Reputation
3,709
Next privilege 5,000 Rep.
Approve tag wiki edits
Badges
8 20
Newest
 Yearling
Impact
~175k people reached

Feb
22
comment Question about calculating age of a uranium and lead containing object, based on the ratio of uranium-to-lead
This appears to be a misunderstanding of what a ratio is. One glass of 2% skim milk is still 2% skim milk; a shot of 90 proof vodka is still 90 proof vodka.
Feb
22
comment If the solar system is a sensitive chaotic system, can gravity waves make orbits unpredictable?
@Yumquat: It is very small indeed, about 1/1000th the size of an electron.
Feb
12
comment If the solar system is a sensitive chaotic system, can gravity waves make orbits unpredictable?
The motion of planets is defined by the gravity field. Waves in the gravity field affects that motion, in proportion to the strength of these waves. It's good to realize that the waves are far, far smaller than the gravity of the sun and its planets.
Feb
12
comment If the solar system is a sensitive chaotic system, can gravity waves make orbits unpredictable?
@Yumquat: LIGO consists of 2 arms at a 90 degree angle. This is intentional: the gravity wave passing squishes matter in the direction of travel while expanding it in the other two dimensions (and vice versa, on the rebound). Gravity waves move at the speed of light, as far as we can tell, so they pass the earth in a few milliseconds, but the period of the decently detected wave was also a few milliseconds. In other words, the wavelength of those gravity waves was roughly the diameter of the earth. That's not "microscopically".
Feb
11
answered If the solar system is a sensitive chaotic system, can gravity waves make orbits unpredictable?
Feb
11
comment How strong were the gravitational waves that LIGO detected at the source?
@John : You're slightly more squishy.
Feb
3
comment How do stars from far away affect Earth?
@cst1992: It's balanced by the fact that the Sun, Moon and other planets are also attracted by Proxima Centauri. Due to the distance between the solar system and Proxima Centauri, the gravitational field of Proxima Centauri is pretty much constant across the solar system (both in strength and direction).
Jan
14
comment Does gravity turn itself off when it has nothing to work with?
@Ricky: LIGO should tell us soon.
Jan
14
comment Does gravity turn itself off when it has nothing to work with?
@igael: True, objects don't appear from the void, but for the purpose of this question you can assume the two objects travel directly towards each other (i.e. speed vector aligned with direction to other object)
Jan
14
answered Does gravity turn itself off when it has nothing to work with?
Jan
13
comment Why can't the human voice produce a Shepard tone?
@DanielSank: The human ear may be able to hear sounds up to 20 kHz, but at those frequencies the accuracy drops of quite rapidly. You can't hear the exact pitch or volume, it's almost binary (sound present/absent).
Jan
12
comment Is white a single color?
Note that this picture is an artistic rendering. In particular the "7 colors" do not match reality, but are an artistic license. The actual spectrum has no sharp edges, and also a fairly narrow green strip.
Jan
5
comment Why not use our own light production to produce new energy instead of wasting it?
Still has the incorrect assumption that a 100W lightsource and a 30% efficient panel produces 30W of electricity. This ignores the light source efficiency, which is far lower than 100%. Also, the r^-2 effect mentioned in the last paragraph is a fall in flux, not power. At a greater distance, you just need r^2 more panels to harness the same power.
Jan
4
comment which is efficient on solar electricity by photo voltaic or thermal
This might be more of an economic question. Wholesale electricity prices have always fluctuated throughout the day, and photovoltaic solar is pushing the midday prices down. Thermal storage of solar heat allows the production of electricity at night, when prices are higher. For personal use, prices are usually quoted up front and constant throughout the day.
Jan
4
answered Why not use our own light production to produce new energy instead of wasting it?
Jan
4
comment Why not use our own light production to produce new energy instead of wasting it?
@AGML: Light being radiated upwards is most efficiently recycled by a simple mirror. This allows you to halve the light source power; far more efficient than a photovoltaic panel could achieve.
Dec
1
answered Why didn't helium continue to generate after a few minutes post-Big Bang?
Nov
18
comment Why can't I see the blue color scattered by the lower atmosphere of the earth?
@coder: The pressure gradient isn't that steep. That's why the atmosphere extends about 100 kilometer. There are more air atoms above one kilometer than below. Secondly, you don't see where the blue is being scattered. Like the scattering of rainbows, the blue light scattering changes the direction of the light which makes it impossible to see where it's actually coming from (i.e. the sun).
Nov
17
answered Why can't I see the blue color scattered by the lower atmosphere of the earth?
Nov
10
awarded  Yearling