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

Black hole simulation

This graphic shows the computer simulation of a black hole from start to finish. Plasma is falling slowly toward the black hole in a (at the upper left). The plasma has a magnetic field, shown by the white lines. It picks up speed as it falls toward the hole in b (at the upper right), c (lower left) and d (lower right). However, the rotating black hole twists up space itself (and the magnetic field lines) and ejects electromagnetic power along the north and south poles above the black hole. The red and white color shows the immense electromagnetic power output, which eventually will pick up particles and form squirting jets. This simulation was conducted using supercomputers at Japan's National Institute for Fusion Science.

source: archive.org

Maths in Europe: John Conway

Card Colm Mulcahy, an irish mathematician and John Conway's friend, on 11 april 2020 published on twitter the news of the death of Conway. His source was a close associate of his and confirmed by the family.
I written a little post in his honour on Maths in Europe, a ahort article about the free will theorem.
The theorem was proposed by Conway with Simon Kochen, inspired by the question about the interpretation of quantum mechanics. The statement is:

If the choice of directions in which to perform spin 1 experiments is not afunction of the information accessible to the experimenters, then the responsesof the particles are equally not functions of the information accessible to them.

(continue to read)

Breaking comets

Comet Atlas, portrait by Tim Connolly

First of all I start from Atlas, a new comet that is coming here! It will arrive at the end of May, passing only 0.25 AU from the sun. It could be a good opportunity for amateurs to observe a new object in the sky, but there is a not so reassuring news:

New data from astronomers around the world show that the once-promising comet is beginning to fade.

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- via spaceweather.com

This is not the only bad news: the first insterstellar comet, 2I/Borisov, that it goes away from the Sun with a speed of about 17 km/s (it will reach a speed of 32 m/s), seems to have lost a piece of the core (ATel #13611, ATel #13613).

Road to Mercury: flyby with Earth

A flyby is close passage of a space probe, at high speed, near a planet or other celestial object. It can be used to speed up or slow down the space probe.

The first successful planetary flyby ever made was performed the 14th December 1962 by the Mariner 2 NASA spacecraft with the planet Venus, but it was with the Mariner 10 mission, thanks to an intuition of the italian Mathematician Giuseppe Colombo in 1970, that we use now the flyby as orbital correction maneuver. Indeed, the professor from Paduan was invited from the JPL to participate in a conference about the Mariner 10 directed to Mercury. When he observed the spacecraft computed orbit, he noted that the Mariner 10 would have an orbital period around the sun twice the Mercury year. Hence, he suggested to carfully calibrate the first passage over Mercury in such a way that the spacecraft would have exactly the delta velocity from the planet to re-encounter Mercury at the next revolution. His suggestion was fully accepted and, thanks to him, Mercury 10 (llaunched in the 1973 on its way to Venus) had its first flyby with Mercury on 5th February 1974, and a second a third flyby on 21th September 1974, and also a third on 16th March 1975. The change in trajectory found by Giuseppe Colombo allowed to greatly increase the scientific return of the mission, as well as the scientific knowledge of the planet Mercury.
(...)
On the early morning of the 10th of April, there will be the possibility, hopefully, to observe the crossing on the sky of BepiColombo spacecraft crossing the sky from East to West. The closest approach is foreseen at 04.25 UTC with a minimum distance of 12.677 km from the Earth's surface.

If you want to compute your own plot for your location by inserting latitude and longitude here: https://bepicolombo.iaps.inaf.it.

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source: esa