Planet Earth and our Sun, as well as the other (now 7) planets are often depicted as larger and larger rings in space, but the Kuiper Belt and the Oort Cloud are made up of billions of comets, meteors and asteroids in three dimensions. But to get an idea of the true makeup of our Solar System, first consider that the entire mass of the gravitational influence of our Solar System is more than 100,000 times the orbit of the Earth, and shaped more like a sphere than a disk.
Light travels from the surface of the Sun to Earth in just over eight minutes, and to Neptune in four hours. The distance from the center of the Sun to the center of the Earth is defined as one Astronomical Unit, or AU. The edges of the Oort cloud are 50,000 AU from the Sun, which would be the radius, the diameter being 100,000 AU.
Within our planetary orbits lies the main asteroid belt. A handful of celestial bodies make up the vast bulk of the mass of this belt. This belt is more disc shaped. But further out from the orbit of our main planets is a much larger mass of billions of objects making up the spherically shaped Oort Cloud.
Here lies the problem with Gliese 710, and its expected approach to our Solar System. In 1.4 million years, Gliese 710 will have traveled over 60 light years at 50,000 mph towards the 100,000 Astronomical Unit diameter mass of our Solar System. While it is unlikely that calculations can be made accurately enough to predict whether Gliese 710, roughly more than half the mass of the Sun, will impact Earth, the Sun or any other planet, it only needs to travel within 25,000 AU or so of the Oort Cloud to start a chain reaction of events.
The billions of objects in the Oort cloud have had billions of years to settle into predictable orbits that keep the bulk of them from intersecting in orbits with Earth or the inner planets. But once gravitational forces from Gliese 710 act on the cloud, billions of objects will have these orbits stretched to different dimensions. While there orbits around the Solar System have periods of many thousands of years, there will at that point be billions of objects whose disrupted orbits over hundreds or thousands of years will now threaten the inner ranks of the Solar System.
Additionally, if Gliese 710 intersects more closely with the Sun, in the neighborhood of a few dozen AU or less, the impact on the orbits of the inner planets would be severe. Then there is the incredibly remote possibility that its path intersects with Earth or the Sun. That would surely be noticed.