Universe stuffed with a bunch more stars

William Atkins
Friday, 03 December 2010 00:26

Science - Space

Two U.S. astronomers contend our Universe has three times more stars than previously thought. That would make for upwards of 300,000,000,000,000,000,000,000 stars.

In a more manageable context, but still quite large number, that's 300 sextillion of stars estimated to be inside our Universe, according to these two astronomers from Yale University and Harvard University, in the United States.

Or, that's 1 trillion (1,000,000,000,000) times 300 billion (300,000,000,000).

Dr. Pieter G. van Dokkum, a professor of physics and astronomy at Yale University, and Charlie Conroy, a junior fellow at Harvard University, have published online (December 1, 2010) the Nature paper 'A substantial population of low-mass stars in luminous elliptical galaxies' (doi:10.1038/nature09578).

In it, they describe the stellar initial mass function (IMF), which describes the distribution of stars, particularly their masses, at the time they were formed.

They state, 'The IMF is reasonably well constrained in the disk of the Milky Way but we have very little direct information on the form of the IMF in other galaxies and at earlier cosmic epochs."

Thus, the two astronomers studied other galaxies (besides our Milky Way) - both spiral-shaped galaxies, such as our Milky Way, and also elliptical shaped galaxies.

They contend that because about one-third of the galaxies in the Universe are not spiral galaxies, but instead are elliptically shaped galaxies, then the number of dwarf stars has been underestimated by astronomers in the past.

That is, when scientists had estimated previously how many stars there were in the Universe, they made a wrong assumption that all galaxies had the same ratio of dwarf stars as in our Milky Way galaxy

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