Wiki's List Of Common Misconceptions.

Pete Tar

Senior Member.
http://en.wikipedia.org/wiki/List_of_common_misconceptions
Makes for very interesting reading, but one wonders how easy it would be to create bunk with these. I think most people take a certain pleasure in having a factoid they can say about "actually, that's a common misconception, what really happened was...", which could easily be used against them by some prankster.
Some random ones -
 

WeedWhacker

Senior Member
Interesting....

Thing about "Wiki" (as I understand the concept) is....despite the many who disparage it....ALL entries are vetted by a host of volunteers.

When "bunk" (for example) is inserted into a "Wiki" page, doesn't take long for some vigilant and smart people to spot it, and edit appropriately.
 

Jason

Senior Member
Black holes, contrary to their common image, have the same gravitational effects as any other equal mass in their place. They will draw objects nearby towards them, just as any other planetary body does, except at very close distances.[120] If, for example, the Sun were replaced by a black hole of equal mass, the orbits of the planets would be essentially unaffected. A black hole can act like a "cosmic vacuum cleaner" and pull a substantial inflow of matter, but only if the star it forms from is already having a similar effect on surrounding matter.[121]
I particularly like this one. Back in my hay day of fearing the end of the world, there were some CT's that involved a black hole lurking in the outskirts of our solar system. It was either making it's way towards earth or the sun, or sitting out there causing comets and minor planets to get thrown in towards the sun, and on a collision course with earth. One of the astronomers that was helping me at the time, explained this (above) to me. He told us that if we were to replace our sun with a black hole of equal mass, all the planets would orbit as they do now. None of them would get sucked into the black hole. Black hole always spelled doom for me, I don't know why, it just did. Possibly because its cloaked in mystery, and even the most intelligent of astrophysicist don't understand it "totally". Obviously, the earth would become uninhabitable because we would lose the energy and heat we get from our sun. But it really helped put things into perspective. Also noting, that CTers do use misconceptions about science to their advantage. Good one Pete

Edit: Thanks Josh
 
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Vomiting was not a regular part of Roman dining customs.[1] In ancient Rome, the architectural feature called a vomitorium was the entranceway through which crowds entered and exited a stadium, not a special room used for purging food during meals.[2]
The term "vomitorium" is still used in theaters, though it is usually shortened to "vom".
 

jaydeehess

Senior Member.
My bar buddies in the late 70s, early 80s would agree.

One common one involved a local lake that is basically round and only about 1000 feet across. Supposedly its " bottomless", a notion I pooh-poohed with some vehemance and disparaging comments about the person uttering it. It is deep for such a small lake, but only about 70 feet.

The black hole nonsense came up a few times as well, as did the middle ages life expectancy issue.

I did not know of the vomitorium one, and had never heard anyone talk about hot meteorites.
 

Hevach

Senior Member.
I particularly like this one. Back in my hay day of fearing the end of the world, there were some CT's that involved a black hole lurking in the outskirts of our solar system. It was either making it's way towards earth or the sun, or sitting out there causing comets and minor planets to get thrown in towards the sun, and on a collision course with earth. One of the astronomers that was helping me at the time, explained this (above) to me. He told us that if we were to replace our sun with a black hole of equal mass, all the planets would orbit as they do now. None of them would get sucked into the black hole. Black hole always spelled doom for me, I don't know why, it just did. Possibly because its cloaked in mystery, and even the most intelligent of astrophysicist don't understand it "totally". Obviously, the earth would become uninhabitable because we would lose the energy and heat we get from our sun. But it really helped put things into perspective. Also noting, that CTers do use misconceptions about science to their advantage. Good one Pete
Interestingly, if the CTers were correct in that, if one moved through the solar system, it could potentially be cataclysmic. Their theory is of a large mass passing through the solar system on an eccentric or hyperbolic orbit, not just one replacing the sun. In n-body physics, this is kind of like somebody rolling an extra ball across a pool table during the break.

Of course, the likelihood of that actually happening is basically zero. Black holes aren't completely invisible, we would be able to detect a close one indirectly by its gravitational lensing and the radiation given off by matter being accelerated around it. Analysis of WISE's sky survey has confirmed there is absolutely no black hole anywhere near us, no red or brown dwarf star or stellar remnant (Nemesis) closer than Proxima Centauri, and no gas giant planet (Tyche) beyond Neptune within 26,000 AU (this doesn't completely preclude the Tyche theory, but it does upgrade it from preposterous to just plain silly).

As far as we can tell the biggest likely thing lying undisocvered in the outer solar system is a possible earth or super-earth sized object around several hundred AU, which could explain the orbital resonance between the Sednoids. This is very similar to the reason we once expected to find a tiny planet inside Mercury's orbit and a fifth gas giant just past Neptune's, so our track record with this kind of thing does not inspire confidence.
 

Jason

Senior Member
Of course, the likelihood of that actually happening is basically zero. Black holes aren't completely invisible, we would be able to detect a close one indirectly by its gravitational lensing and the radiation given off by matter being accelerated around it
What about a dormant black hole that isn't bound to any galaxy or star system. Where no matter is falling in, would those be easily detectable..

