Jim Kalahalliwalli or whataver

[JimC]

It seems that every time there's a new cosmology, whether it be Galileo's, Newton's or Einstein's - not to mention the religious ones - there is a period where it becomes the orthodoxy and people who challenge it risk looking foolish - and even come to harm in some cases. Perhaps the current orthodoxy is about to experience as big a shift.

A red shift or a blue shift?

[Rum]

Is it possible that some basic tool used these days, which much else relies on (for example read shift, 'standard candles' etc.) is fundamentally wrong an that the whole edifice based on assuming some part of the foundation is correct is in fact not?

I wish I understood the maths of the physics more. Ironically I take much of it on faith.

[pErvinalia]

Nah, acceptance of logic and the scientific method isn't "faith".

[JimC]

Is it possible that some basic tool used these days, which much else relies on (for example read shift, 'standard candles' etc.) is fundamentally wrong an that the whole edifice based on assuming some part of the foundation is correct is in fact not?

I wish I understood the maths of the physics more. Ironically I take much of it on faith.

Nah, acceptance of logic and the scientific method isn't "faith".

However, I know what Rum means. I imagine have gone further along the maths path, but certainly not to the point where I can say that I fully comprehend all of the conclusions, so, one relies on the professional opinion of the scientists in the field as a group, which Rum simply used "taking on faith" as a shorthand.

From articles I have read in New Scientist, there is a fairly lively debate about the underpinnings of cosmology, and various scientists are not afraid of challenging the orthodox position. Of course, ultimately it comes down to getting the best set of data possible, then testing your models against that.

[mistermack]

I've often wondered about red shift. What if, over vast distances of space, the wavelength of light lengthens slightly?

What you would see would be light from farthest away more altered than light from nearby. A progressive red shift. Giving the impression of an expanding universe.

Or, what if we are getting smaller, and the universe is just staying the same size? It would look to us like it was expanding. Because our measurements are shrinking.

That's just me musing. A proper physicist would tell you straight away why those things couldn't be. I guess.

[JimC]

I've often wondered about red shift. What if, over vast distances of space, the wavelength of light lengthens slightly?

What you would see would be light from farthest away more altered than light from nearby. A progressive red shift. Giving the impression of an expanding universe.

Or, what if we are getting smaller, and the universe is just staying the same size? It would look to us like it was expanding. Because our measurements are shrinking.

That's just me musing. A proper physicist would tell you straight away why those things couldn't be. I guess.

Red and blue shifts can be observed and measured in the light emitted from fast moving objects on Earth.

[mistermack]

I've often wondered about red shift. What if, over vast distances of space, the wavelength of light lengthens slightly?

What you would see would be light from farthest away more altered than light from nearby. A progressive red shift. Giving the impression of an expanding universe.

Or, what if we are getting smaller, and the universe is just staying the same size? It would look to us like it was expanding. Because our measurements are shrinking.

That's just me musing. A proper physicist would tell you straight away why those things couldn't be. I guess.

Red and blue shifts can be observed and measured in the light emitted from fast moving objects on Earth.

Yeh, of course, I'm not saying that light doesn't undergo shift when the source is moving.
But if it also undergoes an extremely minute shift, for each unit of distance traveled in space, you would get the same result, as if the universe was expanding.

Red light has lower energy than blue. Maybe it's possible that light loses just a tiny amount of energy as it goes through space. That would have to show up as a red shift.

I'm sure that physics will have discounted that possibility, through some sort of observations. Haven't heard of it, but it would be the first thing you would have to do, before making the claim that the universe is expanding.

[Rum]

I have always been suspicious about the apparent 'fact' that a certain type of super-nova emits a standard amount of light at a certain point and that this is then used as a standardised measurement for distance. Not understanding the maths (as per my point above) means I have to take this as given, however I still find myself suspicious of the logic involved.

[mistermack]

I have always been suspicious about the apparent 'fact' that a certain type of super-nova emits a standard amount of light at a certain point and that this is then used as a standardised measurement for distance. Not understanding the maths (as per my point above) means I have to take this as given, however I still find myself suspicious of the logic involved.

As I understand it, it's not so much the maths as the physics.
The super-novas of a certain type can only collapse when they reach a certain critical mass, so the resulting explosion is of a known brightness.

That might be complete bollocks, it's just how I remember it. But I think there is still some doubt about how accurate and reliable they are.

[Rum]

I have always been suspicious about the apparent 'fact' that a certain type of super-nova emits a standard amount of light at a certain point and that this is then used as a standardised measurement for distance. Not understanding the maths (as per my point above) means I have to take this as given, however I still find myself suspicious of the logic involved.

As I understand it, it's not so much the maths as the physics.
The super-novas of a certain type can only collapse when they reach a certain critical mass, so the resulting explosion is of a known brightness.

That might be complete bollocks, it's just how I remember it. But I think there is still some doubt about how accurate and reliable they are.

I think you remember it right - and physics and maths are interchangeable as far as I am concerned at that level. One assumes some of Mr Einstein's equations are in there somewhere in terms of mass being converted to energy, however I'm still not convinced. I am almost certainly wrong but I dunt unnerstand it.