A new study suggests there are a mind-blowing 300 sextillion — or three times as many as scientists had calculated. That is a 3 followed by 23 zeros. Or 3 trillion times 100 billion.
The estimate, contained in a study published online Wednesday in the journal Nature, is based on findings that there are many more red dwarf stars — the most common — than once thought.
The study by Yale University astronomer Pieter van Dokkum and Harvard astrophysicist Charlie Conroy questions a key assumption that astronomers use: that most galaxies have the same properties as our Milky Way.
When scientists previously estimated the number of stars, they assumed all galaxies had the same ratio of dwarf stars as the spiral-shaped Milky Way. But about one-third of the galaxies are elliptical, not spiral. Van Dokkum and a colleague gazed into eight distant, elliptical galaxies and calculated that elliptical galaxies have more red dwarf stars than predicted. A lot more.
Generally, scientists believe there are 100 billion to a trillion galaxies. Each galaxy was thought to have 100 billion to a trillion stars. Sagan, the Cornell University scientist and best-selling author, said there were 100 billion galaxies, each with 100 billion stars.
Van Dokkum’s work adjusts those numbers. That’s because the elliptical galaxies have as many as 1 trillion to 10 trillion.
Richard Ellis of the California Institute of Technology said it is too early to tell whether van Dokkum is right, but his work is shaking up the field “like a cat among pigeons.”
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