An SFN Q&A Session with Lawrence Krauss - Call for Questions.

[hypervalent_iodine]

Some of you may recall that once upon a time we had the idea of doing interviews with prominent scientists and members of the community (see here). For one reason or another, we seemed to stop after the first one - until now!

We have been very fortunate to have Professor Lawrence Krauss agree to do a small Q & A for us. Krauss, for those who aren't aware, is a highly regarded cosmologist and theoretical physicist, professor and director of the Origins project at Arizona State. In addition to his own work, Krauss is also a prominent and outspoken advocate of science and has authored a few bestsellers, namely The Physics of Star Trek and A Universe from Nothing (for more, see here).

The way this will work is slightly different to the way the old interviews worked, in that the questions will be asked by you. The purpose of this thread is for members to pose a question or two that they'd like Lawrence to answer. He is a very busy man, so staff will have to pick and choose which of your questions we will forward on to him; we're aiming for about 10.

I would strongly recommend those who aren't as familiar with his work and who want participate to take a look at some of his lectures and other talks on YouTube. Here are a few to get you started:

https://www.youtube.com/watch?v=qcR4XqLlxSA

Once we have the questions, I will be forwarding them on to be answered. He has advised that it might take a little bit for him to get around to answering them, but I'm sure no one here will have a problem with that. When he responds, we will post a new thread with his answers and possibly a separate one for discussion.

With all that in mind, myself and the rest of staff invite you all to ask your best questions for Prof. Krauss!

[pwagen]

I don't have any question (at least not right now), but this sounds pretty awesome. I hope it works out great!

[iNow]

I'd like some help word-smithing this, but I'd be curious... If the universe came from nothing and is the result of quantum fluctuations, then what was fluctuating if nothing was there? Perhaps you're using a different meaning of "nothing?"

[plsdntanxiety]

I have a question,

What are your thoughts on the apparent mass of the higgs-like particle potentially signifying the possibility of vacuum decay, (that in the distant future another universe may bubble into existence and expand to replace our own based on the (lack of) stability of our universe).

I am aware that there is still many calculations to be taken in to account and this result may change, but what are your thoughts, and is there any potential that the big bang was our universe "bubbling" into existence in another unstable universe and that's what we're expanding into now?

[hypervalent_iodine]

FTR - We will probably help with wording and editing of questions once we have enough to send on.

 

Thank you to all who have responded so far!

[immortal]

Why does he think that Wigner, Roger Penrose, Von-neumann and Henry Stapp are New age hucksters? What if they were all right and he is wrong?

[elfmotat]

I haven't looked into it at all (other than having having watched your popular youtube video), so these questions might have a simple answers. At first glance, the "zero-energy universe" idea seems rather ill-defined in GR. How exactly are you defining "total energy of the universe?" Under some simplifying conditions I suppose the Komar, ADM, and Bondi masses could be considered "total energy." But those are all undefined for cosmological spacetimes like the FLRW spacetime.

 

More fundamentally, the FLRW spacetime and similar spacetimes do not possess a timelike Killing vector, so global energy conservation is not possible. The energy density of the gravitational field isn't defined at all in GR, so it would seem to be problematic to take its contribution into account as well.

 

 

Looking forward to a response if my question is picked.

[michel123456]

Dear professor
thank you for taking time answering these questions, it is simply invaluable.

[Here takes place the presentation of "who is talking"-- dear Mods what do we do here?-- for example; Michel, 52, Architect, from Belgium & Greece]


From one of your interviews over the Net i picked this little excerpt

Quote


FLATOW: 1-800-989-8255. You mentioned in your book that we are lucky to be living in this time in the universe.



KRAUSS: Yeah, I mean for a variety of reasons. One is in the far
future, and by the far future I mean hundreds of billions of years,
astronomers and radio hosts on planets around other stars will look out
at the universe, and what they'll see is the universe we thought we
lived in 100 years ago, all of the other galaxies will have disappeared
expect for our own, and people will assume, or beings will assume, they
live in a universe that's basically infinite, dark and empty except for
one galaxy, with no evidence of the Big Bang.

So as it seems our common understanding of cosmology has created a model that predicts that future observers will be unable to understand the Universe the way we do today.
Here comes the question:
The cosmological principle sates in some way that all observers are equal players in a fair game with the same rules over space.
From your quote it looks like over time, in the far future, the game will become unfair for some observer because this observer will not be able to observe the remnants of the Big Bang.
Does that mean that Nature does not play fair ? and that the cosmological principle cannot apply for objects in the far future and thus cannot apply for objects in the distant past and as a matter of consequence cannot apply for distant objects?
--------------
(edit)
Or, to put it another way:
doesn't this conclusion in your quote rings a bell to you?
Can't we imagine another model of Nature where there are no lucky observers like us but a model where all beings over time are equally "lucky" to observe the same universe as we do ?

