Bloggers: Sabine Hossenfelder and Stefan Scherer
URL: backreaction.blogspot
First post: February 2006

Who is the blog written by?

A husband and wife team, currently separated by the Atlantic Ocean. Theoretical physicist Sabine Hossenfelder is based at the Perimeter Institute in Waterloo, Canada, and Stefan Scherer works in the editorial office of the Landolt-Börnstein scientific database in Frankfurt, Germany.

What topics does the blog cover?

The blog’s tagline is “a scientifically minded blog with varying amounts of entertainment, distractions, and every day trivialities”. Hossenfelder’s research interests are in extensions of the Standard Model of particle physics, such as extra dimensions and “brane” scenarios. She also talks about day-to-day life at the Perimeter Institute – a centre for theoretical physicists established in 1999 by Mike Lazaridis, founder of the company that makes the successful BlackBerry mobile-communication devices (which all staff at the institute are issued with). Meanwhile, Scherer’s interest in the history of science manifests itself in regular posts commemorating the birth dates of famous physicists such as Henri Poincaré and Heinrich Hertz.

Who is it aimed at?

Backreaction features longer posts and more illustrations than the average blog in an attempt to explain complicated topics in cosmology and particle physics to the layreader. For example, in one post, Hossenfelder explains how an Aero chocolate bar can be seen as a model of the universe, with the chocolate representing the tiny amount of baryonic matter, the other ingredients corresponding to mysterious dark matter, and the empty bubbles that make up most of the volume to dark energy.

Why should I read it?

Hossenfelder provides a humorous take on the recent debate over the status of string theory: one post was supplemented with a sound file she created that set heated remarks by physicists such as Leonard Susskind and Lee Smolin to a musical backing by the band the Fun Lovin’ Criminals. But the blog is not all fun and games – there are also lengthy and thoughtful posts on science and society, and a regular series of entries written by guests explaining why they became physicists.

How often is it updated?

There is usually at least one substantial post every couple of days, with the load being shared between the two bloggers.

Can you give me a sample quote?

Hossenfelder writes: “I have a friend (who shall remain unnamed, but you can occasionally find him in the comment section) with the habit of always being late by at least 15 minutes. He is the truest academic that I know, and the 15 minutes are a part of his personality. Here at PI [the Perimeter Institute], coming late to a seminar or a meeting is significantly tougher, because your BlackBerry beeps relentlessly and reminds you of your slackness (that’s the true reason why we get one). But still, it is possible to be late. The easiest way to achieve it is to make a detour via the kitchen to grab a coffee – our executive director Howard Burton made ‘the importance of coffee and good food’ really clear to the architects, and so it became a priority for the building.”