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Spotlight Live: Nomads of the Galaxy

NOTE: Thanks to everyone who joined our discussion. AN INDEX OF QUESTIONS is listed below.

PLANETS SIMPLY ADRIFT IN SPACE may not only be common in the cosmos; in the Milky Way Galaxy alone, their number may be in the quadrillions. On May 24, science writer Bruce Lieberman had a conversation about these nomadic wanderers with astrophysicist Louis Strigari -- lead author of a recent research paper that generated attention when it greatly increased the estimate for the number of these planets, renewing speculation about life beyond Earth.

Illustration of a possible nomad planet

Nomads of the Galaxy - The Roundtable Discussion

Planets adrift in space -- nomadic wanderers that elude the gravitational grip of a star, and possibly move from one solar system to another -- appear to be much more common than imagined. Now three experts -- Roger D. Blandford, Dimitar D. Sasselov and Louis E. Strigari -- discuss what this might mean, whether a nomad planet could drift close to our solar system and how a nomad planet could actually sustain life.


On November 20, scientists on ADMX, LUX-ZEPLIN and SuperCDMS debated about how close we are to identifying dark matter, discussed the status of their experiments, and answered your questions.

Louis StrigariBruce Lieberman

About the Participants (left to right)

  • Louis E. Strigari, research associate at the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University and the SLAC National Accelerator Laboratory. His research interests include dark matter in astrophysics and particle physics, galactic structure, substructure and dwarf satellites, the search for galactic satellites, direct dark matter detection, neutrino astrophysics, and galactic microlensing.

    "I'm really curious about the exchange of planets between solar systems. ...How often does it happen, and how far can a nomad planet travel? How many trips around our galaxy does it make? I think these are brand new, basic questions. And I think that's an exciting place to be."

  • Bruce Lieberman is a freelance journalist with more than 20 years of experience in the news business. He worked as a reporter at daily newspapers for many years before becoming an independent writer and editor in 2010. For The Kavli Foundation, Bruce has interviewed researchers about dark matter and dark energy, string theory, the emergence of the first stars and galaxies, exoplanets and nomad planets. He has also written for Scientific American about the next generation of large segmented mirror telescopes, the search for life on Mars, the Voyager spacecraft and other subjects.
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