Water in the solar system predates the Sun

Earth's water is older than the sun
An illustration of water in our Solar System through time from before the Sun's birth through the creation of the planets. Credit: Bill Saxton, NSF/AUI/NRAO

Water was crucial to the rise of life on Earth and is also important to evaluating the possibility of life on other planets. Identifying the original source of Earth's water is key to understanding how life-fostering environments come into being and how likely they are to be found elsewhere. New work from a team including Carnegie's Conel Alexander found that much of our Solar System's water likely originated as ices that formed in interstellar space. Their work is published in Science.

Water is found throughout our Solar System. Not just on Earth, but on icy comets and moons, and in the shadowed basins of Mercury. Water has been found included in mineral samples from meteorites, the Moon, and Mars.

Comets and asteroids in particular, being primitive objects, provide a natural "time capsule" of the conditions during the early days of our Solar System. Their ices can tell scientists about the ice that encircled the Sun after its birth, the origin of which was an unanswered question until now.

In its youth, the Sun was surrounded by a , the so-called solar nebula, from which the planets were born. But it was unclear to researchers whether the ice in this disk originated from the Sun's own parental interstellar molecular cloud, from which it was created, or whether this interstellar water had been destroyed and was re-formed by the chemical reactions taking place in the solar nebula.

"Why this is important? If water in the early Solar System was primarily inherited as ice from interstellar space, then it is likely that similar ices, along with the prebiotic organic matter that they contain, are abundant in most or all protoplanetary disks around forming stars," Alexander explained. "But if the early Solar System's water was largely the result of local during the Sun's birth, then it is possible that the abundance of water varies considerably in forming planetary systems, which would obviously have implications for the potential for the emergence of life elsewhere."

Earth's water is older than the sun
Looking at the ratio of hydrogen to its heavy isotope deuterium can help scientists learn about the water on our planet's origin. In this study, comparing the deuterium to hydrogen ratio reached in a model simulation to the ratio found in meteorites, Earth's ocean water, and comets told scientists that some of the water in our Solar System has an origin in interstellar space and pre-dates the birth of the Sun. Photo of the California coast by Carnegie President Matthew Scott. Credit: Carnegie Institution for Science President Matthew Scott

In studying the history of our Solar System's ices, the team—led by L. Ilsedore Cleeves from the University of Michigan—focused on hydrogen and its heavier isotope deuterium. Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons. The difference in masses between isotopes results in subtle differences in their behavior during . As a result, the ratio of hydrogen to deuterium in water molecules can tell scientists about the conditions under which the molecules formed.

For example, interstellar water-ice has a high ratio of deuterium to hydrogen because of the very low temperatures at which it forms. Until now, it was unknown how much of this deuterium enrichment was removed by chemical processing during the Sun's birth, or how much deuterium-rich water-ice the newborn Solar System was capable of producing on its own.

So the team created models that simulated a protoplanetary disk in which all the deuterium from space ice has already been eliminated by chemical processing, and the system has to start over "from scratch" at producing ice with deuterium in it during a million-year period. They did this in order to see if the system can reach the ratios of deuterium to hydrogen that are found in meteorite samples, Earth's ocean water, and "" comets. They found that it could not do so, which told them that at least some of the water in our own Solar System has an origin in and pre-dates the birth of the Sun.

"Our findings show that a significant fraction of our Solar System's , the most-fundamental ingredient to fostering life, is older than the Sun, which indicates that abundant, organic-rich interstellar ices should probably be found in all young ," Alexander said.

Explore further

Solar system ice: Source of Earth's water

More information: "The ancient heritage of water ice in the solar system," by L.I. Cleeves et al. Science, www.sciencemag.org/lookup/doi/ … 1126/science.1258055
Journal information: Science

Citation: Water in the solar system predates the Sun (2014, September 25) retrieved 25 August 2019 from https://phys.org/news/2014-09-solar-predates-sun.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Feedback to editors

User comments

Sep 25, 2014
I realize this is a side issue, but you guys really should refrain from using the word 'creation' in your captions. It just gives the crackpots the wrong impression.

Sep 25, 2014
It's crank bait. It's what physorg does nowdays. Theyseem to want to be known as a pseudoscience site.

Sep 26, 2014
"And the Spirit of God moved upon the face of the waters." Ha! Apparently Genesis wasn't off that much according to Mr. Computer Model.

