Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: RobC on 19/03/2018 10:06:18

Title: Is dark energy real?
Post by: RobC on 19/03/2018 10:06:18
The accelerating expansion of the universe due to a mysterious quantity called “dark energy” may not be real, according to research claiming it might simply be an artefact caused by the physical structure of the cosmos.
The findings, reported in the Monthly Notices of the Royal Astronomical Society, claims the fit of Type Ia supernovae to a model universe with no dark energy appears to be slightly better than the fit using the standard dark energy model.
Title: Re: Is dark energy real?
Post by: PmbPhy on 19/03/2018 14:05:51
The accelerating expansion of the universe due to a mysterious quantity called “dark energy” may not be real, according to research claiming it might simply be an artefact caused by the physical structure of the cosmos.
The findings, reported in the Monthly Notices of the Royal Astronomical Society, claims the fit of Type Ia supernovae to a model universe with no dark energy appears to be slightly better than the fit using the standard dark energy model.
We can't take such claims seriously unless we know the source. That means the exact article. Please provide the name of the article and what month it appears in. In the meantime I'll look for it myself.

So far what I see has to do with the separate universe conjecture, which is a term I learned about 1 minute ago. It also pertains to a particular model, i.e. spherically symmetric sub-regions in an isotropic universe behave like mini-universes with their own cosmological parameters.

Is this what you're referring to? Concordance cosmology without dark energy by Gábor Rácz, László Dobos, Róbert Beck, István Szapudi, István Csabai, Mon Not R Astron Soc Lett 2017 slx026
https://arxiv.org/abs/1607.08797
Title: Re: Is dark energy real?
Post by: RobC on 19/03/2018 15:40:51
This is the source -  https://doi.org/10.1093/mnras/stx1858
I am getting 'no follow' after my link due to the number of posts I have made.
Title: Re: Is dark energy real?
Post by: PmbPhy on 19/03/2018 16:42:28
This is the source -  https://doi.org/10.1093/mnras/stx1858
I am getting 'no follow' after my link due to the number of posts I have made.
That article doesn't argue that dark energy may not be real per se. It argues that there are cosmological models which predict the current observations which don't employ dark energy. Nothing new.

When making predictions about cosmology its required to make certain assumptions. Also "may not be real" is not a new argument since everyone knows that physics is not about proving things. There's always going to be the fact that another way to explain observations may exist which are different than current ones.

These two interviews will help you understand this:
http://www.newenglandphysics.org/common_misconceptions/Alan_Guth_03.mp4
http://www.newenglandphysics.org/common_misconceptions/Alan_Guth_04.mp4
Title: Re: Is dark energy real?
Post by: jeffreyH on 19/03/2018 17:41:56
Where else are you going to get a chance to see Alan Guth explaining how the universe may have come about and the limitations of our understanding?
Title: Re: Is dark energy real?
Post by: Bill S on 19/03/2018 19:08:25
Quote from: Pete
These two interviews will help you understand this:

I can't open either of these links.  Is it me, or is anyone else having trouble?
Title: Re: Is dark energy real?
Post by: PmbPhy on 19/03/2018 19:24:04
Quote from: Pete
These two interviews will help you understand this:

I can't open either of these links.  Is it me, or is anyone else having trouble?
What browser are you using?

I have Internet Explorer. I click on it and it starts Windows Media Player and plays. If its not working for you then place the mouse pointer over the link, right click and select "Save target as ..." and then select a place to save it and let it download. Then try opening it.

Jeff - Righto!:)    Alan did those for me two years ago. I asked that he preview them before I made them available. After so long of waiting I gave up and placed them online. Only because I know he'd find them acceptable. After all, I gave him not merely months but years to preview them. And it would have only taken in 15 minutes to do so. That goes to show you how busy he always is. That's one reason I'm thankful never to have been hired at MIT.

Job hunting sucks. I'm now either over qualified or underqualified. I wish I was simply "qualified". Lol! It did feel good to be overqualified for a major hospitals cyclotron lab though. It's run by Harvard. It felt good and bad at the same time not to get the job. I'm soooo cooooonfuuuuuused. ROTFL!!!
Title: Re: Is dark energy real?
Post by: Bill S on 19/03/2018 20:12:57
Thanks, Pete.  I'll do my best to follow your advice.
Title: Re: Is dark energy real?
Post by: Bill S on 20/03/2018 19:54:57
Got the links, thanks, Pete.  Looking forward to having time to see them.