For the first and probably the only time in an 80,000 Years of interstellar travel, comet Leonard (C / 2021 A1) flew close to Earth. Its flyby was captured by two NASA satellites. Comet Leonard, also known as C / 2021 A1, was first sighted on January 3, 2021. It took its name from the astronomer who discovered and described it Gregory Leonard, an employee of Mount Lemmon Observatory in Arizona. The scientist managed to determine, among other things, that the comet is about a kilometer in diameter and consists mainly of ice, rocks and dust.
At the time of its discovery, Comet Leonard was about 5 AU (au) from the Sun, and therefore roughly in the vicinity of Jupiter. (One Astronomical Unit is the distance equal to the distance between the Earth and the Sun.) In recent weeks, Leonard has come closer to the Earth, and in a few days on January 3, 2022 to be exact he is to be closest to the Sun in its entire history.
Comet Leonard satellite video
Since its discovery, Comet Leonard has been closely followed by astronomers around the world. In recent weeks, it has come close enough to Earth for NASA to observe its flight thanks to satellites and probes circulating in space. Two of these devices even managed to record Leonardo's passage. The first video was created thanks to SoloHI, a device called Solar Orbiter Heliospheric Imager. SoloHI, primarily used to observe solar activity, took a series of images of Comet Leonard between 17 and 19 December. The images are stacked into an animation that shows the comet slanting across SoloHI's field of view.
The video clearly shows the comet, which is a bright, fastmoving object. In addition, Venus and Mercury can be seen at the top of the screen. Venus is the brighter of the points that moves from left to right.
Another video, also from a series of photos, was created thanks to the NASA's STEREOA (Solar Terrestrial Relations Observatory) probe, equipped with the SECCHI / HI2 telescope. The probe has been tracking the comet's flight since early November.
Although the image is grainier than that of SoloHI, the changes in the comet's tail are more visible. At first, the tail is small and barely noticeable, but it grows significantly as the comet approaches the Sun.
The comet's tail is a stream of gases and dust emanating from the comet under the influence of the solar wind. Due to the variety of substances emitted from the comet, it has two separate tails gas and dust, each of which is directed in a different direction, which can also be seen in the recordings.
Comet Leonard... how to observe it?
Shortly after the discovery of comet Leonard, astronomers predicted that it would be the brightest object in Earth's sky in the final months of 2021. However, at the turn of October and November, they reported that there had been an unexpected decrease in the brightness of the object. With bodies as unpredictable as comets, this is not unusual. Therefore, perhaps astronomy enthusiasts will have to get by with the taste. But the recent flight over Earth showed that the fears were somewhat exaggerated.
NASA said Comet Leonard was closest to Earth on December 12. The distance between our globe and the comet was then about 34 million km. Although the comet is now moving away from Earth and moving further towards the Sun, it will be visible in our skies until the end of December. It will have a close encounter with the Sun on January 3, 2022, when it will be 0.62 AU away from the Sun, inside Venus' orbit. Later, we will probably say goodbye to her forever. As scientists predict, if Comet Leonard survives the journey around the Sun, we will never see it again, because after passing through perihelion (the point closest to the Sun), it will be ejected from the Solar System.