Microsoft today announced they are open sourcing the WorldWide Telescope under the MIT license. Also it has now become an independent project as part of the .NET Foundation. WorldWide Telescope was originally a Microsoft Research project and offered an unified astronomical image and data environment for exploratory research, teaching and public outreach.
WorldWide Telescope was designed with rich interactivity in mind. Guided Tours, which are especially popular among educators and astronomy enthusiasts, offer scripted paths through the 3D environment, enabling users to view and create media-rich interactive stories about anything from star formation to the discovery of the large-scale structure of the universe.
Microsoft decided to open source it to allow any individual or organization to adapt and extend the functionality to meet any research or educational need.
We believe that extensions and improvements to the software will continuously enhance formal and informal learning and astronomical research. Making the code available will also help ensure that the data, protocols and techniques used are also available for others to inspect, use, adapt and improve upon in their own applications. Ultimately, open sourcing WorldWide Telescope will also allow the wider community to guide and participate future in future development efforts such that it evolves to meet the needs of future users.
Read more about it here.