200 sextillion more stars have been projected to be in the sky according to reports citing data released by Yale and Harvard professors in the Journal of Nature. These claims build on earlier claims regarding universal star count by organizations such as the European Space Agency (ESA). On February 23, 2004, the ESA released a report claiming there were 10 to the power of 22-24 stars in the universe. This means prior estimates already included between ten thousand trillion and a quadrillion i.e. a million trillion stars in the universe.
Since a sextillion is 1000 trillion, there are now an estimated 200 thousand trillion more stars in the sky. 300 thousand trillion stars or three hundred sextillion, are now believed to be in the universe according to the December 3, 2010 Harvard Crimson's Kelly Lam. Since 200 sextillion additional stars were added to arrive at this figure, the previous estimate was 100 sextillion.
No one really knows exactly how many stars are in the sky, and the methods used provide calculations based on the luminosity of galaxies according to the recent findings. Moreover, ground based as well as space telescopes such as the Hubble Space Telescope, and the Herschel telescope are used to make such measurements, and although more accurate in determining the size of galaxies, are not foolproof.
According to the European Space Agency, scientists determined there were sextillions of stars in the sky by first approximating the number of galaxies, then arriving at a reasonable number of stars for each galaxy. From that point the calculation simply involves multiplying the two numbers together. However, figuring out how many galaxies and stars in each of those galaxies isn't simply guess work alone.
Another way space telescopes have been used to find the 200 sextillion more stars in the sky is by viewing galaxies in different wavelengths. By observing the energy omitted by the universe at these wavelengths, a more comprehensive picture of what happened in the universe and when can be drawn. Since galaxies can have greater amounts of one wavelength than another, viewing them in their dominant wavelengths helps view them more vividly.
Space telescopes have also been instrumental in determining an additional 200 sextillion stars are in the sky is by observing galaxy shapes. According to a December 6, 2010 report released by Pakistan news, the galaxies in the universe were thought to be more like the Milky Way i.e. spiral. However, as the news report claims, more elliptical shaped galaxies than previously thought exist. Since these galaxies are believed to hold more stars, there are also thought to be 200 sextillion more stars.