Robittybob1

Agreed all viruses from time to time jump species barriers, but you said it took with it stuff from the previous species. Let's see what? It was the DNA from other species that intrigued me. Has HIV still got DNA from the previous host associated with it? It wouldn't be so hard to tell where it originated (from what previous species), if it did carry this DNA marker longer term.

Well the Asteroid Belt objects, and some are named, have survived. I don't see why if the planet formation process hadn't advance a bit more i.e. the Sun's mass was down a bit, then a planet sized body would have formed and survived just as Ceres has done. The size of Jupiter would be a way less too then IMO of course. If Jupiter was less massive and Ceres had finished building would it survive long term. I have seen a program that could analyse such situations but they are beyond thinking the problem through. It is depended on the timing of the Sun (stars in general) going thermonuclear that determines the size of the planets closer in, and that depends on the mass of the star, that depends on the size of the nebula cloud, and its angular momentum. They are all interconnected. Lump all the Asteroid Belt bodies together. Would that have enough mass to be called a planet? http://en.wikipedia.org/wiki/Asteroid_belt

The missing planet is evidenced by the Asteroid Belt the failed planet build in my opinion. In my calculations it was the Sun becoming main sequence that stripped the terrestrial planets and disrupted the formation of Mars and the Asteroid belt. The surplus material was blown out to the torus of dust and gas out of which Jupiter was formed.

A retrovirus that jumped the species barrier and then becomes endogenized. Have you seen examples of that?

Have you ever read how much of our genome is derived from viruses and virus like sections repeated and then mutated.

Instead of dealing with photons deal with balls and no wind resistance. If a ball was from thrown the ends of the train would the balls reach the center at the same time? "yes" if thrown from within the moving train but "no" if they were thrown at the same time from the right position on platform into the moving train. But if the train was stationary at the platform they would. So the situation is different if the train is moving. Photons fired from two flashlight devices equidistant from the center of the platform (flash occurs when the train is dead center), so light would travel the length of the train at the same rate whether inside the train or outside of it. So when the middle of the train aligns with the center of the platform and the lights flash so that light can both move inside the train (shines through front and back windows as well as along the platform, the observer will see the lights flash at the same time but the person in the train I believe will see the light from the front of the train first. Because light is only traveling at c it didn't matter if the flashlights were on the train or the platform.

I'm not saying it is wrong, just my doubt about aspects of it when applied to frames moving at relativistic speeds, and especially in the way it is being applied in this paradox.

I have argued similar points at time - my primary mechanism for evolution was the incorporation of endogenous retroviruses into the genome. (Look up "Virolution".) Then there is natural selection applied (secondary).

Name one that differs then?

Was that you conflating them together? I said I agree the speed of light is invariant (is the same in all inertial frames) but postulate 1 was formulated at relatively slow speeds. By "speed of light" I mean based on the measurement of the time light takes to travel a distance, there and back, i.e. the two way speed of light.

I agree with #2 but have my doubts about #1 especially when the motion become relativistic.

The postulate I'm thinking of is the one about all physics done in a moving frame will be identical to a stationary frame. Was that what you were referring to?

Don't drink it too fast! OK the train wasn't moving when they synchronized the clocks but it got moving soon after Were the postulates tested at these speeds? They were formulated in slow moving situations weren't they?

IMO even if the clocks stay synchronised and they are equidistant from CM, if the train is moving the stopwatch will not be stopped. OK that view goes against the postulates but if you do the experiment tell me if I'm right or wrong.

That is for the Earth being impacted, there will be different parameters for a Martian impact.

In the thought experiment set up post #1 the clocks are moved along the train.

Each particle within a frame of reference could end up being in another frame of reference. If the clock is moved it moves WRT the original train FoR but the train's FoR stays the same.

Can't they go out of sync if they are moved too fast? (twin paradox etc) to be synchronised they might be brought together but then taken to the ends of the train. so they moved along their frame.

Looking at the formula there is (t - vx/c^2) so is vx/c^2 a measure of time? Can you say that in words? "velocity * x / c squared" what is x? You call it location but how do you put a value on location?

What is correct then?

Looks more like a meteor/asteroid impact crater to me. I think an event that pulled material off the surface would leave a heaped surface not a hollow. I have not seen other examples of extraction events.

Campylobacter can cause long term side effects.

I must admit the equations for the gravitational geodesics are not easy to understand. I want to understand it but someone will have to explain the maths in words before I'll ever get it. Previously you said "A ballistic trajectory is one thing any geodesic most definitely is not", but isn't a rocket orbiting the Earth an extreme case of a ballistic trajectory?

Looking at one site :http://www.astronomynotes.com/relativity/s3.htm but if light follows the geodesic, will a mass orbiting a star at the same distance be following a different curvature? I would say between two points in space there is only 1 geodesic but I have yet to be convinced that light and a massive object will follow exactly the same path between those two points. Do you think there is only one gravitationally induced path? I.e between a distant star and the Earth, if light takes a path as it grazes past the Sun it is deflected by a very small angle. Do you think a rocket ship could follow the same geodesic? That doesn't sound right to me!

There are two places I know of as Science Forums, which one? Scienceforums.net (this site) seems a well moderated place in my opinion. Does the cartographic explanation and the way the word geodesic is used when talking of gravity match? I might have been thinking it was more just the ballistic path an object would take. Maybe you'd agree there are an infinite number of ballistic paths through any point, but let's see if there are fewer geodesics and how they differ. Now I get it; you are talking about two points on the surface on the ball, not between any two points.