Luminosity Evolution in Supernova Cosmology

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Richard D. Saam

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Jan 18, 2020, 6:21:50 AM1/18/20
to
Early-type Host Galaxies of Type Ia Supernovae. II. Evidence
for Luminosity Evolution in Supernova Cosmology
https://arxiv.org/abs/1912.04903

The authors statement:
'We argue, therefore, that this systematic bias must be considered
in detail in SN cosmology before proceeding to the details
of the dark energy.'

Such a statement is revolutionary on its face.

Is this going to bend the arc of cosmological science?

Richard

Phillip Helbig (undress to reply)

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Jan 19, 2020, 6:04:48 PM1/19/20
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In article <Y4OdneM55LfKpr_D...@giganews.com>, "Richard D.
Saam" <rds...@att.net> writes:=20

> Early-type Host Galaxies of Type Ia Supernovae. II. Evidence
> for Luminosity Evolution in Supernova Cosmology
> https://arxiv.org/abs/1912.04903
>=20
> The authors statement:
> 'We argue, therefore, that this systematic bias must be considered
> in detail in SN cosmology before proceeding to the details
> of the dark energy.'
>=20
> Such a statement is revolutionary on its face.

No. One ALWAYS has to take systematic bias into account when analysing=20
data. Perhaps they have found something new. If it holds up, then it=20
has to be taken into account.

> Is this going to bend the arc of cosmological science?

By itself, no. There seems to be a widespread misconception that the=20
ONLY evidence for a positive cosmological constant or (a stronger claim)=20
an accelerating universe is the supernova data. The concordance model=20
is called the concordance model because many different lines of evidence=20
point to the same values of the cosmological parameters. The=20
accelerating universe is still there even completely ignoring the=20
supernova data. These days, JUST THE CMB tells us that the universe is=20
accelerating. So, if this effect affects the conclusions from the=20
supernova data so much that an accelerating universe is ruled out (as=20
the hype surrounding this paper sometimes implies), then one has to=20
explain why essentially ALL THE OTHER COSMOLOGICAL TESTS ARE WRONG. Not=20
only that, they are all wrong but just happen to give the same result.

Note that the quote above is=20

We argue, therefore, that this systematic bias must be considered
in detail in SN cosmology before proceeding to the details of the=20
dark energy.'

DETAILS. Of course it has to be taken into account. Whether it would=20
lead to a conclusion incompatible with other tests is a different=20
question. Even if it does, the interpretation is probably not that=20
there is not a cosmological constant.

See also my reply to Alex (and, indeed, the post and all the comments)
at=20

https://telescoper.wordpress.com/2020/01/14/luminosity-evolution-in-type=
-1a-supernovae/
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