Distant Black Holes Spin Clocked
A new measurement could be the farthest back in time astronomers have ever reached when measuring a black holes spin.
Resolving the Pleiades Distance Problem
A new measurement, made using radio interferometry, argues that the distance to the Pleiades star cluster measured by ESA’s Hipparcos satellite really is wrong – and that ground-based astronomers had it right all along.
This Week’s Sky at a Glance, August 29 – September 6
The Moon is coming back into the evening sky. Look for the waxing crescent low in the west-southwest in twilight, as shown at lower right. Can you make out Spica twinkling beneath it?
Earthshine, the Moon’s Darker Side
With a subtle beauty all its own, the earthshine we see glowing in the lunar night invites us to consider Earth’s many connections to the Moon.
Voyager 2 at Neptune: A Silver Anniversary
NASA’s Voyager 2 spacecraft swept past Neptune exactly 25 years ago, revealing that this distant blue-hued planet is far more dynamic and unique that expected.