S E V E N Earth like planets orbiting o n e star.

[Synobun]

Hobby, nothing is suspicious about 7 planets in a solar system. However 7 Earth like is another matter. These are all rocky worlds full of fast food joints, or something like that. No gas giants or whatever else doesn't qualify as Earth like.

Question for anyone willing to field it... How many Earth like planets, according to the qualifications used on these 7, are there in our solar system? Does Venus qualify?

These aren't being labelled as Earth-like. They're being labelled as Earth-sized. There's a difference. It's quite possible that one or more of these planets are like Neptune.

Mars is the most Earth-like in Sol. Venus also could be considered as such.

 

[Thorgalaeg]

These aren't being labelled as Earth-like. They're being labelled as Earth-sized. There's a difference. It's quite possible that one or more of these planets are like Neptune.

Mars is the most Earth-like in Sol. Venus also could be considered as such.

Earth sized planets can hardly be like Neptune. They are too small to retain hydrogen or hellium, particularly at temperatures in the life zone, and if by whatever reason it can keep its light gases, size will be much larger than Earth because those same gases. Just like Neptune.

 

[CKS]

Question for anyone willing to field it... How many Earth like planets, according to the qualifications used on these 7, are there in our solar system? Does Venus qualify?

Three or four. Mercury may be too small, but Mars is pretty close in size to the smallest of the 7.

 

[Synobun]

Earth sized planets can hardly be like Neptune. They are too small to retain hydrogen or hellium, particularly at temperatures in the life zone, and if by whatever reason it can keep its light gases, size will be much larger than Earth because those same gases. Just like Neptune.

Less than half of the planets are in the habitable zone. I wouldn't be so quick to say "that's impossible!".

 

[Lohrenswald]

Do you hate everything? What's wrong with the term?

I don't remember all the other name suggestions because it was like 10 years ago, but I remember "exoplanet" was the dumbest of the proposed names

 

[Synobun]

I don't remember all the other name suggestions because it was like 10 years ago, but I remember "exoplanet" was the dumbest of the proposed names

you're the dumbest of the proposed names

Real talk, though. What name would you prefer? Exoplanets is easy to say, easy to spell, you know what it's referring to immediately...

 

[warpus]

Question for anyone willing to field it... How many Earth like planets, according to the qualifications used on these 7, are there in our solar system? Does Venus qualify?

Just going by size, Earth and Venus are the only ones that qualify, I think. Mars is too small.

 

[El_Machinae]

Wait, we keep seeing someone say 'Earth like planets'. Um, no. They're not.

 

[warpus]

Yeah, earth-sized. I mis-read what I was quoting

 

[hobbsyoyo]

Hobby, nothing is suspicious about 7 planets in a solar system. However 7 Earth like is another matter. These are all rocky worlds full of fast food joints, or something like that. No gas giants or whatever else doesn't qualify as Earth like.

Question for anyone willing to field it... How many Earth like planets, according to the qualifications used on these 7, are there in our solar system? Does Venus qualify?

A lot to unpack here -

These planets are not Earth like that we know of, just Earth sized.

It's also not suspicious that there are so many of them in one place or that so many lie in the habitable zone. Venus and Mars are both in the habitable zone of our sun. Venus lacks plate tectonics, which prevented carbon from being recycled into the planet's mantle. This lead to a runaway greenhouse effect that fried the planet. Mars is just too small to retain a thick enough atmosphere to effectively regulate the climate.

So that's 3 out of 8 planets in our solar system compared to 3 out of 7 in the other. And as I pointed out already, there is currently a massive selection bias toward not finding these planets due to inadequate technology. There are many more systems just like this (or even better, from the standpoint of life) yet to be found.

Earth sized planets can hardly be like Neptune. They are too small to retain hydrogen or hellium, particularly at temperatures in the life zone, and if by whatever reason it can keep its light gases, size will be much larger than Earth because those same gases. Just like Neptune.

That's really only true if those planets are close to a powerful star - particularly one that emits copious amounts UV and higher-frequency wavelengths. Cooler, smaller stars won't be able to so easily strip lighter elements of Earth-sized planets. Likewise, if a small planet is far enough from even a large, energetic star, it may retain such an atmosphere.

I'm not saying it will necessarily be a super common occurrence but I would not rule it out. There's also lots of potential atmospheric replenishment mechanisms we don't often consider or have not yet discovered.

 

[Thorgalaeg]

Atmospheric escape is prymarily a consequence of gravity and temperature. There are other lesser factors like solar wind and presence or not of magnetosphere. If we are speaking about planets in the habitable zone we have more than enough thermal energy to strip larger than Earth planets of its light gases. The very Earth even with its strong magnetic field deflecting solar winds has lost them completely. Even in the case of cold enough planets i fail to see as it could keep its light gases, which implies a huge atmosphere, and be Earth sized. Never heard of these micro-jovian planets. Can you provide any paper supporting its existence?

 

[hobbsyoyo]

Atmospheric escape is prymarily a consequence of gravity and temperature. There are other lesser factors like solar wind and presence or not of magnetosphere. If we are speaking about planets in the habitable zone we have more than enough thermal energy to strip larger than Earth planets of its light gases. The very Earth even with its strong magnetic field deflecting solar winds has lost them completely. Even in the case of cold enough planets i fail to see as it could keep its light gases, which implies a huge atmosphere, and be Earth sized. Never heard of these micro-jovian planets. Can you provide any paper supporting its existence?

No I almost never get into citation wars and freely admit that I could be wrong and that you're free to disengage with me over my lack of sources.

Atmospheric losses can happen over hundreds of millions to billions of years. Planets can wander around much faster than that. Therefore there could easily be lots of planets like this, despite them actively losing atmosphere. And again that's putting aside replenishment mechanisms or other ways to mitigate the impact of a sun on the atmosphere that we haven't seen yet.

The story of the last 10 years in astronomy is "all the old rules about planet formation and their systems are out the window".

 

[Thorgalaeg]

Fair enough. Not citation war in anyway but real interest since you may have access to more info on these topics than myself.

 

[hobbsyoyo]

The problem I have is that I'm pretty good at absorbing lots of random information - especially in the topics I care about - but I'm terrible at remembering where I came across it. But I should note that all of what I just said is based on my general knowledge of planetary formation and orbital mechanics, not any specific articles or even comprehensive theories. That and the fact that our astronomers have found a parade of exotic planets that absolutely trashed our models of planetary formation and solar system dynamics which makes it difficult to confidently say "such a planet could not exist".