Ask a science graduate anything...

Question:What triggered the first cycle of the Big Bang?

I ask that which no one has yet answered
 
battletoad said:
Something you may be interested in. There are these 3 locations in orbit between the moon and earth which experiences absolutely no gravitational forces (earth-moon-sun system cancels out forces), they're called Laplace spaces if memory serves. They are earmarked as the most viable location for a space settlement. Any launches in those positions do not need extra energy to overcome gravity. Better yet, we'll be able to use the earth and moon to slingshot crafts to any position we'd like (unless of course if the trajectory in a straight line to said location is perpendicular to the imaginary line from the center of earth to the center of the moon, but at least no gravity's holding us back:))
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haha, it's Lagrange Points.
 
Question:
What are the implications for South African coastal cities if a really huge portion of ice shelf breaks off Antartica in one sudden event?
 
Q: How would one derive Heisenberg's uncertainty principle using the Cauchy-Schwarz inequality without moving to the Hilbert space?
Another Q, got an NRF rating? :P
 
wrathex said:
Question:
What are the implications for South African coastal cities if a really huge portion of ice shelf breaks off Antartica in one sudden event?
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Goes without saying that if the portion is big enough the results could be devastating. Question would then be, how big is big enough?

Well, pretty sure it can be modelled mathematically altho i must iterate not perfectly.

Say x tons of water is displaced. Consequently, sea levels will rise by approx x/total surface area of oceans (supposing the block of ice isnt THAT massive). But thats in the end scenario. Before we get there, Cape Town/PE/Durban should have gotten the full brunt of the resultant wave (obviously depending on where the portion broke off).

Since the mass (remember x) of water will be radiated out in all directions (more on this later), an arc on the circumference will be destined for south africa. Thus, depending on the angle (say a) subtending said arc, the mass of water headed for us will be x*(a/2pi). I suspect the wavefront will decay exponentially, with further restriction on the wave once it hits Africa's continental shelf, it'd be great to get input from someone who did fluid dynamics.

Anycase im tired, we can go on with this trail of thought sometime if anyones interested.
 
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wrathex said:
Question:
What are the implications for South African coastal cities if a really huge portion of ice shelf breaks off Antartica in one sudden event?
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Very large ice shelves have already collapsed in Antarctica, and the sea level rise due to the results haven't even been noticed, specifically Larson ice shelves and the Wilkins ice shelf, these I recall off hand and am sure there are others too, mostly located on the Antarctica peninsula. The reason being is that the ocean really is very large and an ice melt causes an overall very small sea level rise. Its not the suddenness of the melt but ofcourse the consequences of many ice shelves melting is cumulative as sea level rise steadily increases.

But what do you mean by "huge" and "sudden", when Larson B broke up, 715 000 cubic meters of ice melted in 3 weeks, there were no noticeable effects on South African coastal cities.

It is also important to note that most sea level rise experienced to date is from the thermal expansion of water. As our planet heats up, most of the heat is going to warming our oceans. Naturally the water gets warmer and as a result less dense and takes up more volume and consequently sea level rise.

Ice simply just doesn't melt fast enough to cause anything like a tsunami event, not even close....
 
Why do protons in the nucleus not repel each other? Basic question but im only doing basic science. Also how do I get my hands on some potassium, I have a largely unused swimming pool.
 
Guantanamo said:
Why do protons in the nucleus not repel each other? Basic question but im only doing basic science. Also how do I get my hands on some potassium, I have a largely unused swimming pool.
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DO YOU want a purple swimming pool? are u not thinking of sodium?
 
BattleMoose said:
Very large ice shelves have already collapsed in Antarctica, and the sea level rise due to the results haven't even been noticed, specifically Larson ice shelves and the Wilkins ice shelf, these I recall off hand and am sure there are others too, mostly located on the Antarctica peninsula. The reason being is that the ocean really is very large and an ice melt causes an overall very small sea level rise. Its not the suddenness of the melt but ofcourse the consequences of many ice shelves melting is cumulative as sea level rise steadily increases.

But what do you mean by "huge" and "sudden", when Larson B broke up, 715 000 cubic meters of ice melted in 3 weeks, there were no noticeable effects on South African coastal cities.

It is also important to note that most sea level rise experienced to date is from the thermal expansion of water. As our planet heats up, most of the heat is going to warming our oceans. Naturally the water gets warmer and as a result less dense and takes up more volume and consequently sea level rise.

Ice simply just doesn't melt fast enough to cause anything like a tsunami event, not even close....
Click to expand...

Actually you are missing a very important point wrt ice shelves (and the melting of the arctic).

