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NEVER FORGET THIS. “Another major drawback of the Standard Model is the fact that it uses two predominant components, dark matter and dark energy, supposed to represent about 95% of the universe energy density, but which have remarkably resisted to experimental identification so far.” https://lnkd.in/daA2SgMy View in LinkedIn

THE KEY. “All of the observational evidence for DM to date comes from its gravitational effects. Therefore it’s not unreasonable to ask whether the observations could instead be explained by modifying the laws of gravity.” (DM = dark matter). https://lnkd.in/e6ifiQMn View in LinkedIn

INDIRECT SENSING. “Large scale structure observations are typically not as powerful or clean a probe of cosmological parameters on their own as the CMB anisotropies are (galaxies are biased tracers of the matter distribution, redshift is a combination of expansion and peculiar velocity etc.).” (CMB = cosmic microwave background). https://lnkd.in/e6ifiQMn View in LinkedIn

FLAT GEOMETRY. “The positions of the acoustic peaks in the CMB angular power spectrum (or equivalently the typical size of the hot/cold spots) are largely sensitive to the geometry of the Universe, and hence the total energy. i.e. the total energy density is very close to the critical density for which the geometry of the universe is flat.” (CMB = cosmic microwave background). https://lnkd.in/e6ifiQMn View in LinkedIn

INEQUALITIES. “In other words, non-baryonic DM is required for perturbations to grow sufficiently from the initial amplitude, as measured from the CMB anisotropies.”(DM = dark matter; CMB = cosmic microwave background). https://lnkd.in/e6ifiQMn View in LinkedIn

MONSTER CRATER. “The Bouguer gravity anomaly shows a large well-defined semi-circular concentric anomaly pattern with amplitudes up to 30 mGals with a 40 km diameter central high and two lows at about 70 km and 120 km diameters (Figure 2). Semi- circular concentric anomalies were inferred at 52.5±5km,77.1±6.3 km, 99.6±6 km and 139 ± 11 km radial distance, which define a multi-ring structure with central peak ring limited by ring 1.” https://lnkd.in/eqAYpQg2 View in LinkedIn

VISIBLE MATTER. “Baryons, however, are tightly coupled to photons until decoupling, at tdec ≈ 0.4 Myr and therefore perturbations in baryons can only grow after decoupling. Consequently in a universe without non-baryonic DM the initial density perturbations have to be larger, and produce larger temperature fluctuations in the CMB, ∆T/T ∼ 10(-4), for observed structures to form.” (DM = dark matter; CMB = cosmic microwave background). https://lnkd.in/e6ifiQMn View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend and concludes tomorrow on the theme of the physiological reason for the extinction of the dinosaurs. Such an existential threat from a meteor strike on our planet is very real, as one glance at the pockmarked surface of the moon will confirm. The universe is violent and unpredictable, on scales beyond our ability to change, so hurry about your business without a care. View in LinkedIn

PRESENT BY ABSENCE. “The detailed scale dependence of the temperature anisotropies in the CMB allow the total, matter and baryon density parameters to be measured precisely. However the measured typical amplitude of the fluctuations, ∆T/T ≈ 10(-5), alone provides evidence for non-baryonic DM.” (DM = dark matter; CMB = cosmic microwave background). https://lnkd.in/e6ifiQMn View in LinkedIn

The Little Prince in his common state, relaxing. View in LinkedIn