Astronomy/Cosmology/Astrophysics thread - Even though there are no gods I still pray

[Shambles]

Interesting story I came across recently - Accelerating Universe? Not so fast

Apparently latest analysis of the light from Type 1a supernovae (ie the type used to ascertain the apparent speed of universal expansion) suggests that not all Type 1a supernovae are quite the "Standard Candle" they have long been considered. It looks like there may be two distinct subgroups which would make currently accepted figures, thoughts and theories on the perceived acceleration of the expansion (and therefore the Dark Energy thought to be causing it) to be awry. It doesn't seem to be suggesting that Dark Energy is not still a "thing" but does throw into doubt the accuracy of work done by Saul Perlmutter et al who won the Nobel for apparently discovering the universal expansion was accelerating.

In other astronomical news, The Lynids (more info on what they are and where to look for them here too) are expected to be at their peak tonight. Have never managed to catch a meteor shower yet. Largely cos it would involve sitting around out in the cold I suspect. I've generally been more interested in the theory than the practice of all things astronomical but am thinking about heading into more practical realms too now.

Last lil tidbit I just spotted via one of the above linkies is that the first colour image of Pluto has been sent back by New Horizons. Still very fuzzy and indistinct but definitely whetting the appetite for July

 

[Shambles]

Well done shambles - ive listened to both Prof Crawford and Morrisons Gresham youtube playlists a few times each

anyone with an interest in this field needs to watch these - they're approx. an hour each and between the 2 of them they cover almost everything you want to know. Prof Crawfords talk on galactic superclusters (her particular field of expertise) is beautiful.

Glad you approve and good to know others have discovered these excellent series of lectures. Really can't recommend them highly enough myself.

Couple other lecture series I'd recommend...

SLAC Public Lectures - Cover a wide range of topics and are generally not overly technical but with plenty meat on the bones all the same.

SETI Talks - Despite the SETI connection there aren't really that many that focus on the search for extraterrestrial intelligence directly. Again, a wide range of topics covered and often fairly technical (plenty of graphs, charts and jargon in more than a few) but well worth a go - especially for those with a reasonable background knowledge of subjects in and around these areas.

Silicon Valley Astronomy Lectures - Once again, good variety of topics that are aimed at the general public but do sometimes contain some more technical elements in some of the talks.

I'll leave it there for now and would again recommend any and all of the talks contained within those linkies depending on what your interests are. I'd also recommend plumping for ones that don't immediately grab your attention now and then cos I've been pleasantly surprised by what I initially considered rather unpromising topics on many occasions now.

 

[pinkpapaver]

It's all about the electrons, constant state of attraction and repulsion between everything that creates a wave.

 

[lurching]

It's all about the electrons, constant state of attraction and repulsion between everything that creates a wave.

OK then.. but how?



Aha, watched Shambles' vids, and it seems we just have to bruteforce Monte-Carlo the relativistic Schroedinger! Spinor fields!Where's me slide ruler..

 

[steewith2ees]

6 hours to go


ppppppluto!

it was still a planet when we left

first proper new world to look at since voyager passed neptune in 1989

9 hours to get a signal there and back at the speed of light

9 years to get just one way via normal propulsion and gravity assists

 

[Don Luigi]

6 hours to go


ppppppluto!

it was still a planet when we left

first proper new world to look at since voyager passed neptune in 1989

9 hours to get a signal there and back at the speed of light

9 years to get just one way via normal propulsion and gravity assists

Yeah it has been a really exciting year. I'm looking forward to the results of Juno next year.

 

[steewith2ees]

Yeah, Junos arrival seems well timed with cassini preparing to wrap up its observations. have you seen how they're going to finish the flight? they're going to plunge the spaceship thru the gap between the planet and the rings a few times before crashing it into saturns aptmosphere

 

[Nom de Plume]

This is also the basis for quantum mechanics (which i have no real understanding of in depth, the standard model, quanta and spin are terms ive yet to properly read into) - "whatever can happen, will happen". Its all about probabilities so with my level of maths thats me fucked, again.

