Early Example of Multi-messenger Astronomy

The article “This Month in Physics History” (APS News, August/September 2019) described the earliest observations of cosmic rays by Theodor Wulf and Victor Hess. The text states that “[Hess] determined that the intensity increased significantly with height, and his radiation measurements during a solar eclipse effectively ruled out the sun as the source of these cosmic rays.”

Those observations by Hess may qualify as the first example of multi-messenger astronomy, since they combined visual astronomy (the solar eclipse, and shielding of the Sun by Earth at night) and particle astronomy (using ionization detectors). Even if Hess did not understand the particle-like nature of the "cosmic rays" he was detecting, he still sensed it was some form of “penetrating radiation” and could conclude that some part of it did not come from the Sun but from elsewhere in the cosmos.

Rolf Sinclair
College Park, Maryland

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Editor: David Voss
Staff Science Writer: Leah Poffenberger
Contributing Correspondent: Alaina G. Levine
Publication Designer and Production: Nancy Bennett-Karasik

November 2019 (Volume 28, Number 10)

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2019 Nobel Prize in Physics
2019 Nobel Prize in Chemistry
A Look into the Future with Augmented and Virtual Reality
Science as a Laughing Matter
The Topical Group on Data Science
Here Be Dragons...
Students and Mentors in the National Mentoring Community
Education and Diversity News
This Month in Physics History
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