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Reading through Hawking's Brief History of time, there is passage which says

"Another prediction of General Relativity is that time should appear to run slower near a massive body like the earth. This is because there is a relation between the energy of light and its frequency. the greater the energy, the greater the frequency. As light travels up in the earth's gravitational field, it loses energy and so its frequency goes down. To someone high up, it would appear everything below was taking longer to happen." enter image description here The last part is what confuses me. I drew a simple illustration to explain the passage from the book. Now if im in space, won't it be the opposite of what the passage says and everything below would be happening more quickly ? The higher frequency, in my head, sounds like something is happening at a faster pace, more quicker. So why does it say " it would everything below was taking longer to happen" . Can someone explain this to me please ?

Also expanding on that, I've read in other articles, that the clock runs slower for astronauts in space. So is this like a bell curve, where the clock runs slow near the earth ( due to high gravitational field ) and then faster at the edges of earth's atmosphere and then slow again in altitudes at where the ISS is orbiting ? This is confusing . Could someone explain this to me please ? Thank you.

whoknowsmerida
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The person in space is not somehow on the outside of the picture looking at the high frequency squiggle on the surface and the low frequency squiggle in pace. Instead, they only see the low frequency part in space. That is, anything and everything they know about the surface, including their understanding of the passage of time on the surface, is based on information sent up from the surface, which gets stretched by the gravitational redshift by the time it gets to them.

That effect is from General Relativity. The effect of astronauts on the ISS you mention is an effect of Special Relativity, and is an effect of motion, not gravity.

Peter
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The ISS doesn't simply float 260km above the Earth's surface. It orbits the Earth. It flies the whole way 'round the Earth every 93 minutes—approximately 7600 meters per second. That's fast enough for us to be able to measure time dilation due to their relative motion.

A clock that's suspended 260km further from the center of the Earth would seem to tick faster than a clock here on the surface. But, a clock zooming past at 7.6km/sec would seem to tick slower than a "stationary" clock. What we actually measure when we listen to signals sent from the ISS is a combination of both of those effects.

Satellites in higher orbits are further still from the Earth's center, and they also orbit more slowly. So, as you consider the apparent "tick rates" of clocks orbiting at different altitudes, the higher you go, the more the gravitational effect matters, and the less the speed-related effect matters.

Ohm's Lawman
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