...n#Lunar_capture
QUOTE
Lunar capture
This hypothesis states that the Moon was captured, completely formed, by the gravitational field of the Earth. This is unlikely, since a close encounter with the Earth would have produced either a collision or an alteration of the trajectory of the body in question, so if it had indeed happened, the Moon probably would never return to meet again with the Earth. For this hypothesis to function, there would have to be a large atmosphere extended around the primitive Earth, which would be able to slow the movement of the Moon before it could escape. This hypothesis is considered to explain the irregular satellite orbits of Jupiter and Saturn.[3] In addition, this hypothesis has difficulty explaining the essentially identical oxygen isotope ratios of the two worlds.[4]
[edit] Co-accretion hypothesis
This hypothesis states that the Earth and the Moon formed together as a double system from the primordial accretion disk of the Solar System.[citation needed] The problem with this hypothesis is that it does not explain the angular momentum of the Earth-Moon system, nor why the Moon has a relatively small iron core compared to the Earth (25% of its radius compared to 50% for the Earth).
That interesting for my hypothesis combines Co-accretion (being within the same torus band) and moon capture (being possible because of the large gaseous state of the Early Earth allows this.)
QUOTE
For this hypothesis to function there would have to be a large atmosphere extended around the primitive Earth, which would be able to slow the movement of the Moon before it could escape.
Just imagine how much atmosphere the Earth lost in the action of slowing the moon?
The Earth might have been 42 Earth masses to begin with, but the moon could have instantly ripped 90% of that off in one foul swoop in process of being captured. As the Moon rushed around the Earth ploughing into the volatiles and knocking them into space to contributing the materials to build the other Gas and Ice Giant Planets and the comets parked up in the Kuiper Belt.
What seemed an unlikely scenario at first sight becomes possible and even the most probable, for there are fewer objections to the Capture Hypothesis as compared to the Impact Hypothesis.
QUOTE
http://en.wikipedia.org/wiki/Giant_impact_theory
There remain several questions concerning the best current models of the giant impact hypothesis. The energy of such a giant impact is predicted to heat Earth to produce a global 'ocean' of magma; yet there is no evidence of the resultant planetary differentiation of the heavier material sinking into Earth's mantle. Further, at present, there is no self-consistent model that starts with the giant impact event and follows the evolution of the debris into a single Moon. Other remaining questions include: when did the Moon lose its share of volatile elements and why does Venus, which also experienced giant impacts during its formation, not host a similar Moon?
Now let's look at the way the Moon is being thrown further out into space.
We can see that there are more than one thing driving this.
1. The continual loss of volatile mass from the Early Earth means the G force between them is lessened all the time.
So as the Moon is being slowed by the atmosphere the mass of the Earth is being reduced at somewhat a faster rate to the point where the Moon orbited the Earth freely.
From that point on there was a transfer of angular momentum out to the Moon.
QUOTE
http://en.wikipedia.org/wiki/Moon#Relationship_to_Earth
Gravitational coupling between the Moon and the bulge nearest the Moon acts as a torque on the Earth's rotation, draining angular momentum and rotational kinetic energy from the Earth's spin.[94][96] In turn, angular momentum is added to the Moon's orbit, accelerating it, which lifts the Moon into a higher orbit with a longer period. As a result, the distance between the Earth and Moon is increasing, and the Earth's spin slowing down.[96] Measurements from lunar ranging experiments with laser reflectors left during the Apollo missions have found that the Moon's distance to the Earth increases by 38 mm per year[97] (though this is only 0.10 ppb/year of the radius of the Moon's orbit). Atomic clocks also show that the Earth's day lengthens by about 15 microseconds every year,[98] slowly increasing the rate at which UTC is adjusted by leap seconds. Left to run its course, this tidal drag would continue until the spin of the Earth and the orbital period of the Moon matched. However, the Sun will become a red giant long before that, engulfing the Earth.[99][100]
QUOTE
Apollo missions have found that the Moon's distance to the Earth increases by 38 mm per year
Now as the previous quote said that would account for a fraction of the distance required!
QUOTE
(though this is only 0.10 ppb/year of the radius of the Moon's orbit)
Right so if you calculate that over the 5.5 Ga the Moon has been around, that only account for a distance of a little over half the Moons diameter.
