This has always blown my mind. The equivalent resistance, Req, of n resistors in series is given as:
Req = R1 + R2 + … +Rn
and the equivalent resistance of n resistors in parallel is given as:
1/Req = 1/R1 + 1/R2 + … + 1/Rn
However,
The equivalent capacitance, Ceq, of n capacitors in series is given as:
1/Ceq = 1/C1 + 1/C2 + … + 1/Cn
and the equivalent capacitance of n capacitors in parallel is given as:
Ceq = C1 + C2 + … + Cn
How fucking awesome is that?
37/50, 74%. Some of my errors were just stupid mistakes that I wanted to hit myself for as soon as I saw the correct answer, but there were definitely a number that I just straight up didn’t know.
44 out of 50 ain’t bad considering I don’t think about this stuff anymore. It felt a little skewed towards chemistry questions though.
“What Earth would look like with rings like Saturn”
As cool as this is, if we really did have rings, we’d probably take them for granted like how we take having a moon or only one sun for granted. In this alternate reality people would post videos like “What would Earth look like without rings?”
Also, these rings would likely cause all sorts of problems for satellites.
fill me in on why mmHg is a unit of pressure? It stands for millimeters of mercury, right? Is it just based on the force exerted by a millimeter of mercury in earth gravity? And a millimeter at what thickness?
mm Hg refers to the height of mercury in a mercury barometer, which is basically a glass tube closed at one end and with the other end immersed in mercury:
To get the vacuum inside, the tube is first filled with mercury then flipped upside down into the container. This allows the mercury to come to an equilibrium position where its weight plus the force due to the vapor pressure (which develops in the space above the column) balances the force due to the atmospheric pressure, such that:
patm = γhg*h + pvapor
where γhg is the specific weight of mercury (133 kN/m3)and h is the height of mercury. For most practical purposes the contribution of the vapor pressure can be neglected because of it’s relatively small magnitude (for mercury, pvapor = 0.000023 lb/in2 (abs) at a temperature of 68oF), so it just becomes patm = γhg*h.
mm Hg is just used as a convention for atmospheric pressure because mercury barometers have been around since 1644, courtesy of a certain Evangelista Torricelli. Most other applications will use Pascals or psi, but if you really wanted to, you could do everything in mm Hg.
Terrformation of Mars: A New Look
We look at Mars now as a forgotten Red Planet that almost seems barren and life-less judging from our available images and study of it. But study shows Mars was once as ecologically prosperous as our own Earth. But what happened to all of its waters? Better yet why is it so dry and lacking any plants? Once the abundance of oxygen left and the waters froze over or dried off the planet became what it is today. But what if we can in a way reactivate’ Mars? Welcome to Mars, Terraformed’.
Transforming Mars will be a long and complicated process. But this is exactly the type of subject that interests space researchers like Christopher McKay of NASA Ames Research Center. First, greenhouse gases, like chlorofluorocarbons that contribute to the growing ozone layer on Earth, will be released into the atmosphere. This traps the heat from the Sun and raises the surface temperature by an average of 4 degrees Celsius. In order to achieve this, factories would manufacture chlorofluorocarbons derived from the air and soil. A single factory would require the power equivalent of a large nuclear power plant.
The increasing temperature would vaporize some of the carbon dioxide in the south polar cap. Introducing carbon dioxide into the atmosphere would produce additional warming, melting more of the polar cap until it has been vaporized completely. This would produce an average temperature rise of 70 degrees Celsius.
With the temperature this high, ice will start melting, providing the water needed to sustain life. This water would raise the atmospheric pressure to the equivalent of some mountaintops. While this would be a survivable level, it may still require the use of an oxygen mask. The next step, which may take up to several centuries, would be to plant trees that thrive on carbon dioxide and produce oxygen.
Terraforming is the process of transforming a hostile environment into one suitable for human life. Being that Mars is the most Earth-like planet, it is the best candidate for terraforming. Once just the subject of science fiction novels, it is now becoming a viable research area. The famed astronomer and Pulitzer prize winner, Carl Sagan, says that there is enormous promise in the search for ancient life on Mars. If life was once sustainable on Mars, it is important to know what caused Mars to evolve into the cold and lifeless planet it is today. With this knowledge, we can terraform Mars by reversing the process.
NASA scientists believe that it is technologically possible at the present time to create considerable global climate changes, allowing humans to live on Mars. But this will not be by any means an easy task. Raising the atmospheric pressure and surface temperature alone could be achieved in a few decades.
This research has strong environmental implications for Earth. What researchers are trying to do involves global warming, a sort of greenhouse effect on the cold planet Mars. Scientists may be able to test their hypotheses about global warming in their attempts to elevate Mars’ surface temperature. Likewise, once theories, they may be applied to our own planet in an attempt to reverse environmental damage done by pollution and deforestation.
Credit: http://cwnl.tumblr.com/
I should’ve majored in terraforming engineering.
It’s easy- just follow these four simple steps.
Source: Seife, Charles. Zero: the Biography of a Dangerous Idea. New York: Penguin, 2000.
There are pictures involved, but I can’t find a good scan of them online.
cwnl:
Life May Exist Within A Super Massive Black Hole
Despite being considered the most destructive force in space and absolutely uninhabitable, the conditions for life exist inside supermassive black holes, a Russian cosmologist has theorised.
Going out on a scientific limb somewhat, Vyacheslav Dokuchaev has even suggested that if life did exist inside the SBH, it would have evolved to become the most advanced civilisation in the galaxy. Supermassive black holes are such powerful gravitational forces that they suck in everything around them, including light, and nothing that crosses the black hole’s ‘event horizon’ is ever seen again.
But now Dokuchaev, of Moscow’s Institute for Nuclear Research of the Russian Academy of Sciences, says existing evidence combined with new research throws up intriguing possibilities for certain types of black holes. Inside a charged, rotating black hole there are regions where photons can survive in stable periodic orbits. Dokuchaev specialises in studying those orbits and their dynamics.
He speculates, in a paper published in Cornell University’s online journal arXiv, that if there are stable orbits for photons, there is no reason why there could not be stable orbits for larger objects, such as planets. The problem is that these stable orbits would only exist once you have crossed the threshold of the event horizon, where time and space flow into one another. The event horizon, at the lip of the black hole, is known as the point of no return. However, beyond the event horizon is another domain, known as the Cauchy horizon, where time and space return to stable states.
It is inside the Cauchy horizon that life could exist, Dokuchaev argues in a paper published in Cornell University’s online journal arXiv, However, the type of life that could exist in those conditions - where they would be subject to massive fluctuating tidal forces - would have evolved beyond ours. The life that could exist there would likely be a civilisation ranked as Type III on the Kardashev Scale. There are three levels to the scale with one being the lowest and three the highest. Humanity is still looking to attain Level 1 status; mastery of its own planet.
‘Interiors of the supermassive black holes may be inhabited by advanced civilisations… invisible from the outside,’ he says. Though that is a spine-tingling thought, Dokuchaev’s proposition can only ever remain theoretical. Because nothing can ever escape from a black hole due to its enormous gravitational pull, we will never know if it is true.
I smell a good sci-fi plot…
Also this is really interesting.
I’m sorry, but this is really pushing the boundaries of what I can accept, scientifically.
