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First Oort Cloud Object May Have Been Discovered
SpuriousLogic alerts us to the discovery of what may be the first object ever discovered from the inner edge of the Oort cloud. 2006 SQ372 was found on images from the Sloan Digital Sky Survey. Its discoverers theorize that this comet-like object and the planetoid Sedna, first spotted in 2003, might be Oort denizens. Sedna is in a stable orbit but 2006 SQ372 has been perturbed by the gravity of Uranus and/or Neptune, simulations suggest, so its orbital history is unknowable. 2006 SQ372 will travel out to 1,600 AU on this orbit, making it the most distant solar-system object yet found. The Oort cloud is believed to extend ten times that far, or about a quarter of a light-year. "Theoretical models of the formation of the Oort Cloud predict that it should also host a massive inner part, but comets from this region never make it near Earth. To see the long-period comets from the inner region of the Oort Cloud requires observing comets whose orbits always stay well outside Saturn's orbit — like 2006 SQ372."
the planetoid Sedna
Wouldn't that be a plutoid?
If you can read this... 01110101 01110010 00100000 01100001 00100000 01100111 01100101 01100101 01101011
Something tells me that a lot of people are going to be looking up Oort Cloud on Wikipedia in the next few minutes... the article summary is nice and scientificky but it hardly explains what's going on in simple terms - the article is actually more summarised than the summary!
For reference, see the article itself or:
http://en.wikipedia.org/wiki/Oort_cloud
From the Wikipedia article:
The outer Oort cloud [...]. Its total mass is not known with certainty, but, assuming that Halley's comet is a suitable prototype for all comets within the outer Oort cloud, the estimated combined mass is 3x10^28 grams, or roughly five times the mass of the Earth. Earlier it was thought to be more massive (up to 380 Earth masses), but improved knowledge of the size distribution of long-period comets has led to much lower estimates. The mass of the inner Oort cloud is not currently known.
Incorrect, the sum of the mass of the Oort cloud objects *might* be larger than the Earth's mass, maybe even a few Earth masses, but it is certainly not "far more than the mass of the sun and all the planets".
While an Earth sized planet might exist in the Oort cloud and not be detected, it is essentially impossible for anything Jupiter-sized to exist there, for two reasons: (a) Infrared all-sky surveys would have detected it by now and (b) a massive object like that would cause a significant detectable influx of smaller objects (comets) from the region where it exists. No such "preferred" direction is detected in long-period comets, and the number of long-period comets we find is at least an order of magnitude lower than we would see if there really was such a massive object out there.
Yes, this is the "Nemesis" theory, which was popular in the '70s and '80s for explaining "regular" extinction events. However, the events are less "regular" than suggested by proponents of the theory, and if such a star really existed, Infrared All Sky Surveys would have detected it by now. They haven't, so it doesn't exist.
Yes, there was a serious theory for a while that a small dim star called "Nemesis" orbits the Sun and would disrupt the Oort could every 40 million years or so sending a hail of comets into the inner solar system which is responsible for mass extinctions on Earth. It never really had many supporters.
I addition to Nemesis, which at least was a theory espoused by legitimate astronomers, many kooks are convinced that there is a weird giant planet out in that same area which swings by Earth every few thousand years and is supposedly the home to a race of lizard people who communicated with the Sumerians. Now go to bed or the lizard people will get you.
Does this
The Oort cloud could hold a planetary mass comet on a collision course with Earth and we would know about it only right before the event or just after.
It's probably a conspiracy to build A Really Big bypass.
Someone should go down to the local planning department to see if any demolition orders are on file.
I am pretty sure we would notice something was amiss during the collision as well.
sheep.horse - does not contain information on sheep or horses.
Interesting thought that.
Let me be pedantic for a minute and state that the Kuiper Belt != the Oort cloud.
The Kuiper Belt and the scattered disc have been studied/observed quite a bit. The Oort cloud, on the other hand, is hypothetical (which certainly does not mean that it doesnt exist). The "boundaries" of the inner Oort cloud are thought to begin well beyond the scattered disk, which in turn extends beyond the Kuiper belt (although the two may well overlap).
Too much hyping. This object seems to be a scattered Kiper Belt object than an Oort Cloud object. Why? Its orbit crosses Neptune's orbit, which means it is strongly influenced by the planet's gravity. Sedna is different, because it never comes near Neptune. That doesn't mean that Sedna is an Oort Cloud object since its aphelion (most distant point of orbit) is not far enough. This newly-found object has a longer orbit, but compared to some long-period comets that originate from the Cloud and which can take several tens of thousands to millions of years to complete one orbit this is not at all unusual.