For Questions That Don't Merit Their Own Thread

[SunlitZelkova]

20 hours ago, JoeSchmuckatelli said:

Makes Webb that much more important!

I don't think currently proposed NASA operated space telescopes are enough. There are about a thousand professional observatories (radio and optical) around the world right now, with 600 of them in the US. In contrast, for the US, there are just three radio space telescopes and three optical ones (soon to be four). The balance is presumably worse in other countries. Even if there is "a eye" a lot will still be lost if the others are unable to search and observe or are hampered in doing so.

To use an analogy to better convey what I am thinking, in a naval operation, if you have one reconnaissance plane, you "have eyes", and that's fine, but you are certainly disadvantaged as opposed to having 16 of them. There is a lot that is going to be missed and you won't know as much.

So for me at least, government space telescopes alone won't eliminate the issue.

Depending on how much Starship actually brings down the total cost of spacecraft, it could be possible to "replace" terrestrial telescopes with an orbital counterpart. But operating costs don't change, so I'm not sure whether that would actually be feasible, especially given the likely (I haven't actually looked) lower budgets private organizations operating observatories (like universities) have.

[JoeSchmuckatelli]

@SunlitZelkova-I hear you, but sadly I think that ship is about to sail. 

Listen to the RocketLab Neutron video.  They want to get into the big, reusable rocket game specifically because satellite constellations are forecast to be a highly profitable service to provide. 

China is talking satellite constellations.  Russia. 

So until and unless the observatories find a tech that can ignore the satellites (perhaps like the Apple photo editor) in the foreground - science teams will have to take advantage of the increase in launch capability to push bigger orbital science stations out past leo

10 hours ago, kerbiloid said:

you have a set of dots on a 30 s long photo

That's really cool... And thanks for the stuff about the nuke rockets - always (idly) wondered what they were! 

[Shpaget]

17 hours ago, JoeSchmuckatelli said:

So until and unless the observatories find a tech that can ignore the satellites (perhaps like the Apple photo editor) in the foreground - science teams will have to take advantage of the increase in launch capability to push bigger orbital science stations out past leo

I don't see internet constellations as an issue for space based scopes. Internet sats are in low orbit (low even for LEO standards) to minimize latency. Telescopes don't need low latency and can be placed higher which is beneficial anyway due to slower orbit decay, more sunlight, less of Earth in the sky etc.

[kerbiloid]

21 minutes ago, Shpaget said:

Telescopes don't need low latency and can be placed higher which is beneficial anyway due to slower orbit decay, more sunlight, less of Earth in the sky etc.

Just replace a thousand of on-ground telescopes with the personnel living in a nearby village and eating in McDonalds with a thousand of orbital telescopes enough reliable to spend decades in orbit without servicing (as there are no shuttles now).

And 1 800 is just the very first 3% or so of all satellite networks planned.

Interesting, who will keep funding the telescope construction and exploitation if the photos will be looking like a disco with stroboscope.

[StrandedonEarth]

7 hours ago, kerbiloid said:

And 1 800...

My mind starts thinking

"1-800-ON-ORBIT" or "1-800-IN-ORBIT"

1-800 MUNSCOP ? MNSCOPE ?

(North American toll-free phone numbers, for our oversea friends)

[JoeSchmuckatelli]

Found this fascinating: 

It's about a unique type of volcano - one not found along tectonic plate margins - located at the Chinese / NK border.  Scientist's access to the region in the last few decades rewrote part of the science of plate movements and contribute to understanding things like the Siberian Traps and other non-plate margin volcanoes (that differ from Mantle-Plume volcanoes like Hawaii and Yellowstone.

Worth a watch: and something @steve9728 might find interesting

 

[SunlitZelkova]

12 hours ago, kerbiloid said:

Interesting, who will keep funding the telescope construction and exploitation if the photos will be looking like a disco with stroboscope.

Good point. I wonder if the astronomy programs of private universities might start declining or even dying by the mid 2040s.

[StrandedonEarth]

Okay, I got one. Why does a game like Civ 6, which is turn-based and is doing nothing if not receiving input (animations off) run so stupid hot? I swear KSP runs cooler, at least at low part counts. It's always done this, and I can't figure out what all the hubbub is about, why it would need to be generating that much heat doing nothing. And then when I do something it's running slow.

I suppose I should take it to that forum, but I don't hang there...

[FleshJeb]

2 hours ago, JoeSchmuckatelli said:

Found this fascinating: 

With good reason. That was an amazing production.

