Record-breaking neutrino is most energetic ever detected • Hacker News Board

Re: Record-breaking neutrino is most energetic ever detected

#121

Post by skissane » Thu, Feb 13, 2025, 9:50 AM UTC

myrmidon wrote: post #119

skissane wrote: post #116

Earlier quoted context omitted.

> The kilogram is the base unit of mass in the International System of Units (SI) Arguably, an ugly wart, but one we are stuck with for historical reasons. The base units of the original metric system (metre and gram) were poorly proportioned for practical use, resulting in the two main scientific/engineering systems of metric units both choosing to prefix one base unit - the centimetre-gram-second (cgs) system chose…

> The base units of the original metric system (metre and gram) were poorly proportioned for practical use What is the dealbreaker here though? Because we have plenty of "poorly proportioned" SI units anyway; e.g. it would be much more practical to have megapascal, microfarad and megajoule as base units from an engineering pov (particle physicists might disagree;).

Pascal, farad, joule aren't base units, they are derived units.

Ideally, the base units should be prefixless. Except for kilogram, they all are.

Imagine a system exactly the same as SI, except instead of the kilogram, it had the kram, where 1 kram = 1 kilogram... then the gram would be the millikram, the milligram would become microkram, the microgram would become the nanokram, etc... if you were starting from scratch, without any historical baggage, wouldn't such a system be superior? But of course, we aren't starting without historical baggage – almost everybody knows what a kilogram is, kram is a word I just now made up.

I think some derived units being "poorly proportioned" is inevitable given the physics we have.

Re: Record-breaking neutrino is most energetic ever detected

#122

Post by jaybro867 » Thu, Feb 13, 2025, 9:57 AM UTC

skissane wrote: post #121

myrmidon wrote: post #119

Earlier quoted context omitted.

> The base units of the original metric system (metre and gram) were poorly proportioned for practical use What is the dealbreaker here though? Because we have plenty of "poorly proportioned" SI units anyway; e.g. it would be much more practical to have megapascal, microfarad and megajoule as base units from an engineering pov (particle physicists might disagree;).

Pascal, farad, joule aren't base units, they are derived units. Ideally, the base units should be prefixless. Except for kilogram, they all are. Imagine a system exactly the same as SI, except instead of the kilogram, it had the kram, where 1 kram = 1 kilogram... then the gram would be the millikram, the milligram would become microkram, the microgram would become the nanokram, etc... if you were starting from scratc…

[dead]

Re: Record-breaking neutrino is most energetic ever detected

#123

Post by myrmidon » Thu, Feb 13, 2025, 9:57 AM UTC

skissane wrote: post #121

myrmidon wrote: post #119

Earlier quoted context omitted.

> The base units of the original metric system (metre and gram) were poorly proportioned for practical use What is the dealbreaker here though? Because we have plenty of "poorly proportioned" SI units anyway; e.g. it would be much more practical to have megapascal, microfarad and megajoule as base units from an engineering pov (particle physicists might disagree;).

Pascal, farad, joule aren't base units, they are derived units. Ideally, the base units should be prefixless. Except for kilogram, they all are. Imagine a system exactly the same as SI, except instead of the kilogram, it had the kram, where 1 kram = 1 kilogram... then the gram would be the millikram, the milligram would become microkram, the microgram would become the nanokram, etc... if you were starting from scratc…

I understand what you mean-- I was just curious about why we could not just stick with gram-meter-second (since we have a bunch of "poorly proportioned" derived units anyway)...

Re: Record-breaking neutrino is most energetic ever detected

#124

Post by tsimionescu » Thu, Feb 13, 2025, 10:19 AM UTC

gus_massa wrote: post #94

tsimionescu wrote: post #65

Earlier quoted context omitted.

There's nothing to optimize here, neutrinos just interact very very weakly with anything else because they don't carry charge (so no electrical interactions), don't carry color charge (so no nuclear interactions), don't carry weak charge (so no weak force interactions) and have tiny tiny masses, but they are still bosons (so don't act as field carriers like photons do, they're just regular matter). Their low chance o…

> don't carry weak charge (so no weak force interactions) Left neutrino have weak hypercharge, so they are produce by weak interactions and are detected using the weak interaction. And also gravity. Right neutrinos (if they exist) have no weak hypercharge so they only interact by gravity.

Thanks for the correction!

Re: Record-breaking neutrino is most energetic ever detected

#125

Post by Sharlin » Thu, Feb 13, 2025, 10:21 AM UTC

myrmidon wrote: post #119

skissane wrote: post #116

Earlier quoted context omitted.

> The kilogram is the base unit of mass in the International System of Units (SI) Arguably, an ugly wart, but one we are stuck with for historical reasons. The base units of the original metric system (metre and gram) were poorly proportioned for practical use, resulting in the two main scientific/engineering systems of metric units both choosing to prefix one base unit - the centimetre-gram-second (cgs) system chose…

> The base units of the original metric system (metre and gram) were poorly proportioned for practical use What is the dealbreaker here though? Because we have plenty of "poorly proportioned" SI units anyway; e.g. it would be much more practical to have megapascal, microfarad and megajoule as base units from an engineering pov (particle physicists might disagree;).

