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Mercury Transit: Smallest Planet to Make a BIG Entrance

Mark your calendars: The smallest planet in the solar system is about to make a REALLY big entrance.

<p>The 2006 Mercury transit as seen by the Japanese solar observatory Hinode. Credit: JAXA</p>

On May 9, little planet Mercury will delight astronomers across most of the planet, and some robotic observatories in space, with its several hour dash across the disk of the sun. The planet, which is the closest to the sun, won't be particularly obvious to the casual observer, but assuming you have access to suitable astronomical equipment, you may be in luck.

ANALYSIS: Visiting the World's Most Powerful Telescopes: #MeetESO

Obligatory warning: Though an exciting event, DO NOT look at the sun unprotected. In fact, you need the appropriate sun-viewing gear, so do not attempt to view the transit with unprotected eyes - as Mercury is too small to see, forget eclipse viewing glasses and definitely do not use sunglasses - and do not look at the sun with an unprotected telescope or binoculars. Permanent eye damage can result - as graphically illustrated by astronomer Mark Thompson in this rather gruesome video.

Astronomical events are being held world-wide, so be sure to check out your local astronomical society to find where your nearest event is. Astronomical societies are a hothouse of professional and amateur astronomers all enthusiastically engaging the public in astronomy, so be sure not to miss out.

The 2016 transit comes 10 years after the last Mercury viewing (in November 2006) and the next isn't due until 2019. After that, there's a long stretch until 2032.

PHOTOS: Transit of Venus Photos From Our Readers

As discussed in this information-packed NASA video, the Mercury transit will also provide astronomers with the opportunity to carry out some pretty cool science. As the planet passes in front of the sun, we can observe the planet's exosphere - a very thin atmosphere. Mercury's exosphere is formed through interactions with the solar wind that continuously washes over the planet's rocky surface, causing the outgassing of particles that are swept back like a comet's tail. By looking at the sunlight passing through the exosphere, astronomers can learn more about fundamental solar interactions on planetary bodies.

As an added bonus, solar observatories, such as NASA's Solar Dynamics Observatory, will have a pristine view of the transit. Interestingly, this will be the SDO's first Mercury transit (it was launched in 2010), but it is no stranger to planetary transits. The SDO was able to gather stunning high-resolution views of the very rare Venus transit in 2012. So this transit will be much like that, only Mercury will be far smaller and not sporting a thick planetary atmosphere.

ANALYSIS: The Transit of Venus: A Personal View

Personally, I am very excited to see the transit from a very privileged location. As part of the #MeetESO social media event, I will be traveling to Chile's Atacama Desert on Friday and, on Monday, will be viewing the transit from the ESO's Paranal Observatory - the home of the awesome Very Large Telescope (VLT) atop Cerro Paranal, a 2,664 meter (8,740 ft) high mountain. It's going to be good!

Depending on internet connection availability, I will be checking in via Twitter (via @Discovery_Space and @astroengine), Instagram (@astroengine), Facebook (Discovery News) and there may be an opportunity to do a live Facebook feed via Science Channel. I will also be blogging here when possible. And there will of course be a series of DNews videos on the event.

click to play video