Astronomy & Space Exploration

Buster15 said:
The link doesn't seem to open which is a shame. But I will try to look direct on Forbes.
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"While it's true that stars convert hydrogen into helium, that's neither the greatest number of reactions nor the cause of the greatest energy release from stars. It really is nuclear fusion that powers the stars, but not the fusion of hydrogen into helium"
 
If I understand that article (which I probably don't), hasn't he broken down the "hydrogen--> helium" into multiple sub-steps which are probably way over the heads of most people (including me) simply to say that the sub-steps are where the energy is largely released? So the simplified version "hydrogen--> helium" is still true?
 
Counterfactual said:
If I understand that article (which I probably don't), hasn't he broken down the "hydrogen--> helium" into multiple sub-steps which are probably way over the heads of most people (including me) simply to say that the sub-steps are where the energy is largely released? So the simplified version "hydrogen--> helium" is still true?
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You do understand it, that's exactly what's happening. It's not news at all, wasn't even news when the article was published in 2017, but still a nice summary of the detailed processes.
 
Counterfactual said:
If I understand that article (which I probably don't), hasn't he broken down the "hydrogen--> helium" into multiple sub-steps which are probably way over the heads of most people (including me) simply to say that the sub-steps are where the energy is largely released? So the simplified version "hydrogen--> helium" is still true?
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The energy comes from Einstein formula E=MC2. It is the mass M released by the fusion process that becomes the energy which powers the sun heat that is needed to overcome gravity.
And if it is not that, then someone needs to tell the scientists who are developing nuclear fusion here on earth.
 
Counterfactual said:
If I understand that article (which I probably don't), hasn't he broken down the "hydrogen--> helium" into multiple sub-steps which are probably way over the heads of most people (including me) simply to say that the sub-steps are where the energy is largely released? So the simplified version "hydrogen--> helium" is still true?
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It seems that way to me. Clickbait science strikes again?
 
This is pretty cool - with interesting implications as well:
The Solar System has a new ocean
Mimas, a small moon of Saturn, turns out to have an ocean beneath its icy surface — despite looking too geologically inert to have water sloshing inside. The fact that unexceptional Mimas has an ocean means that “you could have liquid water almost anywhere”, says astronomer Valéry Lainey. And that means a greater chance of extraterrestrial life somewhere: interactions between a buried ocean and a moon’s rocky core could generate enough chemical energy to sustain living organisms.
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At this point, with the many planets that have already been found (many of which may have moons as well), you have to start thinking there might be life in many places just in our own galaxy.

Link to the popular article: The Solar System has a new ocean — it’s buried in a small Saturn moon (nature.com)
 
Cheimoon said:
This is pretty cool - with interesting implications as well:

At this point, with the many planets that have already been found (many of which may have moons as well), you have to start thinking there might be life in many places just in our own galaxy.

Link to the popular article: The Solar System has a new ocean — it’s buried in a small Saturn moon (nature.com)
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Well it's fairly reasonable to assume there must be some form of life somewhere in infinity of the universe. However, it's fairly moot as space travel is a ridiculous idea. The closest star is what 4 light years away? As far as I'm concerned travelling the vast distances required to discover other life is an unfathomable impossibility.

Disclaimer: I've had a few whiskeys and have not read a page of this thread so if I'm off topic... well that's your answer
 
Withnail said:
Well it's fairly reasonable to assume there must be some form of life somewhere in infinity of the universe. However, it's fairly moot as space travel is a ridiculous idea. The closest star is what 4 light years away? As far as I'm concerned travelling the vast distances required to discover other life is an unfathomable impossibility.

Disclaimer: I've had a few whiskeys and have not read a page of this thread so if I'm off topic... well that's your answer
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Yeah, I didn't mean life as in aliens we're gonna meet. Just life in any kind of sense.

I mean, 'life' doesn't have to mean beings that have evolved enough to do stuff that's noticeable from Earth (I'm not even sure if that applies to us, in terms of being noticed from planets many lightyears away), and even if they're far evolved, it still doesn't mean they do space travel, and even if they do, it may be physically impossible to travel faster than light. I just simply liked the idea that life may be more common than previously assumed.
 
Cheimoon said:
Yeah, I didn't mean life as in aliens we're gonna meet. Just life in any kind of sense.

