Birth and Death of Stars and Planets I

WED, SEP 28, 2005 (37:13)

Astronomer Michael Shara and planetologist Dimitar Sasselov explore the many varied changes that have produced our star and our planet as we examine the "arrow of time" of cosmic evolution.

+ BIO: Michael Shara

Dr. Shara and his research group are conducting an exhaustive survey to inventory and "weigh" all 100,000 stars nearest to Earth. More than one billion stars are being examined in the search. The survey has already determined that many low luminosity stars remain undiscovered just a few light years away, and that a significant portion of the local "dark" matter is concentrated in stars 100 to 100,000 times fainter than the Sun.

Dr. Shara uses the Hubble Space Telescope to survey the densest cores of globular clusters to retrieve and characterize the predicted collision products. These include some of the most exotic stars known to astrophysicists: "blue stragglers." By accurately weighing these stars, Shara and his collaborators have demonstrated that many are at least twice as massive as all other stars in a globular cluster. This strongly supports the hitherto theoretical collisional origin for blue stragglers.

+ BIO: Dimitar Sasselov

Dimitar Sasselov has been a professor at Harvard since 1998. He arrived to CfA in 1990 as a Harvard-Smithsonian Center post-doctoral fellow. Between 1999 and 2003 he was the Head Tutor of the Astronomy Department. Dimitar was born in Bulgaria, and was educated at Sofia University, where he received his Ph.D. in Physics in 1988, almost concurrently working on his degree at the University of Toronto, Canada, where he received his Ph.D. in Astronomy in 1990.

His research explores the many modes of interaction between radiation and matter: from the evolution of hydrogen and helium in the early universe to the study of the structure of stars. He is very fond of unstable stars - ones that pulsate regularly and allow us to determine distances to other galaxies. Most recently his research has led him to explore the nature of planets orbiting other stars. He has discovered a few such planets - with novel techniques that he hopes to use to find planets like Earth.

He is the director of the new Harvard Origins of Life Initiative - a multidisciplinary center bridging scientists in the physical and in the life sciences, intent to study the transition from chemistry to life and its place in the context of the Universe.

+ BIO: Eric Chaisson

Chaisson's major interests are currently twofold: his scientific research addresses an interdisciplinary, thermodynamic study of physical, biological, and cultural phenomena, seeking to understand the origin and evolution of galaxies, stars, planets, life, and society, thus devising a unifying cosmic-evolutionary worldview of the Universe and our sense of place within it writ large. His educational work engages experienced teachers and computer animators to create better methods, technological aids, and novel curricula to enthuse teachers and instruct students in all aspects of natural science.

Museum of Science, Boston
NOVA: Hunting the Hidden Dimension Series
NOVA: Origins Series