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Top 10 Unsolved Space Mysteries
Joe Jordan writes "Space.com is advertising the Top 10 Space Mysteries for 2003, and perhaps for all time, given the current rate of discovery." Some of them are obvious, like the origin of life, and the possibility of alien life forms, but the list is still a good compilation of space's greatest questions.
Why are explosions in space circular and not spherical?
The circular shape you've seen is the hot gas emitted after a massive explosion. Normally the explosion of a star was spherically symmetric. Within the explosion core, higher density part will force the lower density part(gases) escape in a planar direction, provided that the force is uniform in all direction, which is commonly seen in massive explosion like supernova.
Here's a real mystery which we still can't figure out: Anomalous Acceleration of Pioneer space probes. This one, like the dark energy problem, hints at fundamental problems with our view of the universe.
Let's ignore that the parent was surely refering to the absurdity of SciFi in space in general.
Assuming that the force is uniform in all directions, there is no reason that the lower density material escapes in planar direction (what tells the material in which plane it has to escape, so to speak).
My totally uneducated guess is the following:
Stars rotate around one axis. This angular momentum has to be preserved. If memory serves right a supernova occurs, when the equlibrium of gravitational contraction force and the thermonuclar repulsion force collapses, until a certain pressure is reached which leads to a final explosive fusion process. Now think of figure skating, rotating and a contracting diameter.
The outmost material will be hurled back into space, the rest contributes to a white dwarf, neutron star, black hole, or whatever.
But the critical part (for our question at hand) is that the star in it latest moments is not spherical, but eliptical. The material in the rotational plane has a higher momentum, so it will be more likely hurled back into space.
As I said, this is a fairly uneducated guess. The question is, does the centrifugal force matter anything, considering strength the gravitational force and the thermonuclear explosion?
"Between strong and weak, between rich and poor [...], it is freedom which oppresses and the law which sets free"
If I had the ability to mod my own comments I would burn all 50 points in the hope that just one more person would read this book.
Kind thoughts do not change the world
And then there is the theory that we only use 10% of our brain.
This "theory" has been universally debunked. From snopes:
1) Brain imaging research techniques such as PET scans (positron emission tomography) and fMRI (functional magnetic resonance imaging) clearly show that the vast majority of the brain does not lie fallow. Indeed, although certain minor functions may use only a small part of the brain at one time, any sufficiently complex set of activities or thought patterns will indeed use many parts of the brain. Just as people don't use all of their muscle groups at one time, they also don't use all of their brain at once. For any given activity, such as eating, watching television, making love, or reading, you may use a few specific parts of your brain. Over the course of a whole day, however, just about all of the brain is used at one time or another.
2) The myth presupposes an extreme localization of functions in the brain. If the "used" or "necessary" parts of the brain were scattered all around the organ, that would imply that much of the brain is in fact necessary. But the myth implies that the "used" part of the brain is a discrete area, and the "unused" part is like an appendix or tonsil, taking up space but essentially unnecessary. But if all those parts of the brain are unused, removal or damage to the "unused" part of the brain should be minor or unnoticed. Yet people who have suffered head trauma, a stroke, or other brain injury are frequently severely impaired. Have you ever heard a doctor say, ". . . But luckily when that bullet entered his skull, it only damaged the 90 percent of his brain he didn't use"? Of course not.
> High School physics teacher
Centrifugal force does "exist". It is a byproduct of being situated in an accelerating system, where Newtons phyics doesn't apply. Prime requisit of Newtons law. You have to be in a inertial reference frame. Well, the laws of physics still apply, you just have to observe it from a stationary system and then transpose it into the accelerated system.
Calculating in an accelerated system gives you all the non-existant forces or pseudo-forces like centrifugal-force and Coriolis-force.
OTOH, those forces do not exists as they are only a byproduct of calculating in a rotating frame and not a real force which are the result of exchanging particles like photons, gravitons and the like.
Speaking of centrifugal force is inaccurate at worst. So, for educational reasons, one should speak of centrifual effect, or Coriolis effect.
"Between strong and weak, between rich and poor [...], it is freedom which oppresses and the law which sets free"
Actually color perception is only loosely related to wavelength. What you were taught in highschool was an oversimplification that borders on a lie (as is much of high school science!). Color is really a spatial attribute, not a point one (Google for Edward Land's "Retinex" theory of color preception), and perception of color is not absolute - it depends on the spatially adjacent colors; this isn't an optical illusion - it's the nature of color perception. It doesn't even stop there because color is a compatative attribute - things look "leaf green" because they stimulate your visual cortex in the same say as a leaf, but that is still true if you wear red goggles, and experiments have shown that normal color vision returns after a couple of weeks of wearing colored goggles!
You should also note that humans can only see a fraction of the possible colors (combinations of wavelengths of light) even in the visual part of the spectrum), and there is therefore nothing absolute about what we perceive - it's just what we can differentiate. If instead of having 3 differently tuned color cones in our eye (the cones have bell-curve-like light wavelength response that peak around R/G/B) we had more, then we would be able to differentiate more wavelength combinations. With our eyes the way they are you can differentially stimulate our color cones with only three wavelengths of light, but if we had 4 (peak tuned to R/G/B/Yellow say, or ANY different wavelengths) then you would need 4. Some people in fact do have 4 types of color cones and can therefore differentiate colors that you cannot. Your "red" surface is someone else's patterned one!
That absolute "red" that you are worrying about therefore isn't an irreducible gestalt experience/quale - it's a differential surface attribute detection that a machine will be able to duplicate just fine.
Incidently note also that what you see a color as isn't going to be precisely what I see it as - we may agree on things like "green's a bit like blue and a bit like yellow" that are based on the underlying transducers and brain architecture, but what the color actually looks/feels like is going to be as personal as any other experiental phenomena.
What do you get when you multiply six by nine?
(Thereby proving that hyperintelligent pandimensional beings also known as white mice use base 13).
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.