At the end of the year, it is natural to reflect on the many science success stories of 2015. There was the forging of a climate-change agreement in Paris, and the incredible pictures of Pluto beamed back by the New Horizons spacecraft (for more, see our end-of-year review). Beware, though, for the road of progress is bumpy, and new and old technology can clash.

Christmas can break the Internet, the UK newspapers nearly reported this month. Researchers have found that twinkling fairy lights on a household Christmas tree can interfere with the wireless signal between a router and internet-connected devices.

In Britain, the telephony and airwaves regulator Ofcom released a smartphone app so that people can assess just how bad this seasonal effect is. We at Nature know what’s expected of us, so we downloaded the app and put it through its paces.

First, the control test. The Nature Towers Wi-Fi was just fine before we illuminated the office Christmas tree, and — to the relief of all — remained completely unaffected once the halls were decked with the requisite tinsel, mistletoe, boughs of holly and festive lighting. Still, before you eat another mince pie and check the online weather forecast for snow, know that the Wi-Fi was seriously compromised by unknown forces once the illuminations had been switched off for the night. What could have be going on?

As Andrew Smith writes on The Conversation , your festive illuminations might indeed interfere with your Wi-Fi, but they would have to very powerful — much more so than other household features such as microwaves or fluorescent lights.

The Daily Mail newspaper can always be relied on for inventive scientific answers and did not disappoint. Perhaps, it says, goldfish are sabotaging the Wi-Fi? Water, it points out, absorbs radio waves, so you shouldn’t place a router near a fish tank, nor (we suppose) in one.

The story, although little more than a sprinkling of seasonal fluff on the tail end of the year in science, does illustrate more serious matters — the many factors, perhaps small and even undetectable, that can throw an experiment.

We all know colleagues whose Southern blots come out like Rorschach tests and who have to rely on the one lab technician who has ‘the touch’. Nature argues strongly for reproducibility and that experimental details, no matter how small, should be set out for all to see. We have launched a string of publications and platforms to help researchers to do this: Nature Methods , Nature Protocols , Scientific Data and Protocol Exchange . However, when one is working just beyond the cutting edge, other factors might be at play — on the edge of detectability and beyond. One of last year’s highlights was the discovery, after years of careful testing, that migrating birds can be disoriented by the electromagnetic ‘smog’ produced by human activity (S. Engels et al. Nature 509, 353–356; 2014).

This finding sits in a contentious field in which researchers seek to explain the seemingly impossible feat in which animals detect and transduce the very weak signals generated by Earth’s magnetic field. Festive bulbs are a mere drop in the electromagnetic ocean, from the devices around us to the photons that bring messages from the edge of the cosmos.

In the time it has taken you to read this, about 600 trillion neutrinos will have passed through your body, as well as uncounted dark-matter particles, and perhaps even some schleptons, snoozons, axions and other particles of which science has as no knowledge, yet. That is what next year is for.