Simultaneous measurements refer to taking multiple measurements or observations at the same time or during the same period. It means gathering data or information simultaneously instead of one after another. Full definition
High resolution, high precision, simultaneous measurements of. (usap-dc.org)
The energy still gets out, and you have no proof that it doesn't, because you don't have the necessary simultaneous measurements made all over the world. (carlineconomics.com)
The pyrometers are also able to capture the air shock structure of the detonation event, allowing for simultaneous measurement of temperature and pressure. (sciencedaily.com)