Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Another non-rocket scientist, but I think I know the answer.
Planets do not rotate the sun do to gravity but rather the warping of space around the sun ( the marble on the rim of the a funnel idea) The orbit doesn't decay because there is nothing to slow a planets speed. Anyway, before I make a complete ass out my self...
According to Einstein, in the same way that a large ball placed on a elasticated cloth stretches the fabric and causes it to sag, so planets and stars warp space-time. A marble moving along the sagging cloth will be drawn towards the ball, as the Earth is to the Sun, but not fall into it as long as it keeps moving at speed. Gravity, argued Einstein, was not an attractive force between bodies as had been previously thought.
I think the short answer is that the Sun IS swallowing Mercury, but not in your lifetime. Any seeming equilibrium in the Universe is illusory, because everything is gradually changing, and will at some point shift the equilibrium.
Mercury, to the Sun, is in an orbit similar to that of a fairly large satellite circling the earth at 50,000 miles out. The same principles would govern orbital stability.
O.k. astro guru's on here i'm curious as to how the hell does the giant sun with a gravitational pull even on far distant pluto doesn't swallow up tiny and super close mercury? Shouldn't had mercury been pulled into the sun by it's overwhelming gravitation some billions of years ago?
Hey 6 Foot let me try explaining it this way.......I think with a combination of all posts here I can make it fairly clear and concise.
Imagine the Solar Systen is a large basketball hoop with a rubbery material stretched over the hoop(this is spacetime) and held firmly in place....the material can stretch infinitely.
The Sun is in the middle and being the most massive object in our system it bends the rubber sheet down a foot or so. All other objects want to fall towards this low point(gravitational well).
Now each planet etcetera also has mass and bends the sheet in proportion to it's weight....relative to the Sun.
Think of each planet's orbit as being a trough (of potential gravitational energy) that circles the Sun.....imbedded into the rubber sheet.
The planets maintain their momentum from the initial collapse of the protodisc that formed out Star and Solar System.
As long as each Planet maintains it's speed revolving around the Sun....it will stay in the trough within the rubber sheet(the planet's orbit).
Neither falling into the Sun Nor pulling away from it either.
This is gravitational equilibrium...the Solar System is essentially stable unless a very large/massive body were to pass through or nearby knocking a planet out of it's trough(orbit).
No, it's not. It's in a 3:2 spin-orbit resonance. One side faces the sun on every other orbit, not on every orbit. This is not a true (1:1) tidal lock, which is what our moon has with Earth, in which the same side always faces Earth at all times.
It has occurred to me, to question the shape of such warping of space by a body. We’re presented with a picture that shows a planet (like earth) sitting on a warped “fabric” under the influence of Sun. However, I expect this fabric to literally “cup” the earth (from all possible directions and towards the sun) as it would any other planet. The orbital stability, however, would then be dictated by the planet’s mass, its distance and its orbital velocity. All else remaining the same, if earth were to slow down (or the planet in question, Mercury), it would the distance of this “cupping” from the sun would invariably decrease as the outward force generated by the orbital velocity would reduce.
I've never been a fan of that particular graphic, as it is a mixed metaphor that can be more confusing than helpful. There is no trampoline theory of space-time that fits the way the graphic appears. It also provides an implication that there are /people/gods/forces/ holding the ends of those strings taut.
Just wanted to give a '''Shout-Out''' to everyone who answered as i now have a much better understanding not only about my original question but also the other planet's rotation around and distance with the sun as well .
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
.
