By Justin Drabick

PHILADELPHIA (CBS) — Today marks a major phenomenon in space. It is a rare event that will have stargazers out in full force around the world. It hasn’t happened since 2004 and won’t happen again until 2117.

Venus is in transit, which means it will pass between the Earth and the sun. Get a good look, because you won’t get another chance. Venus and Earth are sometimes referred to as “near twins” due to their similar size, but the atmosphere on Venus consists mainly of carbon dioxide, which creates surface temperatures of more than 800 degrees.

Venus will begin its transit just after 6 p.m. on Tuesday, and it will last for almost seven hours. The planet will look like a small moving dot on the sun, but it will be too small to block the sun’s light. The best time to view the transit will be around sunset. Make sure you do not stare at the sun without protection though! If you don’t have eye protection or can’t view the sun because of the cloud cover, you can check out a live webcast of the transit on cbsphilly.com…just click on “Links and Numbers.”