Why does Venus revolves around the sun in the direction opposite to all the other planets?

The reverse ROTATION of Venus is obviously the true subject of this question.

First, we can eliminate what did not cause it. Tidal effects or any other type of slowing mechanism were not the cause because, as difficult as that would have been to accomplish, spinning the planet up in the opposite direction afterward would not have occurred from slowing effects and would be tremendously more difficult regardless of the mechanism used. The "asteroid impacts to slow then reverse rotation" idea, while possible is very unlikely. The amount of energy, and therefore the amount of force, required would be more likely to shatter and scatter the planet. In fact it is very likely that Venus did not have it's rotation reversed!

The second step requires identifying a way the present state could result without such reversal. If the planet's poles were flipped, the rotation would be opposite, as it now is, but this would require an additional element of rotation to bring the south pole up to the north and the north down to the south. Furthermore, that extra element of rotation would then have to be cut off at the right point to keep the poles from continuing to circle the planet even while the planet rotated around the poles. Of the two, rotating then stopping the poles or decelerating then reverse-accelerating the entire mass of the planet, the first is more simple though not much easier.

The third step should provide a way the planet's axis of rotation, the poles, could be rotated nearly 180 degrees. Modern astronomy does not have much to offer this question. However, catastrophism provides one suggestion - that a planet or "dark star" or other massive body closely approached Venus and disrupted its normal motions. A planet's strong magnetic field could possibly interact with another planet's magnetic field or metal content and cause it to flip even to the extent of stopping the flip when the poles were in the opposite, preferred, orientation. But modern astronomers do not accept catastrophism. In the 1950's Immanuel Velikovsky stated that there had been quite a number of planetary catastrophes and encounters with drastic results. Venus in particular played a key role in these planetary dances. The scientific community opposed him and his teachings, heatedly and emotionally. The uproar has never quieted.

In part four we're left with really over the edge considerations. One example, instead of a catastrophic incursion with another planet's strong magnetic field, perhaps the sun's magnetic field caused the flip. But it doesn't seem to do it from it's present distance so Venus would have had to approach the sun more closely - but this is just another example of catastrophism. Or the sun's field may have changed in the past enough to affect Venus in it's orbit. There is no evidence or theory to support that idea.

The question appears to be open, still.

ALL the planets orbit (revolve) around the sun in the same direction.

Venus *rotates* in the opposite direction of the other planets, but that has nothing to do with its distance from the sun.

Astronomers theorize that Venus's axis was tilted over (which resulted in its reverse rotation) when it was hit by a large planetesimal early in its formation.

It doesn't. It orbits the Sun in the same direction as all the other planets. It spins on its axis very slowly in the opposite direction though.

Venus does NOT revolve around the sun in a direction opposite to all the other planets. It does rotate in the retrograde with a 243 earth day period with respect to the stars (sidereal), its year is 225 earth days. The sun rises in the west and sets in the east. Venus' solar day is significantly shorter than its sidereal day, at 117 earth days

Venus is tipped all the way over. Its axis is almost completely upright. One possibility is that Venus rotated normally when it first formed from the solar nebula, and then the tidal effects from its dense atmosphere might have slowed its rotation down.

Another theory is that a series of gigantic impacts early on in Venus' history might have stopped or even reversed its rotation altogether.

The length of a day on Venus is longer than a year so this rotation happens very slowly.

it doesn't. what it does do is *rotate* in the opposite direction to its revolution, but this sort of thing is not unique - uranus' axis of revolution is inclined about 90 degrees to the plane of its orbit. a bit mysterious perhaps but not impossible to imagine how that might happen. as far as I remember the only retrograde orbit of a body of any significant size is that of neptune's moon, triton, thought to be a captured plutoid.