Geological time is inextricably linked with Earth Sciences and the Geological Time Scale (GTS) is the yardstick to measure it. As such the GTS is the key to reconstruct Earth history. Recent developments in numerical dating now permit to build a much improved next generation GTS for the last 100 million years by integrating independent state-of-the-art techniques; this time scale will have an unprecedented accuracy, precision, resolution and stability. Within GTSnext a consortium of world leading European experts will be brought together for the first time to integrate their expertise and provide young scientists with a top training in all these methods. This training is the prime objective of GTSnext, and crucial to its success. Together this team of newly trained scientists is well equipped to construct the new GTS. GTSnext is part of a broader international initiative - EARTHTIME - a community-based scientific effort aimed at sequencing Earth history through an integrated geochronologic and stratigraphic approach. It is our ambition to broaden the Earthtime platform in Europe with GTSnext, which combined with an ESF funded Research Network run in parallel, will also serve as the basis for wider outreach towards the Earth Science community. The expected scientific contributions and breakthroughs are 1) a full integration and intercalibration of different numerical dating techniques, leading to 2) a significant improvement in the consistency of these same techniques; 3) progress towards a fully integrated and astronomical-tuned GTS over the last 100 million years; 4) an essentially stable time scale that is highly beneficial for both academia and industry, and 5) new insights in key geological processes including climate change, catastrophic impacts, and volcanic hazards. Finally, a more fundamental comprehension of geological time and the time scales at which key processes occur in Earth history is highly relevant in view of the impact we have on System Earth.