Sep 26, 2014
"And the Spirit of God moved upon the face of the waters." Ha! Apparently Genesis wasn't off that much according to Mr. Computer Model.

I was going to say something like that, "Hey, the Bible says water was the first thing God created in the universe, and the Sun was made 4 'days' later."


Then it says he divided the "waters" from the "waters", making a "firmament" (a space) between the "waters", and called it "heaven".


If the computer model is right, it would mean the first ~8 verses of Genesis are conceptually very accurate indeed.

Sep 26, 2014
Note that Scientists base knowledge of the Sun on it's photspheric composition, since there's no absolute way to know it's inner composition.

Suppose the Sun is actually made of vast amounts of "Water", which has been ionized and broken into hydrogen and oxygen?

That would throw a real monkey wrench in cosmology, because it would mean much of the Sun's core is burning Oxygen, at the end of the C-N-O cycle, perhaps, and not primarily Hydrogen and Helium.

It makes sense to me, if that much water ended up in comets, moons, and the ice giants, that the Sun must have enormouse amounts of water in it upon it's initial formation.

Assuming it was formed by the same basic processes (nebular compression/collapse and acretion) as any major scientific theory implies.

Photospheric composition ratios are not neccessarily representative of core composition, since Oxygen is 16 times heavier than Protium and 8 times heavier than deuterium. Therefore it should not surface as often....

Sep 26, 2014
Therefore, the inside of the Sun must have a much higher Oxygen to Hydrogen ratio than the Photosphere.

The Sun potentially being made of vast amounts of water, far above the photosphere composition, is a very interesting implication of these findings: one they failed to mention.

This implies the internal dynamics of Sun-like stars may be significantly different than prevailing theory, even without resorting to any freaky physics...

Sep 26, 2014
Well, it implies the Sun's internal composition is at least several percent Oxygen, Nitrogen, and Carbon, instead of the ~1.34% seen in the Photosphere.

A random Oxygen atom should be less likely to surface compared to protium or deuterium or helium, according to it's mass.

15O vs P = 1:15
15O vs D = 2:15
15O vs 3He = 1:5
15O vs 4He = 1:3.75
16O vs P = 1:16
16O vs D = 1:8
16O vs 3He = 1:5.33r
16O vs 4He = 1:4

Now that's considering only mass vs gravity.

But oxygen has much more mass vs charge than Protium (2:1 ratio) and same mass vs charge ratio as Deuterium (but 8 times heavier in gravity) Therefore when considering both charge and gravity, any random Oxygen atom should be much less likely to surface than any random Protium, Deuterium, 3He or 4He atom.

Same logic applies to Oxygen, Carbon, and Nitrogen.

Therefore the Photosphere isn't representative of the core at all, and you'd need to approximate the core composition based on these ratios compared to the photosphere.

Sep 26, 2014
This means, for example, the ratio of Oxygen to Protium (by atom count) in the core should be at least 15-17 times higher in the Core of the Sun than it is in the Photosphere, since it is at least 15-17 times less likely to surface, and similar logic would apply to each other isotopic ratio seen in the photosphere, assuming the Sun is approximately in equilibrium. However, you have to account for the (believed to be) theoretical process of CNO resulting in higher Nitrogen content when it stabilizes.

Nevertheless, it still implies the elemental composition of the Sun may be near 15% CNO, by mole count, compared to the 1.3% seen on the photosphere.

Having the Sun form out of an ice-dust core makes sense, because the partial charges of water molecules can clump together electromagnetically, then form a gravitationally bound proto-core/object much easier than Hydrogen and Helium atoms would do.

If it started with ice-dust core, then it has a lot more oxygen than prevailing theory.

Sep 28, 2014

We can be relatively certain of the composition of stars at this point, to within a few percent. We can see plenty of other stars and they all support our present understanding. We can see very old stars, remains of exploded stars, newborn stars still in the process of forming, etc. There's no reason to call our basic theory of star composition and 'combustion' into question.

on another note:

which indicates that abundant, organic-rich interstellar ices should probably be found in all young planetary systems
From the article

That's a bit of a leap based on only the evidence presented in the story above, but this isn't the only evidence that points in this direction. It's becoming more and more apparent that our solar system is fairly common in a lot of ways. We don't have the ability to identify a true Earth analog yet (not with much certainty anyway), but I don't think it will be long before we confirm that earthlike planets aren't rare.

So, where is everyone?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more