(09-24-2014 12:18 PM)jh Wrote:  

Quote:The paper, which was recently submitted to ArXiv, an online repository of physics papers that is not peer-reviewed, offers exact numerical solutions to this problem and was done in collaboration with Harald Peiffer, an expert on numerical relativity at the University of Toronto. An earlier paper, by Mersini-Houghton, originally submitted to ArXiv in June, was published in the journal Physics Letters B, and offers approximate solutions to the problem.

Maybe I'm missing something, but this seems really odd. She's a physics professor at a respected university publishing something that would be a truly groundbreaking result, yet she is just dropping it in an online repository that isn't peer reviewed?

Many physical scientists and mathematicians upload to arxiv before submitting to a regular journal. A lot of mathematicians do it because that field is going towards complete open access.

(09-24-2014 12:13 PM)UofMstateU Wrote:  

(09-24-2014 11:39 AM)DrTorch Wrote:  

(09-24-2014 11:36 AM)Bull_In_Exile Wrote:  Torch it's not my field but I'd have to imagine the implications to our understanding of the universe would be torn apart by this right? Black holes have been pretty central to things for about what, 50 years?

I'd have to dig in and study her conclusions more. She may be insisting that some of the (potentially important, but likely highly theoretical) properties assigned to black holes, just can't exist, but that these massive gravitational objects are present. In that case, it might not be such a shake up.

Yea, it could be that her math has proven that their existing theories about black holes arent correct. Not that black holes dont exist, but their theorized characteristics are wrong.
I have always had an issue with "singularity", as well as tying time to anything. I have been more of a "distance contraction" believer myself. (Primarily because I have thought of ways to violate Einsteins e=mc2 equation when using multiple objects and adding gravity into the mix.)

I took a quick look at her paper. Her claim is that stars do not collapse into super-massive objects. Instead, as they collapse they reach a point where they "bounce" and start getting bigger. Her calculations are not robust enough to determine if they explode or evaporate, but there doesn't seem to be much room for any super-massive leftovers.

Of course, when the math seems to conflict with the observations, I usually suspect there is a problem with the math.

(09-24-2014 12:18 PM)jh Wrote:  Maybe I'm missing something, but this seems really odd. She's a physics professor at a respected university publishing something that would be a truly groundbreaking result, yet she is just dropping it in an online repository that isn't peer reviewed?

Yea, it almost has the same feel as that "cold fusion" discovery a few years back.

"I've discovered cold fusion!"

really, how'd you get it to work?

"Baking Soda!"

wow, can I see your work on that?

"NO!"

Rethinking the origins of the universe | The University of North Carolina at Chapel Hill

http://unc.edu/spotlight/rethinking-the-...-universe/ Wrote:Before a black hole can form, the dying star swells one last time and then explodes. A singularity never forms and neither does an event horizon. The take home message of her work is clear: there is no such thing as a black hole.

The real takeaway is that black holes act somewhat differently than had been previously thought, and the idea that they are temporary is pretty important.

http://unc.edu/spotlight/rethinking-the-...-universe/ Wrote:Many physicists and astronomers believe that our universe originated from a singularity that began expanding with the Big Bang. However, if singularities do not exist, then physicists have to rethink their ideas of the Big Bang and whether it ever happened.

Physicists, philosophers, theologians have and will continue to rethink their ideas of creation as none of them are or can be satisfactory. That would happen with or without this finding, but, presuming it stands and gains acceptance, this will be a pretty influential finding.

Incidentally, it will be interesting to see if her thoughts on creation change as a result of this work...

Laura Mersini-Houghton - Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/Laura_Mersini-Houghton Wrote:She is a proponent of the multiverse theory which holds that our universe is one of many

(09-24-2014 11:49 AM)VA49er Wrote:  So what exactly is at the center of our own galaxy then?

I'm surprised you haven't brought this up yet...

Laura Mersini-Houghton, a physics professor at UNC-Chapel Hill in the College of Arts and Sciences

(09-24-2014 12:25 PM)jh Wrote:  

(09-24-2014 12:13 PM)UofMstateU Wrote:  

(09-24-2014 11:39 AM)DrTorch Wrote:  

(09-24-2014 11:36 AM)Bull_In_Exile Wrote:  Torch it's not my field but I'd have to imagine the implications to our understanding of the universe would be torn apart by this right? Black holes have been pretty central to things for about what, 50 years?

