
Finding your place in the world
What are global coordinates?
This Swift UVOT image shows galaxy M82 before the explosion and combines data acquired between 2007 and 2013. Mid-ultraviolet light is shown in blue, near-UV light in green and visible light in red. (Image: NASA/Swift/P. Brown, TAMU)
The Universe's expansion may not be accelerating as fast as we thought.
What are mathematical proofs, why do we need them and what can they say about sheep?