Totally insufficient to account for the current position of the Moon if it once came from the Earth or was captured by the Earth.
The Capture theory works best once you realise the mass of the earth allowed the Earth moon combination to have a high angular momentum to begin with. As the Earth's mass reduced year by year the distance between the Earth and Moon adjusted due to the laws of orbital motion.
In other words due to a high Orbital speed to begin with it was able to be thrown further out as the mass of the Earth reduced.
If we take the current momentum of the Moon and held it in towards the centre of its orbit we could calculate how rapid the Moon would have rotated the Earth when it was say 50,000 Km from the Earth as opposed to its current Semi-major axis of 384,399 km.
Conservation of Angular Momentum VR = vr
So the velocity of the smaller orbit will be higher and the circumference being small the orbital rate will go up in the same proportion.
Ratio of radii = 7.68798.... 27.32 Days Orbital period now. ... 3.55 days orbital period of the Moon.
So the G force between the Earth and the Moon would have needed to be much greater, and the only way that could have been possible is if the Earth was considerably more massive.
Using Newton's Gravitational attraction equation I might even be able to work out the relative mass of the Earth then (when it was 50,000 Km from the Earth), compared to now.
http://www.setileague.org/articles/ham/masserth.pdf
Gives the workings of how you can find the mass of the Earth using the orbital characteristics of the moon.
Mass = (Velocity of moon)^2 * orbital radius/Gravitational constant.
but remembering the Velocity * Radius is the conserved value in the law of Conservation of momentum. Assume the angular momentum of moon is basically constant (ignoring the little part transferred via the tidal bulge)
So when you compare the current mass of the Earth and the mass of the early Earth when the moon could have been as close as radius 50,000 km
Looking at the Ratio:
Mass of Earth today/Mass of Early Earth = Velocity of moon today/velocity of Early Moon
As above if the Radius was 1/7 then as it is now, the velocity will be in the inverse proportion. Early Moon had a velocity of 7 times it is today, and that means at the time the Moon began orbiting the Earth, the Early Earth still had retained a mass 7 times of what it is today.
My algebra is not always the best so tell me if I'm wrong.
Which i think I'm wrong the more i think of it. For if the Moon was going at a higher velocity the Energy formula E = 1/2 MV^2 would mean the Moon has lost a lot of Energy and there is no sense to that.
What I want is help with the Angular Momentum issue. There are ways of calculating these factors, for they have done it for the Sun and the Earth. As the Sun loses mass the Earth will go to a larger radius.
So the same must apply to the Earth that loses mass, the Moon goes out to a larger radius.
Ignore the changes due to tidal forces at this stage, and assume the mass of the moon remains the same as well. And just retains its angular momentum that it had.
The Moon capture requires a large gaseous planet Earth to slow the incoming Moon. The amount of matter in the protoplasmic disk allows for an Earth with about 42 Earth masses.
In the process of slowing the moon, the mass of volatiles remove could have been as much as 35 Earth masses.
The vastness of the mass pressing down on the terrestrial part of the Earth caused it to compress. During the decompression the continent plate which was once a continuous covering cracked.
Later in the Earth history the single continental plate broke up into 7 major chunks once the expansion slowed.
So the Moon's position and angular momentum is explained by the capture theory, which is only possible with a large "volatile covered" compressed Earth.
So EE Theory is more likely a fact rather than a myth. Continental drift is quite a late phenomenon. That is then when the theory of Continental drift and plate tectonics plays its part. (During the last 250 million years).
Now I am learning how to write the formulas in $$ but it is easy to work out that if the Moon ever did orbit the Earth at 50^6 m using Newton's gravitational attraction formula the earth mass has to be 7 times the current mass. (Either that or the moon would have to have water on it as well??? ) The two masses are multiplied so the mass has to be on one or the other body. That is basic science, OK it is a hypothetical situation but the Newton formula can be applied.
So one way or the other the matter in the Moon had to get out to its current height. Did the Impact theory suggest the material was thrown up to 300,000 km and it regrouped at that height? I personally struggle see how that works.
