Third Thursday Telecons

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DanZ
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Re: Third Thursday Telecons

Post by DanZ » Mon Aug 20, 2018 4:24 pm

Ah, now I get that last part Augusto - what a wonderful, fun story - I love it! :P

BTW, as my passed down middle name indicates, I come from a long line of Grants, so perhaps that's why you tolerate me??? :lol:

Back to John now, below is the verbatim answer I received from Zack on your question regarding gamma ray microscopes - which I enjoyed immensely. I hope it satisfies you as well!

Dan
Ooh! What a fun question. :-)

It is such a good idea that Werner Heisenberg himself did a thought experiment using a gamma-ray microscope in order to derive an early version of the Heisenberg uncertainty principle.

So, can we build it? Well the short answer is yes and here it is: http://www.spring8.or.jp/wkg/BL31LEP/in ... mmary_view

And we also have a gamma ray telescope: https://fermi.gsfc.nasa.gov

Just to make sure definitions are clear, when we say gamma rays, we usually mean photons that were emitted by atomic nuclei as a result of nuclear processes. The reason the electromagnetic spectrum has a region called “Gamma Rays” is because most of the natural radiation that occurs in that portion of the spectrum is caused by radioactive decay emission. However, many gamma rays have energies that occur all the way down into the X-ray band. However, the point is clear, why can’t we just use *really* high energy (short wavelength) photons in order to get resolutions small enough to see atoms?

While it is true that as you go to smaller wavelengths the theoretical resolution of the microscope gets better and better, at some point other engineering considerations become dominant. Just from an engineering point of view, gamma rays penetrate matter easily and so designing a mirror system to focus them can be a bit tricky.

Now, if you use an electron instead of a photon, then you can get an electron to have wavelengths much smaller than an atom quite easily. In fact, it only takes a few thousand volts to do that. The electron microscopes I use are using electrons between 80,000 and 300,000 V. At 300,000 V, the wavelength of the electron is about 2 picometers — already much smaller than a hydrogen atom (which is small for atoms). For electron microscopes, the best resolution we’ve seen is about 50 picometers, and the limit is not caused by the wavelength of the electrons but other factors influencing how well you can focus the beam and so on. As it turns out, our very own microscopy facility here in Berkeley is on the cutting edge of high-resolution electron microscopes with a number of record firsts. For example, see this: https://physicstoday.scitation.org/do/1 ... 0691/full/

Cheers,

Zack

jsmaje
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Re: Third Thursday Telecons

Post by jsmaje » Tue Aug 21, 2018 2:06 pm

Oh Augusto, you are such fun!

I've found a Wikipedia picture of an ancient carving, supposedly of the original Angus: Óengus mac Fergusso ("Angus son of Fergus"), who was king of the Picts in Scotland until he died in 761 AD, his kingdom (like others throughout England) soon to be disrupted by those pesky Vikings.

It's rather blurry, but I hereby challenge you to find the best match you can within any single SD@H frame!
Image


And thanks Zack for your info on gamma-ray microscopy and astronomy. I'd got a little mixed up between EM radiation and electrons, but aren't they a bit mixed up themseves at quantum level anyway? That "The laser-electron photon (LEP) beam is a polarized GeV gamma-ray beam which is produced by backward Compton scattering of injected ultraviolet (or deep ultraviolet) laser photon off circulating 8-GeV electrons" clearly explains all(?) So thanks for that!

John

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Re: Third Thursday Telecons

Post by DanZ » Thu Aug 23, 2018 1:28 pm

Hi John,

Zack was kind enough to follow up on your additional inquiry.

Enjoy!

Dan
Since electrons and photons can be converted into each other (E=mc^2 is often quoted here) there is sometimes a bit of confusion about them being “the same thing,” but that’s a bit like saying that iron and my car are the same thing because they can be converted into one another. In some sense the statement is true — and actually quite useful when you are in the business of recycling — but it does ignore the conversion process which is substantial! Indeed, most people will yell “lemon!” if you sell them a car and give them a pile of iron instead.

When electrons get shaken up they can produce photons. The way that electrons and light particles interact at the quantum level is luckily pretty different, which is why we sometimes want to use an electron microscope instead of a light microscope, or vice versa. This is a good thing because it gives us more ways to see samples we want to study. Maybe this also highlights why it is important to have many different kinds of microscopes — they are useful for complimentary studies.

Cheers,

Zack

McAngus
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Re: Third Thursday Telecons

Post by McAngus » Fri Aug 24, 2018 8:57 am

The challenge is accepted.
The prize: a beer, of course!

