Mercury’s Transit Across the Sun
Courtesy of NASA
By Jacqueline Jedrych
Mercury made its transit across the sun for the first time since 2016 on Monday, November 11. Catholic University professors and astronomers Tommy Wiklind and Dr. Duilla De Mello set up telescopes outside the Pryzbyla Center to view this historic event. Astronomy classes were required to attend and any students passing by had the opportunity to look into the telescope to view Mercury crossing the sky. The next transit will occur in 2032 and will be most visible from Africa, Europe, South America, and parts of Asia.
“[The cause of the Mercury transit is] the planet Mercury passing in front of the Sun,” said Dr. Wiklind. “It happens approximately 13 times per century.”
The only two planets observable in transit from Earth are Mercury and Venus because they are closer to the sun than Earth. The observation of transits is based on how many planets are between the Sun and the point of observation.
Transits of Mercury are more frequently observable than those of Venus, which will have its next transit in 2117. This is because Mercury is closer to the Sun and orbits the sun more quickly. Mercury transits are visible about 13 times every hundred years, while Venus’ transit has been visible only 81 times in the six millennium period of 2000 BCE to 4000 CE.
“Transits have no effect on the natural goings-on here on Earth, but they can teach us a ton about physics, our solar system, and other planetary systems,” according to the National Air and Space Museum website,
Mercury transits help astronomers and physicists to learn about the way the cosmos work. The distance between the Earth and the Sun can be measured by observing the change in the planet’s position during the transit from two different places on Earth.
Currently, Mercury is in Retrograde, meaning it appears to be moving backward across the sky for about three-and-a-half weeks. In reality, it means that Mercury has lapped the Earth in its orbit around the sun. This happens around three or four times per year.
“Mercury retrograde is a natural consequence of the fact that each planet in our solar system moves with different velocities around the Sun—the further away, the slower it moves,” said Wiklind. “Retrograde motion means that the position of a planet on the sky, that is, relative to the distant stars, seems to shift from moving west to moving east, and then back to moving west.”
Mercury retrograde occurs much more frequently than Mercury transit and has no effect on Mercury’s transit.
“It also means that Mercury is always in retrograde when it transits the Sun,” said the National Air and Space Museum, “when Mercury goes between us and the Sun, it is in the part of its orbit that makes it appear as it is moving from East to West!”
Mercury Retrograde is a period that, for those who believe in astrology, is believed to cause miscommunications and turbulence.
“In astrology,” said founder of Astrology Zone, Susan Miller, “we always believe the following rule is true: “As above, so too below.” By that we mean there is a fractal relationship between the orbits in the heavens and human activity down here on Earth.”
“I haven’t talked to my best friend from home for about two days,” said freshman Mary Pilkington on how she has felt during this period of Retrograde. “Everything’s just felt a little off. Also, there’s been miscommunications with my mother.”
Although astrology has fervent followers, astronomers generally disagree with their views. Dr. Wiklind says there is “absolutely no merit” to the claims of astrology, specifically Mercury Retrograde’s terrestrial emotional effects. The next Mercury transit visible from D.C. will occur on May 7, 2049.
