Check Out These Extraordinary New Images of Mercury
At 06:59 Central European time time on January 8, the BepiColombo spacecraft successfully performed its sixth flyby of Mercury, the innermost planet in the solar system. This was a “gravity assist maneuver,” a move that used Mercury’s gravitational pull to alter the BepiColombo vehicle’s course, which will bring it into orbit around the planet by the end of 2026.
BepiColombo is a joint mission by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) that will study the composition of Mercury. The vehicle, consisting of two probes—ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter—was launched in the fall of 2018 and had previously been orbiting the sun.
When it approaches Mercury again, the vehicle will separate, and the two probes will head for their dedicated polar orbits. BepiColombo’s scientific work is then scheduled for early 2027, when the probes will look for information on how the planet was formed and whether some of its craters contain water in the form of ice.
Until then, we will have to make do with the details contained in these three images taken by the vehicle during its most recent flyby.
Photograph: ESA/BepiColombo/MTMMercury’s North Pole Between Light and Shadow
This image was taken by BepiColombo’s Monitoring Camera 1 (M-Cam 1) when the vehicle was about 490 miles above Mercury’s surface. (At its closest, the spacecraft came within about 180 miles of the planet.) Having approached from Mercury’s shadowed side, the first photos were taken a few minutes later as the planet’s light side came into view. The image shows the planet’s “terminator zone”—the boundary between its illuminated side and the area that’s in shadow. Because Mercury’s axis of rotation is almost exactly perpendicular to its plane of orbit around the Sun (as opposed to Earth’s axis, which is tilted at 23.5 degrees relative to its plane of orbit), some areas of Mercury, particularly the interior of certain craters close to its poles, are always in shadow. These are thought to be among the coldest places in the entire solar system, despite Mercury being the closest planet to the sun. To the left of the terminator, some of these craters are visible, including the Prokofiev, Kandinsky, Tolkien, and Gordimer craters. One of the mysteries that the BepiColombo mission is expected to solve is whether there is frozen water inside them, as some studies suggest. In the foreground, the photo shows part of the BepiColombo vehicle.
Photograph: ESA/BepiColombo/MTMThe Portion of Mercury’s North Polar Region Illuminated by the Sun
This image was taken by M-Cam 1, when BepiColombo was about 900 miles above Mercury’s surface. The photo, ESA explains, shows that large regions of the planet’s crater-filled surface have been made smooth by lava, which originated from major volcanic eruptions in Mercury’s past. This effect is especially visible inside the 180-mile-wide Mendelssohn crater. The crater rim is still clearly visible (and as been marked with an orange-colored circle superimposed on the image) but has been largely filled in by smooth volcanic material that also makes up the surrounding plains. On the lower left of the image, you can see the Caloris Basin, the largest known impact structure in the solar system, with a diameter of more than 900 miles.
Photograph: ESA/BepiColombo/MTMLava Remnants and Debris Make Mercury’s Surface Brighter
Contrary to what these images suggest, Mercury is a dark planet, ESA experts point out. At first glance it might look like our moon, but in reality Mercury’s surface reflects only two-thirds of the light reflected by our satellite. However, younger formations on its surface appear lighter: material from the planet’s interior that reaches its surface becomes darker over time. For example, the bright spot seen at the top of the image, taken by M-Cam 2 when BepiColombo was about 1,300 miles above Mercury’s surface, is a formation known as the Nathair Facula. It is the result of the most significant volcanic eruption that has occurred on the planet. It is a particularly interesting formation, on which several mission instruments will focus their attention. Their aim is to study the composition of the erupted material to allow us to better understand the composition of Mercury itself. Below Nathair Facula, the photo shows the Rustaveli crater, a 125-mile-wide formation with a ring of mountains inside. The crater has since been filled with lava, meaning the mountains’ peaks barely protrude from the crater’s smooth surface.
This story originally appeared on WIRED Italia and has been translated from Italian.