So I favour the Moon capture theory. So after being captured it may have initially been orbiting at that radius 50^6 m.
It then conserves momentum or gains some, for the tidal effects at the shorter radius would mean the tides would be enormous. But I can easily envisage the tidal effect of the Moon continually disrupting the Earth's atmosphere to the point the Solar Wind just kept wafting away the Earth's volatile matter. So while the Earth's mass decreases the Moon drifts to a higher orbit, maintaining and gaining a little angular momentum as it orbits the Earth, and the Earth spins faster than the Moon.
This activity warms up the waters on the Earth making ready for life to be introduced by a panspermia event bring organisms from Mercury directly or with the intermediatary Venus on its way to the Earth.
http://en.wikipedia.org/wiki/Panspermia
So it seems the moon impact theory relies on the transfer of momentum from the rapidly spinning Earth to the Moon, which then kept going to a higher orbit.
Where as with the Capture hypothesis the loss of mass of the Earth allows the Moon to drift to a higher orbit. The tidal effect having a lesser importance, maybe but with the larger mass the tidal effects have the potential to be very significant early on as well.
I.e. the tides on an Earth with 7 times the mass has the potential to transfer a huge amount of angular momentum. Day length changes are less dramatic.
Is there any evidence the Earth spun on its axis once every 5 hours. One would begin to wonder about the stability of a molten planet rotating this fast.
Can anyone show the forum that the Early Earth rotated nearly 5 times faster than today?
(This was transferred from a Sciforums thread on Angular Momentum.)
Now this was a day of reflection. Can I separate the physics between the Giant Impact theory (GIT) or the Moon Capture theory (MCT)
Now the surprising thing about the GIT was that at the time of impact or soon after the Earth's day length was just 5 hours. Was there any proof supporting that?
The above article showed there was a shorter day length (about 22 hours) 600 million years ago but there were more days in the year, so it still took a year to orbit the Sun.
Now this study is highly accurate and must be included in both possible causes of the Moon.
In my theory that should be the Shortest day length and it increases as more momentum is transferred to the moon.
So as you all know I'm not highly trained in the physics so it is quite a difficult search for the data that will identify the theory that is most likely.
Jupiter is an enormous sized planet and it rotates at an impressive 9 hours/revolution, which has given me a little more confidence to think Earth with a mass between 7 - 42 Earth masses could turn at the original 5 hours.
One can begin to see it isn't just random collisions that is going to get the mass the size of 42 Earth masses spinning 4.5 times faster than today's rate.
In my planet building method all the incoming material adds to planet's rotational momentum. For that reason alone I should not be surprised the rotational rate is fast. Nearly to the point where the molten planet would be unstable.
Now let's look at the way the Moon is being thrown further out into space.
We can see that there are more than one thing driving this.
1. The continual loss of volatile mass from the Early Earth means the G force between them is lessened all the time.
So as the Moon is being slowed by the atmosphere the mass of the Earth is being reduced at somewhat a faster rate to the point where the Moon orbited the Earth freely.
From that point on there was a transfer of angular momentum out to the Moon.
QUOTE
http://en.wikipedia.org/wiki/Moon#Relationship_to_Earth
Gravitational coupling between the Moon and the bulge nearest the Moon acts as a torque on the Earth's rotation, draining angular momentum and rotational kinetic energy from the Earth's spin.[94][96] In turn, angular momentum is added to the Moon's orbit, accelerating it, which lifts the Moon into a higher orbit with a longer period. As a result, the distance between the Earth and Moon is increasing, and the Earth's spin slowing down.[96] Measurements from lunar ranging experiments with laser reflectors left during the Apollo missions have found that the Moon's distance to the Earth increases by 38 mm per year[97] (though this is only 0.10 ppb/year of the radius of the Moon's orbit). Atomic clocks also show that the Earth's day lengthens by about 15 microseconds every year,[98] slowly increasing the rate at which UTC is adjusted by leap seconds. Left to run its course, this tidal drag would continue until the spin of the Earth and the orbital period of the Moon matched. However, the Sun will become a red giant long before that, engulfing the Earth.[99][100]
I seem to have misunderstood part of the quote: "Measurements from lunar ranging experiments with laser reflectors left during the Apollo missions have found that the Moon's distance to the Earth increases by 38 mm per year[97] (though this is only 0.10 ppb/year of the radius of the Moon's orbit). "
The transfer of angular from the Earth to the Moon has moved the Moon by a hell of a lot more that half the radius of the Moon, but more like half the distance of the Moon's orbital radius.
