Zooming out - will humans go extinct or what?

[UndercoverElephant]

11:23 emphasis on "alone". He thinks we're alone. I agree with him.

First class. Thanks for posting.

This is Dave's reasoning for leaning to the 'we are alone' view.

https://www.youtube.com/watch?v=PqEmYU8 ... CoolWorlds

Yep. Agreed with all of that. So many smart people have been completely fooled by this one.

[Catweazle]

Most of the video makes sense, but I thought he tripped up towards the end when assuming galaxies were more likely to contain either many or no lifeforms.

[UndercoverElephant]

Most of the video makes sense, but I thought he tripped up towards the end when assuming galaxies were more likely to contain either many or no lifeforms.

I don't think he explained that bit very well. I had the same initial reaction. But what he's actually saying is that the chance of any particular galaxy containing only one habitable planet is much less than it being either more than one or none at all. At the scale of the whole universe this argument doesn't work, for reasons already explained (maybe the presence of the first conscious beings changed the physics of the evolutionary process, such that it was highly improbable that it would happen again anywhere else in the cosmos -- like a lottery where only one ticket can win). But that reasoning cannot apply to individual galaxies. He's saying that if the number of galaxies in the universe is 205 billion and the number of planets where life evolved is also 205 billion and it just turns out that they are distributed so each galaxy has exactly one life-supporting planet (even though they are all different sizes)...then that would be extremely strange and very difficult to explain. I think this reasoning is sound. It's like 650 tickets winning the national lottery one week, and there just happening to be exactly one lottery winner in each parliamentary constituency in the UK. For each individual constituency, it is more likely that the number of winners is either zero or more than one (and that is true even if there are exactly 650 winners, which is itself highly improbable).

[johnny]

The certainty of occurrence of life is absolute, as we exist. The only question is what are the odds of it happening within the scheme of the universe. Again. The probability of occurrence greater than zero is given.

Therefore, the liklohood of life Monte Carloed out across a near infinite set of trials is also non-zero. Everything else strikes me as complex justifications for an answer that one individual or another prefers. Our existence, and the most basic statistical calculation in a near infinite system doesn't leave room for any other answer. Long videos trying to talk their way around immutable and obvious statistics are entertainment, as they don't change any of the math involved.

[BritDownUnder]

I read somewhere that if gravity was about 1.15x as much as the Earths gravity it would be virtually impossible to get into space and visit all these other life forms.

[dustiswhatweare]

I read somewhere that if gravity was about 1.15x as much as the Earths gravity it would be virtually impossible to get into space and visit all these other life forms.

Which is why there is currently so much interest in moon bases as a platform for 'exploration' which really translates to mining wherever we happen to be able to reach (and get back from). Conveniently enough the moon itself contains quite a lot of the raw materials that would be needed to construct and power the craft required to do so. There is both state and private interest involved.

Interestingly there is an extremely scientifically accurate tv series which is set in a future where it's happened. The technology in use in this future will be recognised by the viewer immediately, it's all extrapolation. There are no Star Trek/Star Wars magic things. It's quite riveting viewing once you get through the first 3 episodes (multiple plot lines are set up, and it's necessary for later, very few wasted words throughout) then episode 4 sends it ballistic - literally. Or read the first book in the series, Leviathan Wakes. Do so and subsequent viewing becomes far easier and enjoyable from the off.

It's called The Expanse. It's quite extraordinary in all it's aspects. Unless you read the Sun and you'll be unlikely to get past the first 5 minutes

My favourite uncouth Scottish person reviewed it if you are curious:

https://www.youtube.com/watch?v=RWtbI4t ... calDrinker

[clv101]

I've read Leviathan Wakes, excellent Sci-Fi! Read Delta-V last week, closer to present day, but again nice hard Sci-Fi.

[BritDownUnder]

I read somewhere that if gravity was about 1.15x as much as the Earths gravity it would be virtually impossible to get into space and visit all these other life forms.

Which is why there is currently so much interest in moon bases as a platform for 'exploration' which really translates to mining wherever we happen to be able to reach (and get back from). Conveniently enough the moon itself contains quite a lot of the raw materials that would be needed to construct and power the craft required to do so. There is both state and private interest involved.

I liked those mentions of science fiction and the Scotsman reviewing it but my point was more related to the fact that as things are now with current rocket technology you can get about 1 tonne to low Earth orbit per 100 tonnes of rocket weight. With things like rocket engine specific impulse and rocket technology being constants if the gravity was a little bit stronger (and maybe other things like the atmosphere being more dense and reaching a higher distance from the planetary surface) that ratio might be 1 tonne into orbit for a 1000 tonne rocket or even worse - you simply could not get to orbit with any form of known technology. You could think of it as an inverse EROEI.
Perhaps there are aliens stuck on their home planet getting very frustrated.

So we would not even get to the Moon as there would have been no Sputnik and no Apollo. All the rockets and their payloads would have fallen back to Earth as they could not get fast enough. I think there are ways around this like multi staged rockets but a six stage rocket may be a bit too complex and heavy to build.

