As it was expected, astrophysicists considered the research of transients at high Z (supernovae at high Z) as of utmost importance and especially the light curves for high Z supernovae - will the width of light curves follow 1+Z rule they must follow if Big Bang is valid. The research is in progress and first article [1] is published where James Webb Space Telescope observed the same patch of sky month after month for already more than one year - so any supernova discovered may have at least few time points and some evaluation of the width of the light curve is possible. The project called NEXUS and importance is obvious - the research of supernovae - standard objects (more or less) allows to use those standard beacons to probe the matter and space-time between supernovae and Earth.
As it was mentioned on this blog [2], supernovae is a compact object contrary to galaxy and at high Z must be a point source (resolution of James Webb Space Telescope is several orders below what is necessary to resolve supernova image, so high Z supernova must always have a visible size exactly at diffraction limit of telescope - in Big Bang cosmology). In reality the image is way too large, which is confirmation of tired light theory (light is interacting with something, scattered and image is blurred). Since light is statistically scattered - away from straight path and then back -some photons will have a substantial time delay en route - this is the source of light curve broadening for supernova light curve in the case of tired light theory (it is the same Doppler or Doppler-like effect as cosmological red shift in the case of Big Bang). While for Z~1 the predictions of light curve broadening somewhat close to Big Bang theory prediction (the difference is small and difficult to find because of so big experimental errors present), for high Z (say Z>3) the difference would be huge: Big Bang theory predicts behavior like 1+Z, while tired light something like sqrt(1+Z). For Z=5 the supernova should be observed (if Big Bang is valid) for around 600 days [3] (instead of around 100 days near Earth for supernova type 2) while tired light prediction would be much smaller - something like 250 days. That enormous difference should not possible to miss even for very rough and imprecise measurements.
To perform such measurements I used light curves present as points in Fig. 8 from [1] and manually by eye finished light curves. The results are in picture below with days are in Earth time frame.
Figure 1. The approximate light curves for supernovae detected in NEXUS experiment.
I also added manual fit of the pictures of supernovae at highest Z mentioned in [1]: AT 2025xcu Z=6.15 yields ~200 days and AT 2025amol at Z=4.27 yields ~150 days.
I put all the approximate widths on one plot and compared two possible scenarios:
Figure 2. The plot of all widths clearly differentiates between tired light and Big Bang mechanisms.
I assumed for simplicity that the due to the loss of light for high Z the observation abilities of James Webb Space Telescope would be comparable to weak Earth-based telescope which should show some glow from Supernova type 2 for around 100 days from start till full unobservability [4]. Undoubtedly supernova of any type at Z~0 would be observed by JWST forever (nebulae afterglow assumed to lasts for tens of thousands of years). But at high Z actually supernova is not even recorded easily, so comparison with weak telescope should be fair.
The best fit of the data is actually no dependence at all. If I would put intercept at 100 at Z=0 it would have some slope:
Fig.3 The best linear fit with intercept put at 100 at Z=0 (as it is expected for supernovae at Z~0)
Even elimination of the points at highest Z does not create a strong visible correlation:
As it is clear from figure 2, the approximation of tired light looks much better compare to the Big Bang prediction. While the NEXUS experiment is underway till 2028, it is not expected to show any supernovae shining for a year or more (but according to Big Bang and Doppler mechanism James Webb Space Telescope must already clearly demonstrate such enormously elongated light curves). Most probably all the high Z supernovae will demonstrate light curves in the range of 150-200 days after much more accurate fit instead of my hand-made plots. It seems that time dilation as a function of Z goes to some kind of saturation well below demanded by Big Bang Theory 1+Z time.
This "saturation" seemingly correlated with visible angular sizes of supernovae shown in [2]:
Indeed, the time dilation and angular size of blurring has the same origin: some photons are traveling away from direct line and returning back (that changes the travel time creating the temporal widening of any event and changing an angle at arrival, thus creating visible origin of the photon not at the center of supernova). Both phenomena governed by diffusion-like law very approximately like sqrt(Z) or sqrt(1+Z), which at high enough Z must be very different from 1+Z demanded by Doppler mechanism.
References.
1.Ming-Yang Zhuang, Lei Hu, Justin D. R. Pierel, Zhiwei Pan et all "NEXUS: Transient Searches and First Results from Year One Observations" // Published on ARXIV, September 2026.
NEXUS: Transient Searches and First Results from Year One Observations
https://arxiv.org/pdf/2609.06985
https://tipikin.blogspot.com/2025/01/the-higher-z-stronger-effect-of-light.html
3.Ming-Yang Zhuang, Lei Hu, Justin D. R. Pierel, Zhiwei Pan et all "NEXUS: Discovery of a Luminous Young Transient at z=5" // Published on ARXIV, September 2026.
[2609.38373] NEXUS: Discovery of a Luminous Young Transient at $z=5$
https://arxiv.org/abs/2609.38373
4.Astronomers investigate type IIP supernova with a long plateau
https://phys.org/news/2018-06-astronomers-iip-supernova-plateau.html




