What are mysterious cosmic objects shining brighter than the sun?
They produce way more energy than the sun and appear to break a physical boundary called the Eddington limit - now scientist found a possible explanation.
Swift X-ray observations of galaxy NGC 5408 indicate its ultraluminous X-ray source undergoes periodic changes every 115.5 days. This cycle, astronomers suspect, is linked to the orbit of a donor star around a middleweight black hole, as shown in this artist's view.(photo credit: NASA/PUBLIC DOMAIN/VIA WIKIMEDIA COMMONS)ByJERUSALEM POST STAFF