Did you know that the Scots say the word beer as we Italians (birra)?

Augusto
Image
ad augusta per angusta

jsmaje
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Re: Third Thursday Telecons

Post by jsmaje » Fri Aug 24, 2018 12:10 pm

McAngus wrote:
Fri Aug 24, 2018 8:57 am
The challenge is accepted.
The prize: a beer, of course!
Did you know that the Scots say the word beer as we Italians (birra)?
Augusto
Great, Augusto! I look forward to seeing what you come up with.

Yes, the Scots do like to roll their "R"s (be careful how you pronounce that!)
How might I send you the birra? Perhaps via the yet-to-be-invented transference process that my local pub once advertised: "Meals ordered by email will be gratefully received".

And thanks again to Zack for yet more photons of enlightenment to shine on the darkness of my understanding.

John

caprarom
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Re: Third Thursday Telecons

Post by caprarom » Fri Aug 24, 2018 4:07 pm

Great exchange, Guys, thanks! At the moment there are six people logged in to this forum (me and five "guests"). How long has it been since we've had that much action?
Yay 42, Augusto!
Mike

jsmaje
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Re: Third Thursday Telecons

Post by jsmaje » Tue Sep 25, 2018 1:21 pm

I really enjoyed the last telecon on 20 Sept with Anna Butterworth. Her enthusiasm is so infectious.
But as a Brit, currently living "up north" in Manchester with a father from Huddersfield, I couldn't detect anything in her accent to suggest she'd ever been a Yorkshire lass; there was more of an Ozzy twang to my ear if anything (my wife was Australian).

Besides her sterling work on Stardust, her Enceladus Organic Analyzer project sounds just wonderful. Can she tell us what the current status of NASA's commitment is to that project, as well the privately-funded one backed by Yuri Milner that I've read about?

What a fascinating place that moon is, and what a wonderful Hollywood script could be made out of its ice-bound surface littered with dangerous crevasses to rescue our hero from (or more likely his feisty female colleague, with whom he later falls in lust), all in an attempt to plumb the depths of a geyser's subsurface water world full of both scary and cute alien CGI creatures. They ultimately decide to leave them alone for ever; hooray! Roll credits.
I hereby claim prior intellectual ownership of this idea, and a 10% share in profits from the film!

But seriously, what organics are being looked for that would be unequivocal signs of life? As I understand it most simple ones are ubiquitous in space or produced by volcanoes; even more complex ones can then be produced by the effects of high energy radiation/lightening. Am I right that one of the Stardust papers reported that the entire interstellar side of the collector (including foils) had in fact been found to be covered by a thin deposit of the amino acid and neurotransmitter glycine, for example? What of the cometary side? Was contamination ruled out?

Finally, regarding the discussion of foils, which involved TitritEL (Fatima), can Anna comment of the latter's post about the advantages or not of using copper rather than aluminium foil, which I admit having found a little difficult to follow because of her idiosyncratic English.

John

DanZ
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Re: Third Thursday Telecons

Post by DanZ » Wed Oct 10, 2018 6:00 pm

Ah, good to have you back John! And as usual, it's hard to keep track of all the different questions, so once again, I reply within your original message below :lol: Cheers! Dan
jsmaje wrote:
Tue Sep 25, 2018 1:21 pm
I really enjoyed the last telecon on 20 Sept with Anna Butterworth. Her enthusiasm is so infectious. But as a Brit, currently living "up north" in Manchester with a father from Huddersfield, I couldn't detect anything in her accent to suggest she'd ever been a Yorkshire lass; there was more of an Ozzy twang to my ear if anything (my wife was Australian).
Well her and her husband just became US citizens I know, so perhaps it's that, coupled with a bombardment of other influences here in Berkeley.
Besides her sterling work on Stardust, her Enceladus Organic Analyzer project sounds just wonderful. Can she tell us what the current status of NASA's commitment is to that project, as well the privately-funded one backed by Yuri Milner that I've read about?
I have to be careful here because there is some ongoing "competition" in this area, but suffice it to say that both NASA and Yuri have been encouraging Anna to keep going!
What a fascinating place that moon is, and what a wonderful Hollywood script could be made out of its ice-bound surface littered with dangerous crevasses to rescue our hero from (or more likely his feisty female colleague, with whom he later falls in lust), all in an attempt to plumb the depths of a geyser's subsurface water world full of both scary and cute alien CGI creatures. They ultimately decide to leave them alone for ever; hooray! Roll credits. I hereby claim prior intellectual ownership of this idea, and a 10% share in profits from the film!
Sorry, but it's been done already. Click here.
But seriously, what organics are being looked for that would be unequivocal signs of life? As I understand it most simple ones are ubiquitous in space or produced by volcanoes; even more complex ones can then be produced by the effects of high energy radiation/lightening.