I mean, 'life' doesn't have to mean beings that have evolved enough to do stuff that's noticeable from Earth (I'm not even sure if that applies to us, in terms of being noticed from planets many lightyears away), and even if they're far evolved, it still doesn't mean they do space travel, and even if they do, it may be physically impossible to travel faster than light. I just simply liked the idea that life may be more common than previously assumed.
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Yeah sorry I get you. Maybe it's just me,
and it probably is, but much like I consider the existence of God to be out of the question and irrelevant, the existence of life somewhere, somehow is a given for me, based on the variables involved, the infinite amount of stars and the even larger number of planets. I would be absolutely astounded if there was no other form of life anywhere so unless an alien rocks up in a space ship then it's a bit meaningless to me. I suppose I don't do theoretical very well,or at all, so I should probably bow out of the thread and leave you all to it.
 
Withnail said:
Yeah sorry I get you. Maybe it's just me,
and it probably is, but much like I consider the existence of God to be out of the question and irrelevant, the existence of life somewhere, somehow is a given for me, based on the variables involved, the infinite amount of stars and the even larger number of planets. I would be absolutely astounded if there was no other form of life anywhere so unless an alien rocks up in a space ship then it's a bit meaningless to me. I suppose I don't do theoretical very well,or at all, so I should probably bow out of the thread and leave you all to it.
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Oh, I totally agree with that. The universe is so inconceivable large that, even if life and our own particular evolution were ginormously unlikely to occur, there would still be many, many plantes where something similar would have happened. To me, that's a given.

But if life is actually not all that unlikely to occur, then maybe you don't need to invoke the enormity of the universe, and there is life in many places in our galaxy, too. That doesn't make it much more likely that we'll actually meet them (at least not in our lifetimes), but it might make it more likely that more advanced observation techniques will lead to positive proof of life on some particular planet in our galaxy. I think that'd be cool.

I'm a total crap theoretician when it comes to astronomy btw. The more detailed discussions in here are entirely over my head - and what I'm writing here might also be old hat for our resident astronomers. :wenger:
 
Cheimoon said:
Yeah, I didn't mean life as in aliens we're gonna meet. Just life in any kind of sense.

I mean, 'life' doesn't have to mean beings that have evolved enough to do stuff that's noticeable from Earth (I'm not even sure if that applies to us, in terms of being noticed from planets many lightyears away), and even if they're far evolved, it still doesn't mean they do space travel, and even if they do, it may be physically impossible to travel faster than light. I just simply liked the idea that life may be more common than previously assumed.
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This is such a fundamental subject, but incredibly difficult to comprehend.
And of course there isn't a right or wrong answer. Because no one knows....

And we need to consider what we mean by life.
Life might be relatively abundant in our galaxy. And it is possible that we might even discover some kind of life forms in our solar system.

But if we are talking about what we term complex or even intelligent life, it is just my opinion that this would be quite rare in our galaxy. And certainly not within some tens of light years from us.

The laws of physics that we understand are universal. And getting spacecraft to even very low percentage of the speed of light will require propulsion systems way beyond the basic rockets we have.

The key thing is for humanity to be around for long enough to discover it.
 
Buster15 said:
This is such a fundamental subject, but incredibly difficult to comprehend.
And of course there isn't a right or wrong answer. Because no one knows....

And we need to consider what we mean by life.
Life might be relatively abundant in our galaxy. And it is possible that we might even discover some kind of life forms in our solar system.

But if we are talking about what we term complex or even intelligent life, it is just my opinion that this would be quite rare in our galaxy. And certainly not within some tens of light years from us.

The laws of physics that we understand are universal. And getting spacecraft to even very low percentage of the speed of light will require propulsion systems way beyond the basic rockets we have.

The key thing is for humanity to be around for long enough to discover it.
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All good points. I meant life of any kind really - but I suppose intelligent life is most interesting; and it's anyway the only thing we could ever detect from out here. And I suppose there are a lot more parameters that need to be right for intelligent life to emerge: a relatively mineral/nutrient-starved body of underground water probably wouldn't cut it.
 
Any signs of life fossilised or present will do for me, in my lifetime, I hope we discover for a fact that life has evolved elsewhere. Come on JWST!
My hunch however, along with I believe B15 is that were the only intelligent life in our galaxy.
 
Drake equation

N = R☆ • fp • ne • fl • fi • fc • L


N=number of civilizations with which humans could communicate
R_*=mean rate of star formation
f_P=fraction of stars that have planets
n_e=mean number of planets that could support life per star with planets
f_l=fraction of life-supporting planets that develop life
f_i=fraction of planets with life where life develops intelligence
f_c=fraction of intelligent civilizations that develop communication
L=mean length of time that civilizations can communicate
 
Buster15 said:
This is such a fundamental subject, but incredibly difficult to comprehend.
And of course there isn't a right or wrong answer. Because no one knows....

