How certain is our scientific knowledge? Honestly?

[Omnifarious]

First off let me say I mean no disrespect. And if I seem brutally honest it's because it's my nature and belief in being forthright.

There are a lot of things said in science documentaries and scientifically mined people that upset me. And they always speak with absolute certainty. Like this thing is perfectly well known and proven beyond a shadow of a doubt, like gravity. 

I wanted to ask you weather or not they were really true but then I thought it would be easier to ask you about science and our certainty of it in general. I've heard that scientists are supposed to be open minded and never to be too certain of any thing. But in my experience, scientists are people who say "This is the way thing are and that's the end of it." That you could not be a scientist unless you took things as absolutes. It's particularly difficult for me to question these people because I can't help but assume they speak from a position of knowledge of which I am ignorant. When people talk like it's already proven, I can't help but assume it has been. When you're sitting in class or studying a book, you don't question what they're saying. If you did, how would you learn anything?

 

For example this one says that we will NEVER be able to leave our local group of galaxies because the rest of the universe is accelerating away from us faster then the speed of light. 

This one and this one state that traveling faster then the speed of light is impossible. Not just that it's impossible with current technology but it's impossible no matter how advanced we get. I tried to tell myself that we are always discovering new things, things we could not imagine before. I looked in the comments to see if anyone had the same thought and some did. But then someone countered that bay saying if we did learn anything could go faster then light, it would undo the laws of physics going back to Newton, who's work has proven solid to this day.

And something that's always bothered me, the theory that the entire universe will inevitably end. So many time I've heard about how and when it will end. Once I went on one of those question posting websites and I asked "Will the universe end?" Not how will, not when will, just will? Is this something the scientists of the world know and agree on. The very first post I go simply said "Of course it will."

 

What I want to ask is, not so much about the above stuff but about our scientific knowledge in general. What is the reason for all this certainty and rejection of doubt? Is our grasp of science that good? When we know something do we really know it for sure?

Or is it something else? Are scientists today too sure of themselves? Is everyone taking their word as gospel? Do people talk as if things are facts because they want to sound convincing? Do documentary makers simply assume we will know they are not talking about absolutes even though they never said they were? Even though they implied everything they said was fact over and over again?

I read somewhere that we might be living in a new dark age, because we don't think to investigate what our "higher ups" tell us.

[OceanBreeze]

On 11/10/2020 at 11:28 AM, Omnifarious said:

First off let me say I mean no disrespect. And if I seem brutally honest it's because it's my nature and belief in being forthright.

There are a lot of things said in science documentaries and scientifically mined people that upset me. And they always speak with absolute certainty. Like this thing is perfectly well known and proven beyond a shadow of a doubt, like gravity. 

Good, and I must say I appreciate that attitude.

 

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I wanted to ask you weather or not they were really true but then I thought it would be easier to ask you about science and our certainty of it in general. I've heard that scientists are supposed to be open minded and never to be too certain of any thing. But in my experience, scientists are people who say "This is the way thing are and that's the end of it." That you could not be a scientist unless you took things as absolutes. It's particularly difficult for me to question these people because I can't help but assume they speak from a position of knowledge of which I am ignorant. When people talk like it's already proven, I can't help but assume it has been. When you're sitting in class or studying a book, you don't question what they're saying. If you did, how would you learn anything?

That isn’t my experience, and I work directly with many scientists, often for months at a time, usually at sea. In my experience, all good scientists are skeptics and only feel confident about their understanding when there is a preponderance of evidence supporting their position. There may very well be still unresolved issues and loose ends; in fact, there are usually many, but as long as there is a preponderance of carefully examined and empirically tested evidence, scientists can feel confident they are at least on the right track to understanding.

You mention gravity as an example. There are many loose ends about that subject, in fact we do not know the exact cause of gravity but we do know it is related to mass. Even without knowing the exact cause, we have workable equations such as for acceleration ( a_g = GM/r^2) and force (F_g=GMm/r^2) and we know both of these equations obey the inverse square law. These relationships have been tested and mathematically derived so there is a preponderance of evidence to support them. Only someone who does not understand basics Physics would argue against them and if someone does, they would need to present their own preponderance of evidence, and not their own personal crackpot “theory”.

