Last Universal Common Ancestor

Cypress said:
I'm not a biologist either, but it seems life can exist in a wide range of temperatures (as shown by extremophiles).

I think the key thing about tidal force heating on the Jovian moons keep their interior subsurface oceans from freezing solid, and life obviously depends on a liquid medium.
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I just want to make a comment about the word-form being used by several people in this discussion, and I am using a reply to you to do so.

In discussions of this type, people tend to use the word "life" in comments such as "life obviously depends on a liquid medium"...when logic dictates that they should be using "life as we humans understand it."

Same thing goes with the word "universe"...when "what we humans suppose to be the universe" would be much more appropriate.

We humans are the currently dominant lifeform on a nondescript speck of dust circling a nondescript star in a nondescript galaxy...in what might well be a nondescript blob in what might actually exist.

Using the more accurate descriptor more frequently (and at least once in each exchange) would go a long way toward making the conversations more logical.

Or so it seems to me.
 
Frank Apisa said:
I just want to make a comment about the word-form being used by several people in this discussion, and I am using a reply to you to do so.

In discussions of this type, people tend to use the word "life" in comments such as "life obviously depends on a liquid medium"...when logic dictates that they should be using "life as we humans understand it."

Same thing goes with the word "universe"...when "what we humans suppose to be the universe" would be much more appropriate.

We humans are the currently dominant lifeform on a nondescript speck of dust circling a nondescript star in a nondescript galaxy...in what might well be a nondescript blob in what might actually exist.

Using the more accurate descriptor more frequently (and at least once in each exchange) would go a long way toward making the conversations more logical.

Or so it seems to me.
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You seem to be overthinking it. Life on Earth is the only life known to humans to exist in the Universe. Saying "life as we humans understand it” is a given since there are ZERO other examples to use.

If you want to postulate that planets or stars themselves can be alive, thinking entities but operating on a level we could never understand, then I agree your phrase would help clarify the conversation.
 
Frank Apisa said:
I just want to make a comment about the word-form being used by several people in this discussion, and I am using a reply to you to do so.

In discussions of this type, people tend to use the word "life" in comments such as "life obviously depends on a liquid medium"...when logic dictates that they should be using "life as we humans understand it."

Same thing goes with the word "universe"...when "what we humans suppose to be the universe" would be much more appropriate.

We humans are the currently dominant lifeform on a nondescript speck of dust circling a nondescript star in a nondescript galaxy...in what might well be a nondescript blob in what might actually exist.

Using the more accurate descriptor more frequently (and at least once in each exchange) would go a long way toward making the conversations more logical.

Or so it seems to me.
Click to expand...
Yes, there might be some exotic forms of life, and there is more to the cosmos than the part we can see. I'm just too lazy to write 'life as we know it ' or 'the observable universe' each time.

I am using life as a stand in for carbon based life. The chemical properties of carbon are so unique, I don't even know if we would recognize non-carbon life even if we saw it.

Some kind of liquid medium has to be available for transport of nutrients, metabolism, exchange of ions.


We were taught in junior high that our planet, our sun, are galaxy are just very average and normal. But that's not really the modern view. Obviously our planet is fairly unique if one just looks at the solar system. Hopefully the search for exoplanets will turn up Earth analogs. Our sun is actually not average at all in a variety of ways, and our galaxy is actually quite massive compared to most galaxies
 
Cypress said:
Yes, there might be some exotic forms of life, and there is more to the cosmos than the part we can see. I'm just too lazy to write 'life as we know it ' or 'the observable universe' each time.

I am using life as a stand in for carbon based life. The chemical properties of carbon are so unique, I don't even know if we would recognize non-carbon life even if we saw it.

Some kind of liquid medium has to be available for transport of nutrients, metabolism, exchange of ions.


We were taught in junior high that our planet, our sun, are galaxy are just very average and normal. But that's not really the modern view. Obviously our planet is fairly unique if one just looks at the solar system. Hopefully the search for exoplanets will turn up Earth analogs. Our sun is actually not average at all in a variety of ways, and our galaxy is actually quite massive compared to most galaxies
Click to expand...

Hmm, interesting. As Carl Sagan said, we are made of star stuff. Could it be possible that in order for a planet to be seeded with the elements that life (as we know it lol) is composed of, it would take a fairly massive galaxy to provide those materials as its stars go nova?
 
ThatOwlWoman said:
Hmm, interesting. As Carl Sagan said, we are made of star stuff. Could it be possible that in order for a planet to be seeded with the elements that life (as we know it lol) is composed of, it would take a fairly massive galaxy to provide those materials as its stars go nova?
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Good point, life definitely requires heavy elements like carbon, nitrogen, iron, etc, and our star and the nebula it formed from were enriched in heavy elements compared to the average star in the cosmos.

That is obviously the result of a supernova. I've never heard that supernovae cannot occur in dwarf galaxies or globular clusters, I always assumed they could but have not double checked that assumption
 
ThatOwlWoman said:
Hmm, interesting. As Carl Sagan said, we are made of star stuff. Could it be possible that in order for a planet to be seeded with the elements that life (as we know it lol) is composed of, it would take a fairly massive galaxy to provide those materials as its stars go nova?
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I think galaxy mass would be relative to the rate of life.

Example; if life formed on 1 of every 10,000 planets, on average, then a galaxy with 1 million stars would have twice as many planets with life than a galaxy with 500,000 stars.

Not all stars go nova due to a lack of mass. The Sun will become a Red Giant one day but lacks the mass to go nova. The above scenario about galaxies would presume that the ratio of stars with enough mass to nova was equal.
 
Cypress said:
Good point, life definitely requires heavy elements like carbon, nitrogen, iron, etc, and our star and the nebula it formed from were enriched in heavy elements compared to the average star in the cosmos.

