How did elements and building blocks of life arrive on Earth?

In summary, according to current models, lighter elements were created by fusion in stars, but even so, how could these lighter elements reach us when the stars are so far away? I could see perhaps some of the elements reaching us as dust or something, but how did enough of it reach us to allow for start of life? Carbon for example is absolutely essential to life, so we would need extremely large amount of it for the first living cells to begin synthesizing themselves.
  • #1
Aziza
190
1
we are currently learning about radioactivity and i have become curious of how these heavier elements came to Earth in the first place? From what i understand, the lighter elements are formed by fusion in stars, but even so, how could these lighter elements reach us when the stars are so far away? I could see perhaps some of the elements reaching us as dust or something, but how did enough of it reach us to allow for start of life? I mean carbon for example is absolutely essential to life, so we would need extremely large amount of it for the first living cells to begin synthesizing themselves.

Also, according to current model, the early Earth was big glob of lava and whatnot, so all of the chemicals must have been mixing around all together, so then why today we have more or less even "deposits" of certain chemicals, like uranium? I mean if in liquid form the Earth was all mixed up, then how come when it cooled, it became more ordered in terms of chemical composition?
 
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  • #2
The nebula from which the Solar system was created was from a Supernova from a previous generation. All naturally occurring isotopes beyond [itex]^{56}\mathrm{Fe}[/itex] are created that way.
 
  • #3
Yup, while a nonzero potion of the Earth's minerals were deposited by meteors, comets and falling space dust, the vast bulk of the Earth coalesced at the same time as the the other planets and the sun from the original collapsing nebula. That original nebula of gas an dust is the remnants of earlier supernovae ejecta.

The reason it isn't all perfectly homogenous is because parts of the Earth cool at different rates, heavier parts sink, lighter parts float so you get sedimentation layers - and then - tectonic activity stirs it all up.

And that's an ubersimplification. The dynamics of a forming and cooling planet are very complex and result in a great degree of heterogeny in materials.
 
  • #4
Dickfore said:
The nebula from which the Solar system was created was from a Supernova from a previous generation.

Are sure that is was a single supernova and not a protostellar nebula enriched with metals by many supernovas?
 
  • #5
DrStupid said:
Are sure that is was a single supernova and not a protostellar nebula enriched with metals by many supernovas?

It is highly unlikely that ALL of the elements came from 1 supernova. The galaxy has been riddled with supernovae since it's initial formation 12+ billion years ago.
 
  • #7
Just heard on tv a few nights ago something even more astonishing: One of the four building blocks of RNA [AGTC] was found just a few years ago in an asteroid or meteor found here on earth...I think it was "G"...

So not only the elements above Fe are here from supernovas, which is correct, but the building blocks for life may have arrived here from elsewhere as well...
 

1. How did elements first form?

The elements were formed during the Big Bang, which occurred approximately 13.8 billion years ago. During this event, the universe rapidly expanded and cooled, allowing for the formation of subatomic particles such as protons and neutrons. These particles eventually combined to form the first elements, such as hydrogen and helium.

2. Where did the elements come from?

The elements found on Earth were formed in the cores of stars through the process of nuclear fusion. When a star runs out of hydrogen fuel, it begins to fuse heavier elements like helium and carbon. When the star dies, it releases these elements into space, where they can eventually form new stars and planets, including our own.

3. How did elements get on to Earth?

Elements were brought to Earth through various processes, such as meteorite impacts, volcanic activity, and chemical reactions. The early Earth was also bombarded by comets and asteroids, which contained a variety of elements that were incorporated into the planet's composition.

4. How did elements become essential for life on Earth?

Elements are essential for life on Earth because they make up the building blocks of all living organisms. For example, carbon is a key element in organic molecules, and oxygen is crucial for respiration. The diverse range of elements on Earth allows for the complex chemistry necessary for life to exist.

5. Are there any new elements still being formed on Earth?

There are no new elements being formed on Earth, as the processes that create elements, such as nuclear fusion, only occur in extreme environments like the cores of stars. However, scientists have been able to synthesize new elements in laboratories through nuclear reactions, but these elements are highly unstable and do not exist naturally on Earth.

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