"Humans have been watching patterns in the sky for millennia".
During a transit, Mercury passes between Earth and the sun, becoming a small, round silhouette against the yellow glow of the solar disk.
We won't see a Mercury transit again until 2032.
You should not try to watch this event directly, since you'd risk severe eye damage.
NASA will broadcast the transit as seen from the orbiting Solar Dynamics Observatory, with only a brief lag. However, because serious damage to the eye, including blindness, can result from looking directly at the sun without proper eye protection, the telescopes will be equipped with special solar filters to permit safe viewing. Some of those viewing aids are custom-made with the filters, and you might be able to pick them up over the weekend at a well-equipped telescope or camera store if you're so inclined.More news: Chemical reaction leaves 1 dead, several ill at Buffalo Wild Wings
More news: 'Gossip Girl' Sequel: Kristen Bell Set to Return in Iconic Role
More news: Mexico finds human-built 'mammoth traps' 15000 years old
It is extremely unsafe to look directly at the sun through instrument eyepieces because concentrated solar rays can damage your eyes instantly and even blind you.
There are also solar filters that fit over the front lenses of binoculars, or attach onto the barrel of a telescope.
"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, or go to an organised event if the weather is clear, or alternatively follow one of the live webcasts". It begins at 7:35 a.m. EST. That's because the orbits of the planets are tipped with respect to each other.
This coming Monday you have the chance to witness an event that only happens once in a lifetime.
Every 88 years Mercury completes each orbit around the sun, and passes between the Earth and sun every 116 days. And if you're waiting for Venus to do a reprise of its widely watched 2012 solar passage, take good care of yourself: The next transit of Venus takes place in 2117.