Mercury sets up a rare celestial body like next week, when you're staring at the sun in front of much of the world.
The smallest, innermost planet in the solar system will resemble a tiny black spot on Monday when it's directly between Earth and Sun. It starts at 7:35 EST.
The entire 5 ½-hour event will be visible depending on the weather in the eastern US and Canada as well as throughout Central and South America. The rest of North America, Europe and Africa will be part of the action. Asia and Australia will miss it.
Unlike his transit in 2016, Mercury will almost hit the bull's eye this time and will practically pass the deadlock in front of our star.
Mercury's next transit is not before 2032 and North America will not be able to see it until 2049. Earthlings are treated in a century with only 13 or 14 mercury passes.
Proper eye protection is required for the Monday Spectacle: Telescopes or binoculars with sun filters are recommended. It does not hurt to pull the eclipse out of the total solar eclipse in the US two years ago, but it would take an "extraordinary view" to detect tiny mercury, NASA solar astrophysicist Alex Young said in comparison to 1.4 million kilometers (864,000 miles) of the sun.
During the 2012 Sun Transit, Young could barely detect a larger and closer Venus with his sunglasses.
"That's really close to the limit of what you can see," he said earlier this week. "So Mercury will probably be too small."
Venus transits are much rarer. The next one is not before 2117.
Mercury cuts a diagonal path from left to right over the sun on Monday, enters lower left (around the 8 hour mark on a clock) and leaves it on the upper right (around 2 o'clock) Hour mark) mark).
Although the migration seems slow, Mercury will race across the sun at a speed of about 241,000 km / h.
NASA sends the transit off the orbit of the Solar Dynamics Observatory with only a short delay. Scientists will use transit to optimize telescopes, especially those in space that can not be tuned manually, Young said.
With this transit scientists can discover foreign worlds. Regular, fleeting break-ins of starlight indicate a planet orbiting.
"Transits are a visible demonstration of the planetary movement around the Sun, and anyone with access to the right equipment should take a look," said Mike Cruise, president of the Royal Astronomical Society, in a statement England.