I'd have to dig in and study her conclusions more. She may be insisting that some of the (potentially important, but likely highly theoretical) properties assigned to black holes, just can't exist, but that these massive gravitational objects are present. In that case, it might not be such a shake up.

Yea, it could be that her math has proven that their existing theories about black holes arent correct. Not that black holes dont exist, but their theorized characteristics are wrong.
I have always had an issue with "singularity", as well as tying time to anything. I have been more of a "distance contraction" believer myself. (Primarily because I have thought of ways to violate Einsteins e=mc2 equation when using multiple objects and adding gravity into the mix.)

I took a quick look at her paper. Her claim is that stars do not collapse into super-massive objects. Instead, as they collapse they reach a point where they "bounce" and start getting bigger. Her calculations are not robust enough to determine if they explode or evaporate, but there doesn't seem to be much room for any super-massive leftovers.

Of course, when the math seems to conflict with the observations, I usually suspect there is a problem with the math.

CLIMATE DENIER

(09-24-2014 12:31 PM)LSU04_08 Wrote:  

(09-24-2014 11:49 AM)VA49er Wrote:  So what exactly is at the center of our own galaxy then?

I'm surprised you haven't brought this up yet...

Laura Mersini-Houghton, a physics professor at UNC-Chapel Hill in the College of Arts and Sciences

I did notice that but didn't want to go that route.

(09-24-2014 12:26 PM)I45owl Wrote:  

http://unc.edu/spotlight/rethinking-the-...-universe/ Wrote:Many physicists and astronomers believe that our universe originated from a singularity that began expanding with the Big Bang. However, if singularities do not exist, then physicists have to rethink their ideas of the Big Bang and whether it ever happened.

Physicists, philosophers, theologians have and will continue to rethink their ideas of creation as none of them are or can be satisfactory. That would happen with or without this finding, but, presuming it stands and gains acceptance, this will be a pretty influential finding.

I don't see how this would prove that singularities don't exist. If true, it would merely prove that one proposed method of creating a singularity does not work.

(09-24-2014 12:35 PM)jh Wrote:  I don't see how this would prove that singularities don't exist. If true, it would merely prove that one proposed method of creating a singularity does not work.

I agree. It may also mean we need a new name for the near-end-stage of massive stars. I propose "blackish holes".

Although I am way past the stage where I may have followed her mathematics, the one part that stands out to me is the duration of the star's collapse prior to "bouncing". How long that duration is would dramatically effect how much Hawking radiation is observed, and I'd presume that it is much shorter than the period where a putative black hole would consume the volume of its stellar remnants. In her proposal, you'd still observe Hawking radiation after a collapse, and you'd still (fail to) observe the existence of a black hole (i.e. either way, you'd observe circumstances that fit the existence of a black hole), but since the time that those conditions existed, I'd expect to see dramatically fewer such circumstances.

(09-24-2014 01:01 PM)I45owl Wrote:  

(09-24-2014 12:35 PM)jh Wrote:  I don't see how this would prove that singularities don't exist. If true, it would merely prove that one proposed method of creating a singularity does not work.

I agree. It may also mean we need a new name for the near-end-stage of massive stars. I propose "blackish holes".

Lame. How about "puce"?

(09-24-2014 12:31 PM)LSU04_08 Wrote:  

(09-24-2014 11:49 AM)VA49er Wrote:  So what exactly is at the center of our own galaxy then?

I'm surprised you haven't brought this up yet...

Laura Mersini-Houghton, a physics professor at UNC-Chapel Hill in the College of Arts and Sciences

This guy..

(09-24-2014 12:13 PM)ODUgradstudent Wrote:  

(09-24-2014 12:06 PM)QuestionSocratic Wrote:  Another misconceived concept is infinity. What is infinity?

Well it drove Cantor mad

(09-24-2014 12:06 PM)QuestionSocratic Wrote:  Here's the cute part. It can be proven that 100% of all the real numbers are irrational.

I've never heard of this idea before, it doesn't make sense to me. Can you post an article or paper about it?

I took Number Theory in 1966. I recall it was a rather simple proof but although the details escaped me about 45 years ago, the general idea has stuck because, as you pointed out, it seems so strange. Maybe the Khan Academy has something.

Bottom line is that, as physicist Leonard Susskind has said (paraphrased): "I doubt we will ever know everything."