/sci/ - Science & Math

>>6365823
If you're not remotely worried about it being realistic, try this one on for size.


A large scale experiment to test the feasibility of creating an artificial, traversible wormhole appears to be successful at first, giving researchers in the lab a brief glimpse to another part of the Universe. Suddenly something goes catastrophically wrong, the lab is damaged, and the wormhole appears to close.

Unbeknownst to the researchers the experiment has produced an unstable wormhole in our solar system. The wormhole periodically opens in the night sky, revealing distant stars and planets and is at first hailed as a magnificent achievement - a bridge for humans to eventually utilize to travel throughout the Universe.

But as the wormhole's aperture grows and as the length of its periodic openings increases, gravitational effects permeating through the wormhole begin to cause serious perturbations in the Earth's orbit.

The scientists realize it's only a matter of time before the increasing perturbations disrupt the orbits of the solar system or the wormhole opens up to an exploding star or the jet of an AGN or a black hole, scientists and hurry to devise a means of permanently closing the wormhole.

>>5524564
Before you even drop anything, you take your egg and the egg the school gave you, you hold 'em up and you make the following postulation:


"The state of an egg being intact or broken is a two-state system - any measurement of the egg at any time can only yield one result or the other, not a superposition of both. Let us approximate the eggs as a set pair of fermionic particles with mass m.

Given two indistinguishable fermion eggs prepared in the same initial state in the same system, by the Pauli Exclusion Principle we can say that if a measurement of one of the eggs at time t yields a measurement of intact or broken, then the second egg MUST be in the other state at that time."


Now place both eggs in the box and drop it. There will be a sickening crunch and splat but with any luck your box will be intact and hopefully not leaking too much. Open the lid and remove the splattered remains of one of the eggs, and declare that since a measurement of that egg has yielded the result 'broken', the other egg must therefore be intact.


Good luck OP.

A farmer decides to build a new pen for his livestock and turns to his friends - a physicist, an engineer, and a mathematician - for help designing the enclosure.


The physicist takes out a legal pad and a pen and crunches some numbers for a few minutes before exclaiming, "Eureka! My derivations show that a circular pen will give you the largest enclosure for a given length of fencing!"

"Now hold on a second," says the engineer. He pulls out a notebook full of graph paper, he draws a few sketches and jots down some calculations and finally says, "Aha! My models show that a rectangular pen will make the most efficient use of the existing fences and buildings!"

The physicist and the engineer argue for a time before finally coming to an agreement on a design. They shake hands, pick up some tools and help the farmer start building the pen.


Not to be outdone by his colleagues, the mathematician grabs four sections of fencing from the pile. He grumbles and curses under his breath as he drags them out into the middle of the farmer's property, sets them up in a small box around himself and shouts out:

"Behold! I define myself to be outside the fence!"

>Is it possible for a jet plane to melt the steel supportive structure of a building?
No, jet fuel doesn't burn hot enough to melt structural steel. The fires present in both the North and South tower as well as Bulding 7 were, however, more than hot enough to significantly weaken the steel supports - steel melts at ~1400 C, but it loses half its strength at a little over 500 C, and almost 90% of its strength at just 800 C. It also would have lead to thermal expansion of the beams, floor grids, and other support structures leading to warping and buckling of the building's skeleton. These two effects were enough to exacerbate the existing damage to the building structure caused by the airliner/debris impacts and eventually triggered the collapse.

>Was the weight of each floor enough to cause a pan cake effect on a building?
Not exactly. One often quoted claim submitted by conspiracy theorists is that the towers' support structures were designed to, in theory, support 20-times the empty weight (or deadweight) of all the floors above a given level. This is true, but the force imparted by the collapsing mass and the stresses experienced by the surviving support far exceeded what the building was designed to support. As more and more of the structure became weakened and damaged during the collapse it was able to offer less and less resistance against the collapsing mass.

It all comes down to one simple phrase: "reasonable suspension of disbelief"

If the argument the film/novel makes for how some technology or phenomenon works is convincing enough, is demonstrated properly, and is consistent with the rules established in that universe - most sci-fi fans will give it a pass even if it doesn't jive with the laws of physics, because it's a "reasonable suspension of disbelief".

