... The Very Large Array Turns Twenty . ... Scroll right to virtually climb the largest volcano in the Solar System. ... Skylab Over Earth . ... Many scientific tests were performed on Skylab, including astronomical observations in ultraviolet and X-ray light. ... Solar Sail . ... M4: The Closest Known Globular Cluster . ... M4 is a globular cluster visible in dark skies about one degree west of the bright star Antares in the constellation Scorpius. ... Light Bridges on the Sun . ...