Ryzom

Posted: **Thu Apr 06, 2006 6:27 pm**

The Solar System Theory

UNOBSERVED: There should also be a wobble in the sun through the day, depending on the mass of the blackhole verses the mass of the sun and the distance between the two, of course it would be one wobble per day cycle so it may not even be noticable without more precise instruments than the homin eye.

UNOBSERVED: There should be a notable increase in the number of shooting stars (meteorites) observed in the cooler months, peaking in frequency at the middle to end of winter... Due to moving through the dust/ debris field.

Signed: Loryen Roqvini

Posted: **Thu Apr 06, 2006 6:32 pm**

riveit wrote:OOC: The gravitational field of a black hole does bend and distort light, particle trajectories and space itself.

But only in the direction of the event Horizon right? As in, if the hole was directly between you and the star, any light coming from the star (if the black hole was appearing to be the same size due to perspective) would be bent towards and into the 'back' of the black hole, not around it. Or is that wrong?

Loryen's theory was that the black hole was massive - multiple solar masses could mean it blocks the star/sun completely. In that situation, would any light actually be bent 'around' the black hole, and be visible from the opposite side?

EDIT: Heh, just looked at this image on WikiPedia - you're exactly right, if you could see the outer edges of the event horizon down on the planet, you'd probably see the star warped around the outside

Darn it! Back to the books for me...

EDIT2: I think my brain is melting

Another potential problem, or another misunderstanding

lol. If this black hole is large, would it actually fit in the space between the star and the planet, without being a danger to both?

Posted: **Thu Apr 06, 2006 6:49 pm**

riveit wrote:OOC: The gravitational field of a black hole does bend and distort light, particle trajectories and space itself.

Indeed, do a little googling for 'gravitational lens' and you should find plenty of nice pictures of the effect. It's not just black holes that do this, galaxies do it too, even our sun does it ever-so-slightly.

Anyways, the problem with anything moving in front of the sun causing it to darken out, is that we'd have to see it. A large planet or brown dwarf star would be seen as a black disk against the sun. Another star would show us two suns when they're not aligned. A neutron star or black hole would cause a gravitational lens.
We don't see any of that, the sun simply dims out. If anything passed in front of it, it'd have to be some kind of gas cloud.

I like the idea of a gas cloud being responsible for the seasons though. It's obvious there's a lot of debris in the space around Atys, from the large number of shooting stars appearing every night. You only see that amount on Earth when Earth passes through a comet's trajectory. And what's with that nebula in the sky? That's not a nebula, it moves against the stars, it's something within the Atys solar system.

kitnyx wrote:The other planets/ moons (If anyone cares, we of the Dragonblades named them for our own use IC. The big one with the rings is Shyl, the medium sized one is Drak, and the small bright one is Lor.)

There is no small bright moon, what you're referring to is the sun as it looks at night. Watch the sun through a full night and you'll see it go from a huge bright white flash to a large yellow fiery ball to a small dim blueish one, and back. (Earth's sun is so boring in comparison, always looking the same

) Atys has two moons, the large ringed one and the medium-sized yellowish one, and then that nebula thingy orbiting it too.

Oh, additional observation I just made - even though it's currently winter on Atys, it already started getting light at 04h. Obviously the seasons aren't caused by the hours of daylight.

Posted: **Thu Apr 06, 2006 8:16 pm**

dazman76 wrote:Loryen's theory was that the black hole was massive - multiple solar masses could mean it blocks the star/sun completely. In that situation, would any light actually be bent 'around' the black hole, and be visible from the opposite side?

EDIT2: I think my brain is melting ... If this black hole is large, would it actually fit in the space between the star and the planet, without being a danger to both?

One problem with this theory is that black holes are extremely dense. A black hole with the mass of the sun has an event horizon only 3 kilometers in diameter. So I really have difficulty imagining how this intervening black hole could block the view of a star from a sizeable portion of Atys without swallowing Atys for breakfast.

