In our second online poll to find out what Plus readers would most like to know about the Universe, you told us that you'd like to know if the constants of nature really are constant. We took the question to cosmologist John D. Barrow, Professor of Mathematical Sciences at the University of Cambridge, and here is his answer. Please feel free to discuss the answer by leaving a comment on this blog. We'll periodically check back with the experts to try and answer interesting further questions.

This article is part of a series to celebrate the International Year of Astronomy 2009. The third poll to find out what you'd like to know most about the Universe is open now, so get voting!

Labels: IYA2009

posted by Plus @ 1:15 PM

6 Comments:

At 2:36 PM,  Shelly said...

The speed of light is assumed to be constant. Einstein, Hawkings and many, many other scientists of great renown have assumed this.

Why? Is there any theoretical proof?

 

At 4:50 AM,  Seeley said...

Insightful.

 

At 9:42 AM,  The Plus Team said...

This post has been removed by a blog administrator.

 

At 9:49 AM,  The Plus Team said...

Hi Shelly,

We took your question about the speed of light to John D Barrow and here is his answer:

"No, there can never be a proof that the speed of light is constant. Relativity theory requires the speed of light in vacuum to be constant and the same for all observers. All we can do is test whether that is true and hence whether the theory of relativity is a corrrect description of nature. There may be tiny quantum mechanical corrections to the theory which produce very small changes in extreme environments (very small distance, high frequencies or strong gavitational fields)."

We hope this answers the question!

 

At 12:03 PM,  Martijn said...

"An added subtlety is that in most of these possible worlds life cannot exist."

This leads to another question: what do you mean by 'life'? What makes life special? How can it be that there might be a world where rocks etc. can exist but 'life' (whatever definition you choose for that word) can't?

 

At 1:55 AM,  dheeraj said...

A constant is nothing but it is a derived numerical ratio between the two same fundamental quantities.The constant is said to be a point function,since it is constant at a point when it is made to travel at different atmosphere with different velocities,the value of constant may varie and moreover an example to say that the velocity of light is constant,when abody is made to move with a velocity equal to light then the constant may vary relative to this object speed.so constant is an induvidual point function and independent from the different variables.