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

Biology? Specifically human-centric medicine? Miasmas and bodily humors because we didn’t have the ability to identify what is now mundanely easy to identify.

Dark Matter isn’t something newly made up because science needs a rescue mechanism for their clearly false ‘’‘theories’‘’. It’s almost 150 years old and is both a place holder phrase to make discussing it easier and a clear statement of the best hypothesis of the problem as seen,

In 1933, Swiss astrophysicist Fritz Zwicky, who studied galaxy clusters while working at the California Institute of Technology, made a similar inference. Zwicky applied the virial theorem to the Coma Cluster and obtained evidence of unseen mass he called dunkle Materie (‘dark matter’). Zwicky estimated its mass based on the motions of galaxies near its edge and compared that to an estimate based on its brightness and number of galaxies. He estimated the cluster had about 400 times more mass than was visually observable. The gravity effect of the visible galaxies was far too small for such fast orbits, thus mass must be hidden from view. Based on these conclusions, Zwicky inferred some unseen matter provided the mass and associated gravitation attraction to hold the cluster together. Zwicky’s estimates were off by more than an order of magnitude, mainly due to an obsolete value of the Hubble constant; the same calculation today shows a smaller fraction, using greater values for luminous mass. Nonetheless, Zwicky did correctly conclude from his calculation that the bulk of the matter was dark.

While Fenyman is specifically talking about new laws I’m quite certain he’d agree that what he says applies to theories and hypotheses too.

Now I’m going to discuss how we would look for a new law. In general, we look for a new law by the following process. First, we guess it (audience laughter), no, don’t laugh, that’s the truth. Then we compute the consequences of the guess, to see what, if this is right, if this law we guess is right, to see what it would imply and then we compare the computation results to nature or we say compare to experiment or experience, compare it directly with observations to see if it works.

Excellent video. It may seem pedantic, but I think it’s also important to point out the difference between an incorrect scientific theory vs. appeals to ignorance. Theories like the luminiferous aether, evolution by means of acquired characteristics, the steady state theory of the universe, etc., are all scientific theories that happened to be incorrect. Saying that God did it (a young Earth or whatever else) because my pastor / priest / imam / shaman / whatever says so isn’t scientific. They’re both wrong, but for different reasons.

Not all science is experimental, but all of it is evidence-based. And very often some of the fundamental evidence does come from experiment. For instance climate science isn’t experimental but our knowledge of the radiative transfer properties of greenhouses gases comes from the lab.

@MrDibble provided an excellent summary of what we know about the origins of water on Earth in an earlier post.

They may call themselves “creation scientists” but these people are not scientists following the scientific method, they’re crackpots. I very much doubt that they “observe the same evidence” since it’s unlikely that they have the resources to do so, but even if they did, they lack the necessary deep knowledge to know how to evaluate it or to understand the underlying biological processes. Creationists aren’t just interpreting the same evidence in a different way, they’re just plain wrong because they’re ignorant and are catering to believers in superstitious dogma.

The word “theory,” and related words and phrases like “in theory,” “theoretically,” “theorizing,” and “theorem,” have enough different meanings and connotations that it’s not surprising that laymen get confused sometimes.

That’s my theory, anyway.

Creation ‘’‘’‘science’‘’‘’ and the obvious problem with it,

Or yet another comic:

Here’s something even crazier: the entire Earth is made of extraterrestrial material! Yes, everything you see around you was originally part of a cloud of space dust. And the space dust didn’t just happen, it’s actually the detritus of stars. We are made of star-stuff.
/sagan

Incredulity is fine when it leads to wonder.

The last paragraph understates the strength of scientific support for concepts like evolution, climate change, and many others. It also understates the vast difference (and disconnect) between a layperson and a scientific expert on any one of those subjects, the latter typically having ten or more years of post-secondary education in their field coupled with many years of direct experience. The layperson reads a single claim on the internet that seems outlandish by itself, but the scientific expert sees that claim in the context of all the field work he’s done, all of the conferences he’s attended, all of the technical papers he’s read, all of the technical papers he’s written, and all of the analysis he’s been doing, all over the course of 50 hours a week for the past 20+ years. For that expert, that seemingly outlandish claim on the internet is not only verifiably true and correct, it’s just the tip of a massive iceberg of knowledge that the layperson knows nothing about. And in most cases, the knowledge isn’t just a handful of scientists studying one small detail ad nauseam, it’s thousands of scientists, in dozens of different disciplines, all studying different aspects of a topic and contributing facts that form an interlocking body of support that is far stronger than a layperson (or even any one scientific expert) may realize:

So when a skeptic casts doubt on the whole concept of evolution, they’re almost always completely unaware of the iceberg of scientific support behind it. The theory of evolution is backed by a ridiculous amount of evidence - not just by the shape of living creatures, but also in the fossil record, in genetics, in biochemistry, and in experiments. Similarly, if you want to refute climate change, you’ll need to explain away massive bodies of diverse, consilient evidence accumulated over decades from diverse fields including geology, chemistry, physics, and meteorology.

As for the OP’s questions on the source of Earth’s water, well, I’m a layperson in that sort of thing. I’ll put some faith in the claims that are verifiably attributed to experts in the field, but YouTube videos are often poor examples of this. Wikipedia is one of my favorite resources because it often summarizes info from a lot of sources, and articles typically include references and links to other websites with more info on the subject. The article @needscoffee linked to (regarding the origin of water on Earth) is a great example of this. Even having read that, a layperson still would be a layperson, and would be way out of their depth in challenging a scientific expert on the matter. At some point, a layperson who has no interest in pursuing a lifelong career in a particular scientific discipline is just going to need to accept the claims of those experts and have some faith in what they report as fact.

