Members get a snapshot view of new Long Now content with easy access to all their member benefits.
Published quarterly, the member newsletter gives in-depth and behind the scenes updates on Long Now's projects.
Special updates on the 10,000 Year Clock project are posted on the members only Clock Blog.
Filmed on Monday April 11, 02016
Dr. Priyamvada Natarajan is a Professor in the Departments of Astronomy and Physics at Yale University. Her latest book is Mapping the Heavens: The Radical Scientific Ideas That Reveal the Cosmos.
No one thinks longer, or bigger, than astrophysicists.
“This is the golden age of cosmology,” says Priya Natarajan, one of the world’s leading astrophysicists, because data keeps pouring in to vet even the most radical theories. And the dominant mysteries are profound. She observes that “The vast majority of stuff in the universe—both dark matter and dark energy, which dominate the content and fate of the universe—is unknown.“
The universe’s greatest exotica are the focus of her research—dark matter, dark energy, and black holes. She is an expert, for example, in the complex behavior and gravitational lensing of galaxy clusters, where arrays of 1,000 galaxies are 95% dark matter. Her theory of the “direct” formation of supermassive black holes may explain the profound mystery of quasars.
Priyamvada Natarajan is a professor in the Departments of Astronomy and Physics at Yale University and at the Dark Cosmology Center, Niels Bohr Institute, University of Copenhagen, Denmark. She is an active proponent for the public understanding and study of science.
ALL THAT WE KNOW of the universe we get from observing photons, Natarajan pointed out. But dark matter, which makes up 90 percent of the total mass in the universe, is called dark because it neither emits nor reflects photons — and because of our ignorance of what it is. It is conjectured to be made up of still-unidentified exotic collisionless particles which might weigh about six times more than an electron.
Though some challenge whether dark matter even exists, Natarajan is persuaded that it does because of her research on “the heaviest objects in the universe“ — galaxy clusters of more than 1,000 galaxies. First of all, the rotation of stars within galaxies does not look Keplerian — the outermost stars move far too quickly, as discovered in the 1970s. Their rapid rate of motion only makes sense if there is a vast “halo” of dark matter enclosing each galaxy.
And galaxy clusters have so much mass (90 percent of it dark) that their gravitation bends light, “lenses” it. A galaxy perfectly aligned on the far side of a galaxy cluster appears to us — via the Hubble Space Telescope — as a set of multiple arc-shaped (distorted) galaxy images. Studying the precise geometry of those images can reveal some of the nature of dark matter, such as that it appears to be “clumpy.” With the next generation of space telescopes — the James Webb Space Telescope that comes online in 2018 and the Wide-Field Infrared Survey Telescope a few years afterward — much more will be learned. There are also instruments on Earth trying to detect dark-matter particles directly, so far without success.
As for dark energy — the accelerating expansion of the universe — its shocking discovery came from two independent teams in 1998–99. Dark energy is now understood to constitute 72 percent of the entire contents of the universe. (Of the remainder, dark matter is 23 percent, and atoms — the part that we know — makes up just 4.6 percent.) When the universe was 380,000 years old (13.7 billion years ago), there was no dark energy. But now “the universe is expanding at a pretty fast clip.” Natarajan hopes to use galaxy-cluster lensing as a tool “to trace the geometry of space-time which encodes dark energy.”
These days, she said, data is coming in from the universe faster than theory can keep up with it.” We are in a golden age of cosmology.”--Stewart Brand
Condensed ideas about long-term thinking summarized by Stewart Brand
(with Kevin Kelly, Alexander Rose and Paul Saffo) and a foreword by Brian Eno.
We would also like to recognize George Cowan (01920 - 02012) for being the first to sponsor this series.Would you like to be a featured Sponsor?
Seminars About Long-term Thinking is made possible through the generous support of The Long Now Membership and our Seminar Sponsors. We offer $5,000 and $15,000 annual Sponsorships, both of which entitle the sponsor and a guest to reserved seating at all Long Now seminars and special events. In addition, we invite $15,000 Sponsors to attend dinner with the speaker after each Seminar, and $5,000 Sponsors may choose to attend any four dinners during the sponsored year. For more information about donations and Seminar Sponsorship, please contact email@example.com. We are a public 501(c)(3) non-profit, and donations to us are always tax deductible.
The Long Now Foundation • Fostering Long-term Responsibility • est. 01996 Top of Page