Scientist for a Day

Emma Li

School: Crosby Heights Public School

Teacher: Jennifer Boehlke

City: Richmond Hill, Ontario

Topic: Miranda

---

"On February 16, 1948, at the McDonald Observatory in western Texas, the first documented sighting of Miranda was reported. Upon discovery, it was given the name, “Miranda”, in reference to the daughter of Prospero in William Shakespeare's play, “The Tempest”. They had just spotted one of the most unique aspects that our corner of the universe has to offer. Not only was it the first satellite of the planet Uranus sighted since the past century, but it has a much different climate than it’s neighbours. At the time before Voyager 2’s journey, only 5 moons of Uranus had been identified. Among those, in order of their discoveries, were Oberon, Titiana, Umbriel, Ariel, and Miranda. The first is about half ice and half rock, with craters scattered on the surface, while the second has fault lines running across it. The third has a strangely dark surface, except for an even weirder 140 kilometer ring of light on the surface. Younger than the rest and featuring a light surface, the fourth features valleys surrounded by faults. Small, icy and the closest to the planet, the mean surface temperature of the fifth has been recorded as low as -187° C; which makes sense for something over 120,000 km from the sun. On this faraway moon, gravity levels are lower than Earth due to a much smaller diameter of 500 km, approximately one-seventh of Earth’s. It was the last planetoid discovered orbiting Uranus until the launch of NASA’s space probe, Voyager 2, in 1977. After 9 years in space, the probe was able to capture photos and grant us additional details about the moon’s strange landscape and remains the only one flying close enough to do so.

​No two surfaces on Miranda are alike; from canyons that are twelve times deeper than on Earth to being the home of Verona Rupes, the tallest cliff in our solar system, the moon is full of contrasting terrain. Because of this, the appearance of the moon has been said to look the likes of Frankenstein’s monster, stitched together from pieces that don’t belong together. It has earned itself the nickname “Frankenstein’s Moon”. Astronomers had once believed that Miranda had been shattered to pieces and reassembled several times throughout its long history. However, more recent and probable theories suggest that the upwelling of partially melted ice may be responsible for this curious landscape. Images have shown that it also contains three giant 'racetrack'-like grooved structures dubbed “coronae”, each one at least 200 km wide and up to 20 km deep. They have been named Arden, Elsinore and Inverness after various locations in Shakespeare's plays, much like how Miranda was named. The real reasoning behind these strange formations, unlike any other in our solar system, is yet to be determined. For now, their origins remain secret…

Viewing Miranda is difficult for amateur telescopes, as it is near invisible to them due to its strange apparent magnitude. Significant portions of the information we know about the moon were obtained during the flyby Voyager 2 made of Uranus on January 25, 1986. The probe passed at a much closer distance than it did for any other nearby moons, only 29,000 km from the surface. Unfortunately, no major plans for continuing the exploration of Miranda are being discussed, being overridden by more high-priority missions to Mars and the Jovian System. Despite these obstacles, NASA's Planetary Science Decadal Survey held in 2017 revealed there is a possibility of an orbiter returning to Uranus some time in the 2020s. In the best case scenario, this orbiter would pass by each of the gas planet’s moons including Miranda, while hopefully capturing additional photos and lead us to crack the mystery of the moons strange environments."