Monday, August 11, 2025

Alien visitors, redux: Why are we seeing them now?

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 After my last post on 3I/ATLAS , an interested reader (full disclosure - my wife, Ruth Ehrenkrantz ) asked an interesting question: Why are...
Monday, July 21, 2025

Another alien visitor enters the Solar System

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 The Solar System recently welcomed another visitor from another star:  3I/ATLAS.  We don't know much about it yet, but it seems conside...
Sunday, May 4, 2025

Two slit interferometry – the fully quantum edition

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  Today, I want to write about something a bit different – a unique 2-slit interferometer (aka the double-slit experiment)...
Saturday, April 19, 2025

Neutrinos are lighter

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 One of the biggest questions in neutrino physics is: how heavy are they?  We know that there are three types of neutrinos, associated with ...
Friday, March 14, 2025

The new neutrino heavyweight champion - part 2

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 In October (2024), I wrote about the very high energy neutrino event found by the KM3NeT Collaboration, which is building a neutrino telesc...
Saturday, December 28, 2024

Do we live in a special place - Part 2

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  A closely related question to whether we live in a special (high or low density) place in the universe is whether the u...
Sunday, November 3, 2024

Do we live in a special place (in the universe)?

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Up close, the universe is very inhomogeneous.  There is the odd very-dense star or planet, but most of it is mostly empty space - vacuum.   ...