The speed at which we're learning natural science is phenomenal. 

[JoeSchmuckatelli]

5 hours ago, FleshJeb said:

That was an amazing production.

You should see the one on New Madrid.  Fascinating... And missing part 2 (angry face emoji).  Hoping they will publish 2 soon - its really good! 

[steve9728]

8 hours ago, JoeSchmuckatelli said:

Found this fascinating: 

It's about a unique type of volcano - one not found along tectonic plate margins - located at the Chinese / NK border.  Scientist's access to the region in the last few decades rewrote part of the science of plate movements and contribute to understanding things like the Siberian Traps and other non-plate margin volcanoes (that differ from Mantle-Plume volcanoes like Hawaii and Yellowstone.

Worth a watch: and something @steve9728 might find interesting

 

Ha, the top three places on my travel list within China: Xinjiang, Nanjing and there.

*When I wondered why there were natural hot springs in my hometown where there were no volcanoes, I asked my teacher and found out that there was at least one super volcano in Guangdong province at least 150 million years ago.* :me: what??!!

Edited December 5, 2021 by steve9728

[DDE]

11 hours ago, SunlitZelkova said:

Good point. I wonder if the astronomy programs of private universities might start declining or even dying by the mid 2040s.

Never mind universities, it seems there's a huge struggle to retain astronomy in high schools.

[kerbiloid]

1 hour ago, DDE said:

Never mind universities, it seems there's a huge struggle to retain astronomy in high schools.

Makes sense.

As it's now proven that horoscopes don't work, why  keep counting the stars instead of working?

[Hyperspace Industries]

Nuclear thermal engines can have around twice the isp of combustion engines with ~3200°C reactor temperature, due to accelerating the low mass of just hydrogen, but combustion (hydrolox) engines can easily reach that temperature. So, why can't we use waste heat from the combustion rocket to superheat liquid hydrogen, producing extra thrust and specific impulse, as well as acting as a cooling system?

[DDE]

16 minutes ago, Hyperspace Industries said:

Nuclear thermal engines can have around twice the isp of combustion engines with ~3200°C reactor temperature, due to accelerating the low mass of just hydrogen, but combustion (hydrolox) engines can easily reach that temperature. So, why can't we use waste heat from the combustion rocket to superheat liquid hydrogen, producing extra thrust and specific impulse, as well as acting as a cooling system?

Because you can't arbitrarily move it from the center of the combustion chamber (where the temperature isn't materials-limited). Regenerative cooling and film cooling already do their best to "harvest waste heat" at the perimeter of the chamber.

I mean, the chamber temperature is already reduced from what it could possibly be by running the engine fuel-rich, which seems to be what you're asking to do.

[Hyperspace Industries]

21 minutes ago, DDE said:

Because you can't arbitrarily move it from the center of the combustion chamber (where the temperature isn't materials-limited). Regenerative cooling and film cooling already do their best to "harvest waste heat" at the perimeter of the chamber.

I mean, the chamber temperature is already reduced from what it could possibly be by running the engine fuel-rich, which seems to be what you're asking to do.

Thanks! 

By the way, what about using combustion for the express purpose of heating hydrogen, why wouldn't that work? What about electric arcs?

[StrandedonEarth]

7 minutes ago, Hyperspace Industries said:

Thanks! 

By the way, what about using combustion for the express purpose of heating hydrogen, why wouldn't that work? What about electric arcs?

Well, the Space Shuttle ran fuel rich to both cool the engine and increase the ISP. So basically, that’s already been done

[DDE]

27 minutes ago, Hyperspace Industries said:

By the way, what about using combustion for the express purpose of heating hydrogen, why wouldn't that work?

And where would oxidizer go, then?

28 minutes ago, Hyperspace Industries said:

What about electric arcs?

Arcjets are a thing, but what are you going to power them with? Nothing short of a rocket engine, probably, in which case you're better off jettisoning a bulky heat-to-electricity-to-heat conversion system and using the rocket engine directly.

[Hyperspace Industries]

@DDE and @StrandedonEarth, thanks for answering! I didn't know arcjets were a thing, I'm going to do some research into them and resistojets.

