Why are scientists so confident regarding the specifics of the universe?

In My Humble Opinion
1

I’ve watched a few videos throwing reams of facts regarding space or supposed facts regarding space that seem fantastical and amazing and also make me immediately think “how the fuck do we know that?“

There is so much asserting of what different things are made from, such as stars and planets and so on, things that we’ve never been anywhere near so we cannot claim direct empirical knowledge. How could we possibly say oh, yes, this is the factual reality of this celestial body/event/whatever?

One that’s floated through my consciousness in recent days is water. Somewhere along the line I came across the assertion that all water now on earth is basically foreign. The claim is that every bit of the gazillions of gallons of water that cover the vast majority of the surface of our planet arrived here via comets or meteors or asteroids or some other speeding heavenly body that crashed into us and dumped all that water.

Ummm… That seems kind of unlikely given the vast amount of water that is on our planet, and even if it is so, how did they arrive at that “knowledge”?

So, so many of the “facts“ offered up regarding space and the universe generally strike me personally as wildly unlikely and bizarre and magical and off-the-wall and are you fucking kidding me no matter where they come from, but the fact that they (to my knowledge) come from pure theory makes it even stranger and more confounding that they’re thrown out as supposed facts.

Someone help me here. Why do all these, I don’t know I guess it’s astronomers and astrophysicists, believe that they’ve got it all figured out? And I’m not saying they don’t because the universe and space and all that stuff gives me really big headaches, but still I’d like to understand better why they think they understand so very much.

And I may be what I’m asking for is a factual question but I don’t know something tells me there is room for opinion in all of these issues that’s kind of my point. Or part of it anyway.

Thank you in advance for educating me about these things.

2

It was long thought that Earth’s water did not originate from the planet’s region of the protoplanetary disk. Instead, it was hypothesized water and other volatiles must have been delivered to Earth from the outer Solar System later in its history. Recent research, however, indicates that hydrogen inside the Earth played a role in the formation of the ocean.[3] The two ideas are not mutually exclusive, as there is also evidence that water was delivered to Earth by impacts from icy planetesimals similar in composition to asteroids in the outer edges of the asteroid belt.[4]

3

That’s how I feel about estimates regarding the age of the universe. The number is being changed all the time (and no, I don’t think it happened in 4004BC).

How about the droves of seemingly knowledgeable people some years back who totally believed that Mars rocks were found in Antarctica?

4

While you have good questions, I have to say that watching YouTube videos isn’t necessarily a good way to get accurate information. There are much better places to find the answers to your questions about how scientists think they know what they do. Just googling the questions will usually pull up websites that can explain things better.

5

I would just like to point out that “argument from incredulity” is a “fallacy in informal logic. It asserts that a proposition must be false because it contradicts one’s personal expectations or beliefs, or is difficult to imagine.”

Also, you seem to have a misunderstanding of what exactly a scientific theory is. A scientific theory is not a wild-ass guess that someone pulled out of thin air.

6

Most of what actual scientists will say about such things isn’t “this is the factual reality.” Actual scientists will say something like, “based on the data and observations currently available to us, this is the hypothesis which most scientists who study the field agree is a likely explanation.”

And, they will also acknowledge that additional data or knowledge may well change the hypothesis in the future, as it did with the water-origin hypothesis.

7

Almost nothing comes from “pure theory”. Just about everything we know comes from experiment.

The theory makes the predictions, and we use experiment to determine whether those predictions were true or not. If the experiments support the theory, then we gain confidence in it.

Just as an example, General Relativity (Einstein’s theory) predicts a lot of stuff, including gravitational waves. It’s successfully predicted the motion of Mercury, which was easy to confirm just by telescope. Because of this, there was great confidence in it.

Gravitational waves are very difficult to measure, though, and so remained a prediction of General Relativity without confirmation. It could have been wrong–and if so, we’d have to throw out GR and find something that predicts the motion of Mercury while not having gravitational waves. Fortunately, technology has caught up and allowed us to detect the waves. So a prediction that remained theoretical for many decades is finally confirmed and further enhances our confidence in GR.

Of course, we can never have absolute certainty about the theories. We can always ask if the next experiment will finally prove the theory wrong. But as experiments come in that are consistent with the theory, it takes ever-greater coincidences for there to be a contradiction.

Think of it like what a detective does. They need to come up with an explanation for a crime. They collect clues and come up with a theory that’s consistent with the clues (“Bob committed the murder”). There’s always some room for a contradiction (“Bob’s evil twin brother, separated at birth, was the real murderer!”) but these alternate explanations become less and less likely as we gather evidence consistent with the primary theory.

8

First, I’m not arguing anything I am just expressing my personal reactions and stating plainly that I am not arguing that I know better, I’m asking for more information.

