Where in the Universe is the Milky Way’s Mass??

Dr. Robert Benjamin, Chair of the Physics Dept., will talk about “Where in the Universe is the Milky Way’s Mass?” at 8pm on Fri., Dec. 4, in Upham 140. It’s the 6th and final lecture in the Fall 2015 Whitewater Observatory Lecture Series! A public viewing session at Whitewater Observatory will follow the lecture at 9:15pm, weather permitting. All lectures are free, and everyone is invited to attend. For further information, or if you have a disability and desire accommodations, please contact Dr. Paul Rybski at (262) 472-5766.


Modern astrophysics has precisely quantified our ignorance of what the Universe is made. About 68% of the mass/energy density of the Universe lies in something called “dark energy”, a mysterious component causing the universe to expand at an ever-increasing rate. About 27% of the mass/energy density of the Universe is in the form of “dark matter”, a substance that appears to interact with ordinary matter only through the gravitational force. And the remaining 5% of the mass/energy density is in the form of “ordinary” matter, such as atoms, electrons, photons, and so on, that interact through one or more of the strong and weak nuclear forces, the electromagnetic force and gravity.

The Milky Way Galaxy by mass is about 90% dark matter, 9% stars, and 1% interstellar matter. In this talk, I will review the status of dark energy and dark matter and will provide the current census of all of the mass in the Milky Way. Where is it? What form does it take? How is distributed throughout and beyond the Galaxy? By lecture’s end, you will find that, even in our own Milky Way, significant mysteries remain.

Would you like to learn more? Andersen Library can help!

Search the Books, Media and more of UW Whitewater’s Andersen Library to find titles such as The 4 percent universe: Dark matter, dark energy, and the race to discover the rest of reality (3rd-floor Main Collection, QB981 .P257 2011), Dark energy: Theories, developments, and implications (Ebrary ebook), and Three steps to the Universe from the sun to black holes to the mystery of dark matter (UWW students and staff may borrow from another UW for free using UW Request).

Search article databases for articles such as “A common mass scale for satellite galaxies of the Milky Way” (Nature, 2008, vol.454:no.7208, pp.1096-1097, doi:10.1038/nature07222), “Milky Way sheds mass for latest galactic weigh in” (New Scientist, Aug.17-23, 2013, vol.219:no.2930, p.10), and “Mass models of the Milky Way” (Monthly Notices of the Royal Astronomical Society, 2011, vol.414:no.3, pp.2446-2457).

Please ask a librarian (via email, chat, phone 262.472.1032 or visit the Reference Desk) for assistance with finding materials.

About Barbara

I am a Reference & Instruction librarian, head of that department in Andersen Library, an associate professor, and a member of the General Education Review Committee and Faculty Senate. I've been working at UW-W since July 1, 1990.
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