Jupiter & Saturn crashing next week??? No!

Cool fact: if it weren’t for Saturn —Jupiter would’ve continued its inward orbital dive to Sun & destroyed inner terrestrial planets (ie ). But all was saved by Saturn by pulling J outward.

(HT @girlandkat)

2) this rare event of the Saturn Jupiter alignment is known colloquially as the “Great Conjunction of 2020”. And yes there is a website for this. http://jupitersaturn2020.org/ 

3) Saturn first stopped Jupiter out of its inward orbit dive around current location of Mars because they together achieved 2:1 orbital resonance as @drbecky_ explains. But then they were stable there for a while... until...

4) Until the Uranus and Neptune showed up to disrupt that J-S resonance and broke it. Which then led to them all (J, S, U, N) migrating back out further. But thankfully they did. Good video by @drbecky_

5) Bottomline: if it weren’t for Saturn forcing the orbital resonance with Jupiter and stopping its inward orbital movement to the sun, we would’ve had likely a “hot Jupiter” close to Sun (like seen in many other star systems) & prevented all terrestrial life as we know it.

6) p.s. under the Grand Tack model based on this other video, it doesn’t show Uranus and Neptune being necessary for the later outward migration of J&S, @drbecky_? Video from @girlandkat’s group.

7) Other key thing about Saturn’s maneuver that saved forming-Earth from being destroyed by Jupiter... Saturn-Jupiter being pulled out of the inner solar system together aided delivery of water rich asteroids to Earth that helped in becoming a water rich world.