Maybe I should write a similar blog for particle physics/quantum mechanics. That's my field, after all. Would be a nice accompaniment to this blog - the large and the small! Plus there do seem to be a lot of misconceptions about QM floating around this thread
A basic introduction to Astrophysics - Page 4
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eonrulz
United Kingdom225 Posts
Maybe I should write a similar blog for particle physics/quantum mechanics. That's my field, after all. Would be a nice accompaniment to this blog - the large and the small! Plus there do seem to be a lot of misconceptions about QM floating around this thread | ||
Teoita
Italy12246 Posts
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Amestir
Netherlands2126 Posts
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Ssin
United States88 Posts
Very cool! | ||
Teoita
Italy12246 Posts
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Ssin
United States88 Posts
AGN is fascinating as well, but I guess that applies to everything in the field. So much of it is amazing. Good luck on your exams, those last few are the most tense! Are you currently studying in Italy? | ||
Teoita
Italy12246 Posts
Once i graduate i'll look for a phd around Europe. Unfortunately Italy is a god awful country for scientific research, the funds just aren't there and researchers are underpaid and treated like shit compared to the rest of the world, so if you want to go make a career out of it you are almost forced to move abroad. We have some of the best universities as far as actually teaching us stuff goes, but after that it's just downhill. The upside is, italian scientists tend to be really appreciated and really good because the selection is so tough, only the best and most committed actually make it. | ||
DSK
England1106 Posts
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Ssin
United States88 Posts
One of the most unfortunate things about Physics in general is that the students are always "rushed" to catch up with the fast developments of the field. Just so much information has come out since the developments of quantum mechanics, quantum field theory, experimental applications. The density is unbelievable. | ||
revy
United States1524 Posts
I eventually ended up like EM a touch more so I went the electrical engineering route. I'm happy with what I do, but on occasion I wonder what it would have been like to go the astronomy route. I still have a copy of PJE Peebles' Physical Cosmology, I think I'll read through it slowly and try to digest it. Anyway thanks again! | ||
micronesia
United States24495 Posts
Also, someone finally mentioned gamma ray bursts! | ||
Teoita
Italy12246 Posts
On April 26 2015 22:51 revy wrote: Thanks very much for this post. Was a bit of a trip down memory lane for me. I did my bachelor's in Physics, and I added quite a number of astronomy/astrophysics courses. For my undergrad thesis I made a statistical model of # of gamma ray bursts vs Flux for exploding primordial black holes as would be visible to one of the instruments on the fermi gamma telescope. The end result was that the fluxes were way too low, and that at the high flux end the log-log slope was too close to that of just natural expansion. Still it was a really fun project, and my advisor loved it because I made him all sorts of scripts to calculate useful stuff (redshift to proper distance and FLRW metric to calculate R/R0). It's all a touch blurry since I was working on this stuff like 8+ years ago. I eventually ended up like EM a touch more so I went the electrical engineering route. I'm happy with what I do, but on occasion I wonder what it would have been like to go the astronomy route. I still have a copy of PJE Peebles' Physical Cosmology, I think I'll read through it slowly and try to digest it. Anyway thanks again! You are welcome I've done my bachelor thesis on Gamma Ray Bursts myself, although i focused on ultra long GRBs. Out of curiosity, how does the primordial black hole evaporation tie with GRBs? All i know is that it's a suggested explanation, but most people prefer the collapsar models. I guess the gamma radiation is the tail end of Hawking's radiation? How would you explain the afterglow? And yeah, i didn't mention GRB's in the OP since Hubble specifically hasn't contributed all that much to their study, other than occasionally studying afterglows | ||
spinesheath
Germany8679 Posts
On April 25 2015 02:29 Serejai wrote: So what kind of telescope do I need to attach my camera to in order to take some sweet ass stellar photos? As far as I am aware you'll need to take infrared photos from a telescope in space and massively photoshop them for color and contrast. These pictures are great, but you should remember that they have been edited for the general public, not for scientific value. | ||
Teoita
Italy12246 Posts
But yeah, scientific images aren't nearly as pretty. | ||
Mordanis
United States893 Posts
On April 26 2015 23:01 Teoita wrote: You are welcome I've done my bachelor thesis on Gamma Ray Bursts myself, although i focused on ultra long GRBs. Out of curiosity, how does the primordial black hole evaporation tie with GRBs? All i know is that it's a suggested explanation, but most people prefer the collapsar models. I guess the gamma radiation is the tail end of Hawking's radiation? How would you explain the afterglow? And yeah, i didn't mention GRB's in the OP since Hubble specifically hasn't contributed all that much to their study, other than occasionally studying afterglows I'm pretty sure the curve of energy release is all wrong. An evaporating black hole emits energy at an exponential rate. If you look at the curve of flux from a supernova it sort of increases, levels off, and then slowly falls. Black hole evaporation is very violent. Also, you wouldn't get a black hole to evaporate in a region that has enough material to form a remnant nebula, as it would gain mass faster than it loses mass. Edit: Also, all black holes should release about the same energy (equal to about the rest mass of the moon, ~6.6 x 10^39 J), and supernovae are more complex events, with type I and type II and their subtypes. Also, Supernovae emit a few orders of magnitude more energy than black holes evaporating. | ||
Teoita
Italy12246 Posts
Seeing as black hole evaporation has never actually been detected, and its full understanding requires quantizing gravity anyway, it sounds like you are oversimplifying things, but if they are supposed to release that little energy (why is that by the way? Do they all detonate at a similar point like type 1a supernovae?) then yeah, they are nowhere close what GRB's emit. | ||
opisska
Poland8852 Posts
On April 27 2015 01:31 spinesheath wrote: As far as I am aware you'll need to take infrared photos from a telescope in space and massively photoshop them for color and contrast. These pictures are great, but you should remember that they have been edited for the general public, not for scientific value. You can actually make pretty great images of the sky using just a DSLR camera and a good lens - the only "special" thing you need is a mount with a clock drive to compensate for the rotation of the Earth - and actually there is even the possibility to do all-sky images with very fast fish-eye lenses, those you can do just from a fixed tripod and at very dark locations, you can get really stunning images in even in this very simple way. If you want to do semi-wide shots of the sky (think 50-100 mm lens), you can buy a mount for $100 and have a lot of fun (I sure did), if you want to use a real telescope and work with focal lengths around a meter (more is very rarely useful), then it gets more complex, because mounts that can track Earth rotation so precisely are terribly expensive and thus you need autoguiding - anyway, for $1000 you can already get a somewhat decent setup and feel like you have a small Hubble in your garden. | ||
ZenithM
France15952 Posts
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Mordanis
United States893 Posts
All of the equations in here can be found here (and prettier :D), but there isn't much theoretical development. Wikipedia | ||
Teoita
Italy12246 Posts
Your calculation doesn't include the fact that the CMB radiation temperature actually increases with redshift as 1+z, and GRB's are seen at redshifts as high as 9 (meaning CMB temperature ends up being 30 K instead of 3), which doesnt help. You are also assuming there is no accretion but let's not go there | ||
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