SDO Sees the Moon Transit the Sun. Twice.


On 9 and 10 September, 2018, the Solar Dynamics Observatory, SDO, saw two lunar transits as the Moon passed in front of the Sun. A transit happens when one celestial body passes between another and an observer. This first lunar transit lasted one hour, from 2030 to 2130 UTC and covered 92 percent of the Sun. The second transit happened several hours later, 0152 until 0241 UTC and only obscured 34 percent of the Sun at its peak.

From SDO’s perspective, the Moon seems to move in one direction and then double back. It appears to do so because the spacecraft’s orbit catches up and passes the Moon during the first transit.

Image Credits: NASA

Polar Ice


These pictures show the distribution of surface ice at the Moon’s south pole (left) and north pole (right) as detected by thes Moon Mineralogy Mapper instrument. The blue areas are the icy regions plotted over images of the lunar surface with the gray scale corresponding to surface temperature (darker representing colder areas and lighter shades indicating warmer zones). As expected, the ice is concentrated at the darkest and coldest locations, the shadows of craters. This data is the first direct, definitive evidence of water ice on the Moon’s surface.

Image Credits: NASA