Alien Eclipse Tourism

[Sociotard]

There's this movie pitch that asserts that

1. More air travel is used for tourism than business (not sure if this is true, unless you count going to visit family as tourism)
2. Aliens would have better tech advances, such that they would find space travel is as easy as we find air travel. (insert anal probe joke here. Seriously though, I'm not confident there are any sentient aliens, and seriously doubt FTL travel is possible, and I doubt anybody will spend 10,000 years on ice for tourism purposes)
3. Our solar eclipses are interesting and unusual in the galaxy, because they require
   1. a planet with a reasonably clear atmosphere and other conditions that would let an alien stand on it and do tourism activities, even if it has to do them in a hawiian print space suit
   2. a moon just exactly the right size and distance from the planet and a sun that is just exactly the right size and distance from the planet that they appear to be the same size from a planetary observer.

It's this last criteria that he thinks is super rare, and so aliens will come to see it, because it is one of those strange celestial phenomena that Kirk was always investigating. And he wants to make a movie about it. The full pitch is spoilered below, because it is long.

 

"What an incredible coincidence it is that our moon fits exactly over our sun. Talk to astronomers and they’ll tell you that Earth’s moon is relatively much bigger than any other moon round any other planet. Most planets, like Jupiter and Saturn and so on, have moons that are tiny in comparison to themselves. Earth’s moon is enormous, and very close to us. If it was smaller or further away you’d only ever get partial eclipses; bigger or closer and it hide the sun completely and there’d be no halo of light round the moon at totality. This is an astounding coincidence, an incredible piece of luck. And for all we know, eclipses like this are unique. This could be a phenomenon that happens on Earth and nowhere else.

 

"So, hold that thought, okay?

 

"Now, supposing there are aliens. Not E.T. aliens – not that cute or alone. Not Independence Day aliens – not that crazily aggressive – but, well, regular aliens. Yeah? Regular aliens. It’s perfectly possible, when you think of it. We’re here, after all, and Earth is just one small planet circling one regular-size sun in one galaxy. There are a quarter of a billion suns in this one galaxy and quarter of a billion galaxies in the universe; maybe more. We already know of hundreds of other planets around other suns, and we’ve only just started looking for them. Scientists tell us that almost every star might have planets. How many of those might harbour life? The Earth is ancient, but the universe is even more ancient. Who knows how many civilisations were around before Earth came into existence, or existed while we were growing up, or exist now?

 

"So, if there are civilised aliens, you’d guess they can travel between stars. You’d guess their power sources and technology would be as far beyond ours as supersonic jets, nuclear submarines and space shuttles are beyond some tribe in the Amazon still making dugout canoes. And if they’re curious enough to do the science and invent the technology, they’ll be curious enough to use it to go exploring. “Now, most jet travel on Earth is for tourism. Not business; tourism. Would our smart, curious aliens really be that different from us? I don’t think so. Most of them would be tourists. Like us, they’d go on cruise ships. And would they want to actually come to a place like Earth, set foot – or tentacle, or whatever – here? Rather than visit via some sort of virtual reality set-up? Well, some would settle for second-best, yes. Maybe the majority of people would.

 

"But the high rollers, the super-wealthy, the elite, they’d want the real thing. They’d want the bragging rights, they’d want to be able to say they’d really been to whatever exotic destinations would be on a Galactic Grand Tour. And who knows what splendours they’d want to fit in; their equivalent of the Grand Canyon, or Venice, Italy, or the Great Wall of China or Yosemite or the Pyramids?

 

"But what I want to propose to you is that, as well as all those other wonders, they would definitely want to see that one precious thing that we have and probably nobody else does. They’d want to see our eclipse. They’d want to look through the Earth’s atmosphere with their own eyes and see the moon fit over the sun, watch the light fade down to almost nothing, listen to the animals nearby fall silent and feel with their own skins the sudden chill in the air that comes with totality. Even if they can’t survive in our atmosphere, even if they need a spacesuit to keep them alive, they’d still want to get as close as they possibly could to seeing it in the raw, in as close to natural conditions as it’s possible to arrange. They’d want to be here, amongst us, when the shadow passes. “So that’s where you look for aliens. In the course of an eclipse totality track. When everybody else is looking awestruck at the sky, you need to be looking round for anybody who looks weird or overdressed, or who isn’t coming out of their RV or their moored yacht with the heavily smoked glass.

 

"If they’re anywhere, they’re there, and as distracted – and so as vulnerable – as anybody else staring up in wonder at this astonishing, breathtaking sight.

 

"The film I want to make is based on that idea. It’s thrilling, it’s funny, it’s sad and profound and finally it’s uplifting, it’s got a couple of great lead roles, one for a dad, one for a kid, a boy, and another exceptional supporting female role, plus opportunities for some strong character roles and lesser parts too…"

 

 

Anyway, I'm not sure that point of his about perfect eclipses is correct. He claims that either the Moon or the Star would usually appear to be much larger/smaller than the other, and so you wouldn't get the cool eclipses you see on earth. I find this suspicious. Can any astronomy buffs clarify how rare this phenomena is suspected to be?