Ice shelves (and the arctic) are floating (i.e. buoyant), there's no land mass holding them up, like glaciers and a large majority of Antarctica.

So you need to apply the Archimedes Principle; the volume of ice is equal to volume of water it displaced.

If you ignore things like ice is mostly fresh water and the ocean saline, if the entire arctic &ice shelves were to melt there would be no increase in sea level.

For the skeptics out there: If you have a drink with ice and full it to the brim then let the ice melt, the glass won't overflow.
 
Guantanamo said:
Why do protons in the nucleus not repel each other?
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They do, but the nucleus stays together because of something called the "strong nuclear force" you can read about it more at wiki. http://en.wikipedia.org/wiki/Nuclear_force Asking why it exists would be like asking why gravity exists, it just does, and I am afraid that is about as much as I know about it.


Guantanamo said:
Basic question but im only doing basic science. Also how do I get my hands on some potassium, I have a largely unused swimming pool.
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You steal it from you high school science chemical store room. Actually no you don't, that stuff is dangerous and kids have blown of their hands playing with it and caught on fire, because they thought it would be cool to steal it from their highschool while the teacher was not watching or similiar.

That stuff as I am sure you know explodes in contact with water. It also ignites on contact with air which is why it is stored in bottles in oil. There are stories of kids stealing some, putting it in their pocket and then all their clothes are on fire.
 
dequadin said:
Actually you are missing a very important point wrt ice shelves (and the melting of the arctic).

Ice shelves (and the arctic) are floating (i.e. buoyant), there's no land mass holding them up, like glaciers and a large majority of Antarctica.

So you need to apply the Archimedes Principle; the volume of ice is equal to volume of water it displaced.

If you ignore things like ice is mostly fresh water and the ocean saline, if the entire arctic &ice shelves were to melt there would be no increase in sea level.

For the skeptics out there: If you have a drink with ice and full it to the brim then let the ice melt, the glass won't overflow.
Click to expand...

Yes you are quite correct, but only for free floating ice such as the arctic ice cap. Ice shelves interact with the land and while the ice that is submerged (and some above) won't lead to sea level rise, the ice that is resting on that ice will.
 
BattleMoose said:
Yes you are quite correct, but only for free floating ice such as the arctic ice cap. Ice shelves interact with the land and while the ice that is submerged (and some above) won't lead to sea level rise, the ice that is resting on that ice will.
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I haven't seen any calculations on that, and would be quite interested. How far out from where the ice shelf meets the land is it fully buoyant? I assume the gradient is quite small (so quite far), but most of the ice shelves that are breaking up aren't at the coast are they? They're kilometers out...?

Anyway it's an important point that most people neglect.
 
battletoad said:
This thread is geared toward undergrad science subjects.

Im tutoring in some courses, and the calibre of students leaves much to be desired, maybe its OBE. Be that as it may, perhaps we formites can come together and help those suffering through these courses.

To those that need help, im pretty sure you'l ask your homework questions. Keep in mind, even if i or someone else answers you, its imperative you work thru examples and exercises on your own to strengthen your understanding of the subject matter. Your textbook is your best friend if you want to have an easier ride on varsity, make time for it.

Im a maths (pure) major, i gather Edduck would only be too happy chatting about matters regarding microbiology and such;), and im sure formites specialising in other types of sciences would be happy to oblige. Just ask nicely and display some initiative on your part.

So... let the games begin:)
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Can we go home early on Friday?
 
BattleMoose said:
Yes you are quite correct, but only for free floating ice such as the arctic ice cap. Ice shelves interact with the land and while the ice that is submerged (and some above) won't lead to sea level rise, the ice that is resting on that ice will.
Click to expand...

dequadin said:
I haven't seen any calculations on that, and would be quite interested. How far out from where the ice shelf meets the land is it fully buoyant? I assume the gradient is quite small (so quite far), but most of the ice shelves that are breaking up aren't at the coast are they? They're kilometers out...?

Anyway it's an important point that most people neglect.
Click to expand...

Worst case scenarios, here and here

Lets say average 65m rise in sea levels if all the ice in Antarctica melts. Can't find a proper map to illustrate what the world would look like in the event such an occurrence took place. Best I get is this, so looking at the metric its a safe bet to say all the dark green places along the coast would be in danger(those dark green places inland would most probably survive submersion).
Points of interest: eastern seaboard of the US, parts of Brazil, Bangladesh, +-500km inland of the east coast of china, etc. Sad to say Cape Town (altho its obvious), you lucky okes up on the escarpment!!!

Have to add tho, not sure how they figured it out. As in if they left the surface area of the oceans as a constant or if they adjusted to compensate for the rise (probably the latter but it has to be noted)
 
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