That is obviously the result of a supernova. I've never heard that supernovae cannot occur in dwarf galaxies or globular clusters, I always assumed they could but have not double checked that assumption
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No doubt they can and do occur there, but the odds are higher with a larger galaxy, right?
 
ThatOwlWoman said:
No doubt they can and do occur there, but the odds are higher with a larger galaxy, right?
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I think you're right that the number and quantity of supernovae in a large galaxy exceeds that of small galaxy,

I suppose it really comes down to how many massive stars on the main sequence a galaxy has. I seem to recall that the really old galaxies have mostly red dwarf stars, and those things live forever and never blow up!
 
Doc Dutch said:
You seem to be overthinking it. Life on Earth is the only life known to humans to exist in the Universe. Saying "life as we humans understand it” is a given since there are ZERO other examples to use.

If you want to postulate that planets or stars themselves can be alive, thinking entities but operating on a level we could never understand, then I agree your phrase would help clarify the conversation.
Click to expand...

Since I am saying that IT IS POSSIBLE that "life" may be something other than what humans suppose it to be...we ARE in agreement, Dutch.
 
Cypress said:
Good point, life definitely requires heavy elements like carbon, nitrogen, iron, etc, and our star and the nebula it formed from were enriched in heavy elements compared to the average star in the cosmos.

That is obviously the result of a supernova. I've never heard that supernovae cannot occur in dwarf galaxies or globular clusters, I always assumed they could but have not double checked that assumption
Click to expand...
According to the link below, the Sun is of average star mass which leads me to believe that the distribution of star with greater and lesser mass is distributed equally within galaxies regardless of size. What I don’t know is if the distribution of star masses is distributed evenly within a galaxy such as more massive stars toward the center and less mass stars in the arms.

astronomy.nmsu.edu/holtz/a110/a110notes/node4.html
We find that not all stars have the same mass. The most massive stars are about 100 times as massive as the Sun, while the least massive stars are about 1/10 the mass of the Sun. So in this respect, the Sun is roughly average. However, there are many more low mass stars than there are high mass stars
 
Frank Apisa said:
Since I am saying that IT IS POSSIBLE that "life" may be something other than what humans suppose it to be...we ARE in agreement, Dutch.
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Agreed on the possibility.

However, given that a planet is “alive” but existing on a time scale measured in millions of years instead of years, there’d be no way we could communicate with them. If they communicated with each other, we might be able to read those messages from the past, but not send any of our own.
 
Cypress said:
Yes, there might be some exotic forms of life, and there is more to the cosmos than the part we can see. I'm just too lazy to write 'life as we know it ' or 'the observable universe' each time.
Click to expand...

Using the full term once in a while to impress that that is what you mean, is worthwhile.

I am using life as a stand in for carbon based life. The chemical properties of carbon are so unique, I don't even know if we would recognize non-carbon life even if we saw it.
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Okay...so I am recommending that anyone doing what you are doing should use "carbon based life" once in a while, is worthwhile.

Some kind of liquid medium has to be available for transport of nutrients, metabolism, exchange of ions.
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Or at least that is what humans suppose. That may not be the case...since the physics of other places may not be the physics of here.

And...the transport of nutrients, metabolism, exchange of ions...may not be an essential to all life...just to life as we humans know it.


We were taught in junior high that our planet, our sun, are galaxy are just very average and normal. But that's not really the modern view. Obviously our planet is fairly unique if one just looks at the solar system. Hopefully the search for exoplanets will turn up Earth analogs. Our sun is actually not average at all in a variety of ways, and our galaxy is actually quite massive compared to most galaxies
Click to expand...

Everything we humans suppose exists...MAY BE non-descript in the grand scheme of things. Considering the enormity of just what we humans KNOW exists, it is not unreasonable to describe what we have here using that descriptor.
 
NovoJank said:
Ah, I see. So the 2 versions most people are familiar with with the first verse pulled out for emphasis and Job added in.
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the first verse is not "pulled out"......it is a different genre than the other two found in Genesis........as can be seen, the versions overlap chapter and verse designations which do not exist in the original texts......
the first verse is written in the imperative......the second verse and following are not......the word "now" which identifies Hebrew poetry appears in the second verse, not the first......
 
Doc Dutch said:
According to the link below, the Sun is of average star mass which leads me to believe that the distribution of star with greater and lesser mass is distributed equally within galaxies regardless of size. What I don’t know is if the distribution of star masses is distributed evenly within a galaxy such as more massive stars toward the center and less mass stars in the arms.

astronomy.nmsu.edu/holtz/a110/a110notes/node4.html
We find that not all stars have the same mass. The most massive stars are about 100 times as massive as the Sun, while the least massive stars are about 1/10 the mass of the Sun. So in this respect, the Sun is roughly average. However, there are many more low mass stars than there are high mass stars
Click to expand...

Average is a misleading statistical concept.

The average salary between me, you, and bill Gates is twenty billion dollars. It's my fault for even bringing up the word average.

The key comment in that article is that 'however, there are many more low mass stars' in the observable universe.

Most stars are red dwarfs. Our sun falls on the main sequence at G2. That makes our G2 sun a quite large and massive star compared to most.

Our star is also a solo star. Most stars occur in binary systems, and it seems to me that planetary orbital mechanics might be more unstable in binary systems
 
Doc Dutch said:
Agreed on the possibility.

However, given that a planet is “alive” but existing on a time scale measured in millions of years instead of years, there’d be no way we could communicate with them. If they communicated with each other, we might be able to read those messages from the past, but not send any of our own.
Click to expand...

Agreed.

But...we may not be able to communicate with life forms almost exactly like our own.
 
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