Let's talk planets.

[We Never Know]

According to hypotheses/theory's Mecury once had liquid water and might have been habitable. As our young sun aged, getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next Venus once had liquid water and may have been habitable and again as our young sun aged getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next here we are on Earth. We have liquid water and are habitable. As our sun continues to age getting hotter and brighter is earth the next planet to dry up with rising temperatures, losing its water and become uninhabitable?

Planets behind earth/other planets moons are said to have much ice. Are they the next in line to thaw, have liquid water and become habitable as our sun keeps getting brighter and hotter?

Your thoughts.

If you can watch Nova, S46-E12 you will see were this post/my thoughts arise from.

 

[exchemist]

According to hypotheses/theory's Mecury once had liquid water and might have been habitable. As our young sun aged, getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next Venus once had liquid water and may have been habitable and again as our young sun aged getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next here we are on Earth. We have liquid water and are habitable. As our sun continues to age getting hotter and brighter is earth the next planet to dry up with rising temperatures, losing its water and become uninhabitable?

Planets behind earth/other planets moons are said to have much ice. Are they the next in line to thaw, have liquid water and become habitable as our sun keeps getting brighter and hotter?

Your thoughts.

If you can watch Nova, S46-E12 you will see were this post/my thoughts arise from.

Is this right, though? It sounds odd to me.

Since the theory of the origin of the solar system suggests even the Earth was incandescently hot when it first formed, at what point would Mercury have had a surface cool enough to support liquid water? And where did the water come from, seeing that on Earth it is thought to have come in from colder regions of the solar system via the impact of comets?

As for Venus, my understanding is it is as hot as it is, not so much because of proximity to the sun, but due to a runaway greenhouse effect in its atmosphere.

Lastly, and perhaps most importantly, my understanding of the lifecycle of stars is that during the "main sequence", where our sun now is in its life, the output is stable, not progressively increasing. So this notion of a progressive increase in heat output, gradually causing the habitable zone to move outward in the solar system, sounds wrong to me.

But I admit I am not an astronomer. I'd be interested in input from someone better qualified.

 

[ChristineM]

According to hypotheses/theory's Mecury once had liquid water and might have been habitable. As our young sun aged, getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next Venus once had liquid water and may have been habitable and again as our young sun aged getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next here we are on Earth. We have liquid water and are habitable. As our sun continues to age getting hotter and brighter is earth the next planet to dry up with rising temperatures, losing its water and become uninhabitable?

Planets behind earth/other planets moons are said to have much ice. Are they the next in line to thaw, have liquid water and become habitable as our sun keeps getting brighter and hotter?

Your thoughts.

If you can watch Nova, S46-E12 you will see were this post/my thoughts arise from.

Younger suns burn fuel much quicker than main sequence stars and are considerably hotter.

Although Mercury has an odd orbit I understand it does contain water at its poles. But i doubt, given its proximity to the sun it was ever habitable.

The problem with Venus is a run away greenhouse effect. Possibly earths future .

If earth doesn't succumb to mans stupidity then its demise (excluding major disasters such as being struck by a rogue planet or very large asteroid) will occur when our sun begins to go red giant. That's a few billion years away yet and i believe life on this ball of rock will be long gone by then.

 

[Twilight Hue]

According to hypotheses/theory's Mecury once had liquid water and might have been habitable. As our young sun aged, getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next Venus once had liquid water and may have been habitable and again as our young sun aged getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next here we are on Earth. We have liquid water and are habitable. As our sun continues to age getting hotter and brighter is earth the next planet to dry up with rising temperatures, losing its water and become uninhabitable?

Planets behind earth/other planets moons are said to have much ice. Are they the next in line to thaw, have liquid water and become habitable as our sun keeps getting brighter and hotter?

Your thoughts.

If you can watch Nova, S46-E12 you will see were this post/my thoughts arise from.

It would be fascinating if we could come across fossils on any planet first.
.
It seems that our next contender might be Titan in the future as it's rich in carbon compounds.

 

[PureX]

I thought Mars had liquid water, too, but no longer does, and it's further out. So that sequential sun theory doesn't hold.

I don't think we know what happened to Mars' liquid water. It's odd, though, that all these planets show signs of having HAD liquid water, but do not have it any longer. I suspect it's not about the proximity to the sun, but something in their formation process that has left the surface signs of fluid liquids (of some sort).

 

[Revoltingest]

I thought Mars had liquid water, too, but no longer does, and it's further out. So that sequential sun theory doesn't hold.

