The action of UV-C against covid19

The research about the action of ultraviolet radiation against covid19 arrived at an interesting conclusion: the team, leaded by Istituto Nazionale di Astrofisica and Università Statale di Milano and with the collaboration of Istituto nazionale dei tumori and Irccs, has provided the first experimental data about the high germicidal power of ultraviolet rays against Sars-Cov-2.
Andrea Bianco, head of the astronomers' team, says to MediaINAF (Google Translate):

We have seen very distinct behaviors. At the lowest concentration, we had to wait six days for the virus to replicate and infect cells without being subjected to UV-C illumination. In the intermediate concentration, which we took as a reference, already with the lowest dose of irradiation, after 24 hours we had a reduction of a factor greater than 1000. Waiting longer, we saw that the virus no longer grows back, that is, it is no longer able to replicate itself: it is said that it has been completely inhibited. While in the highest concentration, at the lowest dose of irradiation, at the beginning there is a fairly significant decrease in the amount of active virus but after it goes back up, which means that the virus has been inactivated but the concentration is so high that it is able to restart (because it has not been completely inhibited). When we gave him the second dose - 16.7 mJ / cm² - it was seen that it is sufficient to completely inhibit him : even after 72 hours he is unable to "regain his strength". In this high concentration of the virus, therefore, this aspect emerged: at low doses I can have a significant decrease in the active virus but he is still able to infect the cells, so after a certain time he restarts with his activity.

But:

Going from Uv-A to Uv-C the danger for man increases, in the sense that Uv-C radiation causes mutations, therefore increases the probability of having skin cancers considerably. So much so that, by law, the maximum dose of Uv-C that one can take daily is very low. Uv-B and Uv-A are much less so, so much so that we tan, protecting ourselves with creams to avoid the risk of cancer and skin rashes. The risk is there but with much less probability.

Bianco, A., Biasin, M., Pareschi, G., Cavalleri, A., Cavatorta, C., Fenizia, C., ... & Saulle, I. (2020). UV-C irradiation is highly effective in inactivating and inhibiting SARS-CoV-2 replication. medRxiv. doi:10.1101/2020.06.05.20123463

The potential virucidal effects of UV-C irradiation on SARS-CoV-2 were experimentally evaluated for different illumination doses and virus concentrations (1000, 5, 0.05 MOI). Both virus inactivation and replication inhibition were investigated as a function of these parameters. At a virus density comparable to that observed in SARS-CoV-2 infection, an UV-C dose of just 3.7 mJ/cm2 was sufficient to achieve a 3-log inactivation, and complete inhibition of all viral concentrations was observed with 16.9 mJ/cm2. These results could explain the epidemiological trends of COVID-19 and are important for the development of novel sterilizing methods to contain SARS-CoV-2 infection.

Nicastro, F., Sironi, G., Antonello, E., Bianco, A., Biasin, M., Brucato, J. R., ... & Trabattoni, D. (2020). Modulation of COVID-19 Epidemiology by UV-B and-A Photons from the Sun. medRxiv. doi:10.1101/2020.06.03.20121392

It is well known that 200-290 nm ultraviolet photons (hereinafter UV-C radiation) photo-chemically interacts with DNA and RNA and are endowed with germicidal properties that are also effective on viruses. Fortunately, Solar UV-C photons of this wavelength are filtered out by the Ozone layer of the upper Atmosphere, at around 35 km. Softer UV photons from the Sun with wavelengths in the range 290-320 nm (UV-B) and 320-400 nm (UV-A), however, do reach the Earth s surface. The effect of these photons on Single- and Double-Stranded RNA/DNA viruses and the possible role they play on the seasonality of epidemics, are nevertheless little studied and highly debated in alternative or complementarity to other environmental causes. Notably though, the effects of both direct and indirect radiation from the Sun needs to be considered in order to completely explain the effects of UV radiations in life processes (with e.g. the UV virucidal effect enhanced in combination to the concomitant process of water droplets depletion because of Solar heat). Herein we present a number of concurring circumstantial evidence suggesting that the evolution and strength of the recent Severe Acute Respiratory Syndrome (SARS-Cov-2) pandemics, might be have been modulated by the intensity of UV-B and UV-A Solar radiation hitting different regions of Earth during the diffusion of the outbreak between January and May 2020. Out findings, if confirmed by more in depth data analysis and modeling of the epidemics, which includes Solar modulation, could help in designing the social behaviors to be adopted depending on season and environmental conditions.

Where planets born

T Tauri stars are a class of variable stars that are less than about ten million years old. This class is named after the prototype, T Tauri, a young star in the Taurus star-forming region discovered in October 1852 by John Russell Hind. They are found near molecular clouds and identified by their optical variability and strong chromospheric lines. T Tauri stars are pre-main-sequence. In photo you can see 21 T Tauri stars with their protoplanetary disks, rotating circumstellar disks of dense gas and dust. This is probably the beginning of a solar system formation.

