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MrKap January 2nd, 2018 04:08 PM

Phaeton (hypothetical planet)
 
I've been mulling this "historical" scientific theory around for some time now.

https://en.wikipedia.org/wiki/Phaeto...hetical_planet)

Quote:

Phaeton (or Phaėton, less often Phaethon) is the hypothetical planet posited to have existed between the orbits of Mars and Jupiter whose destruction supposedly led to the formation of the asteroid belt. The hypothetical planet was named for Phaethon, the son of the sun god Helios in Greek mythology, who attempted to drive his father's solar chariot for a day with disastrous results and was ultimately destroyed by Zeus.
I suspect it may still be valid. even though it's original promoters, have been discredited.

Quote:

According to the discredited Titius–Bode law, a planet was believed to exist between Mars and Jupiter.
Has anyone taken this idea seriously? It seems to be forgotten and lost.

Perhaps mars orbited this planet, and once plucked by jupiters gravity, forced into an orbit around the sun, phaeton became unstable, and exploded?

I do believe people are started to accept that perhaps venus used to have our moon in it's orbit. Perhaps it became unstable, after it lost it?

Any thoughts?

Whyte January 2nd, 2018 11:58 PM

Quote:

Originally Posted by MrKap (Post 2880103)
Perhaps mars orbited this planet, and once plucked by jupiters gravity, forced into an orbit around the sun, phaeton became unstable, and exploded?

That is not how gravity works. Planets don't explode on their own. (There is a reason why massive stars do, and planets don't have the same physical process working inside them.) Instead, you need to put in energy from somewhere, such as a collision with another planet, in order to break a planet apart, i.e. to counteract the gravity pulling everything together.

The current thinking is that the asteroid belt never coalesced into a single body, probably due to Jupiter's gravitational influence. But it certainly did have planetesimals, planet embryos, as we can see in the larger asteroids like Ceres and Vesta. Some of these planetesimals were impacted by other planetesimals, which explains why we have nickel-iron asteroids: they are from the core of a differentiated planetesimal (that is, a molten body where the heavy metals sink into the core and lighter rocks stay on the surface, like on Earth). But not one, single planet, since we also have many chondrite meteorites, which have never been part of a larger, molten body, i.e. a differentiated planet.

Quote:

I do believe people are started to accept that perhaps venus used to have our moon in it's orbit. Perhaps it became unstable, after it lost it?
Venus is not unstable. It is very hard to see how Earth could capture Venus' moon from at least hundred times farther away than the moon would be from Venus, given that the planets are roughly the same mass. Earth's gravitational influence on that moon would be of the order of 1/10000th of Venus (depending on the distance of the moon from the Venus' center, and all that jazz, but good enough for a magnitude estimate). When a capture scenario is proposed for Moon, it has been assumed to be a free body (like a comet or an asteroid), not already captured by another planet.

Instead, it is looking like that the giant-impact theory for the formation of Moon is the best one: a Mars-sized planetesimal impacting with the young Earth, and the impact sending a lot of the crustal and mantle material out to the orbit, which then coalesced to form Moon. See here for more details: https://www.space.com/19275-moon-formation.html

MrKap January 3rd, 2018 09:38 AM

Quote:

Originally Posted by Whyte (Post 2880249)
Earth, and the impact sending a lot of the crustal and mantle material out to the orbit, which then coalesced to form Moon. See here for more details: https://www.space.com/19275-moon-formation.html


Yeah, I know. I'm a computer programmer.

These guys from the Royal Society are more interesting, as they are real physics people, rather than abstract mathematicians.

Did Venus Give Earth the Moon? Wild New Theory on Lunar History

https://www.space.com/22966-earths-moon-from-venus.html

I should have posted that link earlier.

Royal society has been around since 1660.

That computer simulation that came up with the moon impact theory was commodore 64 era simulation.

Whyte January 3rd, 2018 10:52 AM

Quote:

Originally Posted by MrKap (Post 2880553)
Did Venus Give Earth the Moon? Wild New Theory on Lunar History

https://www.space.com/22966-earths-moon-from-venus.html

I read the article. As far as I can see, it is just a scientist throwing out an idea and saying that we ought to see if Venus' composition matches that of Earth (and Moon), in case Moon might have a Venusian origin. There is no orbital dynamics simulation, showing how close a pass and what mass of a planetesimal you need to knock Moon out of Venusian orbit, and the likelihood of Earth capturing it. The scientist himself says that he still supports the impact theory.

