Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.

The connections between light, matter, and energy are central to Einsteinian physics education in the age of renewable energy and modern technologies. Using activities, models, and analogies for presenting modern physics in the classroom is effective in helping students understand challenging topics. This paper describes three classroom activities designed to explore the physics behind a beautiful experiment that measured an atom’s mass increase when it absorbs a single photon and its mass reduction when a photon is emitted. The experiment demonstrates the direct link between E = mc2 and E = hf. Classroom math problems linked to the experiment use the powers of 10 to explore the large and small numbers associated with the physical concepts. The lesson we developed as part of the Einsteinian energy curriculum for year 8 students as part of the Einstein-first project in Australia, which aims to design and implement Einsteinian physics curricula for schools.

The most famous equation in physics, E = mc2, is rarely introduced in middle school physics curricula. Recent research has shown that teaching Einsteinian concepts at the middle school level is feasible and beneficial. This paper analyses an Einsteinian energy teaching module for Year 8 students (13–14 years old), which encompasses the two fundamental energy formulas in modern physics, E = mc2 and E = hf. In the context of activity-based learning, the Einsteinian energy module relates to all the forms of energy in traditional school curricula. This study uses a design-based research approach within the Model of Educational Reconstruction framework. Modern experiments, historical events, and educational research helped us identify relevant Einsteinian energy concepts, activities, and assessments. The study included 22 students who participated in nine in-class Einsteinian energy lessons. Analysing results in the post-test showed a 31% mean increase from the pre-test, a clear and significant positive change in students’ conceptual understanding. The results demonstrated students’ ability to deal with very large and small constants of proportionality and physical concepts involved in the module.