Astronomy

We tend to think about our solar system as being a certain size and that size seems to extend out to the farthest orbit of Neptune, which actually is further away from the sun at this point than Pluto, the body that is no longer officially a planet. If you ask one hundred people where the solar system ends they will tell you that either Pluto is at the end of the solar system, Neptune is, or they don't know. There would probably be a lot more I don't knows than one would expect. I guess the question is not a fair one, because scientists are not exactly sure where the solar system does end. Astronomers are in a dilemma They thought that they would find thousands of what are known as Plutinos or icy asteroids past the planets and yet only 300 have been discovered. What does this mean? It could mean that they just haven't looked far enough away yet, or there are not many asteroids past the last planet.

Gerard Kuiper
Photo Source: NASA

If we go far enough away from the sun we encounter the Kuiper Belt. The scattered disc and the Oort Cloud. All there areas contain asteroids and rock fragments. The main difference between them is that the Kuiper Belt is much closer than the Oort Cloud. It encircles the solar system outside the orbit of Neptune. An astrological unit or AU is equal to the distance from the sun to the earth. The Kuiper Belt extends from about 30 AUs to 55 AUs. If we were to compare the asteroid belt to the Kuiper Belt, we would find out that the Kuiper Belt is larger by far, being about 20 times as wide and 20-200 times as massive, science is just not sure. We know that there are a lot of small bodies tucked away in the Kuiper Belt. Does this mean that they all came from exploded planets, some came from exploded planets, or none of them came from that? The accepted theory right now and I say right now because things change, is that this is left over material from the formation of the solar system.

Eris In Center Is Ninth Largest Body In Solar System, 27% More Massive Than Pluto. It Is In The Scattered Disc
Photo Source:NASA Hubble Telescope

The scattered disc is an area of our solar system, or at least it might be, the theory on where the solar system ends might be changing. This is where we find some icy minor planets known as scattered disc objects. The nearest that most of these objects come to the sun is about 30 – 35 AUs. The furthest that an orbit of one of these objects extends to, is believed to be about 100 AUs. It is believed that most periodic comets originate in the scattered disk area. Some scientists also believe that the icy bodies known as centaurs, that exist between Jupiter and Neptune got there by migrating from the scattered disc. The first astronomers to recognize this area were the astronomers based at Mauna Kea in Hawaii in 1996. The area was identified from a sky survey.

Location Of Oort Cloud
Photo Source: NASA

Of the three known areas where objects exist, the Oort Cloud is by far the farthest. It is so far that if we were to measure the distance to the Oort Cloud from the sun, we would find that it is almost a light year away or one quarter of the distance to Proxima Centauri, the star that is nearest to the sun. This translates to about 50,000 AUs. When we talk about the Oort Cloud, most scientists believe that we are talking about two separate regions of space. It is believed that there is a spherical outer Oort Cloud and a disc shaped inner Oort Cloud. This belief, while upheld by many scientists, is not universal. Just because the Oort Cloud is far from our sun doesn't mean it didn't come from our neighborhood. Many scientists believe that the material in the Oort Cloud was indeed created by our sun and scattered far out into space. Could any of these pieces of material have been created by exploding planets?

Science believes that the Oort Cloud is an area that is only loosely bound to the solar system. They also believe that some comets come from this area such as the famous Halley's Comet. It is believed that the material in the Oort cloud is affected not only by the gravity from our solar system, but also the gravitational pull of passing stars. Some of the comets that the scattered disc gets credit for may have actually come from the Oort Cloud. It was 1932 when an Estonian astronomer named Ernst Opik developed his theory that long period comets come from an orbiting cloud at the farthermost edge of the solar system. The estimate for the amount of bodies in just the outer Oort Cloud is several trillion and they are considered comet nuclei that are larger than 1.3 km. No one knows what the mass of the inner Oort Cloud could be.

Is there enough material and evidence in our solar system to prove that several planets that previously existed have blow up? I guess the answer depends on several things. The first that comes to my mind is where does our solar system end? We could be generous and say that the Oort Cloud is still at least under the influence of our solar system, so we can count it. What if we have had more planets, but their explosions have caused most of their mass to be sent outside the solar system? Would it be possible to someday fly to a close star and find bits of former planets from the Sol solar system? That means that the next problem is that we may not have all the mass trapped in our solar system from any planets that have exploded. More problems arise if we take the definition of what is in the Oort Cloud from the scientists. As I said, they think that there is only the cores of comets. Could they be wrong? Absolutely. First of all, to my knowledge we have not sent any missions there to examine the contents of the Oort Cloud and if we do they will take more than a lifetime to accomplish unless we find some faster mode of transportation.

It could turn out that there were many more planets in our solar system and that it reaches out many times further than the orbit of Neptune. We might even be shocked in the future with a new planet discovery or two right here in our own backyard. Finally we can not eliminate the fact that a planet in our solar system might have been knocked out of the solar system intact and is now drifting in space. Science knows that such wandering planets exist.