We know that the sun accounts for 99% of the mass of the solar system, which is the core of the solar system. Since the sun's gravity is so great, why can't the planets be sucked away by the sun?
Because the sun is a sphere, and space is essentially a vacuum. When planets revolve around the sun, there is no friction to slow them down. Therefore, their forward power is in balance with their falling to the sun. They fall towards the sun in a circle. If you throw a ball parallel to the surface of the earth, it has forward momentum, but because of the gravity of the earth, its trajectory forms an arc, and the air resistance on the earth makes it lose its forward power more quickly. If you throw the same ball fast and there's no air resistance to slow it down, the ball will eventually land on the earth, but if it's fast enough, the downward curve will match the curve of the earth. This is a sphere. By then, the ball will be in a stable orbit around the earth, only a few meters above the ground. If you throw the ball faster, it will still fall on one track, but that is a higher track. In fact, due to the lack of an atmosphere on the moon, scientists worry that there may be objects flying around the moon at a low enough orbit, thus endangering the safety of spacecraft. Debris ejected from meteorite impact may be the source of these theoretically low altitude flying satellites.
Planets fly in very special stable flight patterns, at the right speed and direction, to achieve this precise balance called orbit. In the early days of the solar system, a lot of matter did fall into the sun, and objects fell occasionally. Some objects are pulled by the sun, but their power is not just in the right path. They pass through the sun and may never come back.
In fact, most asteroids that are close to earth fall so close that our atmosphere slows them down, causing them to crash into our planet, or they miss our planet altogether and fly away. Some objects fly directly into our path and hit us. The last real earthquake, 65 million years ago, did cause mass extinction.
In this part of our galaxy, all the objects close to us are basically flying around an object, and after such a long time, the stable orbit has been able to run on its own. But in the Milky way and elsewhere in the universe, there are many collisions and objects flying in strange ways. Some of these planetary sized objects may one day fly out of nowhere and enter our solar system under the influence of the sun's gravity.
Finally, if you launch a rocket directly away from the earth, once it's out of the earth's atmosphere, it won't move on. Once the fuel runs out, the gravity on the rocket will pull it straight down and it will crash as your problem suggests. That's why once a rocket escapes the atmosphere, it has to turn and fly parallel to the earth. They need the forward power that bends around the earth to make their orbit.
In fact, the sun itself throws a lot of matter upward, and most of it just falls. However, some of the matter, very hot gas, is really disappearing. This is the so-called solar wind.
The gravity of the sun not only keeps the planets in their orbits, but also keeps their moons and other planets in their orbits. If planets don't go around the sun, they will be attracted by the sun and eventually swallowed up.. Contrary to intuition, the closer the planets are, the faster they move, and the slower the outer planets are. If not, they will be drawn toward the sun.
It's true that planets fall toward the sun and satellites fall toward their planets, but their orbital velocity prevents them from hitting the sun or planets in their orbit. If the whole system stops working, eventually everything within the influence of the sun's gravity will be pulled inward.. Even in Pluto, it's much more than that.
Strangely enough, although gravity is one of the most influential forces in the universe, it is also one of the weakest. But it's constant, it's not unstable. Before the formation of the moon, for example, the earth's orbit spun faster, its rotation faster, and it would wobble. If it wasn't for the moon, it would slow down the rotation speed of the earth and eliminate the shaking of the earth, but it would also make the earth rotate vertically. Life would have been almost impossible.