Ask an Astrophysicist - APOD's Dr. Jerry Bonnell

[owlice]

I'm tempted to ask Dr. Bonnell what color his eyes are, if only to ensure that he actually gets to answer a question that is posted here for him!

[quote="JTB"]

brown[/quote][/i][/color]

[grz]

I am creating a planetarium presentation. Do I need permission to use pictures posted on APOD?

Thanks,

Andrew Grzadzielewski

[quote="JTB"]

I think you do for the ones that are copyrighted. You should be able to just contact the copyright holders from the credit links in the APOD.[/quote][/i][/color]

[Chuck51]

Why is the browser frame around the APOD bright white, despite the fact that the night sky surrounding the usual APOD feature is almost entirely black? I can't think of ANY image that wouldn't look better without the glare of the frame (i.e., background). Some people claim that mostly dark screens are more energy efficient than mostly bright ones; I can't verify that, but I suppose it could be true in some cases. Certainly, we must have the technology somewhere to change the default image background color! When I see a fine deep sky APOD, I like to turn the lights down and imagine that I'm seeing it through a telescope... but there's that light-pollution around the edges.

[quote="JTB"]

We do control the background color for the APOD page, but I don’t remember what the actual html code is. We chose the color to be slightly off white after some experimentation because that made the text easiest to read.[/quote][/i][/color]

[rochelimit]

Can we have more solar system visualization stuffs in APOD, I like diagrams for planets and the moons, like cut section of satellites, etc, etc.

[quote="JTB"]

Well, the short answer is, yes we can have more. APOD certainly has shown illustrations in the past, although we do tend to use more images than illustrations. I actually thought we had a nice visualization (video) of an exoplanetary system just a few weeks ago;

APOD: 2010 August 25 - HD 10180: Richest Yet Planetary System Discovered[/quote][/i][/color]

[Beyond]

Doctor Jerry; How long does it take for the Milky Way Galaxy to make one complete revolution and would we call that a Galactic Day, or a Galactic year, if we called it anything at all? Also, how far does the Milky Way Galaxy travel while it is makeing a complete revolution?
Thank you.

[rstevenson]

Doctor Jerry; How long does it take for the Milky Way Galaxy to make one complete revolution and would we call that a Galactic Day, or a Galactic year, if we called it anything at all? Also, how far does the Milky Way Galaxy travel while it is makeing a complete revolution?
Thank you.

To avoid wasting the good doctor's time, you can read the answer to all those questions at Wikipedia, under Milky Way.

Rob

[Beyond]

To avoid wasting the good doctor's time, you can read the answer to all those questions at Wikipedia, under Milky Way.

Rob

Oh, sorry, i keep forgetting that there is no longer any need to ask questions anymore because of Wikipedia. Must be because I'm old and decrepid. I can't be pathedic - bystander has taken all that. So if i can't find an answer in wikipedia, then there is no answer and if there is no answer, then there cannot be a question and if there cannot be a question -- then why is anyone bothering to ask an Astrophysicist (or anyone else) anything? I have never heard what i asked being discussed anywhere, so i thought it was a half-decent question. Thanks for pointing out to me the error of my ways. From now on i do not ask questions. However, i do reserve the right to make meaningless statements now and then for no reason what-so-ever except for the fact that i am old and decrepid and need to punch a few keys now and then.

The way things are labeled in Wikipedia, i could not tell, from what i could find, if i found the answers to my questions or not. One day i may discover the answers in regular english. Until then - EH! Its not really important to know.

[rstevenson]

Oh, sorry, i keep forgetting that there is no longer any need to ask questions anymore because of Wikipedia. Must be because I'm old and decrepid.

You are unlikely to be any older or more decripit than I, but when I have an idle curiosity I search the web first. The questions you asked are readily answered on any number of sites, not just Wikipedia. And that Wiki page has a large number of links to further information, in case you don't trust what is there.

The way things are labeled in Wikipedia, i could not tell, from what i could find, if i found the answers to my questions or not. One day i may discover the answers in regular english.

