Naked Science Forum

On the Lighter Side => That CAN'T be true! => Topic started by: Shark on 29/10/2018 01:05:20

Title: How do we know the Universe is expanding if we cannot see its edge?
Post by: Shark on 29/10/2018 01:05:20
They say that the universe is expanding. But how can they tell if they haven't seen the edge (end) of the universe? You can't say it's expanding if you don't know how big it is! This is not how math works!
But even if they would see past the last star into pure blackness, that still wouldn't mean it's the edge (end) of the universe! Because it could only be a very big emptiness in space until the next star.

My point? They don't assume that the universe could be limitless. Without a beginning and no end. But if the universe is limitless, it is impossible to test if the universe is limitless by observation. Because a limitless universe would have no edge (end). Therefore how big the universe is, is a theoretical question which also requires a theoretical answer. And since I already solved this mystery you can read my other topic at the "New Theories topic area", "Why is there anything at all? Why not nothing? My solution".
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Kryptid on 29/10/2018 02:18:19
The observation is that the space between galaxies is expanding (detectable because the redshift of light from distant galaxies increases with increasing distance from us). It is true that we cannot know what is happening in the expanse outside of our visible Universe, but the visible Universe is indeed observed to be expanding.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Shark on 29/10/2018 02:32:36
The observation is that the space between galaxies is expanding (detectable because the redshift of light from distant galaxies increases with increasing distance from us). It is true that we cannot know what is happening in the expanse outside of our visible Universe, but the visible Universe is indeed observed to be expanding.

Then it's not about facts. And it's not. No one has done the same tests on other galaxies. So you have no guaranty that your devices work properly.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Kryptid on 29/10/2018 02:37:50
Then it's not about facts.

Of course it is. Redshift values are measurable. It isn't a guess.

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And it's not.

It's not... what?

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No one has done the same tests on other galaxies.

I don't understand what you mean. The redshift values of other galaxies are the very thing being tested.

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So you have no guaranty that your devices work properly.

Redshift is something that can be directly tested on Earth. How do you think the radar guns work that police use? Of course we know whether or not a device can properly measure redshift.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Shark on 29/10/2018 02:47:01

Of course it is. Redshift values are measurable. It isn't a guess.

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And it's not.

It's not... what?

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No one has done the same tests on other galaxies.

I don't understand what you mean. The redshift values of other galaxies are the very thing being tested.

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So you have no guaranty that your devices work properly.

Redshift is something that can be directly tested on Earth. How do you think the radar guns work that police use? Of course we know whether or not a device can properly measure redshift.

Proper science doesn't work that way. They do 100 if not 1000 tests to be sure. And that would include tests from other galaxies. You'd have to travel with a spaceship there and do the same tests. And you would have to find the edge of the universe on all directions. Only then it would be near facts! But like I said, it could only be a very big emptiness in space until the next star. Facts is 1+1=2.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Kryptid on 29/10/2018 03:18:49
Proper science doesn't work that way.

Of course it does. Science is about making observations, formulating hypotheses based on those observations and then testing those hypotheses with experiments/further observations.

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They do 100 if not 1000 tests to be sure.

That depends very much upon what is being measured. Regardless, many thousands of galaxy redshifts have indeed been tested and have been done over many different surveys: http://www.astro.ljmu.ac.uk/~ikb/research/galaxy-redshift-surveys.html

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And that would include tests from other galaxies. You'd have to travel with a spaceship there and do the same tests.

Based on what reasoning?

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And you would have to find the edge of the universe on all directions.

Why?

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Only then it would be near facts! But like I said, it could only be a very big emptiness in space until the next star. Facts is 1+1=2.

Then call it evidence. Nothing in science is known for certain. Everything is subject to being falsified.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Shark on 29/10/2018 03:32:26

Then call it evidence. Nothing in science is known for certain. Everything is subject to being falsified.

First you say it is about facts and now you say it's not? The big bang is an illusion. Imagine if relities collide. For example a random dream reality that doesn't make sense here. Collides with this reality. Do you think the big bang would have any meaning after that?

The biggest problem that I have with it is that they don't assume everything else. Like what if the universe is limitless, what if there are other realities, etc.

Observation vs theoretical science (what is and what is not, what is real). Theoretical science is also known as Metaphysics.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Kryptid on 29/10/2018 03:58:36
First you say it is about facts and now you say it's not?

That depends on how you define a fact. If you define a fact as "something observed to be true with high confidence" then science is about facts. If you define a fact as "something that is absolutely known to be true beyond any possible doubt" then not even mathematics is about facts (because, for all we know, we could all just be AIs in a giant computer that were preprogrammed to have intentionally faulty reasoning and we'd never know it).

The big bang is an illusion.

That's your claim, but where's your evidence? Other than the redshift evidence, The Big Bang theory is very good at modeling the observed abundances of the chemical elements.

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Imagine if relities collide. For example a random dream reality that doesn't make sense here. Collides with this reality. Do you think the big bang would have any meaning after that?

If you're going to posit things that don't "make sense here", then you can come up with absolutely any scenario you want to and claim that it renders any theory of your choosing to not "have any meaning". So basically, it would be up to you to demonstrate that such a reality collision (whatever that means) had actually occurred if you're going to argue that it somehow invalidates the Big Bang.

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The biggest problem that I have with it is that they don't assume everything else. Like what if the universe is limitless, what if there are other realities, etc.

The Big Bang theory does allow for those things to be true, so what's your point?

