How accurate is Monty Python's "Galaxy Song" today?

Question

The Youtube link is here with lyrics:

http://www.youtube.com/watch?v=NQu_RRLbVDA

Answer 1

I agree with Vincent G

It is pretty accurate

My only problem is that astrophysicists and astronomer work in metric units - so I have to convert all the numbers,

It even helped me through an undergraduate astrophysics course!

Answer 2

"Just remember that you're standing on a planet that's evolving and revolving at 900 miles an hour"

Not bad, but it's actually 1,038 mph at the equator (the speed depends on your latitude).

"That's orbiting at 19 miles a second, so it's reckoned, a sun that is the source of all our power"

Very close - 18.6 miles per second. The sun is the source of *most* of our power, but we do derive some energy from geothermal and tidal energy which are not directly from the sun. The proportion is minuscule by comparison though.

"The sun and you and me and all the stars that we can see are moving at a million miles a day

On an outer spiral arm at 40,000 miles an hour of the galaxy we call the Milky Way."

If you take that as relative to the galactic centre, that's way out - the sun is orbiting the galactic centre at around 500,000 mph. However, relative to the velocity of neighbouring stars it's moving at about 45,000 mph - which is indeed roughly a million miles a day.

"Our galaxy itself contains a hundred billion stars"

It's at least double that, 200-400 billion stars.

"It's a hundred thousand light years side-to-side"

Pretty much spot on. The stellar disc is about 100,000 light years across.

"It bulges in the middle, 16,000 light years thick, but out by us it's just 3,000 light years wide"

The gaseous disc is at most 12,000 light years thick, but the stellar disc (which they used in the previous line) is much thinner, just 1,000 light years wide. Either way they're a bit wide of the mark.

"We're 30,000 light years from galactic central point, we go round every two hundred million years"

It's more like 26,000, give or take 1,400 light years, a figure that has been revised downwards in recent years (so it was more correct at the time the song was written). Our sun completes a circle of the galaxy every 225-250 million years, so pretty close there.

"And our galaxy is only one of millions of billions in this amazing and expanding universe"

We're not sure exactly how many, but "millions of billions" is a serious overestimate.There are at least 125 billion galaxies, as observed by the Hubble, though some models suggest there may be up to 500 billion galaxies in the observable universe.

The rest of the song is mostly lacking in astronomical statistics, but their estimation of the speed of light ("twelve million miles a minute") is fairly close - it's actually 11,176,943.8 miles a minute. I love the song regardless of any inaccuracies though.

Answer 3

Still pretty good. Nothing massivly wrong in the figures.

Why?

Answer 4

I haven't done this exercise in years.  And as you've already gotten a competent answer, i won't do it again now.

Eric Idle came to Detroit a few years back.  I caught his show "Eric Idle Exploits Monty Python".  (so? he's entitled.)  And he performed the Galaxy Song.  And, he changed one of the lines to something obviously wrong - just to get a rise out of us geeks.  It was hilarious.  It would have been worth $50, even if that's all he did.

"Monty Python was together for twelve years.  You only get ten years for armed robbery."