What is the Oort Cloud, Hypothesized Area of Comets?

Oort Cloud Facts

• The Oort Cloud is a theorized cloud of billions of comets encompassing the Solar System located roughly one light year from the Sun. We do not know how many comets are there exactly in the cloud because it is too far away to be seen.
• The length or thickness of the Oort Cloud could be over a light year.
• Flying through the Oort Cloud is not like the Millennium Falcon flying through the asteroid field in Empire Strikes Back film. The comets are spread out.
• The Voyager and Pioneer space probes will eventually reach the cloud, they will no longer be in contact with Earth so far away. The Pioneer probe have been turned off.
• The theory was made by Dutch astronomer Jan Hendrik Oort. It is also referred to as the Opik-Oort Cloud. The Oort Cloud has yet to be discovered which is why it is only a theory. More...
• Long-term comets are thought to originate from the Cloud, unsettled by an outside influence which some believe is caused by an evil twin of the Sun called Nemesis More...
• There are believed to be two Oort clouds, an inner and an outer.

What is the Oort Cloud?

The Oort Cloud in brief is an hypothesized area in space that is estimated to be located roughly one light year away from the Sun. Its not like a cloud you would find on the Earth, it doesn't rain. The Oort Cloud is a huge area of space that encompasses our solar system where long term comets are believed to originate before they are sent on their way towards the inner solar system, our planet Earth and the Sun.

The theory's creator was Jan Hendrik Oort who was a Dutch astronomer of the twentieth century. He came up with a theory to explain where the long distance comets that we see, comets such as Hale-Bopp, West etc, not Halley's or Encke which are short term comets.

The reason why we can't see the cloud is because the objects are too far away and too small. The Oort Cloud is not like the asteroid field in Empire Strike Back where the objects are close together, the objects are spaced out.

There are no pictures of what the Oort Cloud looks like, those that do purport to show the Oort Cloud are only artist impressions.

Location and Distance to the Oort Cloud

There are theorized to be two Oort clouds that surround our solar system. The original one's location was believed to be about one light year from Earth. The two Oort Clouds are :-

• The Inner Oort Cloud is believed to be outside the orbit of Pluto and contain the Kuiper-Belt Object Sedna.
• The Outer Oort Cloud is believed to be at a distance of 1 Light Year from the Earth or about 5.88 trillion miles away or 50,000 A.U. 1 A.U. is the distance between our planet, Earth and the Sun.

To put some more context into the description, the next nearest star Proxima Centauri is four times further away than the Oort Cloud. There has been no definitive evidence that the Oort Cloud exists. There is a debate currently raging as to whether Sedna, the so-called "Tenth planet" is actually part of an inner Oort Cloud. This is because the Sedna is three times further away from the Sun than Pluto, well beyond where the kuiper belt is said to inhabit. Sedna is not the only object that is believed to be part of the Inner Oort Cloud, 2012 VP113 was discovered to be in the same region of space as Sedna. Ref: Carnegie Science

Oort Cloud objects are too far away for our telescopes on Earth to see any of these objects, plus you also need to take into account the fact that they are very small. Thousands upon millions of comets are believed to be "holding up" in the Oort Cloud, waiting to be sent on a journey to the Sun. They are not clustered in one area of the galaxy but surround the entire Solar System like a cloud. No one has ever seen the Oort Cloud so no-one knows how big and how far is ranges out from its location. Comets are actually quite small so you're not going to be able to see one a light year away.

The Oort Cloud will be big, it completely surrounds the Solar System at its perceived distance. How deep the Oort Cloud is an unknown amount. It is unlikely to be a mass of comets equivalent to asteroids in Star Wars V - The Empire Strikes Back.

Travel to Oort Cloud

Voyager 1 is the furthest from Earth that any space probe has ever reached. At the time of writing, Voyager 1 is 20,606,155,702 KM from Earth or 137 times the distance from Earth to the Sun. N.A.S.A. have produced a page that will show you in real time how far each voyager space probe has travelled.

It is expected that Voyager I will reach the Oort Cloud is about 300 years from now. The probe would have to navigate through the Oort Cloud to come out the other side. The probe wouldn't exit the Oort Cloud for another maybe 30,000 years.

If we had technology that enabled us to travel at the speed of light. It would take the spaceship a year to get to the Oort Cloud. If we had Warp Speed, it'll be faster, we can dream for Star Trek technology.

Planet hiding in the Inner Oort Cloud

There is believed to be two Oort Clouds, an Inner and an Outer. The Outer Oort Cloud would be at the distance theorized by Jan Hendrik Oort whereas the Inner one would be after where the Kuiper Belt has ended.

There is a theory that is being tested that there could be a planet orbiting the Sun at a distance that would match the distance that the Inner Oort Cloud is. The planet is about 10 times the mass of the Earth and would orbit the Sun every 20,000 years.

There is evidence that at one time, we might have had a ninth planet which existed between Saturn and Uranus but was catapulted out. The missing planet could be found existing in the Oort Cloud. The planet would be so far away and too dark to be spotted. IB Times.

At such a distance, its going to be hard to spot because its won't have light reflecting off it and our telescopes aren't possible powerful enough to spot. The planet might be at the farthest point so its going to be especially hard to see at this moment in time. We may see it if it interacts with something else, maybe block something out.