 

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For example this one says that we will NEVER be able to leave our local group of galaxies because the rest of the universe is accelerating away from us faster then the speed of light. 

And that video is wrong. According to this link, The Hubble parameter is decreasing with time, so there can be cases where a galaxy that is receding from the Earth just a bit faster than light, but does emit a light signal that, once it enters the Hubble sphere, reaches the Earth eventually. This future visibility limit is calculated at a comoving distance of 19 billion parsecs (62 billion light-years), assuming the universe will keep expanding forever, which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, is  larger than the number currently observable by a factor of 2.36.

So, contrary to the dark universe predicted in that video, the future universe may actually be brighter than today, with more galaxies visible.

 

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This one and this one state that traveling faster then the speed of light is impossible. Not just that it's impossible with current technology but it's impossible no matter how advanced we get. I tried to tell myself that we are always discovering new things, things we could not imagine before. I looked in the comments to see if anyone had the same thought and some did. But then someone countered that bay saying if we did learn anything could go faster then light, it would undo the laws of physics going back to Newton, who's work has proven solid to this day.

The premise presented in that video may be correct but I must say it is very poorly presented and it was a waste of my time to watch it. In general, these sorts of videos are a poor substitute for a good Physics text book.

As for Newton, his laws of motion and many other theories he has formulated are still good to this day except at relativistic speeds. Then, we need to rely on Einstein’s theory of special and general relativity.

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And something that's always bothered me, the theory that the entire universe will inevitably end. So many time I've heard about how and when it will end. Once I went on one of those question posting websites and I asked "Will the universe end?" Not how will, not when will, just will? Is this something the scientists of the world know and agree on. The very first post I go simply said "Of course it will."

 Nobody knows if the Universe will end or continue to exist forever. Personally, I find this to be of no concern to me, one way or the other, so I would never waste my time arguing over it.

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What I want to ask is, not so much about the above stuff but about our scientific knowledge in general. What is the reason for all this certainty and rejection of doubt? Is our grasp of science that good? When we know something do we really know it for sure?

 

As I said above and at the risk of repeating myself over and over, all good scientists are skeptical up to a point, but there are some things that we do feel confident about because they are supported by a preponderance of evidence.

 

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Or is it something else? Are scientists today too sure of themselves? Is everyone taking their word as gospel? Do people talk as if things are facts because they want to sound convincing? Do documentary makers simply assume we will know they are not talking about absolutes even though they never said they were? Even though they implied everything they said was fact over and over again?

I read somewhere that we might be living in a new dark age, because we don't think to investigate what our "higher ups" tell us.

 

I would stay away from the documentary makers, especially the type of videos you linked to in this post, and read some good Physics books. Science isn’t an easy subject; you need to work at it and learn the advanced math that is needed for a deeper understanding.

As for us being in a new “dark age” that is hardly the case! We are closer than ever to understanding the nature of reality and our own place in it. But this knowledge is not easily grasped by the average person who does not have an advanced degree in physics and mathematics. Plus, there are many crackpots with their own crackpot theories and it may be difficult for the average person to know what to believe. In fact, human nature often compels people to believe in the most outrageous claims. Only a good education can separate the wheat from the chaff.

[Omnifarious]

On 11/12/2020 at 4:30 PM, OceanBreeze said:

 

The premise presented in that video may be correct but I must say it is very poorly presented and it was a waste of my time to watch it. In general, these sorts of videos are a poor substitute for a good Physics text book.

 

Are you saying it's a known fact that FTL is impossible?

[OceanBreeze]

4 hours ago, Omnifarious said:

Are you saying it's a known fact that FTL is impossible?

[spartan45]

On 11/10/2020 at 4:28 AM, Omnifarious said:

There are a lot of things said in science documentaries and scientifically mined people that upset me. And they always speak with absolute certainty. Like this thing is perfectly well known and proven beyond a shadow of a doubt, like gravity. 

