Solar system

...is a big topic. Posing here just two questions:

What are the most dense and least dense objects in solar system?

 

Object large enough to be bound by gravity.

I think we are pretty sure there are no black holes in solar system. Really sure there are no neutron stars.

No shame if one needs to look it up - I had to

 

Jimbo, one of us just needs to say it. Nobody else will bother to look it up, and it's fun to know!

 

Both excellent guesses in terms of common sense. But the answer is more fun than that.

 

Least dense grav-bound body is SATURN. It is half as dense as the Sun. The other gas giant planets bracket Sun's density, Uranus and Jupiter are under and Neptune is over.

Saturn at 0.687 grams/cm3 closely matches some hardwoods, in case you want to make a ball and hold in your God-like hand.

No idea why Saturn is such an underperformer here. But all eyes are on Cassini space probe now doing 22 loop de loops that will end with 'entry'.

Most dense is EARTH! Tahdah! we win. Mercury finishes second, then Venus, with Mars coming in distant 4th. My only guess as to why Earth is this way, is that collision with another Mars-size body that made the Moon. On what would have been a contender for The Worst Day Ever.

Double up on iron (etc.) and maybe irretrievably blow off some light stuff.

Anyway, Earth has the density thing nailed. Perhaps related to being the only one (around here) that has sustained tectonics and a good 'nuff magnetic field. Possibly of interest in hunting for biological exoplanets.

If you want to make an Earth Ball of correct density to hold, start with zinc (because its cheap) and drill out about 23%. Then you have 5.514 gram/cm3

Make a Sun Ball from aluminum foil wad it up and squish down to about 48% 'air'. Saturn ball gets half as squished.

As iron meteors are...iron... they have density of 7.85. Thus they'd be winners here if gravitationally bound. But not. Just nice crystals, which we hope mange to miss Target Earth for as long as possible.

 

Any red giant star will have very low density as fuzzy1 pointed out. But still a hot dense fusion core. That photon energy goes though so many handoffs that, by the time it gets out, they are...well...red.

+++

Saturn (maybe all gas giants?) emit more energy than solar input. Seems a bit mysterious. Likely they are all slowly shrinking and it's basically friction.

 

drysider, my arbitrary game rules do not allow you to 'part out' the sun. Disregarding that, Jupiter's metallic hydrogen core is very much more dense*.

I think ya got me with the Oort Cloud though. It is arguably grav-bound, whacking big, and perhaps only 2 Earth masses in total. But it subsumes the entire solar system so I wiggle ut by way of no parting out rule.

Two Earth masses of water, carbon monoxide, and whatever else Oort is, is a lot though. Stay far away please.

*This incorrect assertion corrected below

 

Ah Pluto, we still love you. Density 1.86 means mostly ice and not much 'rock' there. Absolutely the last object found by photo flickering. Eyeball astronomy has since been supplanted.

Among minor planets (planetoids), Pluto will always be the best.

 

By different estimates, Jupiter would need to be 10 to 100 times more massive to conduct fusion. Other gas giants haven't nearly enough to give. Can't happen. Metallic hydrogen core of this non-star is the strangest place aside from fusion places. Best not to visit either.

Studies of exoplanets reveal many super-jupiters (that did not 'light' either). Only a small subset of the Galactic Zoo is represented in our local system. We happen to be living in a most congenial corner.

 

My "Jupiter's metallic hydrogen core"@11 is incorrect. Near as I can work it out, Jupiter's weird place has density about 2.6. Solar core is about 150.

 

At PriusChat one can only give one 'like'. drysider told us that Sun fusion core far exceeds Jupiter and I am happy to be corrected on that.

May just go to show that Fusion is a Hard Road, and all other means of earthly energy production ought to be fully explored first. But dang, those laser/inertial confinement and magnetic confinement gadgets are fun to look at, yes?

 

Solar System 0.1; 4.6 billion years ago. Hydrogen, ice, and rocks. Then things happened...

 

Oh Man! Fuzzy1 killed my Saturn-win on the low density side. I really wanted Saturn to win this as an odd fellow.

But OK, a grav-bound snowball comet of 0.3 is The Least Dense.

Hope you're happy. Meanwhile Saturn is a fabulous planet. All that ring-sheperding moon stuff? C'mon