As far as we can tell the biggest likely thing lying undisocvered in the outer solar system is a possible earth or super-earth sized object around several hundred AU, which could explain the orbital resonance between the Sednoids.
Would it have to be earth like in mass to create the resonance. Could it be a gas planet as well, or since it's so far away, an icy world is more likely?

Are astronomers and physicist puzzled with the fact that H20 seems to extremely abundant in one form or another. How do they propose the first molecule of water came to be during early star formation after the big bang, or is water a relatively newer molecule. Can water be created in the vacuum of space or is it bound to celestrial object?
 

Hevach

Senior Member.
What about a dormant black hole that isn't bound to any galaxy or star system. Where no matter is falling in, would those be easily detectable..
The universe is never completely empty, even if there's no active accretion disk there's still matter falling into black holes and giving off X-rays. An inactive black hole can be effectively impossible to detect at the ranges they actually exist at, but at the sort of range that would pose a threat to Earth gravitational effects and X-rays should still give it away.

Would it have to be earth like in mass to create the resonance. Could it be a gas planet as well, or since it's so far away, an icy world is more likely?
WISE's survey means it can't be a gas giant, it would have been easily detected. WISE didn't rule out a rocky or icy planet in that range, though. The mass range that would explain the orbital resonance is estimated around 1-10 Earth masses. An icy world is most likely, but a terrestrial object might be possible (it would challenge our model of how solar systems form, but no more than many exoplanets do on a regular basis). Either one might challenge our classification system again, as well, since the term "dwarf planet," would start to look poorly chosen. The only criteria separating a dwarf planet from a major planet has nothing to do with size, and this hypothetical planet would probably not have cleared its orbit, meaning it would be classified as a dwarf planet. Having a dwarf planet kicking around that's larger than half the major planets would come off sounding absurd.

Are astronomers and physicist puzzled with the fact that H20 seems to extremely abundant in one form or another. How do they propose the first molecule of water came to be during early star formation after the big bang, or is water a relatively newer molecule. Can water be created in the vacuum of space or is it bound to celestrial object?
Water's pretty easy to generate if you have the ingredients, pressure, and a spark. The dominant theory right now is that this happens in protoplanetary disks. Young stars blast off powerful solar wind in their early phases, which we've seen compressing and heating disks enough that water should be able to form. The Herschel space telescope has been looking for the precursors of water in various star forming and star remnant nebulae, and found evidence that CO molecules are being broken down by UV light, and the freed oxygen is reacting with hydrogen to produce various charged hydrogen-oxygen molecules, which aren't water, but can react to create water.

So, yeah, in short, they are somewhat puzzled. Water's already everywhere, and they've found water precursors forming in a lot of different kinds of places, but the link from precursors to actual water hasn't been observed yet. As mysteries go, it's not up there with Thorne-Zytkow objects or the 102 second gamma ray burst in 2006, but it is big enough that we have a space telescope on the job.
 
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Jason

Senior Member
An icy world is most likely, but a terrestrial object might be possible (it would challenge our model of how solar systems form, but no more than many exoplanets do on a regular basis). Either one might challenge our classification system again, as well, since the term "dwarf planet," would start to look poorly chosen.
Isn't how our solar system and others form already highly disputed and turned upside down? I mean we see gas giants forming close to stars and migrating out, and vice versa. I don't think there will ever be an exact science on how solar systems form because no two are alike.
 

Pete Tar

Senior Member.
Is a dormant black hole just a large source of gravity that doesn't have anything close enough to it to 'feed'?
I mean it seems a little odd to say a black hole is ever inactive, as gravity is always 'on'.
 

Jason

Senior Member
102 second gamma ray burst in 2006
Why is it that long gamma ray burst are only detectable from the far reaches of our Universe? I know long ones last over 2 seconds but usually not much longer. 102 seconds boggles the mind, and obviously there must be something new waiting to be discovered. They didn't detect a nova or anything in this area after it diminished, so I guess no one will find out until the next one happens. How do they determine how far away these burst are when they originate? We're talking about billions of light years away, right? Can scientist work out where we were in the Universe when this burst originated or other burst to gain a perspective of proximity...
 

Hevach

Senior Member.
By "inactive" I mean not acreting matter. I'm not sure I'm using the right term for a stellar black hole, it's usually used that way with supermassive black holes.


How do they determine how far away these burst are when they originate?
Most of them are followed by an "afterglow" in longer wavelengths, which can be used to tie them to a specific galaxy, from which point distance can be estimated by redshift. If it's caused by a supernova, those often stay bright for months after the explosion and can be easy to locate. If no object (or several objects) match up to the afterglow, though, we're basically out of luck. There was another ultra-long duration GRB in 2010 that was determined to be between 10,000 and 5.5 billion light years from Earth, and was something between a comet hitting a neutron star and an exotic form of hypernova. I can't even offer a metaphor for how wide that gap is - it's like the doctor telling you you might have the sniffles or maybe everybody in the world has all the cancer.
 
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