Garufi, A., Avenhaus, H., Pérez, S., Quanz, S. P., van Holstein, R. G., Bertrang, G. M., ... & Zurlo, A. (2020). Disks Around T Tauri Stars with SPHERE (DARTTS-S)-II. Twenty-one new polarimetric images of young stellar disks. Astronomy & Astrophysics, 633, A82. doi:10.1051/0004-6361/201936946

A journey to Proxima Centauri

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Proxima Centauri is a red dwarf located approximately 4.2 light years from us, in the area of ​​sky covered by the Centaur constellation. Thanks to ESO's telescopes, in particular to the HARPS spectrograph, and using the Doppler (or radial velocity) method, in 2016 it was anounced the discovery of a planet around this star, Proxima Centauri b.
Given the proximity, one might think that the world of comics has devoted much attention in recent years to the star and its planet. In fact, to have a comic set around this star, you have to wait until the second half of 2018 when Image Comics publishes the six-issue miniseries Proxima Centauri by Farel Dalrymple.
The work, subsequently collected in volume in January 2019, is halfway between science fiction and fantasy. The main character is Sherwood Breadcoat, a teenage magician trapped on an artificial spheroid called Proxima Centauri, evidently put in orbit around the homonymous star. Of course, this information is not very clear, but overall the whole Dalrymple comic is rather lack of information, closed in a hermetic narration with an open ending that allows the author keep some subplots open, like the relationship between Sherwood and the scientist, that sometimes seems help the teen, other times usi it for his purposes; or as one of Sherwood's opponents, which is actually a sort of virtual, but also physical manifestation of a character hidden somewhere on the spheroid and who seems to be a videogame player, given that he explicitly states that he wants to repeat the vlash with Sherwood, although it ended badly more than once.
In all this, although science would seem to play a fundamental role, at least according to some lines of Breadcoat, a character who believes only in science and magic (?), it is a simple narrative accessory, a way to not deepen the technology used or to hide all the magical aspects of the story, only apparently sci-fi.
In any case, Dalrymple's comic is good to remember that, quite recently, a team of Italian astronomers, studying the data coming from Proxima Centauri with more accuracy, has supposed the existence of a second planet around the star, roughly six times more massive than Earth. We will see if it will be confirmed or not.

The other side of the matter

We know that exist a particular type of matter: the antimatter. Antimatter is composed by antiparticles. An antiparticle has the same mass as the corresponding particle but has opposite charge. And luckily for us antimatter is substantialy absent from our universe: indeed the interaction between matter and antimatter leads to the annihilation process, with the disappearance of particle and antiparticle and energy production. So, if in the universe there were the same amount of matter and antimatter, it would be filled exclusively with radiation. For this reason it is particularly interesting understand where this asymmetry originates: we know that would be a symmetry violation in some place and time of the universe, and the T2K experiment in Japan tested neutrinos' oscillations, in particular the oscillation from muonic to electronic neutrino. The results of ten years of data say that 90 neutrinos and only 15 antineutrinos were caught oscillating from muonic to electronic: different numbers mean violated symmetry.
The most interesting detail is that the experimental result doesn't exclude an interesting idea about an anti-universe that exists at the other side of the Big Bang.

Abe, K., Akutsu, R., Ali, A., Alt, C., Andreopoulos, C., Anthony, L., ... & Ashida, Y. (2020). Constraint on the Matter-Antimatter Symmetry-Violating Phase in Neutrino Oscillations. Nature volume 580, pages 339–344. doi:10.1038/s41586-020-2177-0

Boyle, L., Finn, K., & Turok, N. (2018). C P T-Symmetric Universe. Physical review letters, 121(25), 251301. doi:10.1103/PhysRevLett.121.251301

Sun in High-Res

A team of researchers from the University of Central Lancashire and NASA's Marshall Space Flight Center published images of the Sun in unprecedented resolution. Obtained with NASA's high resolution Coronal Imager, used incandescent plasma filaments never seen before:

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Using ultraviolet radiation against SARS-CoV-2

Alessio Zanuta

Astrophisicts of Brera's Astronmical Observatory in Milano are collaborating with researchers at Milano University are developing and testing ultraviolet devices for air disinfection and inactivation of the SARS-CoV-2 virus. The italian science magazine, Media INAF, has interviewed Alessio Zanuta. Here there is the english tranlsation. In the post I extracted an interesting quote:

(...) we are developing new ideas for fighting the virus in terms of disinfection
First of all by conducting targeted studies to understand how it behaves and which are in weak points of this virus if subjected to radiation. We speak above all of ultraviolet rays, and we wonder if they are effective in inactivating it, at what wavelengths, how long exposure it takes, and what doses. While there is a large literature on how Uv rays - especially the most energetic ones (the so-called Uv-C rays) - have effective sanitizing effects also on viruses, currently specific information on the doses necessary to specifically annihilate the Sars-Cov-2 virus is lacking responsible for the current pandemic. This bibliography information is missing right now, either because the virus is new, or because the similarities with other types of viruses are labile. After collecting all the necessary data, we aim to develop devices useful for disinfection. Furthermore, the idea that even less energetic rays, those emitted by the Sun and which are not absorbed by the atmosphere, can have a disinfectant effect, with important epidemiological consequences and with interesting information to manage the so-called "Phase 2" in return from the lockdown. In the summer, there could be a drop in infections, also thanks to greater illumination by the Sun.

The road to reality

The discussion around what we know about the universe is in continuous development. If we take the infographic below, for example, we are faced with three possible scenarios: an accelerated expanding universe that will conclude is run in a big rip, in which the universe eventually turns completely black; a universe in which expansion is in balance with gravity, but nevertheless destined to make the skies of planets black and starless; a universe where expansion is blocked and reversed to a big crunch.

Source: visual.ly