Omnifarious, I like your post’s curiosity and determination to find answers, but you have brought up too many points for me to cope with so I thought I’d start with gravity.

Gravity is intriguing; the best description of its nature I recently found is from the reference below the summary from that reference titled ‘Does the influence of gravity extend out forever?’

‘In summary, the influence of gravity only extends to the edge of each gravity group. Beyond that, spacetime no longer behaves like gravity. It's not that the gravitational attraction of a star simply gets too weak to notice when you leave its galaxy group. Rather, the gravitational attraction goes completely away outside of the galaxy group. A hammer in the solar system that is let go at rest relative to the sun falls towards the sun. A hammer released at rest in a different galaxy but in the same galaxy group as our sun would also move towards the sun (in addition to moving towards the other, closer masses). In contrast, a hammer in a different galaxy group does not move towards our sun at all. It moves away from our sun, and it moves away at an accelerating rate. In fact, the hypothetical distant hammer moves away from our entire galaxy group at an increasing rate. Spacetime simply does not behave at all like attractive gravity on cosmic scales. For this reason, gravity fundamentally does not extend beyond gravitationally-bound groups of galaxies’.

Ref https://wtamu.edu/~cbaird/sq/2015/06/09/does-the-influence-of-gravity-extend-out-forever/

[Omnifarious]

11 hours ago, OceanBreeze said:

Is that a no? I don't recognise this clip.

You said that the premise is correct, what do you mean by that?

I have heard that lightspeed is the absolute speed limit. Even if we build faster ships, the physical effects of going that fast would stop them. Even that there has to be an unbreakable limit, if things could accelerate indefinitely, matter would not be able to exist.

They say the FTL might be possible but not by going faster then light but by getting around it. Like a wormhole or an Alcubierre Drive. But FTL is still impossible for anything operating in normal space? Is this something known for a fact?

Also it sounds like you are saying that most galaxies will recede forever beyond sight but there will be a little more then the video said. Is that right?

Edited November 14, 2020 by Omnifarious

[Omnifarious]

I appreciate the 2 of you responding but I want to make something clear. While I did want to hear about the points, I raised them mostly as examples.

The main reason I started this was because I wanted to get a feel for the world of science in general. Is it all as absolute as I think it is? Are we that certain about what we claim to know? When someone says to me "this is true" are they speaking from fact or just over confidence?

How likely is it that what we are so sure of now will change?

I don't want to believe in these things but I don't know if I have a choice.

I know people are free to believe whatever they want but personally I don't think they should. If people can really believe in what ever they want we could have people believing in all sorts of crazy and harmful things.

And again, when people talk in certainties I can't help but assume it's because they know something I don't.

Plus, the way my brain is wired, I have a very black and white mentality, I think in extremes. Once new information is taken in, it's filed either true or false.

For these reasons I feel like I have no right to disagree with the scientific information I have been given. My father used to be a scientist, the most intelligent and knowledgeable man I've ever known. He has this habit of talking about theories like they were commonly known facts, with out using words like hypothetically, theoretically or it's possible that... And so I couldn't help but belive these were truths. 

The reason I started this was to test the scientific waters, I wanted to know what it's really like, are scientists that certain, when we say we know something, do we really know? How good is our science? 

If it turns out that scientists are not certain about our current science, that the everything we claim to know is floating in conjecture rather then carved in stone, that the people I've shown you in those videos are not in fact speaking a proven truth, then I would know it would be ok to believe what I want.

[OceanBreeze]

16 hours ago, Omnifarious said:

Is that a no? I don't recognise this clip.

I thought the body language is very clear.

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You said that the premise is correct, what do you mean by that?

Did I say that?  No, I said that the premise “may be correct”.  That's an important distinction.

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I have heard that lightspeed is the absolute speed limit. Even if we build faster ships, the physical effects of going that fast would stop them. Even that there has to be an unbreakable limit, if things could accelerate indefinitely, matter would not be able to exist.

They say the FTL might be possible but not by going faster then light but by getting around it. Like a wormhole or an Alcubierre Drive. But FTL is still impossible for anything operating in normal space? Is this something known for a fact?

