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View Full Version here: : The goal posts just moved: Standard Candle Changes


xelasnave
14-01-2011, 08:47 AM
Just when everything is set in cement we get this....

http://www.sciencedaily.com/releases/2011/01/110112143218.htm


alex:):):)

CraigS
14-01-2011, 09:37 AM
Hmm .. I did a thread a while ago (http://www.iceinspace.com.au/forum/showthread.php?t=68637&highlight=Cepheid) on how they'd used an eclipse of a Cepheid to accurately determine their mass thus adding more 'weight' to the theory of "Stellar Pulsation" and its predictions, over "Stellar Evolution Theory".

Now they're saying:


Hmm .. interesting.

Cheers

CraigS
14-01-2011, 09:44 AM
And then … just to make the idea of 'Standard Candles' even less firm:

High-energy surprises found in 'constant' Crab Nebula (w/ Video) (http://www.physorg.com/news/2011-01-high-energy-constant-crab-nebula-video.html)



Careful use going forward in the concept of 'Standard Candles', eh ?

Have to remember this one when wrangling over distance measurement issues.

Cheers

xelasnave
14-01-2011, 09:52 AM
CAn you hold the end of this tape and I will run it out and check;).

Sorry I missed the earlier material but thankfully I now know everything:rolleyes:

Thanks for that Craig:thanx:.

alex:):):)

CraigS
14-01-2011, 10:09 AM
Alex could I make a request of you to change the name of this thread to something which includes the words: "Standard Candles" .. something like 'Standard Candle Changes' or something like that ?

The reason being that I've got another article I'd like to add to it and it just makes it easier than creating another thread and easier to search for at sometime in the future

Appreciate it if you could do this

Cheers

Grendel
14-01-2011, 10:12 AM
Alex if you want I'll hold one end here in the UK, you could hold the other end down under and that should give us a good baseline.
Grendel

CraigS
14-01-2011, 10:26 AM
Here comes another variation to the Standard Candle .. this time for the cornerstone .. Type IA Supernovae !!! …

The best way to measure dark energy just got better (http://www.physorg.com/news/2011-01-dark-energy.html)



His study includes 100 Supernovae. The assumption that all Supernovae are on average, the same colour, and redder due to intervening dust, now seems to be outdated.


Cheers

xelasnave
14-01-2011, 10:26 AM
Hi Peter
May I take the opportunity to welcome you to Iceinspace.
You will find a few of the old gang here. Seeker put me onto this most wonderful site many years ago and I am very happy that he did.
I hope you can join in.
Anyways I will dash off to the hardware store and find a suitable tape... mmm maybe one of those fancy ones that you point and it calls out the answer.

Craig... I will if I can but editing in not one of my strengths:D...anyways a new thread is always cool particularly if you start it;).

alex:):):)

[1ponders]
14-01-2011, 10:33 AM
Thread title edited.

CraigS
14-01-2011, 10:49 AM
Ahh thanks muchly, Paul.

Most appreciated.
:)

Cheers

astroron
14-01-2011, 10:50 AM
That is a great article, Just like with Supernova being asymmetrical and not exploding in all directions equally,so this mass loss in this type of star adds another dimension to the accuracy of information used to define the distance scale.
Cheers

CraigS
14-01-2011, 10:55 AM
G'Day Ron;

Yes .. but the Supernova change is stated as being only a second order effect.
(In other words, just making it more accurate, I think .. no dramatic changes).



But the funny thing is that improvements in understanding of all the three 'Standards' have been announced almost on the same day !!!

Perhaps its only us who've realised this !! A new discovery here at IIS, every day, eh ?
:)

Cheers

Rob_K
14-01-2011, 11:05 AM
I don't really see a paradigm shift in any of this - the goalposts were never set in the first place. I doesn't operate like that. We were always acutely aware of the underlying assumptions involved in the use of Cepheid variables as 'standard candles', and there were observational anomolies that needed mechanisms to explain them. Now with better and better observational data flooding in we can come to grips with this and further refine their use. :)

Cheers -