Second I know exactly what a theory is, I’ve had that argument with creationists a lot. We just get sloppy with our language… Evolution is a fact but there are multiple theories about exactly what drove it and how it operates.

Just a little imprecise with my language

9

Specifically with regards to Earth’s water - there’s a whole lot of knowledge that’s required to understand how we know that almost all (and it is almost all, not all) our water is of extraterrestrial origin.

Absent that knowledge, incredulity, while not logical, is understandable.

But if you’re not going to look for that knowledge, it’s no longer excusable.

So read what Earth was like in the Hadean. Learn about the Late Heavy Bombardment. Find out about asteroidal vs cometary isotope ratios. See what deep mantle xenoliths tell us about the water of the primitive Earth. Discover why extrusive outgassing alone isn’t an adequate source for all our oceans.

Or don’t, and remain incredulous.

10

Physical proximity is nice but hardly the only way to make observations and measurements. I’m hardly a scientist myself, but when I took introductory astronomy in college I learned that analytic tools such as mass spectrometry and the Doppler effect are evidence-based ways to determine characteristics of celestial objects.

11

Do you accept evolution to be true, and that humans have a pretty good idea that we understand how it works?

If so, have you ever seen a creationist attempt to attack evolution?

If so, do you recognize how much they sound like you’re attacking astronomy and cosmology? "Evolution is only a THEORY. We weren’t there. How can we know what happened? We really think we have an understanding of how life developed over hundreds of millions of years?!

Do you seriously expect me to believe that human beings, in all our complexity, are just animals? That we came from single celled organisms? That we’re not far removed from monkies? Ridiculous. How can scientists possibly think that some crazy theory they came up with is fact?"

How would you respond to this evolution denier?

Because the analogy is pretty spot-on. The process of science works the same way. We make observations, conduct experiments, create models we think things work. As our observations and experiments contradict our model or better explain how things work, we update the model with the best knowledge we have. This is what a theory is.

Your idea that we cannot empirically experience the cosmos because we haven’t been there is false. Being able to see something is an empirical experience. Being able to measure things with instruments is empirical. Just as we can dig through the Earth and see what existed in the past, we can look deeper into the galaxy and observe things that were an earlier state. Even though we weren’t there to observe life 100 million years ago, we can dig up fossils. In cosmology, we can look at the evidence of things that existed in the past, like fossils, like the cosmic microwave background radiation.

I’m sure you trust other areas of science. We understand chemistry. We understand physics. Why is it so difficult to believe that smart people studying their whole lives, building on the work of countless people, applying the same process, can gain an understanding of how the universe works, too?

You could learn the answer to any particular question you have, you would just need to educate yourself. And that should give you confidence that the other questions are answerable, too, that we have a reason for thinking what we do. Because quite frankly, the idea that science works in general, and we can build computer ships and launch probes to jupiter and gene sequence a tree and we understand all of that, but that cosmology and astronomy are all just wild guesses that have no rigor or underlying evidence is absurd and makes no sense.

This is pretty much a textbook argument from incredulity.

12

I don’t know about where water came from but I think a lot that claims to be science isn’t really.

Here is a definition of science
“the systematic study of the structure and behaviour of the physical and natural world through observation, experimentation, and the testing of theories against the evidence obtained.”

So for something like gravity scientists can observe things fall to the ground experiment how fast they fall in different medium, experiment how it works with objects other than earth (two heavy suspended objects will be attacted to each other very slightly, objects fall slower on the moon) come up with a theory and do repeated experiments to test the theory.

For something like where water comes from you can observe but you can not experiment to test theories. The result is scientists have axioms of fundamentals that they think are indisputable, they then observe and draw hypotheses which match there observations and fit in with their axioms, it takes a huge amount of evidence to move the away from their axioms, until the 17th Century those axioms based on an (incorrect) interpretation of the bible was the universe revolved around the earth, Galileo observed the movement of the planets and came to the conclusion that the universe revolved around the sun and received great opposition for stating that, now that has also been disproved.

Another example is how different forms of life appeared on earth.

The majority of evolutionary scientists have as an axiom that there is no God. They observe the variety of life on earth, natural selection (creatures better adapted to their environment survive longer and are therefore more likely to reproduce) and mutations and conclude that all life evolved from the simplest microrganism through these methods (grossly simplied)

There are a small number of “creation scientists” whose base axiom is the bible is the word of God and contains no errors. They observe the same evidence but conclude natural selection doesn’t create new genetic information it only changes the proprotions among the population, different breeds of dog can be created through (unnatural) selection but you skill have the canine kind, they observe that the human eye is vey similar to the eye of an octopus but the rest of the bodies are so different they could nave the same evolutionary ancester and come to the conclusion that natural selection only occurs within “kind” and similarities between different kind are due to having the same designer / creator.

13

NM … plus some characters to make Discourse happy.

14

Let me try again:

First of all, it was Copernicus, not Galileo, who first postulated that the earth is not the center of the universe.