And we need to consider what we mean by life.
Life might be relatively abundant in our galaxy. And it is possible that we might even discover some kind of life forms in our solar system.

But if we are talking about what we term complex or even intelligent life, it is just my opinion that this would be quite rare in our galaxy. And certainly not within some tens of light years from us.

The laws of physics that we understand are universal. And getting spacecraft to even very low percentage of the speed of light will require propulsion systems way beyond the basic rockets we have.

The key thing is for humanity to be around for long enough to discover it.
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If we do find an organism with cells that divide in our solar system, I think the likelihood of intelligent life in our galaxy would be high. That's purely based on evolution as cells would split and if there's enough nutrients to create the cell, it would become something that would naturally survive better in its environment given enough time. I don't think it will be too many years before we know the answer to that in our solar system, although if found will likely be likely unicellular or very primitive.
 
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If mankind were to wipe itself out completely in just 1m years (entirely possible) would life evolve independently, again another intelligent life-form on earth
With art, science and industry etc?
Life would have a blank canvass with us gone and 5b* years time to work with.

*When the sun will render life impossible on earth by reaching the end of its life.
 
Balljy said:
If we do find an organism with cells that divide in our solar system, I think the likelihood of intelligent life in our galaxy would be high. That's purely based on evolution as cells would split and if there's enough nutrients to create the cell, it would become something that would naturally survive better in its environment given enough time. I don't think it will be too many years before we know the answer to that in our solar system, although if found will likely be likely unicellular or very primitive.
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Yes exactly. Cells that were capable of dividing would be a very strong indication.
As you say. The most likely would be single cell bacteria type. But anything else could be possible.
Doubt it will be in my lifetime though.
 
Buster15 said:
Yes exactly. Cells that were capable of dividing would be a very strong indication.
As you say. The most likely would be single cell bacteria type. But anything else could be possible.
Doubt it will be in my lifetime though.
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Don't we just need the Webb telescope to identify molecules in the atmosphere of an exoplanet that could only have come from life? Job done. It could even happen before the Vogons arrive.
 
giggs-beckham said:
If mankind were to wipe itself out completely in just 1m years (entirely possible) would life evolve independently, again another intelligent life-form on earth
With art, science and industry etc?
Life would have a blank canvass with us gone and 5b* years time to work with.

*When the sun will render life impossible on earth by reaching the end of its life.
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That is an interesting thought.
I would expect that it would be a mammal that would rise up to become the dominant species.
Most likely one of the ape family. Especially one that had learnt certain things from humans. A replacement for homosapiens would take quite a long time to evolve.
 
Counterfactual said:
Don't we just need the Webb telescope to identify molecules in the atmosphere of an exoplanet that could only have come from life? Job done. It could even happen before the Vogons arrive.
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I guess so. Assuming it was carbon based life, the JWST would be able to detect organic gases.
 
Buster15 said:
Yes exactly. Cells that were capable of dividing would be a very strong indication.
As you say. The most likely would be single cell bacteria type. But anything else could be possible.
Doubt it will be in my lifetime though.
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I am actually confident of strong evidence of single cell extraterrestrial life, either now or in the past, being found within the next few decades. Complex life though, is a completely different question. It took life on earth billions of years and very specific circumstances to move from single cells to complex organisms (it basically happened just once in all of earth’s history, but it only had to happen once) , which suggests it’s an extremely unlikely event.
 
Eric_the_Red99 said:
I am actually confident of strong evidence of single cell extraterrestrial life, either now or in the past, being found within the next few decades. Complex life though, is a completely different question. It took life on earth billions of years and very specific circumstances to move from single cells to complex organisms (it basically happened just once in all of earth’s history, but it only had to happen once) , which suggests it’s an extremely unlikely event.
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Well not really. If complex life eats primitive life that forms in its vicinity then it would never get a chance to keep developing once complex life had formed once.
 
Buster15 said:
That is an interesting thought.
I would expect that it would be a mammal that would rise up to become the dominant species.
Most likely one of the ape family. Especially one that had learnt certain things from humans. A replacement for homosapiens would take quite a long time to evolve.
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Life evolves to fill niches so life could in time evolve to fill the void we leave. Might not have to be great ape in origin. It was more a case of imagining the difficulties in life like us evolving with all the serendipitous steps that happened to get where we are. That if we and the great apes weren't here and nature on earth started from scratch would it happen once again? The universe is big sure, but how rare is intelligent life is my point.
 
giggs-beckham said:
Life would have a blank canvass with us gone and 5b* years time to work with.

