The Virtual Observatory
As a consequence, around the start of the new millennium, representatives of the worldwide astronomical community initiated the development of the Virtual Observatory (VO) framework. This was envisioned as a complete, distributed, web-accessible research environment for astronomy with massive and complex data sets, connecting in a user-transparent manner the data assets, computational resources, tools and even literature [3–6]. The concept was embraced by the astronomical community worldwide, with national and regional VOs unified in the International Virtual Observatory Alliance (IVOA; http://ivoa.net). Similar ideas and frameworks were developed around the same time in other fields, in what is sometimes referred to as the cyberinfrastructure movement .
A key idea behind the VO concept is that whereas the individual data repositories remain the responsibility of contributing groups, observatories and space missions (the people best qualified to curate the data), the VO framework assures their interoperability through a set of common standards, formats and protocols, enabled by associated metadata. The individual data holdings can then be registered within the VO framework, documented with the proper metadata, and their access and subsequent analysis by various astronomer clients facilitated by the VO's common standards implemented by each participating data node. Thus, the entire federated data ecosystem was designed to grow, with interactivity kept both manageable and scalable. It enabled easy data sharing and re-use, whether mandated by the funding agencies, or performed by data producers wanting to see their data used.
The VO approach also enabled scientists less skilled in programming to explore the data. This was possible because the design of the VO emphasized interoperability, creating standards for data and application programming interface (API) management and implementation. The rigid enforcement by the VO of a structured approach to a universal vocabulary of metadata types in observational space was also an essential step. Today, the astronomy community has an infrastructure that fosters the development of tools to implement complex searches across diverse and disparate data archives. Exploration of the skies using the VO can be performed either locally on your desktop computer, or remotely on, for example, NASA supercomputing resources. The VO's inherent flexibility combined with its strong sense of community ensures its continuing success today as a global big data informatics project.