emitted as neutrinos, produced when protons and electrons from the nucleus combine to form neutronsgetty
As a subatomic byproduct of radioactive decay, the tiny neutrino wasn’t even theorized until nearly a century ago. Italian for small neutral, it is a fundamental particle with no internal parts and no electric charge.
Both harmless and ubiquitous, around 300 relic neutrinos dating trillionths of a second after the big bang pass through your little finger every second. And because they rarely interact with ordinary matter, they can also cut through stars and planets like a hot knife through butter.
Though they haven’t revealed all their secrets yet, a captivating new book, “Ghost Particle: In Search of the Elusive and Mysterious Neutrino,” brings us up to speed with what we humans have gleaned about them. since 1930. University of Texas at Arlington research professor Alan Chodos and famed science journalist James Riordon dissect what we’ve learned about neutrinos and how we might exploit them for all forms of applied science.
Produced naturally via gamma-ray bursts, supernovae, nuclear reactions in our own star, and particle decay deep within the Earth, they are also byproducts of today’s particle accelerators and nuclear reactors. Perhaps most chillingly, they were first detected as a side effect of 1940s nuclear weapons testing in New Mexico.
Here are five excerpts from the book.
—- Probing the cosmic neutrino background around the beginning of time
The cosmic background of neutrinos dates from about a second after the big bang. If such relict neutrinos could be studied, the authors note, they would reveal the earliest universe in a way that has so far eluded cosmologists.
But detecting this early neutrino background is still a work in progress. The Princeton Tritium Observatory for Light, Early-universe Massive-neutrino Yield (PTOLEMY) could reveal this neutrino background by looking for samples of tritium that display electrons with slightly elevated energy levels, the authors note.
The idea is to use about 100 grams of tritium, or about a quarter of the commercially available annual supply, to discriminate between electrons from natural tritium decay and those induced by relict neutrinos, note authors. But that would be no small feat and would require an accuracy measurement of one part in 50,000.
ghost particle
MIT Press
—- Using neutrinos as an early warning system for supernovae
The first neutrinos detected from a star about to go supernova occurred 36 years ago. It was only hours before the now famous supernova 1987A erupted in our neighboring dwarf galaxy, the Large Magellanic Cloud.
The few neutrinos that appeared in the three Earth-based detectors at the time were just a tiny fraction of those that emerged from the 1987 supernova, the authors note, because about 99% of a supernova’s energy goes into neutrinos.
The idea is to use the existing Super Nova Early Warning System (SNEWS 2.0) network to identify stars about to go supernova. By examining the timing of signals in neutrino detectors, SNEWS 2.0 can triangulate to locate the region of the sky where a supernova is about to appear, write Chodos and Riordon.
The hope is that this burgeoning network of ground-based neutrino observatories will soon reveal pre-supernova neutrinos as far away as the center of the Milky Way galaxy, the authors write.
—- Using neutrinos to catch nations violating nuclear non-proliferation agreements
United Nations nuclear inspectors are not always prepared to monitor a given country’s nuclear reactors, which may also be used to generate weapons-grade uranium. But the neutrino can provide a workaround to on-site inspections.
The first neutrino detector specifically intended to demonstrate technology for remotely monitoring plutonium production in reactors is the Water Cherenkov Monitor for Antineutrinos (WATCHMAN), the authors note. From 1,000 meters underground inside the Boulby Salt Mine in northern England, WATCHMAN will test the idea next year by looking for neutrinos from the Hartlepool nuclear power station around 25 kilometers.
—- Using neutrinos to explore the deep interior of the Earth
If neutrinos can be produced artificially at energies of a few trillion electron volts, they can become more interactive with their environment. This would thus give geoscientists the means to learn much more about the deep interior of the Earth in a way close to medical tomography.
But to generate such high-energy neutrinos, the authors note, it would likely require an underwater particle-accelerating ring about 24 kilometers in diameter. The idea is to accelerate protons to 20,000 billion electron volts (20 TeV) and then smash them against a target to produce a beam of particles which would then decay into high-energy neutrinos.
—- ET could use neutrino beams to modify stars for interstellar signaling
Highly advanced extraterrestrial civilizations could alter pulsating Cepheid variable stars using very high-energy neutrino beams to transmit information across the galaxy. The authors refer to a 2012 article published in the journal Contemporary Physics.
The idea is that ET could use pulsed neutrino beams to alter the pulsation period of a Cepheid variable star. The paper notes that such neutrino beams could generate a binary signature of the star, consisting of a normal pulsing period coupled with a shortened period triggered artificially by the neutrinos.
Cepheids would make a natural fit because they can be seen at great distances and, as the paper’s authors point out, any developing technological society like ours would likely observe them as markers of distance. The authors of the paper therefore propose that we search these variable stars for patterns indicating intelligent signals.
As for the book?
“Ghost Particle” deserves a lifetime for decades to come.
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I’m a science journalist and host of Cosmic Controversy (brucedorminey.podbean.com) as well as the author of “Distant Wanderers: the Search for Planets Beyond the Solar System”. I mainly cover aerospace and astronomy. I am a former Hong Kong bureau chief for Aviation Week & Space Technology magazine and a former Paris-based technology correspondent for the Financial Times newspaper who has reported on six continents. Winner of the Royal Aeronautical Society’s AJOYA Aerospace Journalist of the Year Awards in 1998, I’ve interviewed Nobel laureates and written about everything from potato blight to dark energy. Previously, I was a film and arts correspondent in New York and Europe, primarily for newspapers like the International Herald Tribune, the Boston Globe, and Canada’s Globe & Mail. Recently, I have contributed to Scientific American.com, Nature News, Physics World, and Yale Environment 360.com. I am currently a contributor for Astronomy and Sky & Telescope and correspondent for Renewable Energy World. Twitter @bdorminey
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