Maybe a quartet of bees with a dash of ganj will help my thinking in such areas

This is not the "basis" for quantum mechanics. You're talking about one out of dozens of interpretations of quantum mechanics—specifically, the so-called 'Many Worlds' interpretation of QM.

The interpretation most people are taught in school is the Copenhagen interpretation.

QM is perplexing, and it is one of the most well-tested and verified theories in all of science. However, while physicists know how to research and apply QM, nobody seems to have considered in much depth what QM is and how to interpret it.

Quintessential physicist: "I cannot make sense out of it, but hey, it works. So that's all that matters".

There's an interesting YouTube video (obviously for laymen) I suggest one watch to learn more:

 

[BecomingJulie]

Now that we have some amazing quality pictures of Pluto, it's important to remember that Pluto is no longer a planet.

Bear in mind, there are other things out there which have at least as much right as Pluto to be called planets, under rules that would let Pluto qualify to be one; besides which, it's still there, even without full planet status. And I respect the personlump of rock, not the uniformIAU designation. Beside which, essentialism is dead and buried since Dmitry Mendeleyev produced the Periodic Table -- get with the programme, losers.

Anyway, the upshot of it all is that we are going to need a new mnemonic to remember the order of the planets without Pluto. Based on a conversation elsewhere on the Internet with some friends, I propose the following:

My Vagina Eats Men -- Just Shut Up Now​

i.e. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune (no Pluto). Well, it certainly beats the one I helped my common law stepdaughter to come up with when she was still in school and Pluto was still a planet: Molly, Very Excited, Met Jim Smith Under Nottingham Playhouse.

 

[steewith2ees]

It is a planet. Its a dwarf planet, a term invented as a compromise for those upset by plutos demotion from the main gang.

Its orbit is so elliptical that for the majority of my llfe neptune was further away, with plutos orbit only overtaking neptunes in early 1999.

Im well impressed with the images so far. Ditinctly terrestrial looking world where i was just expecting a snowball..

 

[Vurtual]

Interesting that it's geologically active - usually they'd assume a planet that small would have to be squished by local gravity like round jupiter to make it active. Some scientist was speculating that there might be an ocean of liquid water in the centre and it's slow freezing is what is driving the geology. Maybe there's a whole civilisation in there. IT'S THE FUCKING ANNUNAKI MAN!

 

[F.U.B.A.R.]

I was wondering what would be the heat source for the geologic activity, but apparently it's long been thought that decay of radioactive elements provides enough heat to produce a 'mantle' layer of liquid water between the rock core and the thin crust of frozen nitrogen and carbon monoxide at the surface. This liquid mantle has allowed all the solid elements (including the radioctive ones) to settle to the core. The heat emanating from the core would presumably generate rising and falling convection currents in the mantle resulting in a plate tectonics system analogous to that on earth - and constantly reshaping the surface. The 'mountain' ranges of water ice recently observed would form from 'cryovolcanoes' where liquid water rises through faults in the crust like lava and freezes at the surface. I believe that organic molecules have also been detected. Therefore, all the accepted prerequisites for life are present - organic molecules, a liquid medium and a source of energy. The interface between the core and the mantle could provide an environment conducive to the reactions required to form more complex molecules. So ya never know...

 

[pinkpapaver]

What I want. To know is why they were all hush about Pluto a while back saying it's not a planet, printing text books and all sorts and confusing everyone round about the theme they sent this. Now it's all plutothis and Pluto that . Astrology is truth. Not Russell grant. All part of some big lie. I'm gonna read my muncaster text book. Have u seen Patrick Moore play the xylophone?

