I Does a person's mass affect time?

[Johndough_]

TL;DR

mass affecting time for individuals

If space time is affected by mass then does each persons perception of time can correlate with their mass? does that leave an impact at all? and do buildings have that affect too. or is everything too small for it to have any affect to speed up or slow down time for that individual. each persons perception of time is different even if it appears to be the same speed for everybody I'm not necessarily sure if there's a genuine affect on each individual or if its all mental.

 

[PeterDonis]

If space time is affected by mass

This is very vague. The correct statement is that the curvature of spacetime is affected by the presence of stress-energy, via the Einstein Field Equation.

does each persons perception of time can correlate with their mass?

No. An individual person's effect on the curvature of spacetime is negligible. So is the effect of even something like a building. You need things like planets or stars or larger things to have a perceptible effect on spacetime.

 

[.Scott]

TL;DR: mass affecting time for individuals

If space time is affected by mass then does each persons perception of time can correlate with their mass? does that leave an impact at all? and do buildings have that affect too. or is everything too small for it to have any affect to speed up or slow down time for that individual. each persons perception of time is different even if it appears to be the same speed for everybody I'm not necessarily sure if there's a genuine affect on each individual or if its all mental.

Taking the International Space Station as an example, at a distance from Earth of about 425 km, time would pass slightly faster than on the Earth's surface - about 3.3msec per year. But, since the ISS is in orbit, and is also affected by time dilation from speed, the net affect is about 14 msec lost every year.

So, as you guessed, time dilation due to mass (ie, gravity) is not noticeable in common circumstances.

 

[PeterDonis]

as you guessed, time dilation due to mass

The OP was asking about an individual person's mass affecting their perception of time. That is not only "not noticeable in common circumstances". It is negligible by many orders of magnitude as compared to the effect of being in the ISS vs. being on Earth as you describe. In other words, while being in the ISS does result in a small amount of time dilation relative to being on Earth (much too small for a person to perceive directly, but it can be measured with sensitive enough instruments), muiltiple people in the ISS will all experience the same time dilation even if their own personal masses vary quite a bit. The time dilation is due to the mass of the Earth, not the people in the ISS, or even the ISS itself.

 

[Ibix]

Your perception is always one second per second.

In principle, someone else's watch might tick slow or fast compared to your watch due to the different gravitational time dilation of your masses, but the effect would be of the order of one part in $10^{27}$, if my mental arithmetic is reliable. That is, if you waited around a hundred billion billion years, there might be one second drift due to this effect. We don't have any clocks that reliable, as far as I'm aware, and your watch certainly isn't that good. So for practical purposes the answer is no, there is no difference in the tick rate of your watch versus your neighbour's watch due to gravitational time dilation.

Back of the envelope, and barring something exotic like a micro-black hole, even with good lab clocks you'd need something on the order of a large asteroid to be able to measure gravitational time dilation.

 

[Johndough_]

Your perception is always one second per second.

In principle, someone else's watch might tick slow or fast compared to your watch due to the different gravitational time dilation of your masses, but the effect would be of the order of one part in $10^{27}$, if my mental arithmetic is reliable. That is, if you waited around a hundred billion billion years, there might be one second drift due to this effect. We don't have any clocks that reliable, as far as I'm aware, and your watch certainly isn't that good. So for practical purposes the answer is no, there is no difference in the tick rate of your watch versus your neighbour's watch due to gravitational time dilation.

Back of the envelope, and barring something exotic like a micro-black hole, even with good lab clocks you'd need something on the order of a large asteroid to be able to measure gravitational time dilation.

Thank you, this makes sense. -John

 

[sophiecentaur]

much too small for a person to perceive directly, but it can be measured with sensitive enough instruments

With a Caesium Clock, you can detect the effect of the variation of gravitational potential between adjacent floors of a building. This link shows how even smaller differences in altitude and measurably affect time.