Starship Asterisk*

Artist’s schematic of how MESSENGER provided data to estimate neutron lifetime. Cosmic rays striking Venus’ atmosphere eject neutrons that gradually fly into space. As neutrons move to higher altitudes, more time passes, and more neutrons radioactively decay. MESSENGER counted the number of neutrons at various altitudes, allowing scientists to compare neutron numbers across altitudes. Using models, researchers could then estimate the neutron lifetime. Credit: JHU APL

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Neutrons aren’t a model of resilience when it comes to living a single life. Strip one from an atom’s nucleus and it will quickly disintegrate into an electron and a proton. But scientists can’t determine how quickly, despite decades of trying, and that’s problematic because knowing that lifetime is key to understanding the formation of the elements after the Big Bang.

Now, a team of researchers ... has provided a way that could end the decades-long stalemate. Using data from NASA’s MESSENGER spacecraft, the team shows that the lifetime of a neutron can be measured from space. ...

Since the early 1990s, scientists have disagreed about how long lone neutrons last, mainly because the two methods used so far give highly precise results that don’t line up.

The “bottle” method traps neutrons in a bottle and tracks how long they take to radioactively decay, which on average is around 14 minutes and 39 seconds. The “beam” technique instead fires a beam of neutrons and tallies the number of protons created from radioactive decay. On average, this takes about 14 minutes and 48 seconds — nine seconds longer than the bottle method.

Nine seconds isn’t much, but relative to the uncertainty in either method’s measurements — at most two seconds — it’s enormous. ...

• Physical Review Research 2(2):3316 (Jun-Aug 2020) DOI: 10.1103/PhysRevResearch.2.023316

bystander wrote: ↑Thu Jun 11, 2020 7:13 pm
MESSENGER Shows How a Spacecraft
Could End Neutron Lifetime Stalemate
Johns Hopkins University Applied Physics Laboratory | 2020 Jun 11

Click to play embedded YouTube video.

Since the early 1990s, scientists have disagreed about how long lone neutrons last, mainly because the two methods used so far give highly precise results that don’t line up.

The “bottle” method traps neutrons in a bottle and tracks how long they take to radioactively decay, which on average is around 14 minutes and 39 seconds. The “beam” technique instead fires a beam of neutrons and tallies the number of protons created from radioactive decay. On average, this takes about 14 minutes and 48 seconds — nine seconds longer than the bottle method.

Nine seconds isn’t much, but relative to the uncertainty in either method’s measurements — at most two seconds — it’s enormous. ...

BDanielMayfield wrote: ↑Sat Jun 13, 2020 2:48 pm
Might the trapped neutron rate be the true rate of decay

while the fired beam neutrons are lasting slightly longer
because outside observers are seeing a relativistic time dilation effect?

https://en.wikipedia.org/wiki/Neutron_temperature wrote:

Code: Select all

Neutron energy 	Energy range
............................................
0.0–0.025 eV 	Cold neutrons
0.025 eV 	Thermal neutrons
0.025–0.4 eV 	Epithermal neutrons
0.4–0.5 eV 	Cadmium neutrons
0.5–1 eV 	EpiCadmium neutrons
1–10 eV 	Slow neutrons
10–300 eV 	Resonance neutrons
300 eV–1 MeV 	Intermediate neutrons
1–20 MeV 	Fast neutrons
> 20 MeV 	Ultrafast neutrons