NASA’s Astronomy Picture of the Day is a spine-chilling picture of the Sun when Earth was closest to it.
The distance from Earth to the Sun is 93 million miles or 149 million kilometers. And every year, Earth makes its closest approach to the Sun. And it is a picture based on this phenomenon that NASA has dedicated as the Astronomy Picture of the Day for January 14, 2023 – Perihelion Sun 2023. Earth’s closest approach to the Sun was on January 4 at 16:17 UTC, when it was orbiting at about 91.4 million miles (147 million kilometers) from the Sun. NASA explains the photo, “That was less than 24 hours after this sharp image of the Sun’s disk was recorded with a telescope and H-alpha filter from Sidney, Australia, planet Earth. An H-alpha filter transmits a characteristic red light from hydrogen atoms.”
The view of the Sun in NASA’s astronomy image of the day emphasizes the Sun’s chromosphere, which is a region just above the solar photosphere or normally visible solar surface. “In this H-alpha image of the increasingly active Sun planet-sized sunspot regions are dominated by bright splotches called plages,” NASA added. The dark filaments of plasma crawling across the solar disk transition to bright prominences when seen above the solar limb. But how does Earth make its closest approach towards the Sun? What exactly does perihelion mean? Know all here.
What is perihelion?
The word “perihelion” comes from Greek and refers to the point in the orbit of a planet or any other astronomical body, at which it is closest to the Sun. Hence, Earth’s closest point is known as Perihelion. You should know that Earth doesn’t orbit the Sun in a perfect circle, instead, it moves in an elliptical shape. This simply means Earth moves closer to the Sun during certain parts of the year. Similarly, it moves farther from the Sun, depending on which part of the year it is. Perihelion is all about the planet’s physical distance from the biggest star of our solar system.
However, it doesn’t have any specific date. The perihelion is always shifting or changing by two days every century. This is due to the small quirks in our planet’s orbit.