“I remember when I first visited Mercury…”

Bwog likes to inform our readers of every event around campus, from social justice jamborees to science seminars. We sent our own little Martian Mason Amelotte to space Low Library on Tuesday to learn more about Mercury.

Why do we explore our solar system? It’s a question people don’t often think about. Most would say we explore our solar system to learn more about the planets, comets, and stars around us. However, Sean C. Solomon, director of the Lamont-Doherty Earth Observatory at Columbia, believes otherwise. He believes we explore our solar system to learn more about Earth itself.

On Tuesday night, Solomon gave a university lecture in Low Library titled “Why We Explore the Solar System: The MESSENGER Mission to Mercury.” Solomon is director of the largest research division within the Earth Institute at Columbia, and he is also principal investigator of NASA’s Messenger mission to Mercury, the “most comprehensive investigation yet of the planet closest to the sun.” Solomon is a 2014 recipient of the National Medal of Science, and even has an asteroid named after him, Asteroid 25137 Seansolomon, which is currently in orbit around the sun between Mars and Jupiter.

University President Lee C. Bollinger opened the presentation by giving praise to the University Lecture as a forum that reflects “the ideals of…the university.” Prezbo went on to commend the work of the faculty at the Lamont-Doherty Earth Observatory. He mentioned that the purpose of the MESSENGER mission was to provide him with “a quick and easy way to escape the students administration,” before handing the microphone off to John H. Coatsworth, University Provost. Coatsworth introduced the audience to Sean C. Solomon, the keynote speaker, by listing off Solomon’s many degrees and accomplishments. One endeavor that stood out was Solomon’s role as principal investigator of the MESSENGER project, which puts him in charge of “all aspects of the mission…from financing to executing.” Coatsworth then welcomed Solomon to the stage.

Solomon began his lecture by listing off some of the reasons we should study Mercury more closely. First, while NASA has sent 21 spacecrafts to Mars, 34 to Venus, and 14 to comets around our solar system, only two spacecrafts have ever been successfully delivered to the planet closest to the sun. This number is so low because “delivering a spacecraft into Mercury’s atmosphere requires a huge change in velocity (~10km/s).” Additionally, the planet’s proximity to the sun poses extreme thermal hazards to any spacecraft attempting to land on it. However, the MESSENGER mission became a success in March of 2011 when it entered Mercury’s orbit for the first time ever, despite having to travel around the planet three times. Solomon divided his lecture into three parts, each of which focused on a major discovery made by the MESSENGER spacecraft.

First, Solomon described the composition of Mercury’s surface. According to the measurements taken at the planet’s poles, Mercury’s formation yielded not only a high metal to silicate ratio, but also retained substantial amounts of interior volatile elements. This has led scientists to question the generally accepted ideas involving the formation of the inner planets, including Earth. Second, Solomon revealed to the audience that Mercury’s magnetosphere, today yielding an axisymmetric, equatorially asymmetric field, has been active for ~4 billion years. This raises questions about the past geometry of Earth’s magnetic field and how it has changed over time. Third, Solomon found that in Mercury’s polar craters, there exist radar-bright deposits consistent with near surface or surface water ice, plus dark, possibly carbonaceous materials (the same materials that are responsible for creating life itself). This would serve as witness that both water and organic compounds are delivered to the inner solar system by masses like comets traveling from the outer solar system.

Solomon concluded his presentation by revealing that although the spacecraft was expected to run out of jet fuel by 2014, “thanks to the cleverness of [their] propulsion engineers,” MESSENGER is expected to come within 15km of the planet’s surface in March and April of 2015, “the furthest we’ve ever travelled through the planet’s atmosphere.”