 

 

It seems you entirely missed the point I made, even though I repeated it several times, that “all good scientists are skeptical up to a point, but there are some things that we do feel confident about because they are supported by a preponderance of evidence”. There are no absolute facts in science but there are things that are supported by scientific evidence, things that are not scientific and things that are nonsense. It is important to learn how to tell the difference.

As for FTL, a distinction should be made whether you are asking about FTL movement (of something that has mass) or FTL communication using massless particles like photons.

At present there is a preponderance of evidence against the former but at least some evidence that the latter may be possible, perhaps by coding and decoding information using quantum entanglement.

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Also it sounds like you are saying that most galaxies will recede forever beyond sight but there will be a little more then the video said. Is that right?

Again, you are somehow managing to misread what I wrote:

The  “future visibility limit is calculated at a comoving distance of 19 billion parsecs (62 billion light-years), assuming the universe will keep expanding forever, which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, is  larger than the number currently observable by a factor of 2.36.

So, contrary to the dark universe predicted in that video, the future universe may actually be brighter than today, with more galaxies visible”

That would be a LOT more than what the video said, since that video was predicting a much darker sky than we have at present and what I wrote is there may be an even brighter sky that we have at present. But a great deal depends on how the Hubble parameter behaves with time.

[Omnifarious]

10 hours ago, OceanBreeze said:

 

As for FTL, a distinction should be made whether you are asking about FTL movement (of something that has mass) or FTL communication using massless particles like photons.

 

I was talking about travel.

[Omnifarious]

I think we've drifted a little far from the main topic.

[A-wal]

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How certain is our scientific knowledge? Honestly?

Not very in some cases. Dark matter and dark energy for example are artifacts of a model that didn't match reality so they invented them rather than discarding the model, that's really the only 'evidence' that they are actually a real thing.

 

On 11/10/2020 at 4:28 AM, Omnifarious said:

For example this one says that we will NEVER be able to leave our local group of galaxies because the rest of the universe is accelerating away from us faster then the speed of light.

Also the big bang is bollocks in my opinion. When it was found that redshift is proportional to distance that should have been taken as evidence that the redshift must be occurring during the light's journey rather than being caused by motion of the source away from us. When redshift was shown to be higher than what you'd get if distant galaxies were moving away at the speed of light that should definitely have been the end of this silly expansion model, they claim that an expansion of space between two objects is somehow different from those objects moving away from each and therefore doesn't violate the faster than light relative Velocity limit. Which brings me nicely to the next point...

 

On 11/14/2020 at 7:43 PM, Omnifarious said:

This one and this one state that traveling faster then the speed of light is impossible. Not just that it's impossible with current technology but it's impossible no matter how advanced we get. I tried to tell myself that we are always discovering new things, things we could not imagine before. I looked in the comments to see if anyone had the same thought and some did. But then someone countered that bay saying if we did learn anything could go faster then light, it would undo the laws of physics going back to Newton, who's work has proven solid to this day.

This one's legit. No object can reach the speed of light relative to any observer, that's known because the speed of light is the same for all non-accelerating observer's.

Two other objects can be moving at anything below twice the speed of light from the perspective of an observer because one could be moving away from you at almost the speed of light in one direction while the other is moving away from you at almost the speed of light in the opposite direction for example, but from the frame of either of those objects the other is moving away at less than the speed of light.

It might seem inconsistent but the upshot is that each observer measures moving clocks to be slower than their own (time dilation) and the length of moving objects in their direction of relative motion to be contracted (length contraction). This causes an objects mass to increase as its relative velocity increases so that no amount of energy can accelerate it up to light speed.

[OceanBreeze]

14 hours ago, Anchovyforestbane said:

Do you actually know any of the terms you're throwing around? It doesn't seem like you do.

BenBrok is just another reincarnation of the banned member polymath and is bonkers. You are wasting your time replying to him and also making it more difficult for me to remove his posts once you quote them.

[Anchovyforestbane]

8 hours ago, OceanBreeze said:

BenBrok is just another reincarnation of the banned member polymath and is bonkers. You are wasting your time replying to him and also making it more difficult for me to remove his posts once you quote them.

