SDO/AIA Witnesses the Transit of Mercury on May 9th 2016

The Atmospheric Imaging Assembly (AIA) is a prime instrument on NASA's Solar Dynamics Observatory (launched on February 11, 2010; observing the Sun in science mode since May 1, 2010). AIA comprises four telescopes that take 16-megapixel images of the Sun in four channels simultaneously, alternating between two complementary sets of channels, and thereby providing eight distinct views every 12 seconds. It sees our neighboring star in the light of ionized helium, iron, and carbon, and in the ultraviolet and visible "white light" continuum. AIA's channels include He II (304Å), Fe XVIII (94Å), C IV (1600Å), ultraviolet continuum (1700Å) white light (4500Å), Fe IX (171Å), Fe XIV (211Å), Fe XII/XXIV (193Å), Fe XI (335Å), Fe XX/XXIII (131Å). For more information about AIA, visit the AIA home page.

Mercury Transit Ingress: An AIA (left) 1700 Å image of the planet Mercury entering the disk of the Sun on May 9th 2016.

On May 9th 2016, AIA witnessed the Transit of Mercury. At ingress the disk of Mercury completed its entry into the solar disk at 11:25 UT (see above). However, the silhouette of the planet was already visible against the bright corona of the Sun (in EUV images) half an hour prior.

A rocky planet transits our star: The Transit of Mercury reminds us the Earth is a tiny place in the vastness of space. The Sun is large, and the Earth small. How small? When placed side by side with the Sun, the Earth would be only a fraction larger than Mercury appears in this image (click here for full resolution image, here for a full 4096x4096 pixel movie [224 MB], and here for a movie tracking Mercury [120 MB] ). NASA's Kepler mission detects planets around other stars by measuring minute dips in their brightness at visible wavelengths during planetary occulations.

Below are links to sites with more AIA information and images, and a select set of highlights from its 5-year mission to explore the Sun, its explosive nature, and the consequences throughout the solar system, including all forms of space weather.

SDO is frequently in the news:

A search for "Sun" and "SDO" in Google news returns some 9,000 results (as per May 9th 2016).

A few web links to AIA images and scientific discoveries:

AIA's home page for background information and many links to what it does, how to access and use its observations, and what it discovered.
SunToday for images and daily summary movies of the Sun on any day since April 16, 2011.
A list of month-long AIA movies.
A compilation of highest-rated solar flares, eruptions, and active regions.
A listing of AIA-related scientific publications from the NASA/ADS search engine.
SDO at NASA/GSFC.

Last modified: Mon May 9 11:28:46 PDT 2016