Monday, May 9, 2016

Images of Today’s Transit of Mercury From Around the World

Images of Today’s Transit of Mercury From Around the World:

Mercury Transit

(Note: Awesome images are being added as they come in!)

It's not every day you get to see a planet pass in front of the Sun.

But today, skywatchers worldwide got to see just that, as diminutive Mercury passed in front of the disk of the Sun as seen from the Earth. This was the first transit of Mercury across the face of the Sun since November 8th, 2006, and the last one until November 11th, 2019.

Public events worldwide put the unique spectacle on display. Transits of innermost Mercury are much more frequent than Venus, the only other planet that can cross between the Sun and the Earth. Venus transited the Sun for the second and last time for this century on June 5th-6th, 2012, not to do so again until 2117.

Unlike a transit of Earth-sized Venus, you needed safely-filtered optical assistance to see tiny Mercury today against the Sun. At about 9" arc seconds in size, you could stack over 180 Mercury's across the 30' arc minute disk of the Sun.

Lots of live feeds came to the rescue of those of us with cloudy skies, including Slooh, NASA, and our good friends at the Virtual Telescope project.

As is customary, we thought we'd feature a running blog of all of the great images as they trickle in to us here at Universe Today, throughout the day. This is one of our favorite things to do, as we show off some of the unique images as they trickle in from the field. Watch this space, as we'll most likely be dropping in new images today throughout the day through to tomorrow.

Unlike solar eclipses, which are only usually picked up by solar observing satellites in low Earth orbit, spacecraft with different vantage points in space tend to see transits of Venus and Mercury as well, albeit at slightly different times. We're expecting to see images from the joint NASA/ESA SOHO mission located at the L1 sunward point, as well as NASA's Solar Dynamics Observatory, JAXA's Hinode, and ESA's Proba-2, all in orbit around the Earth.

It's amazing just how far the imaging tech has come, since the last transit of Mercury in 2006. Back then, Coronado hydrogen alpha 'scopes were the 'hot new thing' to observe the Sun with. Today, folks projected and shared the Sun safely with the world via social media online... and folks heeded our admonishment to stay cool and hydrate, and no reports of heat stroke from solar observers were noted.

Transits of Mercury occur on average about 13 times per century. The first was observed by Pierre Gassendi on November 7th, 1631. And although they have more of a purely aesthetic appeal than scientific value these days, transits of Mercury and Venus in past centuries were vital to pegging down the distance to the Sun via measuring the solar parallax, which in turn gave the scale of the solar system some hard numerical values in terms of the distance from the Earth to the Sun. Today, we know the solar parallax is tiny at a value of about 8.8", tinier than the disk of Mercury as seen against the Sun today.

Fun fact: a transit of Mercury as seen from space actually turns up in the 200- science fiction flick Sunshine... to our knowledge, a transit of Venus has yet to hit the big screen. We also made mention of Mercury transits and more unique astronomical events spanning space and time in our original scifi tale Exeligmos.

Ready for more transit weirdness? Journey to Mars in 2084, and you can witness a transit of the Earth, Moon AND the innermost Martian moon Phobos. Let's see, by then I'll be...

Looking further out, one can wonder just when Mercury and Venus will transit the Sun... at the same time. We came across an interesting paper this weekend on just this subject. Keep in mind, the paper notes that orbits of the planets become a bit uncertain the farther out in time you look.

Mark your calendars, as the next simultaneous transit of both Venus and Mercury occurs on September 17th, 13,425 AD. And hey, journey to Antarctica on July 5th, 6,757 AD and you can also witness a transit of Mercury during a partial solar eclipse;

Did anyone manage to catch a transit of the International Space Station during the Mercury transit? There were two good opportunities across North America today at 15:42 to 15:50 UT and 17:16 to 17:24 UT... a unique opportunity!

Well, it looks like the skies over southern Spain are clearing... time to set up our solar projection rig and observe the 2016 transit of Mercury for ourselves. Be sure to check this space for updates, and send those pics in to Universe Today's Flickr forum!

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