About the positioning of stars and planets
February 1, 2021 7:44 PM   Subscribe

I'm no astronomer, so my description might be lame. But in the opening sequence of the Big Bang Theory, the viewer enters the solar system from the outer orbits, after traveling through the cosmos and beyond several other galaxies. They pass Saturn, Jupiter, the Sun, Mercury and Venus before coming upon the Earth.

I was just wondering if an astronomer could determine what year, time of year and/or day that fictitious trip through space to Earth took place based on the positions of those planets, stars, galaxies and positional rotation of the Earth? That is all. Or was it computer generated with no relevance to the heavens whatsoever?
posted by CollectiveMind to Science & Nature (9 answers total)
As a person in the creative field who was previously a physics major, I can tell you that there is a 99.99% chance that if the creator of this sequence tried to make it astronomically accurate, they were then forced by their boss to make it more visually interesting (and the boss was right).
posted by ejs at 8:09 PM on February 1, 2021 [11 favorites]

I'm no sciencemaster, but I think the concept of comoving and proper distances is relevant here. My impression is that, since all objects at a cosmological (and every other) scale are moving in different directions and at different rates, if you had an accurate recording of everything it would at least be possible to correlate one specific configuration with a particular point in history.
posted by XMLicious at 8:12 PM on February 1, 2021 [1 favorite]

But yeah, as far as the actual graphics department, I've never seen it but I'd be inclined to agree with ejs and expect that it's not even to scale, much less cosmological-historically-accurate. Cf. Neil deGrasse Tyson spoiling The Daily Show's fun by pointing out that their globe was spinning in the wrong direction.
posted by XMLicious at 8:18 PM on February 1, 2021

somewhat related
posted by sillysally at 9:49 PM on February 1, 2021 [1 favorite]

The solar system turns out to be chaotic, so in general you cannot use the position of the planets to determine what year it is. (Don't worry, none of the planets are likely to be ejected in the next billion or so years!)
posted by monotreme at 11:20 PM on February 1, 2021 [2 favorites]

Take the mostly Copernican solar system. Each planet circles around in a time based on it's distance from the center. The rub is measurement accuracy and precision and whether or not you accept irrational numbers. With a few exceptions, any set of rational numbers (the 'year' periods) can be multiplied out into a repeating cycle. You can think of this as making an Orrery of integer relations and from that follows that there is a number of cranks that will eventually hit every combination before starting over and repeating for eternity. You just need to add some galaxies to that. Ah, the Mechanical Universe.

I would bet that the person in charge of this either just made it up or scrolled a timescale wheel through some astronomy simulator and used the built-in fly this path video generation and tweaked it a bit. Like making a storyboard before just animating it for looks.

Then again, there's that chaos from irrational numbers and measurement sneaking in.
posted by zengargoyle at 11:54 PM on February 1, 2021 [1 favorite]

Hey, I have Universe Sandbox, so I ran it to check the position of Jupiter and Saturn in 2007, when the show started. Not even close! They were on opposite sides of the sun, not close together on one side of the sun as in the intro.

Now, Saturn takes 30 years to orbit the sun, and Jupiter takes 12. So Jupiter has been chasing Saturn and in fact it is now as near to it as it ever gets. Here's a website that offers a nice simulation where you can see this.

The show ended in 2019, so ironically the intro is more accurate for the date the show ended than when it began.

Even this little exercise shows that getting a specific date from the position of the planets is nearly hopeless. They move too fast, compared to historical time.
posted by zompist at 12:37 AM on February 2, 2021 [3 favorites]

Well, Jupiter and Saturn approached, reached, and left their closest straight line with earth back in like november or so. Given that 30 * 12 = 360 and adding in earth witch is easy because that's 1 so ~ 360 years.
“You can imagine the solar system to be a racetrack, with each of the planets as a runner in their own lane and the Earth toward the center of the stadium,” said Henry Throop, astronomer in the Planetary Science Division at NASA Headquarters in Washington. “From our vantage point, we’ll be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on December 21.”

The planets regularly appear to pass each other in the solar system, with the positions of Jupiter and Saturn being aligned in the sky about once every 20 years.

What makes this year’s spectacle so rare, then? It’s been nearly 400 years since the planets passed this close to each other in the sky, and nearly 800 years since the alignment of Saturn and Jupiter occurred at night, as it will for 2020, allowing nearly everyone around the world to witness this “great conjunction.”
The ‘Great’ Conjunction of Jupiter and Saturn | NASA

Daytime vs Nighttime is a 2 so I'd guess 720 instead of 800. It doesn't matter what line-o-sight your picking, all possible between those three planets would occur every, Eh ~800 years.

Just keep adding planets and galaxies and avoid all of the greater cosmological universe stuff about the nature of existence and reality it either happened or will happen. The numbers might break your computer, or take longer to calculate than the estimated age of the universe.

(OMG I was just pondering the racetrack explanation except it was dog/horse racing. But hell, let NASA write that stuff up.)
posted by zengargoyle at 2:12 AM on February 2, 2021

Response by poster: Thinking about it some more, it suddenly reminded me of the intro of "The Jetsons." And I couldn't resist putting it up. It's so fun - https://www.youtube.com/watch?v=IUIkUg0e-P8
posted by CollectiveMind at 1:19 PM on February 2, 2021

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