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Observation vs theoretical science (what is and what is not, what is real). Theoretical science is also known as Metaphysics.

Only when a metaphysical idea is falsifiable.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Shark on 29/10/2018 04:09:35
Fact:1+1=2. And evidence can be replaced with another evidence. No sense? It's an assumption! That there could be something like that. Anyway, this is the theory that did not answer any of my questions! Good job scientists out there! Thx for wasting my time!

Let him explain:
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Kryptid on 29/10/2018 04:28:11
Fact:1+1=2.

So which of my two definitions of "fact" are you using here?

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And evidence can be replaced with another evidence. No sense? It's an assumption! That there could be something like that.

It's not that evidence is replaced, it's that you gain new evidence that you did not have before. That doesn't render the old evidence invalid. Newton's equations are still useful and accurate for low speeds even though Einstein's equations were later found to be accurate at high speeds.

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Anyway, this is the theory that did not answer any of my questions! Good job scientists out there! Thx for wasting my time!

I think you are mistaken about what the Big Bang even means. It's not a theory about the origins of the Universe. That is still unknown. The Big Bang is simply an event that happened very early in the Universe and shaped its evolution.

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Let him explain:

This man already demonstrated that he doesn't know what he's talking about when he called the Big Bang an explosion. That's a common misconception. The Big Bang was a rapid expansion of space itself that happened very early in the Universe's history. As I said before, the Big Bang theory is not even a theory of where the Universe came from. It's a theory about the earliest known era in the Universe. He's also wrong in saying that you have to have two things in order for an event to occur. Subatomic particles like muons decay all by themselves without interacting with other particles. He's wrong yet again when he says that you can't know anything about the world if you don't know why it exists. A baby doesn't know why the world exists, yet it very clearly does know certain things about the world. It knows that some foods are tasty and some are not, that wet diapers are uncomfortable, what color its crib is, etc.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Shark on 29/10/2018 04:46:17
I think the best way to debunk the big bang is still my other topic about why anything exists at all. Because if you understand that, you know that there are limitless possibilities that could've caused the expanding of the galaxies. And also that everything you see may change any time. For now it looks like an expansion to you, tomorrow you wake up in your bed as a child in a mothership and enjoy the view of space without any memories of this world.

I want to more say that if you go by exact science. 100% detailed and deep thinking. The theory becomes meaningless. Because of limitless possibilities. Ever had a dream that changed abruptly dramatically? Why does science not assume that the same thing can happen here and now? And that it may have happened before? Or that it always happens? What meaning does the big bang theory have then if that's a fact?

Official science lacks of assumption of different possibilities. For them observation is everything.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: Kryptid on 29/10/2018 05:00:13
I think the best way to debunk the big bang is still my other topic about why anything exists at all. Because if you understand that, you know that there are limitless possibilities that could've caused the expanding of the galaxies.

There are limitless possibilities for the explanation of literally any phenomenon. Of course, not all of those possibilities have equal supporting evidence. The ones with the most supporting observational evidence are the ones that science pays the most attention to because they are the ones most likely to be correct.

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And also that everything you see may change any time. For now it looks like an expansion to you, tomorrow you wake up in your bed as a child in a mothership and enjoy the view of space without any memories of this world.

Could anything change at any point in time? Yes. Does that mean it's likely to happen? Not necessarily. Hence why science is about evidence and not proof. Science allows for the possibility of unforeseen discoveries.

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I want to more say that if you go by exact science. 100% detailed and deep thinking. The theory becomes meaningless. Because of limitless possibilities. Ever had a dream that changed abruptly dramatically? Why does science not assume that the
same thing can happen here and now? And that it may have happened before? Or that it always happens?

It doesn't assume that such a thing cannot happen. In fact, the idea of "false vacuum decay" would be an example of just such a thing happening.

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What meaning does the big bang theory have then if that's a fact?

The same meaning as any other theory such as cell theory, atomic theory, or the theory of plate tectonics. If the Universe changed instantly in an unpredictable way, any theory could be rendered moot. Is that evidence that all of our theories are wrong? No, it isn't.

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Official science lacks of assumption of different possibilities. For them observation is everything.

It does indeed consider different possibilities, especially right after a new phenomenon is discovered. The "tired light" theory was an alternative proposal to explain galactic redshift, for example. It was later falsified because the blurring effect it predicted was found not to occur.

But believe what you will. I'm out.
Title: Re: How do we know the Universe is expanding if we cannot see its edge?
Post by: evan_au on 29/10/2018 09:29:36
Quote from: Shark
No one has done the same tests on other galaxies....You'd have to travel with a spaceship there and do the same tests.
I think this is a misunderstanding.

We can measure the distance to other galaxies using "standard candles" and we can measure their radial velocity using Doppler shift.

We see that if a galaxy is traveling away from us at speed x, one twice as far away is travelling away from us at speed 2x.
- This relation holds whatever direction we look in the sky
- So we can actually calculate the velocities that would be seen from any of these other galaxies
- And we can do that without actually traveling to these other galaxies!

A policemen traveling along a road at 60 km/h, and his radar shows that someone else passes him at 60km/h relative to him. He knows that from the viewpoint of the other car, his velocity is -60km/h. Pretty simple arithmetic, really (provided the cars stay well below the speed of light...).

See: https://en.wikipedia.org/wiki/Cosmic_distance_ladder
https://en.wikipedia.org/wiki/Hubble%27s_law

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