Posted: **Thu Apr 06, 2006 8:45 pm**

Ah of course, I completely overlooked that

And even if it was 'super-massive' and had 50 times the mass of the star, it still wouldn't be large enough to obscure it - and nor would it be large enough to eat the planet, I guess - although I can't quite imagine the gravitational field that mass would create

Posted: **Thu Apr 06, 2006 8:55 pm**

dazman76 wrote:Ah of course, I completely overlooked that

* nods with confidence, pretending to be veeeery knowledgeable about the subject... blackowhat? eventhorigan? thinks for self... *

Posted: **Thu Apr 06, 2006 9:03 pm**

Hehe, I'm way out of my depth too Ani

I love this stuff though, and really wish I'd been able to do physics

Gravitational Lens
Light Deflection near a Black Hole

Posted: **Thu Apr 06, 2006 9:12 pm**

dazman76 wrote:Hehe, I'm way out of my depth too Ani I love this stuff though, and really wish I'd been able to do physics

Physics is cool, exams are not

I am in the closing stages of the last year of my Theoretical Physics degree atm and its a nightmare

As for the Theories about the Atys Sun, heres some theories I have had for a year or more but wrote down in another thread:

Kibsword the huggler wrote:Ah Atysian Astronomy, my favourite subject. Doing a physics degree obviously means I have an interest in such things, and I have come up with several theories concerning this:

1 - The Sun is a normal sun, Atys rotates around the ringed planet we see in the sky (as does the other moon), but at an angle to the normal planetry plane, and does not spin relative to the sun. As a result we always see it at the same point in the sky, and gets closer and further away due to orbiting the planet. However, the sun changes in visible size so much that this would have to be a very big lunar orbit relativly speaking.

2 - The Sun is not a sun at all, it is a technological or magical device in the sky that changes size due to the seasons, it is in a geostationary orbit around Atys, which rotates around the ringed planet as normal.

3 - The planet rotates around Atys, personally I have my doubts about this, but I can't rule it out either. However, if Atys was the main planetry body, and the sun was a real star, Atys would have to have a very eliptical and fast orbit.

4 - The sun is on the other side of Atys, it is relected in a mirror like device to give light to our "dark" side of the planet, the part we live on. The sun changes position wrt the mirror (which is in geostationary orbit above Atys) and its viewavle size variation is amplified due to the reflective qualities of the mirror, and the current angle the real sun makes with the mirror. This theory I love, although not the most likely it does solve a few problems in an easy way, such as the sun in the same spot in the sky, the hugely eliptical orbit required, or large lunar orbit is not nessecary and it is easier to explain why the same part of the ringed planet is always visible.

Hope you like and understand the theories, I have a few more but am still working on them so I won't reveil them yet

Enjoy

Posted: **Thu Apr 06, 2006 9:51 pm**

Nice Kibs

Man I wish time travel was possible - why did I lose interest at exactly the wrong time in school?

Posted: **Thu Apr 06, 2006 10:11 pm**

Interesting theories.
I would have to say that the black hole theory is neet, but cannot be correct due to the many secondary phenomenon people have noted on in this thread allready.

Though: What if the "sun" is smaller than Atys and orbiting around Atys? The sun revolves around Atys in a heavilly eliptical orbit that takes the same time as a revolution of Atys. That way you get two bright and two dark parts for each revolution.

Assuming the sun is fusing hydrogen the way our is, it can't be too small, at least the size of Jupiter, and that would mean that Atys is HUGE, and I mean ENORMOUS. However, there is reason to believe that atys isn't very dense, below the Prime Roots is just another layer of caves, and so on it goes down. That way, for earth-resembling gravity it can be and has to be quite large.... or is it the opposite?

Seasons can be explained with the mixed-debris theorem allready proposed, only it rotates around Atys and not around the Sun.

This would also explain how Atys can have a moon that looks like a gas giant. Atys is simply larger.

Hm... I am starting to like this theory..... Comments?

--
Alurach, High Officer of the Dragonblades
aka
Daniel Armyr, Master of Science. ((And yes, that is really my ooc title

))

Ryzom

The Science of Atys

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