I am writing regarding a mistake in Professor Ulf Danielsson's Nobel Prize ceremony lecture [1].

In Paragraph 4, it is written

Time goes by a trillionth of a second slower at my feet than at my head.

Obviously, time can't slow by an arbitrary trillionth of a second. It must slow by a trillionth of a second in a given time.

My back of the envelope calculation [2], making a few simplifying assumptions, like the distance between the feet and the head being 1 meter, radius of the Earth 6000 km and Schwarzschild radius 1 cm is that time would slow by about one trillionth of a second in one hour. This is probably what Professor Danielson intended to say, but, maybe forgot during the lecture.

Thus, the statement should have been

Time goes by a trillionth of a second an hour slower at my feet than at my head.

I did my PhD on LIGO at Caltech with Kip Thorne and Barry Barish who also received the Nobel Prize in 2017. Andrea Ghez has on a few occasions visited our group and I had the pleasure to meet her.

Later, I have used this very calculation Pofesor Danielson mentioned to propose an avenue to use atomic clocks to pick up on minute variations of the speed of time at the surface of the Earth that are linked to underground density perturbations [3].

[1] https://www.nobelprize.org/prizes/physics/2020/ceremony-speech/

[2] https://sites.google.com/view/nobellectureerror/home

[3] https://arxiv.org/abs/1209.2889, Geophys. J. Int. 2012, vol 191, pages 78-82

Ulf Danielsson <ulf.danielsson@physics.uu.se>

Dear Mihai,

Thanks for spotting the missing words. I will make sure it is corrected.

Thanks!

Ulf

Från: Mihai B <mihai7@gmail.com>

Skickat: Friday, 11 December 2020 11:32

Till: Ulf Danielsson <ulf.danielsson@physics.uu.se>

Ämne: Error in Nobel Lecture

Dear Professor Danielsson,

I am writing regarding a mistake in your Nobel Prize ceremony lecture yesterday [1].

In Paragraph 4, it is written

Time goes by a trillionth of a second slower at my feet than at my head.

Obviously, time can't slow by an arbitrary trillionth of a second. It must slow by a trillionth of a second in a given time.

My back of the envelope calculation [2], making a few simplifying assumptions, like the distance between the feet and the head being 1 meter, radius of the Earth 6000 km and Schwarzschild radius 1 cm

is that time would slow by about one trillionth of a second in one hour. This is probably what you intended to say, but, maybe forgot during the lecture.

Thus, the statement should have been

Time goes by a trillionth of a second

an hour slower at my feet than at my head.

I did my PhD on LIGO at Caltech with Kip Thorne and Barry Barish who also received the Nobel Prize in 2017. Andrea Ghez has on a few occasions visited our group and I had the pleasure to meet her.

Later, I have used this very calculation you mentioned in order to propose an avenue to use atomic clocks to pick up on minute variations of the speed of time at the surface of the Earth that are linked to

underground density perturbations [3].

Thank you for your consideration,

Mihai

[1]

https://www.nobelprize.org/prizes/physics/2020/ceremony-speech/

[2]

https://sites.google.com/view/nobellectureerror/home

[3] https://arxiv.org/abs/1209.2889,

Geophys. J. Int. 2012, vol 191, pages 78-82

--

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Mihai Bondarescu

http://www.theory.caltech.edu/~mihai

Cell 1-626-628-4992

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