Mercury Transit May 2016

On Monday, May 9, 2016, Mercury will transit across the sun. This rare event will begin at 7:11 AM EDT and will continue for more than seven hours. NASA's Solar Dynamics Observatory will watch this transit from start to finish, ultra high definition images of the event in near real time as it unfolds. This is the first time SDO has captured this transit, which hasn't occurred since 2006. It won't occur again until 2019. NASA Scientists use the transit method to learn more about planets both in our solar system and beyond. Scientists can monitor the brightness of stars, looking for dips in that brightness that signal a transiting planet. Using the transit method, scientists can determine the distance of these planets from their stars, as well as their size and composition. Upcoming missions like the Transiting Exoplanet Survey Satellite will use the transit method to search for planets orbiting nearby stars.

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  • Mercury Transit May 9, 2016
    This animation shows the May 9, 2016 transit of Mercury across the face of the Sun.
  • Mercury Transit of the Sun
    The planet Mercury is visible passing between the Sun and the TRACE spacecraft. Data collected on May 7, 2003, from 04:32:04 to 08:08:57.
  • Mercury Transit from TRACE (White Light)
    This is a view of the planet Mercury (a black dot) as seen by TRACE through its white light optical telescope. Because the TRACE field-of-view is much smaller than the solar disk, the spacecraft is repointed three times during the transit (creating the position jumps of the movie). This movie was generated from telemetry which has undergone a minimum of processing (to deliver quickly for the media) so data dropouts and other quick-processing artifacts may be visible. Special thanks to Dawn Myers of the TRACE project for this effort.
  • Mercury Transit from SOHO/MDI
    This is a view of the planet Mercury (the tiny moving black dot) as seen by the SOHO MDI. The narrow field-of-view for this camera mode necessitates the addition of black bars at the top and bottom of the frame to match HD720 resolution. This movie was generated from telemetry which has undergone a minimum of processing (to deliver quickly for the media) so data dropouts and other quick-processing artifacts may be visible. Special thanks to Steele Hill of the SOHO project for this effort.
  • Venus Transit 2012 Composited Visuals
    These visualizations were generated by compositing the small field-of-view, high-cadence closeups of Venus with the full-disk, low-cadence imagery from Solar Dynamics Observatory (SDO). Two different instruments are used: the Helioseismic and Magnetic Imager (HMI) which sees light in the visible range, and the Atmospheric Imaging Assembly (AIA) which sees light in several wavelengths in the ultraviolet range. To find out more information about these instruments, check out The Atmospheric Imaging Assembly Tutorial.

    Some artifacts may be visible from the compositing, but you have to look pretty closely to see them.

    The color table threshold was raised for these images, reducing the amount of noise visible in the images.

    Note: There is an interesting artifact worthy of mention and clarification, and that is as Venus crosses the solar limb, the limb appears to be visible through the planet in some of the imagers (most notably the ultraviolet channels). Discussion with the scientists who built the imagers suggest this might be 'crosstalk' between the readouts of the four CCD panels that make up a complete image. It is an artifact of the imaging system.

Additional Resources

  • SDO: Year 6
    The sun is always changing and NASA's Solar Dynamics Observatory is always watching. Launched on Feb. 11, 2010, SDO keeps a 24-hour eye on the entire disk of the sun, with a prime view of the graceful dance of solar material coursing through the sun's atmosphere, the corona. SDO's sixth year in orbit was no exception. This video shows that entire sixth year--from Jan. 1, 2015 to Jan. 28, 2016 as one time-lapse sequence. At full quality, this video is ultra-high definition 3840x2160 and 59.94 frames per second. Each frame represents 1 hour. SDO's Atmospheric Imaging Assembly (AIA) captures a shot of the sun every 12 seconds in 10 different wavelengths. The images shown here are based on a wavelength of 171 angstroms, which is in the extreme ultraviolet range and shows solar material at around 600,000 Kelvin (about 1 million degrees F.) In this wavelength it is easy to see the sun's 25-day rotation. During the course of the video, the sun subtly increases and decreases in apparent size. This is because the distance between the SDO spacecraft and the sun varies over time. The image is, however, remarkably consistent and stable despite the fact that SDO orbits Earth at 6,876 mph and the Earth orbits the sun at 67,062 miles per hour. Scientists study these images to better understand the complex electromagnetic system causing the constant movement on the sun, which can ultimately have an effect closer to Earth, too: Flares and another type of solar explosion called coronal mass ejections can sometimes disrupt technology in space. Moreover, studying our closest star is one way of learning about other stars in the galaxy. NASA's Goddard Space Flight Center in Greenbelt, Maryland. built, operates, and manages the SDO spacecraft for NASA's Science Mission Directorate in Washington, D.C.
  • 2016 Eclipse
    As the moon slowly covers the face of the sun on the morning of March 9, 2016, in Indonesia, a team of NASA scientists will be anxiously awaiting the start of totality – because at that moment, their countdown clock begins. They plan to take 59 several-second exposures of the sun in just over three minutes, capturing data on the innermost parts of the sun’s volatile, superhot atmosphere – a region we can only observe during total solar eclipses when the sun’s overwhelmingly bright face is completely blocked by the moon.

    In partnership with Exploratorium, NASA TV will be showing a live stream of the eclipse on March 8, 2016, from 8-10 pm ET.

  • HD 189733b Exoplanet Animation
    The exoplanet HD 189733b lies so near its star that it completes an orbit every 2.2 days. In late 2011, NASA's Hubble Space Telescope found that the planet's upper atmosphere was streaming away at speeds exceeding 300,000 mph. Just before the Hubble observation, NASA's Swift detected the star blasting out a strong X-ray flare, one powerful enough to blow away part of the planet's atmosphere.
  • Alien Atmospheres
    Since the early 1990's, astronomers have known that extrasolar planets, or "exoplanets," orbit stars light-years beyond our own solar system. Although most exoplanets are too distant to be directly imaged, detailed studies have been made of their size, composition, and even atmospheric makeup - but how? By observing periodic variations in the parent star's brightness and color, astronomers can indirectly determine an exoplanet's distance from its star, its size, and its mass. But to truly understand an exoplanet astronomers must study its atmosphere, and they do so by splitting apart the parent star's light during a planetary transit.
  • Looking for the Shadows of New Worlds
    Astronomers have used many different methods to discover planets beyond the solar system, but the most successful by far is transit photometry, which measures changes in a star's brightness caused by a mini-eclipse. When a planet crosses in front of its star along our line of sight, it blocks some of the star's light. If the dimming lasts for a set amount of time and occurs at regular intervals, it likely means an exoplanet is passing in front of, or transiting, the star once every orbital period. NASA’s Kepler Space Telescope has used this technique to become the most successful planet-hunting spacecraft to date, with more than a thousand established discoveries and many more awaiting confirmation. Missions carrying improved technology are now planned, but how much more can they tell us about alien planetary systems similar to our own? A great deal, according to recently published studies by Michael Hippke at the Institute for Data Analysis in Neukirchen-Vluyn, Germany, and Daniel Angerhausen, a postdoctoral researcher at NASA's Goddard Space Flight Center in Greenbelt, Maryland. They show that in the best-case scenarios upcoming missions could uncover planetary moons, ringed worlds similar to Saturn, and even large collections of asteroids.