Thank you.

Edited February 23, 2013 by michel123456

[Cap'n Refsmmat]

Those of you looking for question inspiration can also read the Q&A Dr. Krauss held on Reddit a year ago after his most recent book was published:

 

http://www.reddit.com/r/IAmA/comments/oe96e/i_am_lawrence_krauss_director_of_the_origins/

[tar]

Dr. Krauss,

 

How do you believe you have no beliefs?

If we are constrained by evolution, to understand the world based on human perception, experimentation, understanding patterns and predicting courses of actions that will work, you have to believe in an objective reality that will always, consistently be there, that you are in and of, that will be available for you to interact with, any and every time you are awake.

 

If this reality is what people who believe in God, are refering to, why is your belief in it proper, and their belief in it, improper?

 

In both cases, it is one's own personal image of it, that is being believed in.

 

Regards, TAR2

 

 

Dr. Krauss,

 

As a follow up question to the question the Political Science student asked you from the balcony during the Q&A when you were with Prof. Dawkins in Australia...Why is not a holistic understanding of our world, including Religion, Science and Politics as important, or even more important, than pursuing an imaginary understanding of what the universe might look like to a Milky Way observer in 100,000,000 years?

 

Regards, TAR2

 

 

Dr. Krauss,

 

If our human abiltiy to recognize and remember and understand the universe has emerged in a mere 13.8 billion years, why would the emergence of additional capabiliies not be factored in to your image of what the universe will look like to a scientist, in 100,000,000 years? Those scientists should probably have indepth knowledge of incredible stuff that has not even emerged as of now, and capabilities far beyond anything we can currently imagine. If the big bang is true, I would think there would be some evidence of it, hanging around, for them to figure it out. Wouldn't you think a thing like the big bang would leave some evidence?

 

Regards, TAR2

 

 

Dr. Krauss,

 

If the cosmic background radiation is red shifted now, would not a view of the same areas of space, imaginarily taken a billion years ago, been less red shifted?

 

Regards, TAR2

 

 

Dr. Krauss,

 

 

How do we know how far away the cosmic background radiation is? How deep an area of space does the cosmic background radiation represent? If we watched those areas of space, for a couple billion years, would we see them evolve into quasars and galaxies?

 

Regards, TAR2

 

 

And would there not then be new cosmic background radiation "visable" behind those quasars, as the wall of the last scattering receeded in our view?

 

 

Are we currently considered background microwave radiation, by a scientist residing on a planet, circling a sun, in a galaxy that formed, from a glob in the background microwave radiation we see from Earth?

 

 

If architects are capable of intelligent design, then intelligent design is something the laws of physics allow. What would you propose was the first instance of intelligent design, evident in our natural history?

Edited February 24, 2013 by hypervalent_iodine
As per request

[elfmotat]

Dr. Strauss, ...

 

Why do you keep calling him Dr. Strauss?

[ydoaPs]

The zero-value for the Higgs field is a non-zero energy value, so could there be normally massive objects floating around in the universe that are at exactly the right temperature to be massless?

[tar]

elfmotat,

 

Because I am feeble minded.

 

Regards, TAR2

 

My errors have been corrected. thanks for pointing them out.

Edited February 25, 2013 by tar

[michel123456]

Why do you keep calling him Dr. Strauss?

Inspired by 2001 a Space Odyssey?

 

 

http://www.youtube.com/watch?feature=player_detailpage&v=D2DQDgp2IMM

 

Sound on for Strauss.

Edited February 27, 2013 by michel123456

[Cap'n Refsmmat]

Dr. Krauss,

 

You often talk about science education, or the lack thereof exhibited by many of our leaders. You've probably heard about the many new companies trying to advance education through the Internet, like Coursera and Udacity. What future do you see for science education in America? Do we have any hope?

[Spyman]

1) Considering the recent close flyby of asteroid 2012 DA14 and the Chelyabinsk meteor blast, what is your opinion of future impact threats and deflection strategies?

2) What are your thoughts on SETI, are we alone in the Milky Way or do you think that we one day will establish radio contact with another technological civilization?

[hypervalent_iodine]

Thank you everyone for your responses. I think we'll close questions sometime on Sunday, after which staff will work on selecting the questions to send through to Prof. Krauss. Once we have that finalized, we'll work on editing and proof-reading in conjunction with whoever authored the questions and then send them on for him to answer.

[Bill Angel]

I would like to submit a question for consideration:

 

The question: Dark matter is supposed to interact with gravity. Does that mean dark matter is sucked into black holes? And are there dark matter black holes?

[hypervalent_iodine]

Time is over to submit your questions, so thank you to all those who participated. Staff will be in touch with the authors of the selected questions for editing before they are sent on to Lawrence.