Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Lawrence Krauss: Do Your Homework Problems with dark energy from improperly analyzed data Michael L. Smith1
Ahmet M. Özta¸s2
1
[email protected] 2 Department
of Physics and Engineering Hacettepe University T-06800 Ankara, Turkey
June 26, 2017
MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Outline Several dark energy problems Declarations of astrophysicists Problems of improper analysis Better analysis Summary Credits and references MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Dark Energy Problems I
Dark Energy (DE) is a mysterious substance which is accelerating our Universe expansion, with properties of I I
I
The DE theory has many problems I
I I
I
responsible for large-scale, galactic group expansion is about 75% of our Universe contents DE effects only intergalactic expansion velocities, not intra-galactic velocities, or anything smaller DE has never been observed on or near earth The magnitude of DE differs many orders of magnitude from expectation, 1030 to 10120 , the cosmological constant problem.
It appears that DE is now a case of special pleading. MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Dark Energy Problems Initial Declaration of DE from SNe Ia data I
Two groups of astronomers declared DE in 1998, 1999[1].
I
We have previously shown that astronomers improperly analyzed the supernovae (SNe Ia) data in 1998 and 1999[2]. I Astronomers used log-transformed data, with FRW variants, not measured values of SNe Ia distances. I These people did not follow the requirements of simple physics for object analysis - using distance and velocity. I Estimated errors of SNe Ia positions are incredibly large. I Improperly discarded the position of our galaxy (earth).
I
Badly flawed evidence for DE is still being presented[3]. MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
The Dark Energy Problem Improper analysis of SNe Ia data I
An example is a graph which is presented in a video by Lawrence Krauss (2015) and the very similar next slide[3].
I
There are a some interesting items of note on this graph I
I
I
I I
The ordinate does not have a metric; modulus (or magnitude) is really not distance[1]. The abscissa is the log(redshift). The redshift, z, is a function of the recession velocity but not velocity. There is no value for our galaxy(earth) position, which is known precisely and should be used as the origin. The standard errors are nearly independent of modulus. Contrast this presentation with Hubble’s (subsequent slide). MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Astrophysics Example - log(distance) vs log(redshift) - improper modeling
Figure 1: modulus, m, vs log(redshift, z) fit with ΛCDM model; 157 SNe Ia (gold) data pairs from Riess[4] displayed w/o data massage. MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
The real Hubble Diagram - velocity vs distance (pc) - better analysis
Figure 2: Velocity vs distance (pc) for several nearby galaxies; from Hubble, 1929[5]. Note the proper use of the origin (earth). MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
The Dark Energy Problem Improper analysis of SNe Ia data I
I
I
I
I
Note the previous slide presented the “Hubble diagram”; the first graph is not a Hubble diagram. The next graph presents the modulus residuals of the log-fit of the ΛCDM model to the 157 SNe Ia of Riess (2004)[4]. Note the residual distances from the best fit are independent of the redshift, z. One expects both standard errors and residuals to be larger with increasing distance, z, from the observation. This reflects improper data analysis and lack of critical reasoning by the article authors. MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Astrophysics Example - fit residuals w/r to log(Z ) - poor technique
Figure 3: modulus residuals for ΛCDM model fit to 157 SNe Ia data pairs (gold) from Riess[4]. MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Improper modeling
I
I I
The next slide presents tabulated results when two simple models are fit using log(distance), that is modulus vs. redshift from 157 SNe Ia (gold) data. Remember the smaller the χ 2 value the better the fit. Here the DE model is the better fit.
MLS, AMÖ
Do your homework LK
Introduction Improper analysis Improper and better modeling Summary and Predictions Credits and Bibliography
Results from improper fits
Table 1: Fitting Semilog (modulus) FRW Models - Results
Model
Ωm
ΛCDM 0.31±0.04 Ωk †
