105
If a planet was completely covered in water, wouldn't it all be freshwater?
(self.nostupidquestions)
this post was submitted on 20 Oct 2024
105 points (98.2% liked)
No Stupid Questions
35660 readers
2309 users here now
No such thing. Ask away!
!nostupidquestions is a community dedicated to being helpful and answering each others' questions on various topics.
The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:
Rules (interactive)
Rule 1- All posts must be legitimate questions. All post titles must include a question.
All posts must be legitimate questions, and all post titles must include a question. Questions that are joke or trolling questions, memes, song lyrics as title, etc. are not allowed here. See Rule 6 for all exceptions.
Rule 2- Your question subject cannot be illegal or NSFW material.
Your question subject cannot be illegal or NSFW material. You will be warned first, banned second.
Rule 3- Do not seek mental, medical and professional help here.
Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.
Rule 4- No self promotion or upvote-farming of any kind.
That's it.
Rule 5- No baiting or sealioning or promoting an agenda.
Questions which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.
Rule 6- Regarding META posts and joke questions.
Provided it is about the community itself, you may post non-question posts using the [META] tag on your post title.
On fridays, you are allowed to post meme and troll questions, on the condition that it's in text format only, and conforms with our other rules. These posts MUST include the [NSQ Friday] tag in their title.
If you post a serious question on friday and are looking only for legitimate answers, then please include the [Serious] tag on your post. Irrelevant replies will then be removed by moderators.
Rule 7- You can't intentionally annoy, mock, or harass other members.
If you intentionally annoy, mock, harass, or discriminate against any individual member, you will be removed.
Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.
Rule 8- All comments should try to stay relevant to their parent content.
Rule 9- Reposts from other platforms are not allowed.
Let everyone have their own content.
Rule 10- Majority of bots aren't allowed to participate here.
Credits
Our breathtaking icon was bestowed upon us by @Cevilia!
The greatest banner of all time: by @TheOneWithTheHair!
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Water and salts are a package deal. If you have a planet with one, you’re going to have all the others as well, because they all come from an exploding star.
When a star goes supernova, it creates oxygen, which can later combine with hydrogen to make water. That very same supernova also makes sodium, potassium, magnesium, chlorine, sulfur etc. so you end up with all the elements for making a bunch of different salts. Ask physicists why supernova does this sort of packaging.
The presence of sodium and chlorine on the planet makes sense to me, but that doesn't necessarily mean it's dissolved in the water. I think the key understanding is if the water cycle is the key component of dissolving salt in water, or if the much less dramatic erosion on the bottom of the ocean is sufficient to make the water notably salty.
So far the best answer I've got is that water in comets and otherwise outside the planet might actually be something like salty, so maybe freshwater is just a temporary aberration of the water cycle.
At the same time, we know there are some processes that remove salt from oceans (e.g. the salt formations at the bottom of the Dead Sea), so in the end I think it would come down to where that balance of salt in vs salt out. It's not totally clear to me that without the continental influx of salt from rivers, that that balance would result in something like freshwater or saltwater. This thread has highlighted several factors that come in on both sides, so it may be something we won't know until we've explored more planets.
According to NOAA, the ocean was originally not very salty but became saltier over time as rivers eroded the land and delivered the dissolved minerals to the ocean. At the same time, salts crystallize out of the water and are deposited on the ocean floor. This input and output are now more or less balanced so the ocean is not getting saltier. Apparently, this salt cycle involves about 4 billion tons of new dissolved salts being added to the ocean each year and about the same amount being deposited from the water to the ocean bottom.
So, why aren't rivers salty? Apparently, it is because rivers carry only a small amount of salt and are kept fresh by constant rainfall, whereas the ocean has been accumulating salt for the last 4 billion years.
Lakes that don't drain to the ocean, like the Dead Sea, can get salty over time, just like the ocean.
Oh man! The fact that our current ocean isn't getting more salty implies that the addition by rivers is very significant to the total saltiness of the ocean! Over billions of years with no rivers, the ocean must get significantly fresher! Wow! That is strong confirmation that an entirely ocean world would at least be significantly less salty!