What is your opinion on the Oort Cloud? Do you think it exists?

Question

From what I've read, there seems to be some contriversy as to whether or not the Oort Cloud is actually out there. I guess it would make sense that something like that could exist (afterall comets have to come from somewhere) but shouldn't we at least be able to detect it somehow? I know that (if it exists) it would be very far away from Earth and would be very very faint, given the fact that it would just be a loose band of comet-like objects. But still, with all the powerful telescopes and infrared devices we have at our disposal, why haven't we been able to authenticate it's existance?

Answer 1

The Oort cloud would have been produced by the gravitational scattering of cometary bodies from massive planets, primarily Jupiter, in the early solar system. Numerical modeling shows that the distribution of the resulting orbital inclinations would be fairly uniform. The distribution of cometary bodies in the Oort cloud would be similar to that of the distribution of stars in a globular cluster. From the middle the Oort cloud would be fairly uniform in all directions, and thus nearly impossible to detect as an unresolved object.

(The asteroid belt ***is*** detectable, and even naked eye visible in some circumstances. Look up "Zodiacal light" and "Gegenschein" for more information.)

As one of the answers above alluded to, there is not all that much stuff out there to see. Confirmation of the existence of the Oort cloud objects will likely rely upon direct detections of objects that belong to that family relying on parallax to determine distances, much like the detection of KBOs. I have not done the radiometric calculations, but I know KBO searches already are only just within the signal to noise comfort zone of current instrumentation. Oort cloud objects will be much smaller; Sedna or Eris (Xena's new official IAU name) type bodies are not likely, given the zone of the proto-planetary disk that Oort cloud objects would have formed in.

So, we are hunting for objects perhaps at best 1/1000th the cross sectional area of Eris, and 10s to hundreds of times further away (thousands to 10s of thousands of astronomical units; see the modeling reference below) By reflected sunlight these will be literally manyu billions of times fainter (say 100^4*1000), and even in the infrared, probably around tens of millions of times fainter (assume the same temperature, 100 times further out and 1/1000th the cross section, 100^2*1000 = 10 million). This is a tall order.

Answer 2

The Oort Cloud hypothesis seems to do a good job of explaining the occurrence of comets, and is consistent with current theories of solar system formation. As far as seeing it goes, we won't see it as a cloud any more than you can see the asteroid belt as a belt. The cometary bodies, assuming they exist, are very sparsely distributed. Eventually, as more powerful telescopes are built, we should be able to start detecting Oort cloud objects.

As to why this cloud might be following the Sun around, the same reason the planets do: gravity.

Answer 3

The Oort cloud, alternatively termed the Öpik-Oort Cloud, is a postulated spherical cloud of comets situated about 50,000 to 100,000 AU from the Sun. This is approximately 2000 times the distance from the Sun to Pluto or roughly one light year, almost a quarter of the distance from the Sun to Proxima Centauri, the star nearest the Sun.

The Oort cloud would have its inner disk at the ecliptic from the Kuiper belt. Although no direct observations have been made of such a cloud, it is believed to be the source of most or all comets entering the inner solar system (some short-period comets may come from the Kuiper belt), based on observations of the orbits of comets.

In 1932 Ernst Öpik, an Estonian astronomer, proposed[1] that comets originate in an orbiting cloud situated at the outermost edge of the solar system. In 1950 the idea was revived and proposed[2] by Dutch astronomer Jan Hendrick Oort to explain an apparent contradiction: comets are destroyed by several passes through the inner solar system, yet if the comets we observe had really existed for billions of years (since the generally accepted origin of the solar system), all would have been destroyed by now. According to the hypothesis, the Oort cloud contains millions of comet nuclei, which are stable because the sun's radiation is very weak at their distance. The cloud provides a continual supply of new comets, replacing those that are destroyed. It is believed that if the Oort cloud exists and supplies comets, in order for it to supply the necessary volume of comets, the total mass of comets in the Oort cloud must be many times that of Earth. Estimates range between 5 and 100 Earth masses.

The Oort cloud is thought to be a remnant of the original nebula that collapsed to form the Sun and planets five billion years ago, and is loosely bound to the solar system. The most widely-accepted hypothesis of its formation is that the Oort cloud's objects initially formed much closer to the Sun as part of the same process that formed the planets and asteroids, but that gravitational interaction with young gas giants such as Jupiter ejected them into extremely long elliptical or parabolic orbits. This process also served to scatter the objects out of the ecliptic plane, explaining the cloud's spherical distribution. While on the distant outer regions of these orbits, gravitational interaction with nearby stars further modified their orbits to make them more circular.

It is thought that other stars are likely to possess Oort clouds of their own, and that the outer edges of two nearby stars' Oort clouds may sometimes overlap, causing the occasional intrusion of a comet into the inner solar system. The star with the greatest possibility of perturbing the Oort cloud in the next 10 million years is Gliese 710.
we havent seen it yet.one day we will

Answer 4

It is not a real cloud. Out beyond the planet Pluto, most things we know as gases are solids and what we call comets, are frozen gases,

The sun is constantly emitting a solar wind of protons, (hydrogen nuclei), and they become hydrogen atoms, and thus the inner solar system is far "cloudier" than any Oort cloud.

If there is a "cloud of comets", why is it following us around the galaxy?

Answer 5

It's just a theory. Over the years other theories have come and gone so only time will tell.

Answer 6

yeah, it exists