[skenasis]

No takers? If it isn't gotten in the next 24 hours, I'll post the answer along with a new question.

[Rylkan]

I want to say Bombay Blood type, but I looked it up, and on average it's around the same as AB negative.

I have another choice that I saw while researching that, so if this is the wrong guess, then I will give my new answer. Best I research it before I reply with it, though.

[skenasis]

No, Bombay is in fact the correct answer. It is actually rarer than AB negative. Rylkan's question!

[Rylkan]

Why do young stellar objects form in dust and large clouds of Hydrogen. I am looking for a specific answer, but am open to your own arguments, and if they are reasonable, since it could be argued possibly for other things, I will accept it. Mind you, why does NOT include arguments about stellar composistion in this case. I am looking for the effect the cloud has on the YSO and why it is important.

[Goto]

To be honest I haven't really done any astrophysics before, but I'll take a rough stab at this one anyway.

Assuming that a 'Young Stellar Object' is a newly created star or what you get before it can be classified as a star (I don't know the terminology, and I'm too lazy to check right now), then...

You have regions of space with a higher density of mass than normal known as clouds (presumably mostly hydrogen I guess, since that's what most matter is), the core of which becomes gravitationally unstable and collapses inward, forming an area of even higher density. More of the nearby cloud is pulled into this core by gravity, and the loss of gravitational potential energy is converted into higher temperatures at the core until eventually it's hot and dense enough for fusion to take place.

I've got no idea if I'm actually addressing what you were asking for, but a reply is a reply.

[Zziggywolf5]

I really don't know anything about astrophysics. I have never taken a class on it or researched it myself. So unfortunately, Rylkan may as well as struck his keyboard several times. Actually, I probably would have understood that better.
Anyway, I don't know the answer. I don't even know of something I could make up.
So... Why did I post here in the first place if I didn't have any idea about the answer?
Simple. It's been five days and this topic needs a... *BUMP*

[Goto]

Good thinking, I'd been meaning to bump this.

Rylkan, if my answer is wrong (and lets face it, it probably is ) then it might be better to post a new question, since we don't seem to be getting too much attention in here currently.

[Rylkan]

Shoot. I'm sorry. I totally forgot about this with a flurry of activity from schoolwork I had to get through.

My answer was along the lines of yours. Your answer is a bit incomplete. It also serves as sort of an interstellar cooler. The radiation from outside the cloud can't penetrate and destroy the molecular hydrogen forming in the center of the cloud. The only issue with your answer is it isnt quite as simple as that, since it collapses and as you said, losses some energy in the form of thermal energy, and thus halts the collapse until it cools again, thus having the shell of gas around it playing the role of radiating the heat outwards, and then preventing more heat from reaching the center.

Sorry about forgetting the question. Definitely should let Goto go. And if I ever make a new question, I promise not to forget again.

[Goto]

Yeah, my answer didn't seem quite right to me either.

Gah, I guess now I have to think of one... Ah well, I'll post something that was bugging me a while ago. A little bit of a backstory first.

'Beta Decay' is a type of radioactive decay, it comes in two forms.
Beta Minus decay involves a neutron decaying into a proton, an electron and an anti-neutrino (tiny chargeless particle, has mass but not a measurable amount).
Beta Plus decay involves a proton decaying into a neutron, a positron (also known as an anti-electron, it's a positive antimatter version of an electron) and a neutrino.


Free neutrons (neutrons not within a nucleus) are quite happy to take part in Beta Minus decay, in fact their half-life is only about 15 minutes. On the other hand free protons have never been observed to take part in Beta Plus decay, and theories which suggest it could happen list the half life of being at least 10^36 years. Since the universe is estimated to be about 10^10 years old, that number is pretty close to 'never'.

Anyway, give me some reasoning why this might be the case, and for extra credit the reason why Beta Plus decay can happen within a nucleus, and the conditions for this to be so. It doesn't really have anything to do with the neutrinos, I just added them in for completeness and so I wouldn't get called on it.

[Rylkan]

Yay. One I could reason out. Though, I admit to checking it before posting.

Simple answer has to do with mass. Since we need to conserve some important quantites here, those being energy and mass. Since the neutron mass is greater than the proton mass, the reaction requires outside energy to push the proton into a higher energy plane of existance to begin with.

Need a more technical answer?

[Goto]

No, that's fine. It can happen within a nucleus if the binding energy of the daughter nuclei is higher than that of the parent, since it can use some of that energy to make up the difference in mass. No chance to do that when it's a free proton though.


The fact that the equation didn't follow conservation of mass had been bugging me for a year or two now, when we revisited nuclear physics a few weeks ago I got our lecturer to explain where the extra energy/mass was coming from. Anyway, your question.

[Rylkan]

Okay, this is more trivia based, and I made it up, so if you can prove me wrong, I'll accept it.

What is the largest observable evidence for quantum fluctuations?

[Zziggywolf5]

Okay, this is more trivia based, and I made it up, so if you can prove me wrong, I'll accept it.

What is the largest observable evidence for quantum fluctuations?

No idea :/

[Rylkan]

Okay, a hint. Think about the largest structure we can see, and also, think about that it means to see quantum structure.

If you read my past questions, it should give a hint from what vein I am thinking.

[Goto]

Sorry, no clue either. I've done very, very little in the way of quantum theory. Still, I guess it can't hurt to take a blind stab at things.

Okay, so a quick google defines quantum fluctuations as the Uncertainty Principle as it applies to the conservation of energy. That more or less makes sense as long as I ignore the crazily difficult looking maths that accompanies it. A quick little bit of wiki-ing seems to relate this to the creation of large-scale structures during the creation of the universe. If that's somewhat along the right track, then I guess the largest examples would be superclusters of galaxies, or something along those lines?

Meh, to be honest my understanding is extremely limited. But it seemed more fun if someone at least had a guess at the question.