The 2013(ish?) “Cosmos” series with Neil deGrasse Tyson had a very interesting segment on the development of this area of astrophysics. I had always been curious about the same thing - “but how the hell do we know what that star is made of, and why is it different from that other star over there?!”

They’re not so confident about all the specifics. For example, there are two ways to figure out the Hubble Constant, and they’re converging on two separate values further apart than the calculated errors in the two ways.
But there’s quite a lot that is known. People who get a degree in astronomy and/or physics tend to get why this is the case. A lot of work went into it. Go read an introductory textbook (not a coffee table book) to get an idea why. I might add that I have a degree in “Physics and Astronomy”.
The thing they know that I can’t understand is, how do they know the names of the stars if they’re so far away?

(Just to be clear, that last one was a joke.)

You’re insulting the true crackpots. What these people are are religious fanatics. Some of them have plenty of knowledge, but they swear allegiance to the Bible, not the truth.
Creationism is a falsifiable hypothesis. That’s not the problem. The problem is that it has been falsified, and these people are too fanatical and too dishonest to admit it.

I wonder how much of this “confidence” is not the scientists but rather irresponsible journalists who can’t resist running misleading sensational headlines.
I saw this lately as Dyson spheres were in the news again. Short summary, a physicist in the 60s theorized that ultra advanced intelligent life may be able to harness the power of a star or stars for energy to support itself. A byproduct of that would be massive amounts of heat or radiation. He thought that if scientists could look for these pockets of radiation it would be a good place to look for his theorized dyson spheres in search of intelligent life.
Now of course a half century later when a pocket like this is found some journalist can’t resist running a misleading headline saying “Scientists may have found evidence of a dyson sphere where they believe intelligent life exists!!!”

One thing astronomers do is study the light that reaches us from those bodies. Check out spectrometry and spectroscopy. The presence of spectral (emission and absorption) lines in the light shows the presence of specific chemicals.

Curiosity is wonderful.

Science is all about questioning. There is a whole philosophy of science, and there is a popular phrase, “science eats its own children”. Nothing is sacred and when new evidence arrives science adapts. That’s what has made it so powerful.

When you actually investigate the evidence and thinking behind these theories it is often amazing what evidence has been found and how it was derived.

Pretending that the origin of meteorites from Mars is somehow in question because you have misinterpreted available information and haven’t investigated properly comes off as ignorant and manipulative.

Of course you can. You can do all sorts of experiments, either on retrieved extraterrestrial material or on terrestrial sources. That’s leaving aside pure synthetic material experiments.

Do you think geolochemists just look at rocks?

As evidenced by the fact that they can never provide details or specifics underlying their ‘alternative’ explanation - partly because there are none, but partly because they don’t see the necessity. They are trying to refute a summary that is derived from a huge body of underlying data, with a different story that was written as if at summary-level, but with nothing underneath it.

Example: YEcreationists argue that biological organisms are divided into ‘kinds’, not species that ultimately have common descent from a single ancestor species and thus ‘microevolution’ is possible within kinds, but no more than that.
Ask them for a mechanism by which that works; ask them how organisms are constrained from having all those ‘micro’ changes add up into a bigger divergence; ask them how it is that organisms that are different kinds have genetic evidence of relatedness (such as evidence of endogenous retroviral insertions), and you either get a blank stare, a change of subject, or they just start over explaining that biological organisms are divided into ‘kinds’. There’s nothing underneath; they started with the answer they wanted and forgot to ask the question.

Maybe some do, but they’re probably very much in the minority among creationists. For example, one of the most prominent Young Earth Creationists, Ken Ham, who runs the “Creation Museum” and the “Ark Experience” exhibit, has no relevant training and has never done any scientific research. I suspect that among creationists, those who are ignorant greatly outnumber those who are dishonest. It’s quite different from a field like climate science, where dishonesty used to be pay well, and to some extent perhaps still does.

Being “wrong” is part of the scientific method, which requires testing a hypothesis to determine if assumptions are true.

As an aside to my own post, on the topic of water…

Many years ago, the 90s, I was listening to Tammy Bruce have a cow on LA Talk Radio about “disgusting contaminated” recycled water being used for something that meant we would ultimately consume it, I cannot recall the details, other than it was something perfectly normal it was just apparently news to her.

I called into the show to enlighten Tammy Bruce to the fact that all of the water on planet earth (whether it was first manifested here on this planet or came here from somewhere else) has already been recycled millions of times, passing through the guts of who knows how many different animals and how many different kinds of animals, along with being passed through who knows how many different kinds of terrain. Water is the ultimate example of perfect natural recycling: use it, clean it, use it, clean it… a marvelous endless cycle supporting the existence of life since forever. Downright magical.

So flipping out because you happen to learn of an exact moment in time when a particular portion of the water on the planet will be recycled in a specific way, as though it’s somehow bizarre and gross and bound to make you sick is fucking stupid.

I got on the air and was explaining this very calmly and when it became clear what I was saying she kind of went blahblahblargh and hung up on me. Which I thought was pretty funny.