Second, neither one claimed that the universe revolves around the sun. Copernicus deduced, and Galileo agreed, that the celestial objects of our solar system revolve around our sun.

15

Would be if I was arguing. I’m not. I’m saying this is the nature of my incredulity, can you help me better understand what’s going on here.

As I said in my post, I’m not good at this stuff. It gives me headaches, but it doesn’t stop me from finding it interesting.

16

What about them? There are 31 recorded Antarctic Martian meteorites so far

https://www.lpi.usra.edu/meteor/metbull.php?sea=&sfor=names&ants=&nwas=&falls=&valids=&stype=contains&lrec=50&map=ge&browse=&country=Antarctica&srt=name&categ=Martian+meteorites&mblist=All&rect=&phot=&strewn=&snew=0&pnt=Normal%20table&dr=&page=0

There are 356 so far outside of Antarctica.

https://www.lpi.usra.edu/meteor/metbull.php?sea=*&sfor=names&ants=no&nwas=&falls=&valids=&stype=contains&lrec=50&map=ge&browse=&country=All&srt=name&categ=Martian+meteorites&mblist=All&rect=&phot=&strewn=&snew=0&pnt=Normal%20table&dr=&page=1

17

@Stoid asks interesting question, gets flippant answers.

The true answer is Turtles all the way down.

Because the answers often boils down to just that:

Space water (from comets ASF). Well, where did that water come from?
Space life (as in life on Earth origined somewhere else and arrived on… comets?) Well, where did the comets pick upp life, and how did it get there?

Dark matter and energy? Well, that has to be the answer or the math doesn’t work out. What other discipline - besides cosmology - is allopwed to make things up from whole cloth to fit a hypotheses? Yeah, yeah, gravitational lensing, glactic spin speed, space expansion.

The investigator most often starts out with a pretty firm idea about whodunnit. And then starts collecting stuff to coraborate that idea. Some conjecture, circumstantial evidence and quite < lot of bias and Bob’s your uncle. Not unlike cosmology.

There are so many things we don’t know and understand. We’re getting a little bit closer all the time, but there are a lot of turtles on the way.

So Star Talk with NdGT isn’t a good source? (“Well. that’s just one…”).
Yes, and there are thousands of others, interpreting and explaining. Any lnowledge will be filtered through someone interpreting and explaining, included peer reviewed research. As with all these things, carefully checking the reliability of the sources is the key. Dismissing YT like that is not helpful.

18

Unfortunately, astronomy in particular, and all the stuff that’s attached to it, like stellar evolution, like planetary formation, etc. are all rather advanced fields. And because all of this stuff is very different from our day to day common sense experience of trees and water and bugs, we have little mental roadmap nor mental tools to help us. With the result as you say, that most everything about these topics seems mind-bending.

The baseline knowledge to prove step-by-painstaking to your (any your) satisfaction that e.g. the Earth formed 4+ billion years ago is huge. Like a several year effort. So you have to accept some of this stuff as just given. Not given by og, but given by folks who have spent their careers figuring out one small brick in this giant wall of knowledge.

@MrDibble said it well.

If you want to learn, you can learn. Videos aren’t the way. Even if they’re factually accurate (and most aren’t), they can’t chase down the rabbit trails to deliver the underpinnings you seem to need to accept the larger conclusions.

19

Yeah, there’s a related phenomenon I like to call ‘This summary isn’t very detailed, is it?’

People want a simplified version of things, which is fine, but then they mistrust the simplified version because it inevitably leaves out a lot of fine detail, in order to be succinct; looking at the summary without knowing the detail, it’s easy to ask “how could you possibly know that?”
But If you try to walk people through the entirety of the detail, they go “Oh, that’s too complicated, can’t you summarise it?”

(I worked for a guy who did this constantly; he’d ask for a report on a technical topic; I’d write the full report, with a half-page summary-abstract at the top; he’d complain that the summary wasn’t detailed enough; I’d point out that the detail was in the remaining pages; he’d say he didn’t have time for that, and just wanted a summary that had everything in it.)

20

If you wanted to learn about how things work, you could’ve just asked and people would be happy to explain it to you. Instead you framed it in a way that sounds like science denial, which is going to make people spending more time explaining to you how science works rather than any specific answers you may be looking for. I mean, you put “knowledge” and “facts” in scare quotes and referred to what we know about the cosmos as “supposed facts”

In any case, cosmology takes quite a broad understanding of science in general and it’s not an easy topic, but I’d imagine there are good resources for learning about it. Listened to hundreds of episodes of AstronomyCast although that may be a slow way of learning about, it’s enjoyable. I wouldn’t listen to people’s blanket dismissals of videos on youtube – there are plenty of good science educators posting videos on youtube these days, and I bet curiositystream has some good stuff too.