Universe possibly bigger and older than thought
Our universe could be 15 percent larger and older than previously thought. Astronomers came to this conclusion after using a new technique to calculate intergalactic distances.
The Ohio State University's Kris Stanek and colleagues have determined the distance of galaxy M33 by studying a bright binary star system within it. They first determined the mass and from this the absolute brightness of the stars orbiting each other. This gives a measure of the actual radiant power of a star. Since the apparent luminosity of a celestial body decreases with its distance, the difference between the calculated and the observed brightness of the stars was used to infer the distance to the galaxy M33. According to this, the galaxy is three million light years away and thus 15 percent further away than previously thought.
If the calculations were correct, the so-called Hubble constant should be this percentage smaller than previously assumed, the researchers believe. The constant was introduced to describe the relationship between the escape velocity of a galaxy and its distance. Since the expansion and the age of the universe can also be calculated with it, these variables would inevitably have to change as well.
The researchers were able to determine the distance to the M33 galaxy with an error of just six percent. Studying other star systems in this galaxy could further reduce the error in the future, the astronomers say. However, suitable double star systems are relatively rare.