Your answers...
1. Sun's galactic rotation period: 250 million years
2. Cosmic Year
3. Speed relative to CMB rest frame: 552 km/s

Rob

[owlice]

I'm tempted to ask Dr. Bonnell what color his eyes are, if only to ensure that he actually gets to answer a question that is posted here for him!

And maybe what size shoes he wears, too!

[quote="JTB"]

US size 9 ½[/quote][/i][/color]

[Chris Peterson]

Your answers...
1. Sun's galactic rotation period: 250 million years
2. Cosmic Year
3. Speed relative to CMB rest frame: 552 km/s

Those aren't the answers to the first two questions he asked, however. And only a partial answer to the third. <g>

The actual answers are somewhat more complex. I'll leave it to either you or Dr Bonnell to continue...

[rstevenson]

Those aren't the answers to the first two questions he asked, however. And only a partial answer to the third. <g>

I took his first question as meaning the period of time it takes for the Solar System to go around the galaxy once, which makes both those answers right, as far as they go. There are other periods of rotation, such as the time it takes the spiral arms to go around once, and so on.

As for the speed, I did say it was relative to the CMB. There are, of course, other things it could be relative to.

The actual answers are somewhat more complex. I'll leave it to either you or Dr Bonnell to continue...

Indeed they are more complex, but beyond admits he wanted the answers in a relatively simple form. And I did originally give him the link to explore to any extent desired.

Doctor Bonnell will no doubt clarify further if he feels the need.

Rob

[quote="JTB"]

All right kids, stop this right now! Don’t make me pull this discussion over. I will, you know. If we can’t all behave we are just going to turn around and go home![/quote][/i][/color]

[neufer]

I'm tempted to ask Dr. Bonnell what color his eyes are, if only to ensure
that he actually gets to answer a question that is posted here for him!

And maybe what size shoes he wears, too!

To avoid wasting the good doctor's time,
you can read the answer to all those questions at WikiLeaks.

I'm rather more interested if Jerry has any good deals on selected blazers:

<<Lately, my research efforts have involved multiwavelength studies of gamma-ray selected blazars...>>
-- Fascinating Biographical Sketch for Jerry T. Bonnell

[quote="JTB"]

Blazars (not blazers!) are active galactic nuclei (AGN) that are detected at gamma-ray energies. I do participate in collaborations that try to make contemporaneous observations of the AGN at lower energies (like ultraviolet and infrared). The goal is to combine all the observations to get a picture of how the AGN behave across the spectrum. Then you try to match the multiwavelength observations to physical models of the emission processes. But the only really good deal I’ve gotten lately is on a nice fossil trilobite, only two galactic rotations old.[/quote][/i][/color]

[Chris Peterson]

I took his first question as meaning the period of time it takes for the Solar System to go around the galaxy once, which makes both those answers right, as far as they go. There are other periods of rotation, such as the time it takes the spiral arms to go around once, and so on.

Maybe that's what he meant. But that's not what he asked, and that's not how I interpreted the questions. So at the least, the ambiguity of the questions should be properly addressed.

As for the speed, I did say it was relative to the CMB.

Which is why I said it was a partial answer. He didn't ask for a speed.

[neufer]

How long does it take for the Milky Way Galaxy to make one complete revolution
and would we call that a Galactic Day, or a Galactic year, if we called it anything at all?

How long does it take for the Solar System to make one complete revolution
and would we call that a Solar System Day, or a Solar System year
(, or would we called it anything at all)?

Also, how far does the Milky Way Galaxy travel while it is making a complete revolution?

How far does the Solar System travel while it is making a complete revolution?

[Beyond]

I'm tempted to ask Dr. Bonnell what color his eyes are, if only to ensure that he actually gets to answer a question that is posted here for him!

And maybe what size shoes he wears, too!

And perhaps also what his wingspan armspam is

[Beyond]

How long does it take for the Solar System to make one complete revolution
and would we call that a Solar System Day, or a Solar System year
(, or would we called it anything at all)?

How far does the Solar System travel while it is making a complete revolution?

