In what is a once-in-a-few-lifetimes experience, I witnessed today the conjunction of Jupiter and Saturn in the evening sky (with a crescent moon thrown in to boot). While every sixteen years or so the two planets end up angularly close because of their different orbital period (Jupiter revolves around our Sun in 11.9 years, Saturn takes 29.4 years), small differences in their orbital planes make the smallest distance they reach usually of the order a degree.
Meteor showers are a spectacular phenomenon that takes place when the Earth intersects the path along which periodic comets (or less frequently, asteroidal bodies) orbit the Sun. Comets lose debris when they get close to perihelion, but the debris does not get lost in all directions - it continues to follow the comet's path in the solar system.
For the (likely going to be dramatically unsuccessful) series "Questions you would have liked your son asked you when you visited CERN together", I feature today a rather unconventional curiosity about LHC and neutrino physics. The source of inspiration for this is a coffee-time conversation I had long ago, I don't even remember with whom - probably a colleague. Anyway, that's the least interesting bit of the whole matter.
The LHC is...
That's right - I finally hit the ground with my creativity, and my jokes are starting to use old material for my post titles. Yet producing a pair of Higgs bosons in a proton-proton collision is seriously cool indeed. The Higgs boson in fact is one of the few particles that does a trick called "self-coupling": in a sort of ermaphroditic act it is capable of giving birth to a pair of objects identical to itself.
Have you ever looked at the moon through a telescope, or even a pair of binoculars? Our satellite is really beautiful to look at - it is full of detail you can get lost in: craters, mountain ridges, canyons, plateaus. And there's no clouds to obscure the view (if you are a planetary observer and you put an eye on Mars a couple of years ago you know what I mean - a dust storm that went on for weeks completely hid the surface from outside observers).
I was blissfully unaware until today of a slightly anomalous effect, which was found by the ATLAS Collaboration when performing a search for top pairs plus Higgs bosons in their Run 2 data. The anomaly I am talking about is an apparent excess of events which could be explained, as ATLAS did in this preprint article
, by dialing up the cross section of some background processes producing a top pair and a W boson.