*When the sun will render life impossible on earth by reaching the end of its life.
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Unfortunately life would only have 500 million to a billion years before the Sun gets so hot that life becomes first problematic and then impossible to maintain. Still plenty of time, I guess.
 
giggs-beckham said:
Life evolves to fill niches so life could in time evolve to fill the void we leave. Might not have to be great ape in origin. It was more a case of imagining the difficulties in life like us evolving with all the serendipitous steps that happened to get where we are. That if we and the great apes weren't here and nature on earth started from scratch would it happen once again? The universe is big sure, but how rare is intelligent life is my point.
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Maybe I was taking your post too literally.
You mentioned art, science and industry.
One key attribute humans have in order to be able to do such things is the articulating fingers and thumb. This allows us to grip and be able to make highly accurate movements with tools that we are able to make.
Can you imagine how difficult it would be to carry out the things we can do without such features.

The ape family already have this meaning it would not need to be evolved.
 
nimic said:
I'm not quite following this. How does it relate to what he said about complex life taking billions of years to emerge?
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It doesn't. He said it only happened once which suggests it's very unlikely. Given what the guy above posted it seems a) it's not true and there's evidence of it happening more than once and b) what I was suggesting was that already-complex-life might destroy newly-complex life as it has had lots of time to specialise so would possibly be at an advantage, in which case you might never have any evidence of it's existence.
 
Buster15 said:
Maybe I was taking your post too literally.
You mentioned art, science and industry.
One key attribute humans have in order to be able to do such things is the articulating fingers and thumb. This allows us to grip and be able to make highly accurate movements with tools that we are able to make.
Can you imagine how difficult it would be to carry out the things we can do without such features.

The ape family already have this meaning it would not need to be evolved.
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Nature evolved the opposing digit and intelligence on earth once, would it happen again was my point. To make a wider assumption to the perhaps extreme rarity of intelligent life in the universe as that was the topic we were discussing
 
nimic said:
Unfortunately life would only have 500 million to a billion years before the Sun gets so hot that life becomes first problematic and then impossible to maintain. Still plenty of time, I guess.
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Yes more than enough time.
 
Buster15 said:
That is an interesting thought.
I would expect that it would be a mammal that would rise up to become the dominant species.
Most likely one of the ape family. Especially one that had learnt certain things from humans. A replacement for homosapiens would take quite a long time to evolve.
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I imagine if we managed to wipe ourselves out we'd probably take out a lot of species with us unfortunately. If we render the earth uninhabitle for humans then apes aren't likely to survive either.

Unless we create something that specifically targets humans like a rogue AI that hunts us down.
 
giggs-beckham said:
Nature evolved the opposing digit and intelligence on earth once, would it happen again was my point. To make a wider assumption to the perhaps extreme rarity of intelligent life in the universe as that was the topic we were discussing
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Yes. Understood thanks.
 
giggs-beckham said:
Nature evolved the opposing digit and intelligence on earth once, would it happen again was my point. To make a wider assumption to the perhaps extreme rarity of intelligent life in the universe as that was the topic we were discussing
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Intelligence is hard to define.

Opposable digits have evolved independently multiple times. Chameleons for example have them. Arguably, birds have them.

r823010_7478038.jpg

There's loads of examples of convergent evolution in nature.
 
Bert_ said:
Intelligence is hard to define.

Opposable digits have evolved independently multiple times. Chameleons for example have them. Arguably, birds have them.

r823010_7478038.jpg

There's loads of examples of convergent evolution in nature.
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It was more about the principle behind the hypothetical situation rather than the specific accuracy of the details within.
 
giggs-beckham said:
If mankind were to wipe itself out completely in just 1m years (entirely possible) would life evolve independently, again another intelligent life-form on earth
With art, science and industry etc?
Life would have a blank canvass with us gone and 5b* years time to work with.

*When the sun will render life impossible on earth by reaching the end of its life.
Click to expand...

I think it's possible but would take a lot more than 1m years

most likely scenario if it were to happen would be another type of primate evolving with larger intelligence, I guess. Assuming we haven't wiped out all primates by then.
 
giggs-beckham said:
It was more about the principle behind the hypothetical situation rather than the specific accuracy of the details within.
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I understand the philosophical thought process but science requires specific accuracy. If it didn't then science wouldn't exist.
 
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