It happens only a little more than once a decade – and the next chance to see it is Monday, May 9.
Throughout the U.S., sky watchers can watch Mercury pass between Earth and the sun in a rare astronomical event known as a planetary transit.
Mercury will appear as a tiny black dot as it glides in front of the sun’s blazing disk over a period of seven and a half hours, between about 7:12 a.m. and 2:42 p.m. EDT. Three NASA satellites will be providing images of the transit and one of them will have a near-live feed.
NASA will post images from the Solar Dynamics Observatory (SDO).
An informal roundtable during which experts representing planetary, heliophysics and astrophysics will discuss the science behind the Mercury transit. Viewers can ask questions via Facebook and Twitter using #AskNASA.