At this point, Occam's razor says that it was giant impact. Subject to review if new evidence arrives to contradict it or to favor another theory. Science! :)

MrKap January 3rd, 2018 11:58 AM

`I only thought there might be a reason for it being tidally locked, perhaps a gentle pluck.

Occam's Razor fails to account for the extreme atmospheric pressure on Venus, it's rotation, and so forth, thus opening up philosophical theory, or hyper-critical requirements.

There is no evidence of an impact, so our typical means by which we study science through our sense of vision, and electromagnetic measurements, must be ignored. It's a huge, absence of evidence is no evidence of anything, moot issue.


Anyhow, yes, it is far fetched.

The other idea, is that perhaps the surface of Venus is littered with pressure releasing volcanoes, is due to a gravito-magnetic core destabilization. Rather than, delayed, accreting, nuclear events. Although, surface chemistry seeping deep into the planet, causing a fission reaction is possible, although, requiring more assumption.

MrKap January 3rd, 2018 12:03 PM

It is known, that of all the planets, Venus conjuncts with Earth, and rather close, from an ancient plantary time perspective.

Rare lunar 'occultation' happens today: How it works & why it's a big deal

https://www.rt.com/news/403666-moon-...ltation-space/

Quote:

Depending on your location, you may get the opportunity to see Earth’s natural satellite ‘cover’ Venus, Mars, Mercury or even one of the brightest stars in the sky, Regulus.

Naomasa298 January 3rd, 2018 12:40 PM

Quote:

Originally Posted by MrKap (Post 2880616)
`I only thought there might be a reason for it being tidally locked, perhaps a gentle pluck.


Venus is not tidelocked.

AlpinLuke January 3rd, 2018 01:12 PM

Quote:

Originally Posted by MrKap (Post 2880103)
I've been mulling this "historical" scientific theory around for some time now.

https://en.wikipedia.org/wiki/Phaeto...hetical_planet)



I suspect it may still be valid. even though it's original promoters, have been discredited.



Has anyone taken this idea seriously? It seems to be forgotten and lost.

Perhaps mars orbited this planet, and once plucked by jupiters gravity, forced into an orbit around the sun, phaeton became unstable, and exploded?

I do believe people are started to accept that perhaps venus used to have our moon in it's orbit. Perhaps it became unstable, after it lost it?

Any thoughts?

First of all we should note that in that band there is a dwarf planet, Cerere which records a diameter of about 950km [Vesta, Pallade and Igea are not so little in comparison ... they are all above 400km of diameter]. In any case they are nothing else than little rocks ... think to our natural moon: its diameter is about 3,476km [3.5 times the diameter of Cerere].

The band is not coherent and there are "external" families of asteroids ["Trojans" and "Greeks", don't ask me why astronomers called them in this way!].

Regarding the origin of this band of asteroids, today astronomers think more to a failed planet than to an existing planet which got destroyed. The gravitational perturbation of Jupiter would have impeded the formation of a decent planet and the not rare collisions among the asteroids would have caused the migration of a large part of the mass of the band towards other regions of the solar system [causing catastrophic collisions with planets, also our planet suffered for these collision in the past].

In a certain sense we could make a parallel with the rings of Saturn: the satellites of the giant planet generate perturbations which don't allow the fragments of the rings to form something bigger. Jupiter has worked in the same way with the band of asteroids.

Naomasa298 January 3rd, 2018 02:17 PM

Quote:

Originally Posted by MrKap (Post 2880103)
Perhaps mars orbited this planet, and once plucked by jupiters gravity, forced into an orbit around the sun, phaeton became unstable, and exploded?

I think the people of Phaeton sent one baby to safety before the planet exploded.

Ancientgeezer January 3rd, 2018 04:40 PM

Quote:

Originally Posted by Naomasa298 (Post 2880668)
I think the people of Phaeton sent one baby to safety before the planet exploded.

Is the material left over "Phaetonite"?


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