94,360 reputation
3126233
bio website ratsauce.co.uk
location Chester, United Kingdom
age 53
visits member for 3 years, 6 months
seen 4 hours ago

Semi retired old time computer nerd who started programming on a Commodore Pet.

Since I'm also active in the Physics forum I should add that I started as a theoretical chemist, moved into solid state photochemistry and finally worked in industry as a colloid scientist. I only became a full time computer nerd in 1997.


Jul
15
comment Absorption cross section and absorption coefficient
@jokersobak: if you use the number density of molecules of CO$_2$ you get the scattering cross section for a CO$_2$ molecule. If you use the number density of atoms you get the cross section for an atom. So it depends on what cross section you want to calculate.
Jul
14
comment BBC radiation: What is it?
Can you provide a link or links to examples of these acronyms
Jul
14
comment Would computers accelerated to high speeds compute “faster” from our point of view?
For any object moving relative to you time moves slower not faster. The computer you send off into space would do the calculation slower than the one on your desk. For more info search this site for time dilation
Jul
14
comment Difference between weight of water and pressure of water
@user52187: the base area doesn't matter. My argument that the pressure must be the same is independant of the base area. If you really want the base areas to be the same just imagine the right hand colum expanded in width to match the base area of the other two.
Jul
14
comment Heat loss using alternating current
@user1163511: ${I_0}^{2} R_t \ne \frac{{V_0}^{2}}{R_t}$ because $V_0$ is the voltage drop over both the transmission resistance and the transformer. The transformer resistance is the house resistance, $R_h$, multiplied by $V_0/V_h$.
Jul
13
comment Light cone and order of events?
You might also be interested in reading the answers to Is there always a frame in which spatially separated events are simultaneous? as it covers the same area.
Jul
13
comment About star groupings and there apparent positions in the sky
Can you clarify what you're asking. Constellations may be important for astrology but play little role in physics.
Jul
13
comment What is the current state of research about the Hayden-Preskill circuit?
This is a repost of this closed question. The previous closed question has been deleted so only high rep users will be able to see it. You will not make friends and influence people by just reposting verbatim a question that has already been closed.
Jul
12
comment If empty space has energy, and space is expanding, is this energy equally distributed as space expands?
@Christoph: indeed :-)
Jul
12
comment Can matter be created from energy?
possible duplicate of What keeps mass from turning into energy?
Jul
12
comment Lee Yang force and cosmology
This chap has written a few papers related to the Lee-Yang force. I can't find any other recent activity. This book mentions it briefly in the context of the development of Yang-Mills theory.
Jul
11
comment Heat loss using alternating current
@user1163511: see the update to my answer
Jul
11
comment Heat loss using alternating current
@user1163511: because in real life the load on a transmission line is never zero and it never gets so high that most of the voltage drop is in the tranmission lines.
Jul
11
comment Heat loss using alternating current
@user1163511: re your first question, if everything is turned off no current flows so the voltage drop in the transmissions lines will be zero. I think your second question is asking what if the destination is short circuited so the only resistance is the transmission line. In that case the voltage drop over the transmission line will be equal to the supply voltage.
Jul
11
comment Heat loss using alternating current
The size of the drop depends on how much current is being drawn through the line i.e. whether the people being supplied have turned on their washing machines/kettles/whatever. So it will vary.
Jul
11
comment How does quantization solve UV catastrophe in black body radiation? What would happen if there was no Planck constant $h$?
@user50322: I've updated my answer to respond to your comment
Jul
10
comment Is there a place with no time dilation?
No, because the phrase someone who stayed put in the center of the universe doesn't make sense. There is no centre of the universe. All comoving observers are in a sense at the centre of the universe, because everything moves symmetrically away from them, and for all comoving observers time flows at the same rate.
Jul
10
comment Intermolecular Hydrogen Bonding
@Gummybears: I've updated my answer to respond to your comment
Jul
10
comment Is there a place with no time dilation?
No, a comoving observer is the nearest you can get to not moving. In an FLRW universe (like ours) no clock will ever run faster than that of a comoving observer.
Jul
10
comment Is there a place with no time dilation?
The link I've provided may not seem an obvious duplicate, but it explains how you can define time in such a way that the time dilation is zero.