The planet is only a theory at the moment. Neptune was first theorized and its position was calculated before it was actually discovered so there's no reason why the same can't hold true for this new planet.

The evidence for the new planet is based on the orbits of other far out objects such as Sedna. All the far off objects are all orbiting in the same direction as the diagram demonstrates, the reason for that is believed to be a massive object in the other direction. Ref: Space.

There could be no planet out there but then they'd have to come up with a reason why all the far off objects that they've seen are all in one direction. There are some objects going in the "void" area but they are far and few compared to the other direction.

If you're interested in being the first to find it, Mike Brown believes the planet is currently in the area of sky populated by the constellations of Taurus and Orion. Daily Star

Oort Cloud Evidence

We have no real evidence that the Oort Cloud exists, we only speculate because of comets. There are no images or pictures of the Oort Cloud because it is so far away that it is only hypothesized about. All pictures of the Oort Cloud are artists impressions including mine. The objects in the Oort Cloud are so small, no camera of ours so far is able to pick them up. The only pictures are artists impressions and illustrations. We have no satellite or space probes out that way and none with a high enough camera resolution to pick them up. Such an object would take thousands of years to get to as we don't have faster than light yet, that is if that is possible.

Jan Hendrik Oort, Theory Creator

The Oort Cloud is named after Jan Hendrik Oort ( Apr 28, 1900 - Nov 5, 1992 ) who predicted them where they are widely believed to be nowadays. Before Oort, Ernst Opik, who in 1932, an Estonian Astronomer had placed the cloud just outside the solar system. The Oort Cloud is sometimes known as the Opik-Ort Cloud in recognition of the earlier hypothesis. Oort bases his cloud theory on :-

• No comet's path has been calculated to indicate as coming from interstellar space.
• All comets so far seen don't all seem to be coming from the one point in space.
• There is a strong belief that many comets furthest point from the Sun lies around 50,000 A.U., roughly 1 Light Year or 50,000 times the distance between Earth and the Sun.

Apart from being associated with the Oort Cloud, Jan also calculated that the centre of the Milky Way is 30,000 light years away in the direction of the Sagittarius constellation. The below pictures shows the furthest any thing from Earth has ever travelled (Voyager 1), the location of Sedna, the area where the Oort Cloud is and the nearest star. The sizes aren't too scale but its main purpose is to give an indication of where things are. It should be emphasised that the Oort Cloud is a line, it encompasses the entire solar system like a bubble with the Earth and Sun in middle.

Creation of the Oort Cloud

The Oort Cloud is believed to have been created five billion years ago when a nebula exploded, creating the Sun and its planets. The intense gravitational strength of Jupiter is said to have pushed them to the outer regions of space. Ref: Harvard

Nemesis, the Brown Dwarf

There is a theory in addition to the Oort Cloud that there is a brown dwarf star called nemesis that interferes with the Oort Cloud, sending comets this way. The idea for Nemesis is based on the perceived cycle of mass extinctions in the geological record, which seem to occur more often at intervals of 26 million years. ref:Daily Mail.

Such an object such as a brown dwarf star would have given off enough radiation that it would have been detected by Earth based instruments which none have been recorded. Nemesis might still exist but might be something else apart from a brown star. With Nemesis being a brown dwarf means it is hard to spot so we can't see it. If it was a yellow dwarf then maybe we'd see light from it and know its here. The closest so far discovered brown dwarf is called WISE 0855-0714 and was discovered in the constellation of Hydra. and is about 7.53 light years away, further out than the Oort Cloud itself. Ref:Space

Do other stars have Oort Clouds?

Our star is not unique, its not special, its small compared to other stars such as Rigel. There's no reason why if the Oort Cloud does exist round our Sun, there shouldn't be any reason why the Oort Cloud shouldn't exist round any other star. Its only speculative as we still have no confirmed proof/evidence that such a cloud actually exists surrounding our own solar system. We may never know unless we gain technology to travel at the speed of light. If we had the ability to travel at the speed of light, it would take a round trip of two years to discover and report back that it existed. It would take a year to get there and a year to get back.

What is the difference between the Asteroid Belt, Kuiper Belt and Oort Cloud?

The main difference between the three is location, the Asteroid Belt is located between the orbits of Mars and Jupiter. They are believed to have been parts of a planets that failed to form because of the immense gravity of Jupiter. The asteroids are small rocky planetoids. In recent years, Ceres, a near spherical planetoid was elevated to dwarf planet status by the International Astronomical Union, the worlds governing body for all things space.

At the edge of the solar system, beyond the planet Neptune is the Kuiper Belt which contains a large number of asteroids. The dwarf planet Pluto is in this region of space. It used to be known as a planet but it was downgraded when other objects such as Eris was found in that region of space and was deemed to be larger than Pluto.

The Asteroid Belt and Kuiper Belt have been verified to exists whereas the Oort Cloud is just a theory. The Asteroid Belt and the Kuiper Belt both consist of asteroids and dwarf planets whereas the Oort Cloud is said to consist of comets, the dirty snowballs. Its not to say that the Oort Cloud doesn't contain asteroids, its just that the theory is that consists mainly of comets.

Related Pages of Interest :-

• Black Hole
• Constellation
• Gamma-Ray Bursts
• Pulsar
• Supermassive Black Hole
• Unnova
• Wormhole

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