150 replies to this topic

[ninhursag]

Khm-khm. So. As I noticed when reading this thread, this discussion lacked some crucial data. Though it could be assumed that anyone replying here knew the information by heart, there is an apt saying in English about what assuming does . So, to make completely sure that everyone is going to be speaking of the same things, I'm going to put some of the more important numbers here. I hope anyone is not annoyed by me putting the metric values here, they just make it easier for me to keep track (miles make big things feel so small!)

So, first some base statistics.

The radius of the Sun at its equator is 695 500 km or 432 200 miles;
The radius of the Earth is 6 378,14 km or 3 963.19 miles;
The radius of the Moon at its equator is 1737,4 km or 1079.6 miles;

Naturally, these numbers here are averages and, in the case of the Sun, somewhat debatable (no hard surfaces).


Now, there's also the common misunderstanding that planets and their moons are always the same distance from each other (esp Earth and Moon) and that they travel the same route over and over again. As the truth is - welll, they don't exactly wriggle, but it's safe to say that the process is much more interesting than just going round and round .

Currently,
Moon's average distance from Earth is 384 400 km or 238,855 miles;
Moon's closest to Earth at 363 300 km or 225 700 miles;
Moon's farthest from Earth at 405 500 km or 252 000 miles;
The difference is about 42 200 km or 26 300 miles.

Earth's average distance from the Sun is 149 597 890 km or 92 955 820 miles;
Earth's closest to Sun at 149 597 890 km or 91 400 000 miles;
Earth's farthest from Sun at 152 100 000 km or 94 500 000 miles;
The difference is about 2 502 110 km or 3 100 000 miles.

Sadly, these extremums given here are statistical averages themselves, not the known farthest or closest distances. The distances are not always the same due to gravitational effects. I was not able to find the reference, but this december the Moon was farther from the Earth than it has been in several years:).

What are the relations between these sizes? Is there anything extraordinary about them? Well, I think this is the basic measurable data from which such conversations can start .



About the coin test - I might be wrong, but wouldn't the results of moving the Moon in front of the Sun always have a bit cleaner effect then in that test because of the Moon's gravitational field twisting the space a little and thus giving the lightrays a bit different direction? That's what happens when we study faraway
objects only made visible through a "gravitational lense". (One might argue, rightly, that the coin twists space, too - but then one would have to think about standing next to an ice cube and an iceberg of the same temperature. Whatever folks might say, size does matter).

[ninhursag]

Before I could decide whether or not to agree that "these odds are impossible to do" (a necessary prerequisite to proceeding to explore the implications), I would need to see described a 'slight bit' more precisely just how long the odds are that are being defied.

Well, we don't actually know that much about planets and their companions to decide what is and what is not truly unusual. We have only studied one solar system in some depth. (there is this new method that has already showed that other stars also have planets , but so far only (Jupiter-like) gas giants are detectable, no smaller planets and certainly no companions . I suppose we'll know more about them in a few decades though - I'll certainly be following any advances made in that area ).

Until then it would be somewhat difficult to calculate the odds. We don't have much firsthand data and so might misunderstond something about the way planets and their companions would generally. Eg. (I think it was) I.Asimov (who) though that gas giants might be rare and so used this fact as a plot device in one of his novels . Also, the numbers show that there is quite a bit of room for the planet's moon to move about without making life impossible on the planet.

A side note, not everyone notices the obvious conlusion from "the ...'s trajectory being influenced by gravitational forces". That means that the moon would generally be the farthest from the Earth in this month's cycle when it's closest to the Sun - some time before the eclipse. I suppose something could be made of this?

Actually, as a proof of conscious creation the rings of Saturn are probably easier to use at the moment. Now, dust around a planet, that's something we know as a fact that has a tendency to fall burning in the planet's atmosphere. Such a thing could not last very long - a few million years max. And yet, there they are, for all to admire - all with a telescope, that is.

[ninhursag]

Dude, that is like, so... last week.

Oops . So, I've not been paying any attention at all, have I? Silly me. Glad you pointed it out.

But before we wander off (again) into estimating the number of planets located in the 'habitable zones' of their respective planets, I'd like to see the business about the solar eclipse phenomenon nailed down; what is the 'dimensional tolerance' for this effect?

Uhhh... actually, for the corona to show - which is arguably the most impressive part of a total eclipse - couldn't the Moon be a little closer or bigger? Total eclipses don't happen when the Moon in its current size is at its farthest (the apogee), because the umbra doesn't reach the ground. Ehhh... now, the shadow of the moon is shaped like a cone and we know both the Moon's radius and the function for calculating a cone's cross-section (well, I will know it after I find my little book of functions, but, generally speaking...). So, basically, for finding the dimension tolerance for our moon, we'd only have to settle what is the closest the Moon can approach to Earth, without making life overly difficult .

Edit: I suddenly can't remember what I wanted to do with the cone's cross-section , but I'll leave it here, just in case anyone else figures it out.

Edited by ninhursag, 22 June 2005 - 02:03 PM.

[chance]

So, without all this preciseness of sizes and placement of these objects, we would not see what we see, or know what we now know about our sun, plus the other stars. So does all this still look like chance and accident? Or a designer placing and forming these objects so precisely?

