Recent content by fizzy

There is a lot of discussion about the "imbalance" of matter/anitmatter in the universe. It is said that the expectation would be symmetric creation of both which would eventually annihilate each other leaving just energy. The remaining matter in the universe is thus anomalous. Since...

Thanks for correcting my dyslexic 1633, I was surprised I got such a high result before adding albedo, which raises the result. Of course the whole idea of modelling the Earth as a uniform ball with no atmosphere, clouds, ice which mean it reflects a lot of solar before it even gets absorbed, is...

Err, no. So the bottom line is that it is the radiated flux density, not power, and this applies to both. Thanks for your help in sorting it all out.

In E=LAs/s2 , I guess that s is the solid angle subtended by the Earth at the sun. However, the sun can hardly be regarded as point source, an implicit assumption idea of the Earth subtending a solid angle somewhere. That has to relate to a point, not a finite and large object. When the angle...

Thanks Charles, that is interesting but that does not seem to answer my quesiton. I know that the integral ∫cosθ dθ dφ across the hemisphere equals π but that is still dealing with a plane emitting into a hemisphere. What I was asking is how to do a similar calculation for a sphere.

Thanks for the reply Charles. I thought the term I asked about came from the double integral of the term you cite. That would make I the radiance (watts per square metre per steradian). I think that was part of the problem I was having with following some of the stuff I'd read on this. So...

Can someone advise on the εσT⁴ term of Stephan-Boltzmann law? Is this the power radiated from a point or flat surface into a hemisphere or a sphere fully enclosing a black body? thanks.

A constant term is not "silly". If the fit evaluates it near zero, it will not cost anything, and that is valuable information in itself, not "silly". Negative results can be as important a positive ones. Blinkering the analysis by trying to coerce the result is not only silly but...

Here is real some meteorological data with significant experimental error in both variables. A linear regression was done, first on x then on y. The two OLS slopes are both invalid because each one ignores the errors in one or other variable. OLS should never be applied to this kind of data in...

Scientific method demands that you conduct an experiment and then compare to theory / hypothesis. You do not start inserting assumptions from your hypothesis into you data then conclude that this "supports the hypothesis". Again it is not a "trendline". That term belongs to time series...

I said your previous answers were not correct but the distances you are now using look good to me. Seems I'd picked up a false idea about inv. sqr law near to a spherical object. The fact it is exact is quite neat. Using the masses you calculate, the barycentre distance estimate is 4244km but...

No, but you can do things properly, so that attentive students can pick things up correctly, rather then showing them bad ways of doing stuff. There are several things which need correcting here. This is not time series data. Time is the dependent variable and should be plotted on the y axis...

Fun experiment. Sure to get the attention of the kids. A few criticisms of the write up. Inductive thinking. It seems that you have 5 DATA points. The origin is not a data point, it is part of the hypothesis you are supposed to be testing. You are not fitted to a trendline, you are fitting a...

yes, effectively there will be a difference in angle between the back of front elements of each pair that I had not accounted for. That could be it.

Thanks Ibix, can't see what was wrong with my logic but doing the integral seems clear.