With my hypothesis having the Earth surrounded with an enormous ocean of volatiles, even though the tides would have been enormous when the Moon was closer, there is a suggestion this situation would not result in tidal acceleration. (Or put it like this at this stage I think that is what it means???)
http://en.wikipedia.org/wiki/Tidal_acceleration#cite_note-10QUOTE
The rotational angular momentum of the Earth decreases and consequently the length of the day increases. The net tide raised on Earth by the Moon is dragged ahead of the Moon by Earth's much faster rotation. Tidal friction is required to drag and maintain the bulge ahead of the Moon, and it dissipates the excess energy of the exchange of rotational and orbital energy between the Earth and Moon as heat. If the friction and heat dissipation were not present, the Moon's gravitational force on the tidal bulge would rapidly (within two days) bring the tide back into synchronization with the Moon, and the Moon would no longer recede. Most of the dissipation occurs in a turbulent bottom boundary layer in shallow seas such as the European shelf around the British Isles, the Patagonian shelf off Argentina, and the Bering Sea.[11]
So an ocean world would have no where to slow down and drag the wave. The wave would advance practically the same rate as the Earth rotates and the wave would be in line with the moon earth centres. Hence limited gravitational attraction would be limited. Ok there must still be some friction in the liquids so it definitely is not going to be absolute zero.
Remember in 1998 I calculated that the Earth started off with a much larger mass than what was previously thought. And then this mass shifted across to the Gas and Ice Giant planets after the Sun fired up.
This mass would be enough to account for a compressed and later Expanding Earth.
For the Moon Capture Hypothesis to work there needed to be a large gaseous atmosphere to slow the captured Moon.
Well 3 possible scenarios all depending on a water covered Earth. I could be wrong but when is someone going to present some evidence which proves the point, one way or the other.
Yes back then it came out to 28 Earth masses.
In this thread the figures came out to 42 Earth masses using figures supplied by NASA.
So the calculation was for real.
Once the Moon become captured at quite a close orbit, from there to where it is now is achieved by the actions of two principles:
1. The continual loss of volatile mass away from the Earth reduced the gravitational attraction between the 2 masses which allows the moon to drift to a higher orbit to equilibrate the centrifugal force with the Gravitational attraction.
2. Some tidal acceleration occurs but becomes more important when the Earth volatiles have been lost and the Earth Expansion has allowed the ocean to fill the ever enlarging ocean basins
3. The Expanding Earth is balanced by loss of mass (but the expansion requires an input of heat energy so there is a delay between the loss of mass and the final expansion).
Could this be the reason study of the tidalites have an Earth with a variable number of days in a year? Did patchy loss of mass (Comets and asteroids, meteorites, warm periods and ice ages) and patchy expansion (rebound and Continental drift) affect the Earth rotational rate to the extent that the number of days could be in the range 400 +/- 9 days per year over reasonably short periods during the last 600 million years?
PS : Even if you doesn't agree, we will let history be the judge of this!
http://en.wikipedia.org/wiki/Sun#Earth.27s_fate
Faint young Sun problem
Main article: Faint young Sun paradox
Theoretical models of the Sun's development suggest that 3.8 to 2.5 billion years ago, during the Archean period, the Sun was only about 75% as bright as it is today. Such a weak star would not have been able to sustain liquid water on the Earth's surface, and thus life should not have been able to develop. However, the geological record demonstrates that the Earth has remained at a fairly constant temperature throughout its history, and that the young Earth was somewhat warmer than it is today. The consensus among scientists is that the young Earth's atmosphere contained much larger quantities of greenhouse gases (such as carbon dioxide, methane and/or ammonia) than are present today, which trapped enough heat to compensate for the smaller amount of solar energy reaching the planet.[119]
Some of that fits in with the theory that life on Mercury would be easier. Especially in the protosun period which was even colder.$$