In 1929, Edwin Hubble measured the brightness and redshift of distant stars to calculate their distance and escape velocity. The resulting data, plotted on the now famous Hubble diagram, showed a proportional relationship between distance and redshift. It is important to note, however, that any measurement of a star's brightness (magnitude) also gives its corresponding lookback time. But is the correlation between redshift and lookback time causal or spurious, or is even the correlation between redshift and distance spurious ?In other words, does the redshift brightness plot reflect the spatial or the temporal evolution of the Universe or both, and to what extent? This article shows that there are many different possible events that could lead to the same redshift brightness diagram. For example, the redshift could depend almost entirely on changes in distance, or almost entirely on changes in lookback time. It turns out that the more redshift depends on changes in distance, the less it depends on changes in lookback time, and vice versa. However, due to a lack of data, no one knows what really happened. But many things would be simpler, if one assumed that the redshift depends almost exclusively on the lookback time: The amazing idea of an expanding space would not be necessary. The expansion rate of the universe would be steadily decreasing.Dark energy and the cosmological constant (Einstein's biggest blunder) would not be necessary. Until new discoveries are made, it is not possible to determine what conclusions can be drawn from a redshift brightness diagram.But these inferences are a key pillar of the ΛCDM model. If this pillar wobbles, the whole structure could collapse.