I belive i hear a neufer echo ringing in my ears. Now where did i put that anti-irritant spray

[quote="JTB"]

Now kids! Remember what we talked about …[/quote][/i][/color]

[Beyond]

Dr. Jerry is going to have to give this thread a shot of "something" to try and cure "whatever" it has.

EUREKA DR. Jerry, What one or two questions have you never been asked, that you would like to be asked so you could speak on it, or them??

[quote="JTB"]

Question: What is your favorite unit of distance? Answer: the light-weekend.[/quote][/i][/color]

[Ann]

Let's see if I can find another one, a serious question (because there haven't been that many of them). There have been some alternative theories about the universe discussed here at Starship Asterisk lately. For example, there has been the question about possible "white holes". What does Dr. Bonnel think about white holes? Can they exist? Should black holes, for the sake of "symmetry", be "inverted" into white holes spewing matter out into whatever matter might be spewed into? I have heard the hypothesis that black holes can give rise to new universes. What does Dr. Bonnel think about that?

[quote="JTB"]

Sorry, Ann. I see you’re trying to raise the level of this. I do appreciate it(!) but I can’t really give any good answers here. My feeblest attempt would just be that white holes exist to the extent that the mathematics of General Relativity admit them as solutions, along with black holes. And in the sense that black holes have event horizons, they can be thought of as separate universes. I think we would both need some more time in graduate school to wrestle with these matters.[/quote][/i][/color]

Another hypothesis that has been mentioned here is the possibility that space and time are separate entities after all, and that "spacetime" is an illusion. What does Dr. Bonnel think about that? Is space separable from time? And if the two are not necessarily one, how might that affect the working and the fate of the universe?

I realize that Dr. Bonnel is an astrophysicist, not a particle physicist, but I'll ask a queation about the Higgs particle anyway. The way I understand, the new "particle separator" or whatever it is called is supposed to be able to find the hypothetic Higgs particle, which is supposed to impart mass to particles. If the Higgs particle can't be found, even after many years of searching for it with this new equipment, what conclusions would that lead to regarding our understanding of the working of the universe?

How well is the very early inflation of the universe understood? Does Dr. Bonnel think that the cause of inflation is in any way related to the cause of the current acceleration of the expansion of the universe?

Speaking of inflation, how could the universe keep expanding after inflation ended?

Personally, I think that the universe is a bit like a three-stage rocket. The first stage was the Big Bang, which created the universe in the first place. The second stage was inflation, which quickly blew up the newborn universe. And then, for some reason, the universe slowly expanded for billions of years, until the third "engine" was started and the acceleration of the expansion of the universe set in. What does Dr. Bonnel think about this? Is there any connection at all between the three stages? And if inflation hadn't happened, is it possible that our universe might have collapsed in on itself almost as soon as it was created?

Ann

[quote="JTB"]

Again, Ann, I think you’ll be disappointed with my attempts to answer here. (Fortunately, Bob Nemiroff can answer all of these questions in impressive detail!). But, inflation is the idea that the universe underwent an extremely rapid expansion before the more gradual Big Bang expansion.

I do think it is stunning that we actually seem to be in the age of precision cosmology and can constrain cosmological parameters so tightly. WMAP (Wilkinson Microwave Anisotropy Probe) was a big contributor to this and they have a website, of course, that outlines important results and offers explanations at a popular level.

http://map.gsfc.nasa.gov/

Also, Ned Wright has a cosmology tutorial on the web, that you may want to check out:

http://www.astro.ucla.edu/~wright/cosmolog.htm

My first brush with cosmology came years ago when I worked on the COBE (COsmic Background Explorer) project at Goddard. My slight contribution to the project was in writing software for one of the experiments on COBE. John Mather was the Principal Investigator for the experiment, demonstrating the blackbody spectrum of the microwave background as predicted by the Big Bang, and he later won the Nobel prize in physics for the COBE results (2006, shared with George Smoot).[/quote][/i][/color]

[bystander]

http://asterisk.apod.com/vie ... 23&t=20731

I have inserted Dr. Bonnell's answers into the appropriate posts. I appreciate all the time and effort he put into this and the attention he gave to the questions. If there are follow up questions, I will submit them and post his replies, if any, but he wasn't committed to any follow up, so replies may not be forthcoming.

