They are nature's very own Death Star beams -- ultra-powerful jets of energy that shoot out from the vicinity of black holes like deadly rays from the Star Wars super-weapon.
Now a team of scientists led by the University of Southampton has moved a step closer to understanding these mysterious cosmic phenomena -- known as relativistic jets -- by measuring how quickly they 'switch on' and start shining brightly once they are launched.
How these jets form is still a puzzle. One theory suggests that they develop within the 'accretion disc' -- the matter sucked into the orbit of a growing black hole. Extreme gravity within the disc twists and stretches magnetic fields, squeezing hot, magnetised disc material called plasma until it erupts in the form of oppositely directed magnetic pillars along the black hole's rotational axis.
Plasma travels along these focused jets and gains tremendous speed, shooting across vast stretches of space. At some point, the plasma begins to shine brightly, but how and where this occurs in the jet has been debated by scientists.
In a new study published today [Monday, October 30] in Nature Astronomy, an international team of scientists led by Dr Poshak Gandhi show how they used precise multi-wavelength observations of a binary system called V404 Cygni -- consisting of a star and a black hole closely orbiting each other, with the black hole feeding off matter from the star that falls through the disc -- to throw light on this hotly debated phenomenon.
Post a Comment