Only the charged particle that induces the emission travels faster than the local speed of light.

For a slower than light particle, you also get emission, but it is completely random and thus does not give the well defined emission in a cone of Cherenkov radiation.

For a faster than light particle, the spherical suddenly line up to form a cone:

https://en.wikipedia.org/wiki/Cherenkov_radiation#/media/Fil...

What Neutrino detector measure is the Cherenkov light emitted by secondary particles that are created when a Neutrino interacts with the matter inside the detector.

E.g. a muon Neutrino reacts with a water molecule producing a muon, which is a charged particle and thus emits Cherenkov light.

Of course I am biased because I work in the field, but the by far most wide reaching application of Cherenkov radiation is in the detection of high energy particles, particularly in astrophysics.

- Imaging Atmospheric Cherenkov telescopes detect the Cherenkov radiation emmited in the atmosphere when a high energy cosmic ray or gamma ray creates an air shower

- Water Cherenkov Detectors detect Cherenkov light when the secondary particles of these air showers reach water tanks on the ground

- Neutrino telescopes like kamiokande, Icecube and km3net detect Cherenkov radiation in water or ice produced by secondary particles produced by the rare interactions of Neutrinos in their detector volumes

Modern, high energy astrophysics is all about detecting different kinds of Cherenkov radiation and then reconstructing the original particle properties.

Computing AFAIK is very much still based on RHEL-based distros, Alma Linux specifically.

https://linux.web.cern.ch/

That must be the worst explanation of complex numbers I ever read. It's not even remotely connected.

Unix time assumes a fixed number of seconds per day. 86400. If a leap second is inserted, either end of June or end of December, the day is 86401 seconds long.

There are different implementations for how your Unix time will behave 24 hours before to 24 hours after the leap second. A timestamp might just repeat during the leap second or the system changes the length of a second in a time range around the leap second introduction to make up the difference. This is called smearing.

A simple example is the elapsed time between these two timestamps:

    2016-12-31 23:59:50
    2017-01-01 00:00:10

    2016-12-31 23:59:60

It did not happen yet. No negative leap second that should have been inserted was skipped.

See this chart here:

https://en.wikipedia.org/wiki/DUT1#/media/File:Leapsecond.ut...

You can see the the positive leap seconds as jumps upward once the graph reaches around -0.5 s.

We were never close to reaching +0.5 seconds with a positive trend and we are still relatively far away from that.

Comments URL: https://news.ycombinator.com/item?id=48293080

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The particles need the atmosphere to interact, Cherenkov light is only emitted in an optical medium and because it's optical light we measure we are affected by satellites. Not as strongly as optical telescopes though, because the air showers last for only tens of nanoseconds.

There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree.

Elrond?

The authority on the definition of SI units is very clear:

> The hertz shall only be used for periodic phenomena and the becquerel shall only be used for stochastic processes in activity referred to a radionuclide

Usually, no radionuclides are involved in web requests.

https://www.bipm.org/documents/d/guest/si-brochure-9-en-pdf

Current instruments are mostly good at finding large planets around small stars, we are basically blind to earth-like planets around sun-like stars.

See e.g. https://www.nobelprize.org/prizes/physics/2019/queloz/lectur...

The authority on the definition of SI units is very clear:

> The hertz shall only be used for periodic phenomena and the becquerel shall only be used for stochastic processes in activity referred to a radionuclide

Neither is usually the case for requests.

https://www.bipm.org/documents/d/guest/si-brochure-9-en-pdf