http://harvardscience.harvard.edu/stories/person/1557 Stories and external links referencing a person (RSS) en http://harvardscience.harvard.edu/environments/articles/lifeless-suns-dominated-early-universe <!--paging_filter--><p>The very first generation of stars were not at all like our Sun. They were white-hot, massive stars that were very short-lived. Burning for only a few million years, they collapsed and exploded as brilliant supernovae. Those very first stars began the seeding process in the universe, spreading vital elements like carbon and oxygen, which served as planetary building blocks. This picture of the early universe comes from new calculations by Harvard astronomers Volker Bromm and Abraham Loeb (Harvard-Smithsonian Center for Astrophysics). The researchers have shown that the first Sun-like stars were lonely orbs moving through a universe devoid of planets or life. "The window for life opened sometime between 500 million and 2 billion years after the Big Bang" says Loeb. "Billions of years ago, the first low-mass stars were lonely places. The reason for that youthful solitude is embedded in the history of our universe." "Life is a recent phenomenon," Loeb states unequivocally. "We know that it took many supernova explosions to make all the heavy elements we find here on Earth and in our Sun and our bodies." This research was published in the October 23, 2003, issue of the scientific journal Nature.</p> Mon, 26 Mar 2007 05:34:47 -0400 70652986 3486 at http://harvardscience.harvard.edu http://harvardscience.harvard.edu/environments/articles/first-supernovae-quickly-seeded-universe-stuff-life <!--paging_filter--><p>The early universe was a barren wasteland of hydrogen, helium, and a touch of lithium, containing none of the elements necessary for life as we know it. From those primordial gases were born giant stars 200 times as massive as the Sun, burning their fuel at such a prodigious rate that they lived for only about 3 million years before exploding. Those explosions spewed elements like carbon, oxygen and iron into the void at tremendous speeds. By the remarkably young age of 275 million years, the universe was substantially seeded with metals thrown off by exploding stars. That seeding process was aided by the structure of the infant universe, where small protogalaxies less than one-millionth the mass of the Milky Way crammed together like people on a crowded subway car. The small sizes of and distances between those protogalaxies allowed an individual supernova to rapidly seed a significant volume of space. New simulations by astrophysicists Volker Bromm (Harvard-Smithsonian Center for Astrophysics), Naoki Yoshida (National Astronomical Observatory of Japan) and Lars Hernquist (CfA) show that the first, "greatest generation" of stars spread incredible amounts of such heavy elements across thousands of light-years of space, thereby seeding the cosmos with the stuff of life.</p> Mon, 26 Mar 2007 05:31:20 -0400 70652986 3402 at http://harvardscience.harvard.edu