I apologize. I simply thought I could learn something from him or vice versa.

[Omnifarious]

We are drifting away from the question I wanted answered.

So many people have made documentaries and written articles saying "this is the way things are" and I can't help but assume they are speaking irrefutable truths because of proven facts, because of science. 

My question is, basically, when these people or scientists say these things how likely is it they are right? If something is a part of science, how likely is it science might be wrong? Is there any room for doubt?

Because in my experience, if it's in a science documentary, if scientists say it, then it's a part of science. And if it's a part of science then that's it, it is so, there is no room for doubt or change. Because to doubt scientists is to doubt the truth, which is just stupid. Because the only people who argue with them are ones with religion or flat-earthers. And frankly I think they're all a bunch of mislead fools and lunatics respectively. 

There are ALOT of things in science that really get to me and rather then asking each of them one by one on this site I wanted a blanket statement on the solidity of science in general. Are these people talking fact of theory? Because I simply can't tell unless they say so. And if science isn't so solid then I could be free to chose not to believe in some of these things. And I know tat people are free to believe in what ever they want but I can't stand that. Because when people are free to believe you get antivaccers, superstitions, conspiracy theorists and people who list Jedi as their religion. 

If people want to believe or disbelieve something then that should be based on some fact. And if it's a fact that science in general can be changed as well as added to then chose to disbelieve them.

So how solid is science?

[Anchovyforestbane]

2 hours ago, Omnifarious said:

We are drifting away from the question I wanted answered.

So many people have made documentaries and written articles saying "this is the way things are" and I can't help but assume they are speaking irrefutable truths because of proven facts, because of science. 

My question is, basically, when these people or scientists say these things how likely is it they are right? If something is a part of science, how likely is it science might be wrong? Is there any room for doubt?

Because in my experience, if it's in a science documentary, if scientists say it, then it's a part of science. And if it's a part of science then that's it, it is so, there is no room for doubt or change. Because to doubt scientists is to doubt the truth, which is just stupid. Because the only people who argue with them are ones with religion or flat-earthers. And frankly I think they're all a bunch of mislead fools and lunatics respectively. 

There are ALOT of things in science that really get to me and rather then asking each of them one by one on this site I wanted a blanket statement on the solidity of science in general. Are these people talking fact of theory? Because I simply can't tell unless they say so. And if science isn't so solid then I could be free to chose not to believe in some of these things. And I know tat people are free to believe in what ever they want but I can't stand that. Because when people are free to believe you get antivaccers, superstitions, conspiracy theorists and people who list Jedi as their religion. 

If people want to believe or disbelieve something then that should be based on some fact. And if it's a fact that science in general can be changed as well as added to then chose to disbelieve them.

So how solid is science?

It seems this has already been answered. Any real scientist would not have the attitude you're describing; a real scientist is always asking questions, always looking for holes in our knowledge to fill. And we fill these holes by researching, hypothesizing, calculating, and testing; using our knowledge to build upon our knowledge. A reasonable scientist wouldn't state a concept as undeniable, unless the concept has failed to be reasonably denied. 

[Omnifarious]

But, putting it simply, how solid is our scientific knowledge?

What is it like these days? Like how one might ask what Russia is like.

Edited November 29, 2020 by Omnifarious

[sluggo]

Omnifarious;

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But, putting it simply, how solid is our scientific knowledge?

My analogy for science is the person who enters a theater in the middle of a movie and tries to determine what has happened  up to the current state of affairs.

There are many possibilities but only one true sequence of events.

The person can stay to watch the missed portion when the film repeats, but that's not possible in the real world. Since no one was present at the beginning of the universe

we can only speculate with theories using abstract mental constructs, lines, circles, forces, etc. that mimic the behavior observed. We retain the theories while there are no anomalies. That's all science can have, since everything is invisible, with light providing awareness of things.

Science is just another human activity where you make it up as you go. Keep what works and discard the rest. Knowing that the ground is solid provides security, until there is an earthquake.

Knowledge is a process of continuous refinement.

 

Edited December 1, 2020 by sluggo