With a speed of approximately 28,000 km/h, the ISS completes one orbit around the Earth in 90 minutes or more, but it only transits across the Sun for about 0.75 seconds. Therefore, capturing high-resolution footage like Legault did was extremely challenging, as reported by Business Insider on June 14th.
“The transit process lasts less than a second,” Legault said. He was fortunate to capture this moment as, 45 minutes later, a large cloud moved in, obscuring the Sun.
In the footage, the ISS can be seen passing in front of three clusters of dark spots on the Sun, one of which is large enough to engulf the Earth. At that moment, NASA astronauts Stephen Bowen and Warren Hoburg were also outside the station, installing new solar panels.
In the video, the ISS appears to be very close to the Sun, but in reality, the distance is immense. The ISS orbits the Earth at an altitude of about 400 km, while the Sun is about 150 million km away.
The dark spots appear darker because they are cooler than other regions on the Sun’s surface, according to NASA. The cooler dark spots form where strong magnetic fields inhibit heat from flowing to the surface from the Sun’s interior. In these spots, the unstable magnetic field can trigger solar flares – powerful eruptions that release energy and high-speed particles into space. Solar flares can create impressive auroras but also disrupt radio waves on Earth. Strong solar flares can even impact satellites, communication systems, power grids, and most severely, cause power outages.
According to NASA, the charged particles from solar flares can also pose radiation risks for astronauts, particularly when they venture outside the ISS for spacewalks. Therefore, scientists continue to carefully monitor solar flares, and NASA may cancel spacewalks before these particles approach Earth to ensure the safety of astronauts.