I don't think we know what happened to Mars' liquid water. It's odd, though, that all these planets show signs of having HAD liquid water, but do not have it any longer. I suspect it's not about the proximity to the sun, but something in their formation process that has left the surface signs of fluid liquids (of some sort).

Mars lost all (non ice) water because it lost its magnetic field,
which protected water & atmosphere from solar wind. We're
lucky that our molten iron core still protects our biosphere.

 

[Aupmanyav]

We are on an small island in the universe far from any other inhabited place, like Tristan de Cunha in Atlantic. It has no incoming or outgoing traffic.

 

[Heyo]

Is this right, though? It sounds odd to me.

Since the theory of the origin of the solar system suggests even the Earth was incandescently hot when it first formed, at what point would Mercury have had a surface cool enough to support liquid water? And where did the water come from, seeing that on Earth it is thought to have come in from colder regions of the solar system via the impact of comets?

As for Venus, my understanding is it is as hot as it is, not so much because of proximity to the sun, but due to a runaway greenhouse effect in its atmosphere.

Lastly, and perhaps most importantly, my understanding of the lifecycle of stars is that during the "main sequence", where our sun now is in its life, the output is stable, not progressively increasing. So this notion of a progressive increase in heat output, gradually causing the habitable zone to move outward in the solar system, sounds wrong to me.

But I admit I am not an astronomer. I'd be interested in input from someone better qualified.

A bit simplistic but accurate description:
Why the Sun Will Become Hotter and Brighter

It's a slow process but 4 billion years ago there was probably liquid water on Mercury and other planets. Even Jupiter started out as a rocky planet

They didn't have as much water as earth has today but water is almost everywhere. It's one of the simplest molecules made out of the most abundant atoms. But whom am I telling that?

 

[exchemist]

A bit simplistic but accurate description:
Why the Sun Will Become Hotter and Brighter

It's a slow process but 4 billion years ago there was probably liquid water on Mercury and other planets. Even Jupiter started out as a rocky planet

They didn't have as much water as earth has today but water is almost everywhere. It's one of the simplest molecules made out of the most abundant atoms. But whom am I telling that?

Thanks. This is interesting. I must admit I don't immediately see why they say, in the gas equation, that PV must remain constant. Sure n will decrease due to fusion, but it seems unsatisfactory to say T MUST rise to keep PV constant. I feel something is missing in this explanation. Can you fill in the gap for me?

Alternatively there's a chap called Janus on the science forums who is an astronomer. I could ask him I suppose.

 

[Heyo]

Thanks. This is interesting. I must admit I don't immediately see why they say, in the gas equation, that PV must remain constant. Sure n will decrease due to fusion, but it seems unsatisfactory to say T MUST rise to keep PV constant. I feel something is missing in this explanation. Can you fill in the gap for me?

Alternatively there's a chap called Janus on the science forums who is an astronomer. I could ask him I suppose.

The temperature keeps the pressure/radiation in equilibrium. When the volume shrinks, atoms get closer together and the fusion goes up (and so does the heat). That is what happens in a supernova. The star has burned through its fuel (up to iron) and collapses on itself. The pressure re-ignites the star and with the extra energy from the collapse bigger atoms form.
Some stars (Red Dwarfs like Proxima Centauri) go through cycles of collapse and expansion. (Strictly speaking the sun does it also in an 11 year cycle but it's minimal.)

 

[Thief]

According to hypotheses/theory's Mecury once had liquid water and might have been habitable. As our young sun aged, getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next Venus once had liquid water and may have been habitable and again as our young sun aged getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next here we are on Earth. We have liquid water and are habitable. As our sun continues to age getting hotter and brighter is earth the next planet to dry up with rising temperatures, losing its water and become uninhabitable?

Planets behind earth/other planets moons are said to have much ice. Are they the next in line to thaw, have liquid water and become habitable as our sun keeps getting brighter and hotter?

Your thoughts.

If you can watch Nova, S46-E12 you will see were this post/my thoughts arise from.

just this weekend......saw a report about the Goldilocks effect

and tied to a book called …..Rare Earth

and it could be......we ARE alone

 

[Terese]

According to hypotheses/theory's Mecury once had liquid water and might have been habitable. As our young sun aged, getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next Venus once had liquid water and may have been habitable and again as our young sun aged getting brighter and hotter water dried up, temperature soared upward and it became uninhabitable.

Next here we are on Earth. We have liquid water and are habitable. As our sun continues to age getting hotter and brighter is earth the next planet to dry up with rising temperatures, losing its water and become uninhabitable?

Planets behind earth/other planets moons are said to have much ice. Are they the next in line to thaw, have liquid water and become habitable as our sun keeps getting brighter and hotter?

