Evidence that the key assumption made in discovery of dark energy is in error

Re:Evidence that the key assumption made in discovery of dar... by mirimir on Monday January 06, 2020 @08:08PM (#21975631)

That's how I understand it.

But maybe there are other standardizable objects. The sense I got from TFA is that there aren't.

[ Parent | on HN ]

Re:Evidence that the key assumption made in discovery of dar... by kiliantics on Monday January 06, 2020 @08:23PM (#21975748)

There are actually. There is a class of star in the "tip of the red giant branch" (TRGB) which have also been used to calibrate luminosities of type Ia supernovae[0] to form a "cosmic distance ladder". I believe they have been used to confirm the accelerated expansion results (though less strongly). I am not super well versed in stellar evolution, but I believe that the TRGB should make this calibration method independent of progenitor age? Hopefully someone could chime in on this. I was formerly a cosmologist and would be very interested to know more about this result from any experts that might be reading this.

[0] There is an explanation of this calibration here: https://aasnova.org/2019/07/26/tldr-the-trgb-gives-us-anothe...

[ Parent | on HN ]

Re:Evidence that the key assumption made in discovery of dar... by sanxiyn on Tuesday January 07, 2020 @12:31AM (#21977209)

Nope, the link is proposing TRGB-SNIa as an alternative to Cepheid-SNIa, not TRGB as an alternative to SNIa.

[ Parent | on HN ]

Re:Evidence that the key assumption made in discovery of dar... by mirimir on Tuesday January 07, 2020 @09:49AM (#21980367)

Yeah. In my reading, it almost characterized SNIa as fact.

[ Parent | on HN ]

Re:Evidence that the key assumption made in discovery of dar... by ncmncm on Monday January 06, 2020 @09:01PM (#21975980)

Of course these could have the same, or a related, problem.

[ Parent | on HN ]