Roi как посчитать

Roi как посчитать его концентрацию, некий знак.

The galactic cores are the brightest part of the galilean clouds. They are about 25 parsecs from the Earth. The best-matched observations have been made by Great Ormond Street Observatory and Ball Astro Telescope.

In a video interview, the astronomers explain the key principles, showing scenes from the solar system, the planet Earth, and the galaxy M33. The energy and shape of the dark nebula are particularly impressive.

After the BBC One documentary, Naked Cosmic Magic, in which the astrobiologists Bob Bratton and Pham Khoran explained the science behind the observatory, John says: "I'm very glad I got the opportunity to be involved in a documentary that lifted a lot of antennae and really put people in awe."

http://www.bbc.com/news/technology-31763161.