Venus slowly crossed the sun on Tuesday in a rare event that will not be visible from Earth again for 105 years. Transits of Venus occur in pairs, eight years apart, with long intervals between cycles. During this recent transit, Venus appeared as a small black dot moving across the northern hemisphere of the sun. People watched the six-hour and 40-minute event online through various websites, including live video feeds from the Prescott Observatory in Arizona showing a solar flare forming near Venus. The transit on Tuesday, which was part of a pair that occurred between 2004 and 2012, started at 6:09 p.m. EDT (2209 GMT). People on all seven continents, including Antarctica, had the opportunity to witness at least a portion of the transit. Even astronauts on the International Space Station participated in observing the event. Don Pettit, a flight engineer on the space station, had been preparing for this moment and brought a solar filter with him in anticipation of the transit of Venus during his rotation. It is not just about beautiful images. Numerous scientific experiments were planned, including research that could contribute to the discovery of habitable planets outside of our solar system. Telescopes like NASA's Kepler space telescope are being utilized to locate extrasolar planets that transit in front of their stars, similar to Venus passing in front of the sun. Astronomers intended to analyze Venus' dense atmosphere during its transit in order to develop methods for studying atmospheres of other planets. Additionally, examining Venus' atmosphere could provide insights into the differences between Earth and Venus despite their similar size and proximity to the sun. Venus has an extremely thick atmosphere, 100 times denser than Earth's, consisting mainly of carbon dioxide, a greenhouse gas. The planet's surface temperature is a scorching 900 degrees Fahrenheit (480 degrees Celsius), with sulfuric acid clouds moving at high speeds and causing acid rain. Despite being known as the goddess of love, Venus' conditions make it a place you wouldn't want to visit, according to an astronomer. Scientists are studying Venus' climate to gain insight into Earth's atmospheric changes. In past transits of Venus, scientists determined the size of the solar system and the distance between the sun and planets. The upcoming transit on Tuesday will be only the eighth since the telescope was invented, and the last until December 10-11, 2117. This transit will also be the first to occur with a spacecraft at Venus. Data collected from Europe's Venus Express probe will be analyzed alongside observations from various ground and space-based telescopes, such as NASA's Solar Dynamics Observatory, the joint US-European Solar and Heliospheric Observatory, and Japan's Hinode spacecraft.