Your thoughts.

If you can watch Nova, S46-E12 you will see were this post/my thoughts arise from.

Mercury is far too close to the sun to have supported any liquid water in all of mercury's lifetime. According to scientists Venus may have harboured liquid water. Mars certainly did, as there are water canals on its surface. A billion years later from now the earth will be uninhabitable for us.

Billions of years later the sun will greatly expand. Its debated whether it will swallow the earth or expand just short of eating it, making Earth the new Mercury. The sun is now a red giant.

Jupiter and Saturn (along with its terrestrial moons) will be in the Goldilocks Zone, which is the zone where liquid water can exist. Life might come to be on some of Jupiter and Saturn's moons.

https://www.sciencealert.com/images/2016-05/habitable_Zone-olds.jpg

Billions of years later the sun will shrink and turn into a white dwarf, then trillions later a black dwarf.

 

[columbus]

just this weekend......saw a report about the Goldilocks effect

and tied to a book called …..Rare Earth

and it could be......we ARE alone

This is rather why I don't put much stock in estimates of the odds about extraterrestrial life.

Nobody really knows what combination of conditions made Earth suitable for life(as we know it), or how likely life is to arise on another planet no matter how similar it is.

"Well, there's trillions of planets out there, surely....." doesn't seem very persuasive to me, especially given that no effort(to date) has yielded any positive results. For all anybody knows the odds against life forming on Earth, despite the demonstrated capacity, might be the statistical equivalent of throwing a quarter off the Empire State Building during a thunderstorm and having it land in the meter in front of your, now illegally parked, car.
Tom

 

[exchemist]

The temperature keeps the pressure/radiation in equilibrium. When the volume shrinks, atoms get closer together and the fusion goes up (and so does the heat). That is what happens in a supernova. The star has burned through its fuel (up to iron) and collapses on itself. The pressure re-ignites the star and with the extra energy from the collapse bigger atoms form.
Some stars (Red Dwarfs like Proxima Centauri) go through cycles of collapse and expansion. (Strictly speaking the sun does it also in an 11 year cycle but it's minimal.)

Aha, that's the point then. The volume diminishes and the temperature goes up due to the more intense fusion. That's more understandable. Thanks.

So this means that the temperature of a star does in fact progressively increase throughout its main sequence, right?

 

[Heyo]

Aha, that's the point then. The volume diminishes and the temperature goes up due to the more intense fusion. That's more understandable. Thanks.

So this means that the temperature of a star does in fact progressively increase throughout its main sequence, right?

Yes, it does. Though the increase is in the order of 10s of percents per a billion years for a Sol sized star. So nothing we could really measure.

 

[We Never Know]

Is this right, though? It sounds odd to me.

Since the theory of the origin of the solar system suggests even the Earth was incandescently hot when it first formed, at what point would Mercury have had a surface cool enough to support liquid water? And where did the water come from, seeing that on Earth it is thought to have come in from colder regions of the solar system via the impact of comets?

As for Venus, my understanding is it is as hot as it is, not so much because of proximity to the sun, but due to a runaway greenhouse effect in its atmosphere.

Lastly, and perhaps most importantly, my understanding of the lifecycle of stars is that during the "main sequence", where our sun now is in its life, the output is stable, not progressively increasing. So this notion of a progressive increase in heat output, gradually causing the habitable zone to move outward in the solar system, sounds wrong to me.

But I admit I am not an astronomer. I'd be interested in input from someone better qualified.

It has to do with the some of the planet's not always orbiting where they are. Here's the episode.

The Planets: Inner Worlds | Season 46 Episode 12 | NOVA

 

[We Never Know]

Jupiter was formed before the sun was lit. Jupiter is basically a failed star because it didn't grow enough.

The Planets: Jupiter | Season 46 Episode 14 | NOVA

I'm not a planet expert, I'm pretty novice. Can someone explain to me how the immense gravity of Jupiter as it moved through the asteroid belt/scattered and thrown about material out of the inner solar system, some into the sun, instead of drawing it to it with its gravity?

 

[exchemist]

It has to do with the some of the planet's not always orbiting where they are. Here's the episode.

The Planets: Inner Worlds | Season 46 Episode 12 | NOVA

OK. Also @Heyo has set me straight on the temperature of stars during their main sequence. Evidently the temperature does gradually rise, due to reduction in the number of atoms as a result of fusion, which causes the density to go up and the fusion to occur within a smaller volume.

Something new I've learnt - which is one reason I subscribe to forums like this.