Superfast stars are a source of knowledge about other galaxies and a possible peddler of life



    Cosmologists have discovered a new way to obtain information about distant regions of outer space and a new possibility of “infecting" the life of planets. Abraham Loeb and James Guillochon of Harvard University have studied super-fast stars that travel through space at speeds of about half the speed of light. Such stars are launched into intergalactic space by binary systems of black holes, which are obtained in collisions of galaxies.

    Usually, the properties of distant objects of astrophysics can be studied only on the basis of radiation that has reached us or particles that have reached us - which, of course, can reach us from the source only in a straight line (apart from a slight possible deviation due to gravitational action). However, in the universe there is another carrier of information that may be available to a tenacious human gaze, armed with appropriate technology. Wandering superhigh-speed stars do not even have to fly into our region of the galaxy - we receive their radiation and from it we can study them and draw conclusions.

    Stars in a galaxy usually travel at speeds of the order of several hundred kilometers per second relative to their neighbors. But in 1988, astronomer Jack Hills predicted that the effect of the gravitational “sling” could accelerate a star to thousands of kilometers per second. At these speeds, the star is already able to leave the galaxy and go on a long journey beyond its borders. Even within our galaxy, there are a couple of dozen stars leaving it at great speeds - apparently, even one black hole in the center of the Milky Way was able to disperse them like that.

    Loeb and Guillochon calculated that binary systems of black holes of colliding galaxies can accelerate stars to relativistic velocities of the order of one third s or more. Collisions on a universe-wide scale should be commonplace, so space can be filled with such super-fast travelers — about a hundred thousand per cubic gigaparsec. Scientists hope that the next generation of telescopes will be able to detect and study such stars. In addition, such stars can entice small cosmic bodies that can serve as carriers of life between galaxies.

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