[Beyond]

EUREKA DR. Jerry, What one or two questions have you never been asked, that you would like to be asked so you could speak on it, or them??

[quote="JTB"]Question: What is your favorite unit of distance? Answer: the light-weekend.

[/i][/color][/size][/quote]
Would that be a "Bud-Light" weekend

[Ann]

Thanks for all the answers! I think I like the synopsis best:

Dr. Jerry T. Bonnell (JTB) wrote:
Thanks for all the questions … at long last, here are some answers! And thanks, bystander and owlice, for suggesting and arranging this thread. For what it’s worth, I’ve collected the short versions of the answers up front in a synopsis. The long versions are embedded with the questions below. - cheers, Jerry (Sep. 7, 2010 - GSFC).

Synopsis: GRBs,QG,TGFs,AGNs;contractor/Cosmic Dawn, New Worlds, Physics of Universe/related,yes, extrasolar planets, GRB distance, accelerated expansion, funding/no/moon landing/parent’s approval/Tighe/no/42/yes/in backpack, sensitivity, no/real soon/yes/T?/T, funding/bob, jerry/filters/ AFAIK? fair enough/tomorrow’s (probably), yes, yes, email/yes/ funny …/ yes, not pros, we have/not science, no, no/SN 1987A, NGC 1976, easily, thank you/oh?/ brown/copyrighted ones?/easy to read/sure/ 250 million yrs at sun, galactic rotation, 400,000 ly/no problem/my trilobite knows/no problem/us size 9 ½/ yes but forgot question/rotation curve?/ good deal in ir/longer answer too/light-weekend?/event horizon, general relativity, standard model wrong, quantum fluctuation, inflation first stage

Well, if 42 is the answer to life, the universe and everything, then I guess Dr. Bonnell's synopsis is a slightly "fleshed-out" version of the 42 profundity!

Ann

[Beyond]

The Nature of Life in The Universe...

I can debate that with one word -- Temporary.

[owlice]

Dr. Bonnell, thank you very much for granting an interview and answering all of our questions!! And oh shucks on your not teaching at UMD!

beyond, you cannot debate a man whose T stands for Tighe; you just cannot!

[neufer]

What does the T stand for?

[quote="JTB"]

Tighe (sounds like tie)

[/i][/color][/size][/quote]

"I'm Buffer Brown, I live in a shoe.
That's my blogger, Tighe, he lives there too!"

http://video.google.com/videoplay?docid ... 5971680941#

<<In 1878 a young man named George Brown invested his life savings to start his own little company to manufacture shoes. Headquartered in St. Louis, Brown Shoe Company grew to become a major corporation of over $2 billion. The company became the Number 1 retailer of moderately priced shoes for the American family, with brands such as Naturalizer, LifeStride and Connie shoes for women and Buster Brown shoes for children.

Buster Brown was a popular cartoon character in the early part of the 20th century. He was a well dressed little rich kid. With his sister Mary Jane and his dog Tige (short for Tiger) they managed to get into the kind of trouble that delighted children. Tige, a Pit Bull Terrier, is believed to be the first comic strip pet that could talk, but like many later pets, only children could hear him.

After George Brown purchased the advertising license for Buster Brown and Tige, they became the familiar logo inside his children’s shoes. Together they sold millions of shoes. Buster's catchphrase is "I'm Buster Brown, I live in a shoe. That's my dog, Tige, he lives there too!" (or "Look for him in there too.")>>

[Beyond]

Dr. Bonnell, thank you very much for granting an interview and answering all of our questions!! And oh shucks on your not teaching at UMD!

beyond, you cannot debate a man whose T stands for Tighe; you just cannot!

Too late owlice. I already beat him 9 letters to 5. Beyond's T - Temporary==9Letters. {} DR. Bonnell's T - Tighe==5 Letters.
I can't help it owlice, i got some neufer on me from one of his posts and can't get it off