The difficulty in answering this question is:
How can we reliably tell the difference between design and a chance alignment? If the occurrences is a unique one off, then we should be cautious and say chance is the likely explanation, however if this situation was present on every planet in our solar system, that would swing the pendulum the other way.

[chance]

Additional information re eclipses, Take a look at these two maps,

total

and for annular eclipses where the moon does not cover the sun.

annular


Remember that an eclipse is very brief the maximum amount of totality time ever can be no more than about 6 minutes, averaging about 3 min.

If you not on the totality path you will not even know it has occurred, the amount of dimming is surprisingly little.

[Heather]

Don't be silly. The universe is huge. We are on the outskirts of our galaxy. There are billions of stars. We are talking billions of planets. You can't tell me, without any real proof, that it's unlikely that our little planet, out of all the billions out there, couldn't have just happened to have a moon that aligns with our sun every now and then. We got lucky. What does this have to do with God? The sun and moon lining up has no point. It's a random event. It doesn't cause anything to happen on earth - it serves no purpose. Everything else on earth serves some sort of purpose. Was God just fooling around for no reason? I don't understand your point here.

Heather

[Heather]

There may very well be life on other planets. The problem is that we can only closely observe 9 out of the billions of them that are out there, and one of those 9 does contain life. In my opinion, that makes it seem likely that there are other planets capable of supporting life.

What is the point again? Who cares about the sun and the moon lining up? There are more important things that we could be looking at. The obvious fact that the sun and the moon line up every now and then does not make any case for the existance of a God. It's excuses like these that make creationism laughable to many scientists. (No offense).

Heather

[John Paul]

There may very well be life on other planets. The problem is that we can only closely observe 9 out of the billions of them that are out there, and one of those 9 does contain life. In my opinion, that makes it seem likely that there are other planets capable of supporting life.

What is the point again? Who cares about the sun and the moon lining up? There are more important things that we could be looking at. The obvious fact that the sun and the moon line up every now and then does not make any case for the existance of a God. It's excuses like these that make creationism laughable to many scientists. (No offense).

Heather

Heather, Have you read the book The Privileged Planet? I would advise you do that before you go around making silly posts like that.



The first peer-reviewed article explains eclipses. Of all the planets & moons in our solar system, we have the only perfect solar eclipses. We also happen to be the only planet with observers and we have a clear atmosphere.

(see also Gonzalez, G., “Wonderful Eclipses,” Astronomy & Geophysics 40, no. 3 (1999): 3.18- 3.20)

This second peer-reviewed article explains why we need a large moon in the first place.

(J. Laskar et al., “Stabilization of the Earth’s Obliquity by the Moon,” Nature 361 (1993): 615-17)

Then we have to consider that the Sun is expanding and the Moon is getting farther away from us. That means perfect solar eclipses will be no more in some 5 million years. So it is a strange coincidence, in the evolutionary way of thinking, that conscious observers appeared just in time to catch and make the most of (scientifically) solar eclipses.

[Heather]

The first peer-reviewed article explains eclipses. Of all the planets & moons in our solar system, we have the only perfect solar eclipses. We also happen to be the only planet with observers and we have a clear atmosphere.

The only planet out of 9, which isn't a very large number and doesn't mean much. We are one of nine (known) planets, and we happen to be the only one that has a near perfect eclipse. What about the billions of other planets that we know nothing about? You assume too much.

I still don't understand the point here. Are you asserting that God put the
near-perfect eclipse here so that we would have the joy of viewing it?

Heather

[John Paul]

The only planet out of 9, which isn't a very large number and doesn't mean much. We are one of nine (known) planets, and we happen to be the only one that has a near perfect eclipse. What about the billions of other planets that we know nothing about? You assume too much.

I still don't understand the point here. Are you asserting that God put the
near-perfect eclipse here so that we would have the joy of viewing it?

Heather

9 planets but many, many moons. And only one combo allows for perfect solar eclipses and that one just happens to be the only one to have observers. Perfect solar eclipses, had you bothered to read the reference, afford us a wealth of scientific knowledge. IOW they are more than an enjoyment.

The point of the book is that the universe was designed for scientific discovery:

The same narrow circumstances that allow for our existence also offer the best over-all conditions for scientific discovery.

Currently there are 20 known factors required to come together in one place in time in order for complex, technologically capable life just to exist. However, those factors don't guarantee life.

of the 10^11 stars less than 5% are said, by the experts, to be capable of sustaining life. More than 1/2 of those are outside of the galatic habitable zone. And that is before we start considering all the other factors required- like a plant being in the circumstellar habitable zone.


Stars:

Total number estimated in the Milky Way- 100 billion
Over 80% are low-mass red dwarfs (most likely lack a habitable zone)
1-2% are massive short-lived blue giants
Only about 4% of the stars are early G-type, main-sequence stars like our Sun
50% of those are in binary systems
Then we have to consider what % of those are in the <b>G</b>alactic <b>H</b>abitable <b>Z</b>one

Earth-like planets:

We now know that our solar system is not typical
We do know other planets exist
At least 4% of Sun-like stars have giant planets at least as massive as Jupiter.