If the base unit were gram, megapascals would be gigapascals, microfarads would be nanofarads, and megajoules gigajoules. Similarly a watt would be what's now a milliwatt and most "everyday" powers (except in electronics) would be kilowatts or megawatts.

Re: Record-breaking neutrino is most energetic ever detected

#126

Post by Someone » Thu, Feb 13, 2025, 10:22 AM UTC

defrost wrote: post #99

cozzyd wrote: post #98

Earlier quoted context omitted.

The funny thing is a km^3 scale detector like km3net or icecube has roughly the same mass as all humans combined

Equally hilarious, the Kalgoorlie Super Pit has a volume of 3.15 cubic kilometers. That's a single, albeit large, gold mining pit and a fraction of the even greater volume excavated by humans looking for shiny stuff.

We mine about a cubic mile of oil every year (https://en.wikipedia.org/wiki/A_Cubic_Mile_of_Oil). That’s 4 km³.

Re: Record-breaking neutrino is most energetic ever detected

#127

Post by voidUpdate » Thu, Feb 13, 2025, 10:58 AM UTC

class700 wrote: post #70

parineum wrote: post #59

Earlier quoted context omitted.

Isn't Ant-Man logic that he still has the same mass when he shrinks and, as such, can generate the same force? Unless you get thrown back by ping pong balls normally, I think you'd be fine.

And yet when he grows he still has enough strength to punch a leviathan out of the sky. I'm not sure there's such thing as ant man logic - It doesn't seem like it should result in strength both ways.

His weight also changes with size, or doesnt, depending on what would be more convenient for the current scene

Re: Record-breaking neutrino is most energetic ever detected

#128

Post by tjpnz » Thu, Feb 13, 2025, 11:07 AM UTC

octocop wrote: post #118

Why do they place the receiver in a large body of water, like the Mediterranean?

Neutrino interactions with nuclei of water produce charged particles which move faster than the speed of light in water (but slower than through a vacuum tube) creating a cone of light known as Cherenkov radiation, which is the optical equivalent to a sonic boom. This is projected onto a ring around the detector.

Doesn't need to be submerged in a body of water as large as this. The Super-Kamiokande[0] detector for instance is located in a body of water inside a mountain.

0: https://en.m.wikipedia.org/wiki/Super-Kamiokande

Re: Record-breaking neutrino is most energetic ever detected

#129

Post by Sharlin » Thu, Feb 13, 2025, 11:46 AM UTC

__MatrixMan__ wrote: post #114

m3kw9 wrote: post #21

Earlier quoted context omitted.

Can we harvest that energy?

Not for that particular neutrino, it's gone. But yes, my home (and yours) is being heated by neutrino power as we speak. It's not a significant enough amount of energy to make a dent in the utility bill however.

Most inefficient thermal power plant possible: utilize the difference in neutrino flux between the hemisphere that's open to space vs. the hemisphere where Earth is in the way.

But now I'm wondering what percentage of the useful thermal power in a nuclear power plant is produced by the neutrinos created in the reactions (the infinitesimally small fraction that happen to interact with the matter within the reactor, that is).

Re: Record-breaking neutrino is most energetic ever detected

#130

Post by adrian_b » Thu, Feb 13, 2025, 12:07 PM UTC

myrmidon wrote: post #123

skissane wrote: post #121

Earlier quoted context omitted.

Pascal, farad, joule aren't base units, they are derived units. Ideally, the base units should be prefixless. Except for kilogram, they all are. Imagine a system exactly the same as SI, except instead of the kilogram, it had the kram, where 1 kram = 1 kilogram... then the gram would be the millikram, the milligram would become microkram, the microgram would become the nanokram, etc... if you were starting from scratc…

I understand what you mean-- I was just curious about why we could not just stick with gram-meter-second (since we have a bunch of "poorly proportioned" derived units anyway)...

Using the gram would not have removed the prefixes from all commonly used units.

In the beginning, the liter was a much more frequently used unit of volume than the cubic meter.

A liter was defined as the volume of a kilogram of water. In a system were the gram was the unit of mass, the corresponding unit of volume was the milliliter.

Which of the gram and the kilogram or which of the centimeter and meter were chosen as the units of mass and length did not matter much for mechanical units, in the way they were used in practice in the 19th century.

A definite choice of the base units has become important only after a bunch of new physical quantities have been defined for use in the theories of electricity, magnetism, heat and light, in the second half of the 19th century. When dealing with so many different physical quantities, not using unique base units would have caused too much confusion. While this necessity has been recognized, for many years 2 different choices for the base units were widespread, that based on meter-kilogram (used mostly by engineers) and that based on centimeter-gram (used mostly by theoreticians). Meter and kilogram were more typical for the sizes of practical machines, while centimeter and gram were more typical for the sizes of laboratory experiments.