Yes, and Titan is full of organics. But this would be finding organics in deep oceans, and so the addition of liquid water (something we think is necessary for life) makes it all the more exciting to find!
Am I right that one of the Stardust papers reported that the entire interstellar side of the collector (including foils) had in fact been found to be covered by a thin deposit of the amino acid and neurotransmitter glycine, for example? What of the cometary side? Was contamination ruled out?
It was in the cometary samples, and yes, I believe contamination was ruled out, especially when Rosetta found it too. Click here.
Finally, regarding the discussion of foils, which involved TitritEL (Fatima), can Anna comment of the latter's post about the advantages or not of using copper rather than aluminium foil, which I admit having found a little difficult to follow because of her idiosyncratic English.
I think Zack addressed this in his telecon did he not? But if not, let's bring it up in Andrew's next one, if someone can remember!

John
[/quote]

jsmaje
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Re: Third Thursday Telecons

Post by jsmaje » Mon Oct 15, 2018 12:58 pm

Thanks for your comprehensive response Dan, and I see that Zack has now supplied extra info regarding Fatima's copper foil, including a magnificent meteorite sectional picture: viewtopic.php?f=23&t=4017#p21008.

Damn, I'd looked forward to earning a fortune by writing my own 'Europa Report', which would have been a good deal more interesting than the well-meaning but ultimately predictable and feeble movie that I streamed!
Meanwhile I've also just been to see 'First Man' today, which made at least some attempt to present the human side of the astronauts in greater depth, particularly Neil Armstrong and his wife Janet. And I recommend reading this interview with Neil's son Mark: https://www.dailymail.co.uk/femail/arti ... -moon.html

However much Space (including it's tiny dust particles) may be fascinating, it is an uncaring and largely deadly place. I side with those who promote robotic rather than human exploration. That's of course as long as we all world-wide get a firm grip on quelling global warming before we might actually be forced to leave the planet or be prepared to accept mass catastrophe.
Latest deadline, 2030: https://www.theguardian.com/environment ... -un-report

John

caprarom
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Re: Third Thursday Telecons

Post by caprarom » Tue Oct 16, 2018 5:52 am

Interesting interview, John, thanks. I was curious about the use of the term "Nasa" in the article, instead of NASA. Is it one of those fun differences between British and American English that acronyms are not fully capitalized? I read "The Economist" regularly and hadn't noticed that.

jsmaje
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Re: Third Thursday Telecons

Post by jsmaje » Wed Oct 17, 2018 12:49 pm

No Mike, most Brits do usually respect capitalised acronyms. After all, most of us claim to live in the UK or GB (not Uk or Gb). But I very much doubt you always write LASER instead of laser, for example. Or do you?
Meanwhile, if it hadn't been for finding that interview with Mark Armstrong on their web page, I wouldn't generally trust anything printed by 'The Daily Mail' in terms of fact, opinion or style. See this splendidly savage assessment of that newspaper here: https://rationalwiki.org/wiki/Daily_Mail.

I do trust the 'Independent' though, now web only in full form and its smaller 'i' paper version, where I found this https://www.independent.co.uk/arts-ente ... 81006.html about the 'First Man' film I mentioned (note they capitalise NASA!) I'd like to believe that final scene of his daughter Karen's bracelet; he was such a sensitive and private man, as well as incredibly brave. Sorry for any spoilers there!

By the way, I actually once lived close to one of NASA's super-secret little offices tucked away in a village near Manchester called Cheadle. I'd get my young children to bed by saying that the space ships could only take off (from the local car park down the road) when they were sure to be fast asleep! The 'NASA' on the office's brass plate actually stood for 'Northern Automotive Systems Assurance' - or something like that!

John

caprarom
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Re: Third Thursday Telecons

Post by caprarom » Thu Oct 18, 2018 7:40 am

Thanks, John. I'd read a nice review of the film (from the Smithsonian, I think), but they had not mentioned the bracelet. Armstrong's son was particularly pleased with the film's excellent portrayal of his mother. You are right, of course, about LASER having devolved from acronym to a generic term. I'd still be surprised to see "Laser" (vs. laser) in the middle of a sentence, but not as much as "Nasa." Great to hear about your friendly neighborhood secret NASA office! ;-)

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