 

[pinkpapaver]

I was wondering what would be the heat source for the geologic activity, but apparently it's long been thought that decay of radioactive elements provides enough heat to produce a 'mantle' layer of liquid water between the rock core and the thin crust of frozen nitrogen and carbon monoxide at the surface. This liquid mantle has allowed all the solid elements (including the radioctive ones) to settle to the core. The heat emanating from the core would presumably generate rising and falling convection currents in the mantle resulting in a plate tectonics system analogous to that on earth - and constantly reshaping the surface. The 'mountain' ranges of water ice recently observed would form from 'cryovolcanoes' where liquid water rises through faults in the crust like lava and freezes at the surface. I believe that organic molecules have also been detected. Therefore, all the accepted prerequisites for life are present - organic molecules, a liquid medium and a source of energy. The interface between the core and the mantle could provide an environment conducive to the reactions required to form more complex molecules. So ya never know...

If it's not at absolute zero there will be some movement and we have not reached absolute zero. Ones and zeroes.

 

[Shambles]

On the subject of Pluto, watched a couple of post-New Horizons (only just though - clearly a little rushed out) Pluto docs last night that may or may not be of interest if y'all've not seen already...

The Sky at Night: Pluto Revealed

Pluto's Mysterious Surface

In slightly more technical mode, from firmly before the recent fly-by but was the best of a flurry of similar lectures as I recall and well worth a watch if interested in all things Plutonian...

Pluto on the Horizon: Anticipating our First Encounter with the Double Planet

This is not the "basis" for quantum mechanics. You're talking about one out of dozens of interpretations of quantum mechanics—specifically, the so-called 'Many Worlds' interpretation of QM.

Don't know about "dozens" there are maybe half a dozen of main contenders afaik with Many Worlds being currently the most popular. I'm not a big fan of it myself (at least as far as my (very) minor understanding of such things go - seems far too messy to me but who knows what the universe finds aesthetically pleasing?) but seems to be the current front-runner. From what I know, Copenhagen (aka "Shuddup and calculate") is mosty seen as being practical but unilluminating and seems to be the least valued in terms of any hope of moving understanding forward. Which would make sense as it specifically avoids trying to do so.

I'd definitely recommend the Sixty Symbols clips though (and related ones Numberphile and a couple others whose names escape me but will all be easily findable through the Sixty Symbols page).

 

[Vurtual]

I'd say it depends which type of physicist you ask - i haven't read much physics for a while but last time i read about it many worlds was still too far out for most (though was increasing in popularity) - but probably because most of them would rather shuddup and calculate as you say - i quite like it myself, but probably because of sci-fi potential (and just for mind blowing-ness (10 to the 100 universes with one particle different??!)), not to mention its not needing any macguffins like most of the others (like i say, it's been a while/my memory's rubbish/creative)

 

[Shambles]

There's obviously a variety of opinions but I was really just basing that comment on recent viewings. Seems to have been mentioned in every lecture I've watched recently that Many Worlds is very much in vogue at the moment. It's probably cos multiverse theories are so popular currently - and there seems to be a bit of a backlash starting against those so will likely switch to another one soon enough.

 

[Vurtual]

Multiverse and many worlds are different kettles of worms though. Cosmologists and theoretical physicists are more fond of many worlds i think (cos it actually makes some sort of 'sense') - i guess most practical physicists consider it as irrelevant as they do string theory

 

[Shambles]

Agree with all of that. Suppose I have a natural bias toward cosmologists and theoretical physics stuff cos that is where my main interests lie. Mutiverse theories and Many Worlds QM are definitely different animals but was thinking of it more as a general trend towards more extravagant ideas (all those "spares" lying around and so forth - very messy). Definitely wasn't so popular a few years back and the given reasons were usually ones of "neatness" as I recall. With Inflation looking like it's likely to become increasingly backed up experimentally, multiverse theories are becoming more mainstream as they are apparently quite hard to avoid in the most popular versions of Inflation. Once you have that in mind as being a far more likely approximation of reality than it was maybe thought of until really quite recently I could well imagine Many Worlds becoming more palatable on the back of that.

 

[Kittycat5]

Have you guys seen Hawkings new insights on blackholes? He says you may either forever get stuck on the event horizon in a 2d hologram or if conditions are right pass through it. He does not rule out them being portals to alternate universes.