A couple of examples of how this is done properly:
- 'Mass Effect' technology in the series of the same name. While it does require the use of MacGuffinium ("Element Zero") all of the technology which incorporates the concept in the series operates within the rules the series establishes, and they go out of their way to provide detailed explanations for how the concept operates.
- The 'Force' in Star Wars is a bit more on the 'magic-y' side, and it's not really properly explained (ignoring the prequels), but it is demonstrated early on and the story takes time to establish that this is how things work in this universe
- A more recent example that I've seen lately, in an episode of Breaking Bad Walt and Jesse rig a powerful electromagnet to wipe the harddrive of a computer in an evidence locker. In a comical moment this ends up pulling their truck up on its side wheels. Is it a realistic portrayal of what would happen? No. But a scene prior to this establishes to the viewer that the magnet is reasonably powerful enough to accomplish this.

An example of how this is done poorly:
- Armageddon
- The Day After Tomorrow
- The Core... good lord, I'm pretty sure the writers and technical advisers for that film gave up on 'reasonable suspension of disbelief' the moment the pitch landed on their table

It all comes down to one simple phrase: "reasonable suspension of disbelief"

If the argument the film/novel makes for how some piece of technology is convincing enough, is demonstrated properly, and is consistent with the rules established in that universe - most sci-fi fans will give it a pass even if it doesn't jive with the laws of physics, because it's a "reasonable suspension of disbelief".

A couple of examples of how this is done properly:
- The 'Warp Drive' in Star Trek is a bit iffy as far as the physics go, but they take a lot of opportunities to lay out the 'rules' that this method of travel follows in that universe and (much to the chagrin of the writing staff I imagine) an effort is made to remain self-consistent with those established rules.
- The 'Force' in Star Wars is a bit more on the 'magic-y' side, and it's not really properly explained (ignoring the prequels), but it is demonstrated early on and the story takes time to establish that this is how things work in this universe
- A more recent example that I've seen lately, in an episode of Breaking Bad Walt and Jesse rig a powerful electromagnet to wipe the harddrive of a computer in an evidence locker. In a comical moment this ends up pulling their truck up on its side wheels. Is it a realistic portrayal of what would happen? No. But the show has a seen just prior to this which establishes to the viewer that the magnet is reasonably powerful enough to accomplish this.

An example of how this is done poorly:
- Armageddon
- The Day After Tomorrow
- The Core... good lord, I'm pretty sure the writers and technical advisers for that film gave up on 'reasonable suspension of disbelief' the moment the pitch landed on their table

A farmer decides to build a new enclosure for his livestock turns to his friends - a physicist, an engineer, and a mathematician - for help designing it.

The physicist scratches down some equations on a sheet of paper and after a few moments declares, "You should build a circular pen, that will give you the largest area given a limited amount of fencing!"

"No hold on," says the engineer. He takes a few minutes to survey the farmer's land and after scratching down some sketches and crunching some numbers declares, "A rectangular pen will make the most efficient use of the existing fences and buildings!"

The physicist and engineer debate for some time and their collaboration eventually produces the most efficient design for the fence. They shake hands and start helping the farmer build the enclosure.


The mathematician, meanwhile, takes four pieces of fencing and builds a tiny pen around himself. He smiles, smugly, before triumphantly stating, "Eureka! I define myself to be outside the pen!"

The important thing to remember when looking at cases like this is you're looking at the apparent or angular diameters of the Sun and Venus.

Angular size doesn't decrease linearly, if we apply small angle approximation is goes like

θ ≈ d/D

Where d is the linear diameter, D is the distance from the observer, and θ is the angle in radians.

So, we can express the ratio of linear diameters as the product of the ratio of angular sizes times the ratio of distances.
(θs/θv) * (Ds/Dv) = ds/dv


The diameter of the Sun in the image appears to be about 30 times that of Venus. Venus has a semi-major axis of around 3/4ths of an AU or so, so the Sun is roughly 4 times farther from us than Venus

30 * 4 = 120 times the diameter of Venus

The actual ratio of diameters is about 115 so it's a pretty close approximation.


If you want to be really precise, you can look up the exact distances and angular sizes and ignore the approximations by working backwards from
θ = 2 arctan(d/2D)