132 reputation
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location United Kingdom
age 73
visits member for 2 years, 3 months
seen Apr 12 '12 at 19:22

I am a cosmology layman. Have been an engineer most of my life, but I'm now technically retired. My work as an engineer, took me into safety audits, logic and logic scenarios, with regards to, the design of,the running and safety control, of industrial plant. Working with many companies such as the Admiralty, BP, etc. Logic scenarios entail, using logic to break down the individual actions/options involved in an action path, and seeing if any of these, can be replaced, to make a better action path. I've always had an interest in space, astronomy, cosmology, etc, but only in the past year, have I got deeper into that interest. I have a personal retirement project, to apply these logic principles, to look at the many actions/options, in some cosmology paths. It will probably come to nothing, but who knows. It keeps me happy.


Apr
3
revised How do I go from exponents to a formula?
added 52 characters in body
Apr
3
answered How do I go from exponents to a formula?
Apr
3
revised Why is the time taken for something to fall proprtional to acceleration due to gravity?
added 97 characters in body
Apr
3
answered Why is the time taken for something to fall proprtional to acceleration due to gravity?
Apr
3
revised Change in Vapour/Liquid change point, at very low pressure
edited title
Apr
3
comment How do we determine the temperature of a Black Hole?
@RonMaimon Thank you all, for your answers. My main reason for the question, was the differences in temperature that have been given for different black holes. Generally black holes temperatures are given as very high, and then all of a sudden someone talks about a cold black hole. I think Wiki "Hawkins Radiation" explains this. I.E. Mass & CMB radiation balance. Are you aware of anyone developing a means to prove this? - NASA etc.
Apr
3
revised Change in Vapour/Liquid change point, at very low pressure
added 236 characters in body; edited title
Apr
3
awarded  Editor
Apr
3
revised Change in Vapour/Liquid change point, at very low pressure
added 236 characters in body; edited title
Apr
3
comment Change in Vapour/Liquid change point, at very low pressure
Calculater of Properties of Fluid Systems: webbook.nist.gov/chemistry/fluid
Apr
3
comment Change in Vapour/Liquid change point, at very low pressure
I should have known better since trying it out I had already had problems where it didn't select the element I had chosen. Whatever, the principle is still the same since it gives a Vapour/Liquid point, of 2.5066K for Helium. Except that, Helium does not have a triple point????. The Vapour/Liquid point of He at 1 atm. is 4.22K. So is 2.5066K the Vapour/Liquid point of He at 0.1atm. If this the case, then the V/L point has changed with pressure, which answers another point in my question. Sorry about that, but hope this makes sense. Will have to go back and get new table.
Apr
3
comment Change in Vapour/Liquid change point, at very low pressure
webbook.nist.gov has a table building feature, where you can input an element, and the pressure/temperature range you want to look at. It goes away, and comes back showing columns such as phase, pressure, density, volume,temperature, etc.I do not have the full domain address for this particular page on the site, but will try and look it out. It is a good feature, but a little cumbersome to use. It does not print the element nameon the table page. in another data area, in small print I have just noticed normal boiling point is 4.23K which is He. I did enter H as the element. See next comment.
Apr
3
asked Change in Vapour/Liquid change point, at very low pressure
Apr
1
awarded  Scholar
Apr
1
accepted How do the Planets and Sun get their initial rotation?
Apr
1
comment How do the Planets and Sun get their initial rotation?
I would expect both the Earth and Mars to have different rotation rates. Both Venus and Mercury are obviously not locked to the suns rotation, otherwise they would be rotating at the same speed of the Sun, as per our Moon/Earth. As they are not locked, and in view of their small size relative to the massive variations of the Sun's surface, tidal effect would have no set pattern. It is then surprising to me, they are able to keep such a steady rotation, if it is in fact, tidal effect slowing their rotation. A personal view. Happy to be shot down, as trying to get it right in my mind.
Apr
1
comment How do the Planets and Sun get their initial rotation?
@martinb Thank you both for you reply. The related question given above, is very interesting with regards to spin, and how spin is developed. With regards to the rotation of Venus and Mercury, I thought it may well be to do with their position relative to the sun, but both planets are rotating at a far slower speed than the sun. Venus which is roughly the same size as the Earth, is rotating at 1/100th of the time it takes the Earth (and Mars) to rotate. Distance wise, proportionally, from the Sun centre, if the sun was having this effect,
Apr
1
asked How do the Planets and Sun get their initial rotation?
Apr
1
asked How do we determine the temperature of a Black Hole?
Mar
31
awarded  Commentator