Recent content by Skaperen

Two spaceships line up to go past each other at a near distance (just far enough to not hit each other). A third ship is stationary near where the other two will go past each other to view the event. The two ships that will go past each other will be traveling at 3/4 (75%) of the speed of...

How many stars are in 2 galaxies? How much memory does your computer have? How fast is your computer? Discrete simulation seems unlikely. Then consider other effects like dark matter and dark energy.

I have seen simulations of galactic collisions such a Andromeda and The Milky Way. How could dark matter affect such a collision, especially if an off-center collision results in one galaxy orbiting the other a few times? It seems to me that another galaxy would have an orbit much like the...

as i see it, the big bang was not an event. instead, it is merely an understanding of "going backwards in time" along the path of the expansion of the universe where time was equal to zero and space was zero as well.

there is no A1-B2. i am wondering if a charged capacitor can be treated as having an electrostattc charge. not the whole capacitor, just one terminal on each (A2 and B1).

suppose you have two capacitors with a 0.1 Farad value and 12 VDC rating. label these as A and B. label the terminals of each as 1 and 2. you also have a voltmeter with a 40 volt linear range for DC. you also have a 9 volt DC power supply fed by mains. you charge each capacitor to 9 volts...

Normally, an electron microscope would be needed to "see" a biological virus or other objects of this size scale because they are so much smaller than wavelengths of light we can see with our red/green/blue sensitive eyes (700 nm down to 400 nm) at any magnification of an optical microscope...

i found Pentane is 36C.

many OSes can run process performing both server and client work at the same time (multiplexed so fast humans believe them to be simultaneous). i could name these OSes, but you already know them.

i am looking for a chemical compound that has a boiling or condensation temperature between 10C and 50C at standard pressure and is not one prohibited for discussion in the Physics Forum or any online chemical forums. something that is organic and not very toxic is preferred. it should be...

when a railroad engine wheel slips on a rail as it tries to move forward i can see sparks mostly going in the rear direction. while thinking about what might happen in other situations, such as a moving engine (being pushed by its massive 100 car load, perhaps), i came to a simplistic case that...

This is one of my thought experiments where I am drawing a big blank, If you have 2 objects approaching a 3rd object from opposite directions (just enough off to avoid collision) at 75% of the speed of light, the first assumption is that each observing the other would see the other object...

That would not be an issue on step-UP where the supply has an SGC/neutral. But clearly there is a complication if the supply has no SGC/neutral. I guess in such a case you don't get to use that exception since its requirement cannot be complied with. No. Since the need for the step-down is...

They list only two ways to make such a transformer, yet there are three ways. The difference between these is that the grounded isolation method connects the neutral side (has the wider blade hole) of the 120 volt output to the ground wire itself, inside the transformer. It seems from their...

In a colocated rack cabinet supplied with ONLY 208 volt power, and a requirement to follow electrical codes that include not permitting NEMA 5 type power outlets with 208 volts on them, we need to supply power to a device that has a "wall wart" transformer with NEMA 1 type (North American flat...