<p>The Earth was friendly to abiogenesis a little over 4 billion years ago because a) it was chemically different and b) there were no predators to consume whatever virus-like life forms were spontaneously generated. The chemistry of the early atmosphere (methane, ammonia, CO2 etc) lent itself to Urey and Miller type experiments on a massive scale, forming various versions of what is known as 'primeval soup' like the residues in Urey and Miller's laboratory flasks.</p>

<p>These conditions soon vanished, and don't exist anywhere today so far as we know, but if  they did, the organic molecules generated would be consumed by micro-organisms. One of those first life forms managed to survive, and over the course of billions of years evolved into the countless life forms which we have today and the equally countless life forms which have become extinct along the way.</p>

CC BY-SA 4.0
2020-02-23T20:53:45.803Z
Citation needed, as always, Michael, and very out of date. The Urey - Miller experiment had lots of flaws. Very few scientists now think that that is how life formed.
David Hammen
CC BY-SA 4.0
2020-02-28T02:28:29.753Z
@DavidHammen, the key part of this answer isn't Urey-Miller, but that any new life forms that spontaneously generate, by whatever means, are likely to be eaten by the competition.
Mark
CC BY-SA 4.0
2020-02-23T20:12:50.717Z
2020-02-23T20:12:50.717Z
Michael Walsby
<p>It's thought that, shortly after Earth was done being <s>refurbished</s> resurfaced during the <a href="https://en.m.wikipedia.org/wiki/Late_Heavy_Bombardment" rel="nofollow noreferrer">Late Heavy Bombardment</a>, life abio-generated almost as soon as it was able to. The short delay led to speculation that: in the right conditions, life arises fairly easily; and, under that assumption, many "lifeforms" arose alongside one another, perhaps some <a href="https://en.m.wikipedia.org/wiki/Shadow_biosphere" rel="nofollow noreferrer">subsisting even today</a>.</p>

<p>Earth, to the standards of the lifeform(s) that won out, is pretty hospitable--perhaps because life made it that way, altering the chemical properties of the atmosphere and terrain. Life thrives in nearly every remote nook and cranny of the planet. </p>

<p>Is there any thinking out there into why abiogenesis may have stopped? Is the process expected/hypothesized to be ongoing concurrently, in the present day? If life came to be so rapidly, why isn't it still coming, especially given Earth's apparent suitability?</p>

<p><sup>(Perhaps our form of life, by its pervasion and alterations to Earth's condition, truly "won out," monopolizing on Earthly resources in such a way that bars newcomers from developing to compete and bars us from detecting their remnants, should they exist?)</sup></p>

CC BY-SA 4.0
2020-02-23T19:11:43.997Z
I couldn't find a nice tag. Does this question belong here?
BMF
CC BY-SA 4.0
2020-02-23T20:49:16.883Z
When it comes to the origins of life on Earth I don't think there is theory that has been fully accepted. As you ask, [abiogenesis](https://en.wikipedia.org/wiki/Abiogenesis) is one theory, [panspermia](https://en.wikipedia.org/wiki/Panspermia) - life seeded from the cosmos via meteor etc., is another.
Fred
CC BY-SA 4.0
2020-02-23T21:02:48.023Z
Please do not accept Michael's answer. He is a problematic member due to his propensity for writing incorrect answers without any support from the scientific media or even from websites. His answer to this question, which someone upvoted, is very outdated and most likely is wrong. You may not like the currently correct answer to your primary question, which  is "nobody knows." There are a number of strongly competing and quite different hypotheses regarding when / how life formed.
David Hammen
CC BY-SA 4.0
2020-02-23T21:04:50.343Z
Regarding the Late Heavy Bombardment, there are signs that that concept too is outdated.
David Hammen
CC BY-SA 4.0
2020-02-23T21:21:54.590Z
@DavidHammen I thanked and upvoted him for his answer--which seemed plausible and agreed with some preconceptions I had--and asked for further reading in part due to his lack of citations. Until his answer has been absolved with a citation or two, I suppose I won't accept the answer.
BMF
CC BY-SA 4.0
2020-02-23T21:22:31.443Z
@DavidHammen As for the part about the LHB being outdated, I'd love to read into that if you have any suggestions.
BMF
CC BY-SA 4.0
2020-02-23T21:29:44.243Z
@BMFForMonica - For example, see https://www.nature.com/articles/d41586-018-01074-6 . There are many, many others.
David Hammen
CC BY-SA 4.0
2020-02-23T21:29:49.930Z
@DavidHammen As for liking the answer, I seem to recall an angry mom once telling me "you don't have to like it, you just have to eat it!"
BMF
CC BY-SA 4.0
2020-02-24T01:54:52.117Z
@gansub I'll certainly keep it in mind moving forward, thank you.
BMF
<earth-history>
Is Earth inhospitable?
BMF
# Is Earth inhospitable?