 

I will say that I hope it isn't a galactic tourist attraction. So near as I can tell, Humans just don't like tourists. Even when their livelyhood depends on them, they view them as stupid, problem generating beasts. Filling the Earth with them would cause all kinds of headaches.

[Drhoz]

Re: Alien Eclipse Tourism

 

Well, it's not the only place in the solar system where a moon blots out the sun - the 4 big satellites of Jupiter cast visible shadows in the cloud tops, and I'm pretty sure we've got photos of Phobo's shadow on Mars. No doubt Titan and the other large moons of the outer solar system eclipse the sun even more easily, since, of course, the sun is an even tinier disc out there.

 

But Earth IS the only place in the solar system where the satellite is an almost exact match for the diameter of the solar disc - but even then, not at *every* eclipse - hence Annular Eclipses. And a large moon, around a small rocky planet, is a little unusual - the formation of our moon required a quite unlikely-seeming glancing blow from a Mars-sized protoplanet.

[Clonus]

Re: Alien Eclipse Tourism

 

Anyway, I'm not sure that point of his about perfect eclipses is correct. He claims that either the Moon or the Star would usually appear to be much larger/smaller than the other, and so you wouldn't get the cool eclipses you see on earth. I find this suspicious. Can any astronomy buffs clarify how rare this phenomena is suspected to be?

 

No other object in the solar system has a moon of the right size to block out the sun but not the corona at their distance from it. It would require a rather precise concurrence of apparent sizes.

[Christopher]

Re: Alien Eclipse Tourism

 

No other object in the solar system has a moon of the right size to block out the sun but not the corona at their distance from it. It would require a rather precise concurrence of apparent sizes.

And these things won't be in that relation forever:

"This means that hundreds of millions of years ago the Moon would always completely cover the Sun on solar eclipses, and no annular eclipses were possible. Likewise, about 600 million years from now (if the angular diameter of the Sun does not change), the Moon will no longer cover the Sun completely, and only annular eclipses will occur.^[104]"- From Wikipedia.

 

When you add in otehr factors, like "needs to ahve an Atmosphere" or "sun needs to be a Yellow Dwarf, spectrall class G2V" then our planet could be very much the nearest one with that correlation.

Of coruse you could fake such an eclipse effect by just taking a moon wiht somewhat smaller relative diameter and jsut park your ship closer to it, but that would be cheating...

[Cancer]

Re: Alien Eclipse Tourism

 

What with the first week of classes being just about over, and it taking me about four times as long to write the script as it should have with all the d***ed interruptions, it took a week plus to get to this.

 

I grabbed all the Solar System planet and moon data out of Wikipedia and did a brute-force check, computing the minimum and maximum angular radii of the Sun as seen from each planet's equator, and then the angular radius of all the moons, again as seen from the equator of the planet.

 

I figured that if the moon's angular radius is in that range of possible solar angular radii, then that moon is close enough to the angular size of the Sun (as seen from the planet) that the "total eclipse" aesthetic should apply.

 

I get more than one hit.

 

Of course, Earth's Moon is a hit. Its angular radius is 948 arc seconds, the Sun's ranges from 943 to 975.

 

Pandora, a moon of Saturn, is a hit. Its angular radius is 103 arc seconds; the angular radius of the Sun as seen from Saturn ranges from 95 to 106 arc seconds. Saturn's orbital period is 29.46 years, but its axial tilt is only 2.4 degrees, so without working anything out carefully, my guess is there would be lots of eclipses in clutches separated by decade-long gaps with none.

 

S/2011 P 1, a satellite of Pluto announced last summer, is one hit. Pluto has a pretty eccentric orbit, with the Sun's angular radius varying between 19.6 to 32.3 arc seconds; if the size of the satellite is to be accepted (seems premature), then the satellite has an angular radius of 23.2 arc seconds. However ... the whole Pluto system is tipped by about 120 degrees, so Pluto would have a series of such eclipses (each about 32 Earth days apart) lasting a couple of Earth decades twice a plutonian year (248 Earth years).

 

Now ... what's all that say about the rarity of the eclipse esthetic the "ad" was purporting? Well ... until we know more about the frequency of real earthlike planets, I don't think a lot can be said, but I think it takes some of the edge off the rarity argument. It might influence your decision about when to visit Earth once you'd already decided to visit, but I doubt it's a unique enough phenomenon to draw the whole galaxy.

 

BTW, not on topic ... there'll be an annular eclipse of interest to lots of HERO board folks on 20 May. Path of maximum eclipse comes ashore on the southern coast of Oregon, and proceeds southwestward, with the Moon's shadow losing contact with Earth when it's over central Texas. Add to that, the transit of Venus on June 5 (US date), and it's an excellent year for naked-eye phenomena.

[Christopher]

Re: Alien Eclipse Tourism

 

Since Pluto doesn't counts as Planet anymore and you have trouble standing on Saturn (unless your name is "Cloudwalker" and you deserve it), earth is still the only planet in our solar system