I think you’d want to hold it a lot closer to yourself, after all the further away you hold it, with gravity there being umpteen times more gravitationy, your outstretched arm is going to tire real quick?

But then closer up your plate isn’t going to cast a big enough shadow… although my Mum has a turkey-sized roasting dish that might stop the whole ‘bursting into flames’ thing?

(Sometimes I don’t think the survival advice offered in these pages is fully thought through.)

Otherwise, yeah, you’re right. Lots more mass in relatively small volume = greater density, not such a mystery. Possibly higher metal levels such as a larger metallic core analogous to Mercury’s also makes some degree of sense too.

Of course, it might just have a neutronium core.

Formation scenario please, including compatibility with the existence of the outer planets.

Really I don’t get why people want to jump to exotic scenarios when the mass/density values are perfectly compatible with a rock/iron planet. Yes the compression factor is somewhat greater than that for the Earth but 55 Cancri e is a more massive planet, hence this is expected.

From Wikipedia:Lead

Boiling point 2022 K, 1749 °C, 3180 °F

So, the atmosphere would likely have vaporized lead in it, though it might not be ONLY lead(ie,mercury, or other low melting temp metals). Probably not a good place for carbon based life forms(sic).

Now, if we just had the tech,,,what a mining colony that could be.

Of course, it might just have a neutronium core.

Gary 7

(Gases are worse, of course. Until we started looking, it was widely thought that the radius of Jupiter was about the largest radius you could make a planet/brown dwarf — piling on more matter would just compress it more than add to the radius. The ‘puffy’ planets — planets 2 or 3 times Jupiter’s radius — are really interesting for that reason.) A bit of an aside here, but this means that a super-jovian gas giant planet that isn’t puffed out by some other force with say 8-12J mass and the 1J radius would be substantially denser than lead. So the densest gas giant planets in the universe are going to be denser than the terrestrials!

From what I understand, the density “heavyweight champion” exoplanet found so far is
HAT-P-2b, a Hot Superjovian exoplanet weighing in at 8.2 Jupiters and as dense as Earth even though its mostly made of hydrogen. A 60 kg person would weigh 952 kg and experience 14 times Earth’s gravity at its cloudtops. HAT-P-2b orbits in 5 days around HD 147506 which is located 440 light years away in the constellation of Hercules.

Although that may be out of date and, of course, I could be mistaken.

And taking this consideration even further, the very largest brown dwarfs, at 79-80J in mass, again in a 1J radius, and the very smallest red dwarf stars, at 80-81J mass in 1J radius (radiant pressure from hydrogen fusion would puff out stars again beyond this mass range, but at the very borderline this effect would presumably be small and the object still remain close to 1J in radius), are going to have densities around 100, about 10X that of lead! Which should make them the densest normal (not degenerate like the superdense stuff of white dwarfs, neutron stars and black holes) matter objects in the universe….

Well, the brains of some people – eg. many in politics, Creationists and Conspiracy Theorists – could perhaps give these a run for their money on that score!

Although, yeah, that’s my understanding too regarding the densest ordinary matter objects being some red & brown dwarfs.

Two party-pooping observations:
* A planet at 2700C would be glowing like a tungsten filament – and thus it wouldn’t make as deep an eclipse shadow as a black disk. Perhaps this makes the eclipse dip look shallower than it really is, meaning the planet is larger than we think.

Perhaps so but a trio of possible party-poopers on your party poopers there :

Firstly, there’s the question of an atmosphere which could block the light from the glowing surface beneath if its thick enough and composed of the right material. The hottest exoplanets ever found HD 149026 b is also the blackest absorbing nearly all the energy it recieves! Ash – hydrocarbons – and burnt material tends to be dark quite often after all!

Secondly, thinking carbon – could this actually be one of the theoretical “Carbon Planet” class with a surface of asphelt-y, tarry material – and a layer of diamond deeper down?

Thirdly and finally, contrast is a big part of transit eclipses isn’t it? Venus is very reflective – the brightest planet in our solar system, I think. However, against the backdrop of our Sun it looks like a dark dot crossing the far brighter face of our daytime star. Wouldn’t something similar apply here with 55 Cancri e?

* I’m not sure there’s enough common heavy metals even in a ‘boiled off Jupiter’ to leave a ball of 8 Earth masses of lead/osmium/uranium etc. Far more likely is a giant ball of liquid nickel-iron with a nickel-iron atmosphere – at about 7-8g/cm3 that’s not too far off the computed density.

Could well be but so much speculation – as are my suggestions and most others also. We have a few observed facts and a few ideas that could fit these facts but really, so little is known. We have no analogue to these sort of worlds in our solar system, and the one thing we’ve found about exoplanets is they keep being ever stranger and more exotic than we’d thought. Who knows what it’s like in reality – if only we had FTL starships already to go see!

55 Cancri (although I prefer the less-accurate Rho Cancri) is my very favourite star-system.

Me too!

I prefer Rho (or Rho-1) Cancris too. Shouldn’t that name take priority being older and higher in the nomenclatural scheme of things?

It’s just so…familiar, somehow. But I wonder if 55 Cancri e is what’s called a “Cthonic planet”, a kind of planet that is just the leftover core of a gas giant.

Absolutely! That’s one of the theories for it that makes a lot of sense.

Which has me wondering what a metallic hydrogen world would be like – how long could the metallic hydrogen stay in that form if the atmosphere is boiled away and what would the density of that be? Could that fit the observations for Rho-1 Cancri e too??