(Asked by: username_0 on 2020-02-23)

It's thought that, shortly after Earth was done being ~~refurbished~~ resurfaced during the [Late Heavy Bombardment](https://en.m.wikipedia.org/wiki/Late_Heavy_Bombardment), life abio-generated almost as soon as it was able to. The short delay led to speculation that: in the right conditions, life arises fairly easily; and, under that assumption, many "lifeforms" arose alongside one another, perhaps some [subsisting even today](https://en.m.wikipedia.org/wiki/Shadow_biosphere).

Earth, to the standards of the lifeform(s) that won out, is pretty hospitable--perhaps because life made it that way, altering the chemical properties of the atmosphere and terrain. Life thrives in nearly every remote nook and cranny of the planet.

Is there any thinking out there into why abiogenesis may have stopped? Is the process expected/hypothesized to be ongoing concurrently, in the present day? If life came to be so rapidly, why isn't it still coming, especially given Earth's apparent suitability?

(Perhaps our form of life, by its pervasion and alterations to Earth's condition, truly "won out," monopolizing on Earthly resources in such a way that bars newcomers from developing to compete and bars us from detecting their remnants, should they exist?)

**Tags:** earth-history

> **Comments:**
> **username_0**: I couldn't find a nice tag. Does this question belong here?  
> **username_1**: When it comes to the origins of life on Earth I don't think there is theory that has been fully accepted. As you ask, [abiogenesis](https://en.wikipedia.org/wiki/Abiogenesis) is one theory, [panspermia](https://en.wikipedia.org/wiki/Panspermia) - life seeded from the cosmos via meteor etc., is another.  
> **username_2**: Please do not accept username_3's answer. He is a problematic member due to his propensity for writing incorrect answers without any support from the scientific media or even from websites. His answer to this question, which someone upvoted, is very outdated and most likely is wrong. You may not like the currently correct answer to your primary question, which  is "nobody knows." There are a number of strongly competing and quite different hypotheses regarding when / how life formed.  
> **username_2**: Regarding the Late Heavy Bombardment, there are signs that that concept too is outdated.  
> **username_0**: @username_2 I thanked and upvoted him for his answer--which seemed plausible and agreed with some preconceptions I had--and asked for further reading in part due to his lack of citations. Until his answer has been absolved with a citation or two, I suppose I won't accept the answer.  
> **username_0**: @username_2 As for the part about the LHB being outdated, I'd love to read into that if you have any suggestions.  
> **username_2**: @BMFForMonica - For example, see https://www.nature.com/articles/d41586-018-01074-6 . There are many, many others.  
> **username_0**: @username_2 As for liking the answer, I seem to recall an angry mom once telling me "you don't have to like it, you just have to eat it!"  
> **username_0**: @gansub I'll certainly keep it in mind moving forward, thank you.  

---

## 1 answers

### Answer by username_3 on 2020-02-23. Score: 0

The Earth was friendly to abiogenesis a little over 4 billion years ago because a) it was chemically different and b) there were no predators to consume whatever virus-like life forms were spontaneously generated. The chemistry of the early atmosphere (methane, ammonia, CO2 etc) lent itself to Urey and Miller type experiments on a massive scale, forming various versions of what is known as 'primeval soup' like the residues in Urey and Miller's laboratory flasks.

These conditions soon vanished, and don't exist anywhere today so far as we know, but if they did, the organic molecules generated would be consumed by micro-organisms. One of those first life forms managed to survive, and over the course of billions of years evolved into the countless life forms which we have today and the equally countless life forms which have become extinct along the way.

> **Comments:**
> **username_2**: Citation needed, as always, username_3, and very out of date. The Urey - Miller experiment had lots of flaws. Very few scientists now think that that is how life formed.  
> **username_4**: @username_2, the key part of this answer isn't Urey-Miller, but that any new life forms that spontaneously generate, by whatever means, are likely to be eaten by the competition.  

---