[dustiswhatweare]

I read somewhere that if gravity was about 1.15x as much as the Earths gravity it would be virtually impossible to get into space and visit all these other life forms.

Which is why there is currently so much interest in moon bases as a platform for 'exploration' which really translates to mining wherever we happen to be able to reach (and get back from). Conveniently enough the moon itself contains quite a lot of the raw materials that would be needed to construct and power the craft required to do so. There is both state and private interest involved.

I liked those mentions of science fiction and the Scotsman reviewing it but my point was more related to the fact that as things are now with current rocket technology you can get about 1 tonne to low Earth orbit per 100 tonnes of rocket weight. With things like rocket engine specific impulse and rocket technology being constants if the gravity was a little bit stronger (and maybe other things like the atmosphere being more dense and reaching a higher distance from the planetary surface) that ratio might be 1 tonne into orbit for a 1000 tonne rocket or even worse - you simply could not get to orbit with any form of known technology. You could think of it as an inverse EROEI.
Perhaps there are aliens stuck on their home planet getting very frustrated.

So we would not even get to the Moon as there would have been no Sputnik and no Apollo. All the rockets and their payloads would have fallen back to Earth as they could not get fast enough. I think there are ways around this like multi staged rockets but a six stage rocket may be a bit too complex and heavy to build.

If gravity were even a tiny bit stronger, or weaker, we wouldn't be here at all. The Universe would be a completely different thing. One tiny change would impact every other 'constant'. Personally I'm grateful for gravity being as it is unless I'm cycling up hill

In the UK gravity is at it's weakest on Dartmoor (all that granite) but even then the difference is barely measurable.

[clv101]

The gravity we experience also changes depending on whether you are travelling east or west.

[BritDownUnder]

Which is why there is currently so much interest in moon bases as a platform for 'exploration' which really translates to mining wherever we happen to be able to reach (and get back from). Conveniently enough the moon itself contains quite a lot of the raw materials that would be needed to construct and power the craft required to do so. There is both state and private interest involved.

I liked those mentions of science fiction and the Scotsman reviewing it but my point was more related to the fact that as things are now with current rocket technology you can get about 1 tonne to low Earth orbit per 100 tonnes of rocket weight. With things like rocket engine specific impulse and rocket technology being constants if the gravity was a little bit stronger (and maybe other things like the atmosphere being more dense and reaching a higher distance from the planetary surface) that ratio might be 1 tonne into orbit for a 1000 tonne rocket or even worse - you simply could not get to orbit with any form of known technology. You could think of it as an inverse EROEI.
Perhaps there are aliens stuck on their home planet getting very frustrated.

So we would not even get to the Moon as there would have been no Sputnik and no Apollo. All the rockets and their payloads would have fallen back to Earth as they could not get fast enough. I think there are ways around this like multi staged rockets but a six stage rocket may be a bit too complex and heavy to build.

If gravity were even a tiny bit stronger, or weaker, we wouldn't be here at all. The Universe would be a completely different thing. One tiny change would impact every other 'constant'. Personally I'm grateful for gravity being as it is unless I'm cycling up hill

In the UK gravity is at it's weakest on Dartmoor (all that granite) but even then the difference is barely measurable.

That would be G the universal gravitational constant but I was thinking of little g (force of gravity) which on Earth is 9.81m/s/s and dependent on the size and density of the planet you happen to sitting on. The Moon and Mars being smaller radius and less dense too have a smaller g but same G. If the Earths radius was about 1.1 x what it is we would probably be all stuck on here forever as the greater g would render the escape velocity impossibly high.

I agree that if G was different/higher then the universe would have probably collapsed by now and we would be a singularity.

[johnny]

The gravity we experience also changes depending on whether you are travelling east or west.

And elevation.

[Vortex2]

The gravity we experience also changes depending on whether you are travelling east or west.

And elevation.

And 'masscons'

ChatGPT:
A mass concentration below the surface refers to an area or region within a planet or other astronomical body where the mass is more concentrated than in surrounding areas. These concentrations can be caused by variations in the distribution of materials within the body, such as denser regions of rock or metal, and can have significant effects on the body's gravitational field and other physical properties. Mass concentrations are often studied through techniques such as gravitational mapping or by analyzing the behavior of orbiting spacecraft.

[mr brightside]

I've been away for a few days and there were four pages to catch up on!! Where do i start?

I often find it difficult to locate the point at which the debate erupted into disorder, ideally, this is where you need to start reading. I've recently been using the tactic of reading volatile threads in reverse to save time.

[northernmonkey]

Evolution does not go backwards.

As a matter of fact it can and has done (see marine tetrapods for an example) if by "backwards" you mean a species has returned to a form that is similar or the same as its evolutionary predecessors. The fact you refer to this as "backwards" evolution is, perhaps, an indication of a relatively recent Western European civilizational view in seeing all historical change as "progressive" (Post reformation/renaissance type of thing). I note you have this view with regards to both cultural and biological evolution. Are you certain it is not a bias?