The Birth of Suns


Australian Institute of Physics Public Lecture

Start Date

30th Nov 2017 6:00pm

End Date

30th Nov 2017 7:00pm


Physics Lecture Theatre 1, Sandy Bay campus

RSVP / Contact Information

No RSVP required. Enquiries:; or 03 6226 8502


Presented by

Professor Mark Krumholz

Research School of Astronomy and Astrophysics
Australian National University

We’ve all learned that space is an empty vacuum, but it’s not. The space between the stars in our Galaxy contains, on average, about 1 atom per cubic centimeter. That’s a better vacuum than the best vacuum chamber we know how to make, but there are a lot of cubic centimeters in interstellar space, so the mass of all the gas between the stars adds up to about 10% of the mass of all the stars put together. The temperature of this gas varies enormously from place to place in the Galaxy, with temperatures as high as
millions of degrees and as low as a few degrees above absolute zero.

In the coldest regions of interstellar space, over millions of years gravity is able to draw the atoms together into immense clouds that ultimately condense into clusters of new stars. In our Galaxy, this process produces stars at a rate of about 1 new Sun per year, and the stars it makes are typically the size of the Sun or a little smaller. While we understand how this happens in general outline, many fundamental questions remain unanswered. What sets the rate at which stars form? What determines the final sizes of the individual stars? Where did our Sun form, and what happened to its siblings, the stars that formed out of the same cloud?

In this talk Mark will describe what we currently know, and what we don’t, about the birth of new Suns.

Mark Krumholz received his PhD in physics in 2005 from the University of California, Berkeley, and then held a Hubble Postdoctoral Fellowship at Princeton University from 2005-8. From 2008-15 he was professor of astrophysics at the University of California, Santa Cruz, and in 2015 he moved to a professorship at the Research School of Astronomy and Astrophysics at Australian National University. Professor Krumholz’s research focuses on the formation of stars and galaxies, and the dynamics of the interstellar medium, mostly using a theoretical and computational approach. His work has been recognised by the Alfred P. Sloan Fellowship, the National Science Foundation Career Award, the Helen B. Warner Prize of the American Astronomical Society, the Blauuw Chair of the Kapteyn Astronomical Institute, and the Hunstead Lectureship
of the University of Sydney.