Only two planets ― Mercury and Venus orbit the sun closer to the Earth than any other planets.
For those without solar filters and telescopes, there are multiple options to watch the Mercury transit live - including the stream embedded above - on Monday without hurting your eyes. So scroll down and enjoy the awesome photos of the 2019 transit of Mercury.
There will be telescopes with solar filters available for public use at Antelope island until 11:30 a.m., and they are also serving hot chocolate.
In most of the United States and Canada, and New Zealand, the transit will be in progress as the Sun rises.
While it takes the innermost planet only 88 days to orbit the sun (about nine months less than our world), Mercury's orbit is tilted, so it seldom lines up perfectly with the Sun and Earth.
The Mercury transit started around 7:35 a.m. eastern time and lasts about five and a half hours.
"Edmund Halley used a transit of Venus in 1761 and 1769 to determine the absolute distance to the Sun".
Astronomers can use this technique to discover alien planets orbiting stars in distant systems.
To spot the small disc of Mercury against the Sun you will need a telescope with a magnification of at least 50x.
Another use of transits is the dimming of Sun or star light as a planet crosses in front of it. "So Mercury's going to most likely be excessively little".
'Transits are a visible demonstration of how the planets move around the sun, and everyone with access to the right equipment should take a look, ' Mike Cruise, president of the Royal Astronomical Society, said in a statement.
"It can lead to serious and permanent vision damage".