Tomorrow night: a rare gathering of Saturn and Jupiter

During grouping, the two planets will be visible to the west, immediately after sunset over the southwestern horizon close to the setting sun. Next upcoming gathering – March 2080 * And how does this relate to the way we discover planets outside the solar system?

This is what the planets will look like on Monday evening (Photo: NASA / JPL-Caltech / TNS)
This is what the planets will look like on Monday evening (Photo: NASA / JPL-Caltech / TNS)

Tomorrow (Monday, December 21, 2020), a very rare event will occur in the evening sky – the two largest planets in the solar system will congregate. That is, the angular distance between them as seen from Earth would be so small that they would look almost like one star in the sky. The two planets are the largest in the solar system and both move relatively slowly – Jupiter completes the orbit around the sun once every 12 years orbiting the Earth and Saturn once every 30 years or so. Therefore, clusters between these two planets are particularly rare.

At the time of grouping, the two planets will be visible in a westerly direction, immediately after sunset over the southwestern horizon close to the setting sun. The angular distance between the two giant planets will be about one-fifth the size of the full moon, or about 6 times the angular size of Jupiter, which means that if viewed with a telescope even at medium or large magnification – both will be seen in one field of view (southern Jupiter). In the same field of view it will be possible to see both the four large moons of Jupiter (using a telescope) and the large moon of Saturn – Titan and of course its rings. The next time there will be a Jupiter and Saturn cluster will be in about 20 years, in October 2040, but then the angular distance between them will be 10 times greater and only on March 15, 2080, these two planets will cluster again and the angular distance between them will be the same as next Monday. The grouping can be seen from anywhere in the country, even with the naked eye. Of course a telescope enhances the experience, as then one can see Saturn’s rings, Jupiter’s cloud belts and its four large moons. Field binoculars will also see the two planets as well as the four moons of Jupiter.

Does grouping have a physical meaning?

Yes. It should be remembered that these are the two largest planets in the solar system, which are far from it. Therefore, at the time of grouping, the center of gravity of the sun will be outside the sun, to a radius of the sun and more, so that virtually all planets and the sun are now orbiting a point outside the sun.

This will in fact continue in the coming years as long as Jupiter, Saturn, Uranus and Neptune are in a relatively narrow shape of the sky relative to the sun. An alien, looking through a telescope at the solar system from a distant solar system, will actually see the sun moving relative to that point and so it will conclude that there are planets around it. This is how we actually discover planets around other suns, causing those suns to circle around the center of gravity of the system.

“The Star from Bethlehem”

Some claim that the gathering of the two planets was the star from Bethlehem, which heralded the birth of Jesus. According to legend, it is said: Aya is the king of the Jews born, because we saw his star in the east. So what is that star of Bethlehem? It turns out that around the year the count began, there were some very close clusters of two other planets – Venus and Jupiter. These are extremely rare clusters that occur only once every hundreds of years. Venus is the brightest planet in the sky so these clusters are more significant.

A grouping corresponding to the time of the beginning of the Christian era and therefore to the time of Jesus’ alleged birth, occurred in August 1 BCE (meaning no day of the month according to the civil calendar in the years before 1582, the beginning of the civil calendar). I angled between Jupiter and Saturn in the current cluster and it is possible that they were seen in the eye as one star, whose magnitude was the sum of the light of the two bright planets.This cluster is problematic because it looked west, while according to legend, Bethlehem looked east.

However, there is a problem with the time of Jesus’ birth. The year of King Herod’s death occurred in 4 BCE and it is not possible that Jesus was born after his death if one accepts the narrator in the New Testament. Therefore, if one seeks to find clusters that coincide with the time of Jesus’ birth, clusters earlier or closer to this year must be found.

Close and rare clustering

Closures were frequent in February 5 AD, when the angular distance between Venus and Jupiter was 3 times greater than the angular distance between Jupiter and Saturn this year, and two planets were seen above the eastern horizon before sunrise. In this case, however, it was clear that these were two planets and they did not appear to be one star. The most interesting clustering, astronomically speaking, occurred in the year 2 BCE in February. This close and rare clustering occurred when the two planets were so close that Noga launched to the southern edge of Jupiter. And therefore does not fit the description.

A cluster that may be the one in question occurred in August 3 BC. It was also a cluster so close that two planets were visible to the eye as one star and it was visible in the east before sunrise. By the way – Venus passed a similar angular distance from the planet Saturn, A very rare event. It is worth remembering that the New Testament was written decades and hundreds of years after the events and therefore it is most likely that the near and frequent gatherings of Venus and Jupiter in those years, were the source of this sentence and the Star of Bethlehem.

Dr. Yigal Pat-El, Space Telescopes.

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