Images obtained from the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS)‐M instrument onboard Venus Express present visible trains of alternating bands of cloud brightness in two different layers: at the upper cloud tops (∼66 km altitude) observed in the dayside hemisphere using reflected ultraviolet light (380 nm) and in the lower cloud (∼47 km altitude) observed in the nightside hemisphere using thermal radiation (1.74 μm). The waves are nearly zonal (with the bands perpendicular to latitude circles), have wavelengths of 60–150 km, propagate westward with low phase velocities relative to the zonal flow, and are confined in wave packets of 400 to 1800 km in length. The waves in the lower cloud observed in the infrared are widely distributed around the planet, and their appearance varies widely throughout the VIRTIS data set. The locations of both types of waves seem not correlated with latitude, local times, surface topography, or the structure of the wind. In both cases the characteristics of the waves correspond to gravity waves propagating in confined stable layers of the atmosphere. We examine the properties of these waves in terms of a linear model and perform a simple analysis to discuss the vertical stability of the atmosphere within Venus clouds.

Neutrino masses might be as light as a few time the atmospheric neutrino mass splitting. The relic cosmic neutrinos may cluster in wide Dark Hot Local Group Halo. High Energy ZeV cosmic neutrinos (in Z-Showering model) might hit relic ones at each mass in different resonance energies in our nearby Universe. This nondegenerated density and energy must split UHE Z-boson secondaries (in Z-Burst model) leading to multi injection of UHECR nucleons within future extreme AUGER energy. Secondaries of Z-Burst as neutral gamma, below a few tens EeV are better surviving local GZK cut-off and they might explain recent Hires BL-Lac UHECR correlations at small angles. A different high energy resonance must lead to Glashow's anti-neutrino showers while hitting electrons in matter. In water and ice it leads to isotropic light explosions. In air, Glashow's antineutrino showers lead to collimated and directional air-showers offering a new Neutrino Astronomy. Because of neutrino flavor mixing, astrophysical energetic tau neutrino above tens GeV must arise over atmospheric background. At TeV range is difficult to disentangle tau neutrinos from other atmospheric flavors. At greater energy around PeV, Tau escaping mountains and Earth and decaying in flight are effectively showering in air sky. These Horizontal showering is splitting by geomagnetic field in forked shapes. Such air-showers secondaries release amplified and beamed gamma bursts (like observed TGF), made also by muon and electron pair bundles, with their accompanying rich Cherenkov flashes. Also planet's largest (Saturn, Jupiter) atmosphere limbs offer an ideal screen for UHE GZK and Z-burst tau neutrino, because their largest sizes. Titan thick atmosphere and small radius are optimal for discovering up-going resonant Glashow resonant anti-neutrino electron showers. Detection from Earth of Tau, anti-Tau, anti-electron neutrino induced Air-showers by twin Magic Telescopes on top mountains, or space based detection on balloons and satellites arrays facing the atmosphere's limbs are the simplest and cheapest way toward UHE Neutrino Astronomy Horizons.

Nighttime stellar photometric measurements have been carried out with a commercial digital single-lens reflex camera to determine the atmospheric optical thickness on large fields of view (FOV). Specific procedures of image analysis allow to extract an equivalent irradiance for a number of stars and for the sky light background; thus, a measure of the optical thickness in each star direction can be retrieved. A larger FOV is obtained by stitching several photographs shot in quick sequence on adjacent regions of the sky: such measurements provide almost instantaneous maps of optical thickness and skylight background that indicate the degree of homogeneity of the aerosol load. Additional information provided by the combined use of the camera and a lidar is presented. The zenithal optical thickness is used with values of the aerosol backscatter provided by a lidar system to obtain the aerosol extinction-to-backscatter ratio.

Ultra High Energy (UHE) Cosmic Rays, UHECR, may graze high altitude atmosphere leading to horizontal upward air-showers. Also PeVs electron antineutrino hitting electron in atmosphere may air-shower at W boson resonant mass. On the other side ultra high energy muon and electron neutrinos may also lead, by UHE neutrinos mass state mixing, to the rise of a corresponding UHE Tau neutrino flavor; the consequent UHE tau neutrinos, via charge current interactions in matter, may create UHE taus at horizons (Earth skimming neutrinos or Hor-taus) whose escape in atmosphere and whose consequent decay in flight, may be later amplified by upward showering on terrestrial, planetary atmospheres. Indeed because of the finite terrestrial radius, its thin atmosphere size its dense crust, the UHE tau cannot extend much more than 360 kilometers in air, corresponding to an energy of about 7.2 EeV, near but below GZK cut-off ones; on the contrary Jupiter (or even Saturn) may offer a wider, less dense and thicker gaseous layer at the horizons where Tau may loose little energy, travel longer before decay and rise and shower at 4-6 10^{19} eV or ZeV extreme energy. Titan atmosphere may open a rare window of opportunity for Up-ward Taus at PeVs. Also solar atmosphere may play a role, but unfortunately tau-showers secondaries maybe are too noisy to be disentangled, while Jupiter atmosphere, or better, Saturn one, may offer a clearer imprint for GZK (and higher Z-Burst) Tau showering, well below the horizons edges.Comment: 8 pages, 16 Figures, CRIS 200