[steve9728]

20 hours ago, JoeSchmuckatelli said:

might find interesting

There is a Japanese historical drama in which a family named "Sanada" is a loyalist of the "Takeda" clan, which is on the verge of death due to defeat in battle.
Masayuki Sanada: As long as Mount Fuji and Mount Asama do not erupt, the Takeda clan will be safe and secure!
On June 24, 1582, after forty-eight years, Mount Asama erupted again*
(Fortunately, the last eruption of Mount Fuji was in 1511, but unfortunately the Takeda clan was destroyed at the Battle of Nagashino in 1582)

Masayuki's son: After all, it's a volcano, and sooner or later it's going to erupt... right?

Edited December 5, 2021 by steve9728

[JoeSchmuckatelli]

@K^2  et.al. (hope you will entertain a hypothetical):

If researchers discovered that photons actually do have mass would the implications of the discovery affect Relativity or the Standard Model more?

[kerbiloid]

They will explain why the previous theory was not right and start laughing at the flat-earthers massless photoners.

As usually.

[K^2]

2 hours ago, JoeSchmuckatelli said:

If researchers discovered that photons actually do have mass would the implications of the discovery affect Relativity or the Standard Model more?

Standard model, for sure. Relativity doesn't really care. Relativity prescribes how massless particles should behave, but it doesn't really care if massless particles exist or not. It does provide us with some experiments that can help us determine if something has mass, of course. So neutrinos are a great example. In most ways, they behave every bit the same as photons, but we've found evidence of flavor oscillation, which relativity says can't happen if neutrinos are massless. Researchers have looked for evidence of similar "aging" of light from distant sources, and found nothing, but from perspective of relativity, that can simply mean that photon mass is too low to be detectable this way.

Standard model, in contrast, cares very much. In standard model, bosons are consequence of local symmetries. Photons are kind of an interesting case. They are closely related to leptons (electrons etc) which have two intrinsic degrees of freedom with related symmetries. There is the phase of the wave function and there is the spin. If you only had the phase, you'd still have photons, they could be massless or massive depending on whether they couple to something else, and then we'd be happy either way. With spin in the mix, you get four photon-like particles. And in order for them to get mass, the symmetry has to be broken making them into Goldstone bosons. In case of photons, what we have is the symmetry between the four bosons of the electroweak interaction being broken by the Higgs mechanism, which necessarily gives us one massless boson and 3 massive bosons. These are photon, Z⁰, W⁺, and W^-. The thing about this mechanism is that it's not that a specific boson has to get zero mass, but rather, they are fully interchangeable and mixable before the symmetry is broken, and symmetry break causes  a particular mixture to be massless, which is what we call a photon.

Before we found Higgs boson, there was a period of time where people had increasing doubts about the nature of photons. Higgs mechanism implies existence of the Higgs boson, and initially, we thought it'd have to be a lot lighter, so the fact that we were turning up zilch in particle accelerators was making people weary. Consequently, people looked for alternative explanations for the electroweak bosons, and some of them would have implied that photons do have a bit of a mass, and people were looking for this. But then eventually the estimates on Higgs were refined, the mass was found to be much higher than initially thought, and it was finally discovered by LHC experiments, which finally had the energy range capable of creating detectable Higgs particles.

So consequently, now we have a pretty big chunk of experimentally verified math that would have to be re-explained in the standard model if photons were to have mass. There would have to be something going on that's consistent with the known symmetries, provide a mechanism to create Goldstone bosons, account for Higgs, and still be different enough from Higgs mechanism to allow for mass of the photon, which would be quite a trick. And if something like this were to exist, it would certainly have other consequences. Too many very fundamental principles are at play for it not to. So if photons were discovered to have mass, it'd turn standard model upside down.

Final note, there is still an ongoing search for something that's occasionally referred to as heavy photons. This is a distinct particle that has properties very similar to these of a photons but is very massive as far as particles go. I don't recall the exact context in which it appears in theory, nor really what the consequences of it would be, but it's just to give you a heads up that not all experiments looking for "heavy light" are trying to disprove massless photons. Most, in fact, are looking for a completely different particle. Not that there's a whole lot going on in that regard at the moment.

[JoeSchmuckatelli]

5 minutes ago, K^2 said:

Standard model, for sure. Relativity doesn't really care.

Wow - not at all how I guessed that would go.

I kind of thought you'd have gone down a MOND path, where photon mass would make MOND more relevant than hopeful.  

Shows I have a heck of a lot of reading ahead of me!

Thanks!

[JoeSchmuckatelli]

Totally random question:

If I buy a cheap photo printer - will that print graphic arts projects better than my color inkjet?

(My daughter is a pretty talented artist - and the inkjet doesn't capture some of the detail she can do with her Wacom).