What You Said: Physics Q&A
One hour. Two physicists. A lot of questions.
This story is part of our summer Book Club conversation about Stephen Hawking’s 1988 book ‘A Brief History of Time.’ Want to participate? Sign up for our newsletter or call our special voicemail at 567-243-2456.
Stephen Hawking’s A Brief History of Time has been praised for how it made physics accessible to a general audience. But even the most clear explanations can use some filling in at times. The SciFri Book Club’s resident readers and physicists, Priya Natarajan and Clifford Johnson, spent one hour on Twitter fielding your questions on physics, from how to detect new dimensions, to their pet peeves about depictions of physics in pop culture. Check out some of their responses below.
On the multiverse:
The idea of the multiverse controversial amongst physicists…there are some who think its mere speculation as it cannot be empirically tested. I am open to the idea as I think the course of future science cannot be predicted and it may become testablehttps://t.co/92Xe5exWBV
— Priyamvada Natarajan (@SheerPriya) August 8, 2018
On particle “spin”:
(1/2) Spin of elementary particles is a form of angular momentum. It comes in whole numbers and half numbers. It does not refer to “how much you’ve turned” , so two amounts of spin 1/2 don’t return you back to where you started…https://t.co/9rMdUtUSHJ
— Clifford Johnson (@asymptotia) August 8, 2018
(2/2) So think of the spin an ice-skater has when spinning. That’s a (different) form of angular momentum, but aspects of it can be helpful for analogies… How much they have is more to do with their rate of spin, not what angle they’ve turned around in a given moment.
— Clifford Johnson (@asymptotia) August 8, 2018
(2/2) So think of the spin an ice-skater has when spinning. That’s a (different) form of angular momentum, but aspects of it can be helpful for analogies… How much they have is more to do with their rate of spin, not what angle they’ve turned around in a given moment.
— Clifford Johnson (@asymptotia) August 8, 2018
[Did you know that the Earth’s crust has created its own natural nuclear reactors?]
On time:
The key point about time is – it is relative and the measurement depends on the state of the person making the measurement i.e. whether they are moving or not, how far they are from gravitational fields Carlo Rovelli’s new book In Order of Time might helphttps://t.co/VigM4dfDNc
— Priyamvada Natarajan (@SheerPriya) August 8, 2018
On new dimensions:
Hi. There are many ideas, but here are two: (1) Missing energy in particle collisions in detector experiments. This is actually how one detects new particles a lot, historically. If some of those particles leaked off… (1/3) https://t.co/b1fw02xR80
— Clifford Johnson (@asymptotia) August 8, 2018
(2/3) …into extra dimensions, that could be a clue. (2) The size of that extra dimension would be a new scale of nature, and might show up in new physics. For example, it could change the scale at which new physics appears in a very specific way you could design detectors…
— Clifford Johnson (@asymptotia) August 8, 2018
(3/3) .. to look for. A favorite version of this for many is that the Planck scale (scale of quantum gravity) could be lower than supposed because of this new scale… Look up books by @lirarandall about this, for example.
— Clifford Johnson (@asymptotia) August 8, 2018
[You’ve heard of ants’ superhuman—er, superant—strength. But that’s just the beginning.]
On stereotypes:
Ah! yes — the way I have found to deal with stereotypes is to be myself (am an assertive but not aggressive person) do the best science I can, and master what I do…I love what I do and usually thats evident so it helps people question their assumptionshttps://t.co/J8o7jvi0Dw
— Priyamvada Natarajan (@SheerPriya) August 8, 2018
On physics pet peeves:
Oh gosh! way too many — but exceeding the speed of light particularly annoys me. One reason I am not a great fan of science fiction bar a few exceptions like Kim Stanley Robinsonhttps://t.co/lQs75Un3Wa
— Priyamvada Natarajan (@SheerPriya) August 8, 2018
On “new physics”:
You *should* be confused! We are too. It means we don’t understand yet what’s going on. The equations suggest that it’s infinite because they are running out of their ability to describe the physics there. We need new physics. https://t.co/Vg2tmuY5xV
— Clifford Johnson (@asymptotia) August 8, 2018
Meet the Writer
About Johanna Mayer
@yohannamayerJohanna Mayer is a podcast producer and hosted Science Diction from Science Friday. When she’s not working, she’s probably baking a fruit pie. Cherry’s her specialty, but she whips up a mean rhubarb streusel as well.