In this video, you will learn about Comet Shoemaker–Levy 9 and one of its possible orbits before meeting Jupiter. It will show the gravitational capture of the comet by the gas giant, the subsequent rotation around it, and the disintegration of the comet into fragments, followed by their fall to Jupiter.
The initial size of the nucleus of Comet Shoemaker–Levy 9 is estimated at 5 km. In the middle of the 19th century, the perihelion of its considered orbit was not far from the orbit of Jupiter. At aphelion, the comet was approaching Saturn orbit. Its orbit had a slight eccentricity, that is, it was slightly elongated. It also had a small angle of inclination to the ecliptic plane and the plane of the orbits of Jupiter and Saturn.
With the selected parameters, the comet’s encounter with Jupiter could have occurred at the very beginning of the 20th century. This encounter led to the gravitational capture of the comet by Jupiter, and it began to rotate around it. The comet hit the Hill sphere, that is, a region of space in which a planet can hold a satellite despite the gravity of the Sun. However, the video clearly shows that the comet’s trajectory is not closed.
The comet performed a series of several elongated orbits around Jupiter. Then it made several revolutions around it in an almost circular orbit. The comet could not enter a closed orbit around Jupiter due to strong gravitational disturbances from the Sun. The plane of rotation of the comet slightly changed its inclination with each revolution, but remained almost perpendicular to the ecliptic plane. The alternation of elongated and circular turns occurred as Jupiter moved around the Sun. The full cycle of alternation took about the same time during which the gas giant made two revolutions around the central star. During this time, the orientation of the comet orbit in relation to the Sun continuously changed. It turned sideways to the star, then turned flat to it. At some points in time, the comet turned out to be somewhat closer to the Sun, which attracted it with greater force. This greatly destabilized the comet orbit and led to a rather abrupt change in its orientation in space.
During the elongated orbits around the gas giant, the comet sometimes passed only a few million km away from it. At such moments, the uncertainty in the estimated position of the comet increases greatly. The fact is that the coordinates of any celestial object are known with some error. Each close approach of an object to a planet increases the uncertainty in coordinates by one or even two orders of magnitude. The reasons for this increase in uncertainty are clearly shown in a video about the probability of collision between asteroid Bennu and Earth. Because of this, it is impossible to say exactly when comet Shoemaker–Levy 9 entered orbit around Jupiter. There are estimates that it could have been captured by it only in the mid-60s or even in the early 70s of the last century. However, the scenario shown in this video (that the comet has been orbiting Jupiter for almost a hundred years) is also quite possible.
It is well known that on July 7, 1992, Comet Shoemaker–Levy 9 came very close to Jupiter. It passed only 40 thousand km from the planet atmosphere. This approach was so close that Jupiter’s powerful tidal forces tore the comet’s core into many fragments. The comet was discovered by Eugene and Carolyn Shoemaker and David Levy on March 24, 1993. At that moment, it was already a lot of debris. At least 21 fragments were found, stretching along the trajectory in the form of a chain. After the discovery of the comet and the calculation of its trajectory, it became clear that further motion of the fragments would lead to their collision with Jupiter. All calculations were confirmed. The fragments fell over the course of a week: from July 16 to July 22, 1994. The fragments fell on Jupiter at a speed of over 60 km/s. This led to a colossal explosions in the atmosphere of the gas giant. The power of each of the explosions was many times higher than the total nuclear potential accumulated on Earth.
The moments of impact themselves were not observed from Earth, as the collision of each object occurred on the far side of Jupiter. However, the consequences of the impacts were clearly visible. The cloud of incandescent gas formed during the explosion at the moment of entry of debris into the atmosphere of Jupiter rose to a great height. As a result, this cloud could be observed from the Earth. Dark traces of explosions in the atmosphere of Jupiter, which were larger than our planet, were also clearly visible from the Earth. These traces could be seen for many weeks after the explosions. The moments of the fragments falling were observed by the Galileo spacecraft, which was heading towards Jupiter at that time.
This grandiose event, which took place 30 years ago, was the first observed collision of two celestial bodies. It gave us an understanding of the important role Jupiter plays in protecting the Earth. The largest planet in the Solar system takes on a significant part of the impacts of asteroids and comets.
Modeling and rendering were performed by author of this video using own software. The calculations took into account the mutual influence of the Sun, all the planets of the Solar System, the Moon and the comet on each other. Relativistic effects were also taken into account in the calculation. Non-gravitational effects associated with the comet nucleus matter evaporation and the possible collision of fragments with each other were not taken into account. Throughout part of this video, the sizes of celestial bodies are shown to be greatly exaggerated compared to the distances between them.
The track The falling by Koi-discovery sounds in this video. This track was not changed. CC0 1.0 Universal (CC0 1.0 DEED) license.
